Paypal Founder's Merlin Rocket Engine Fires Up

Baldrson writes "Wired News reports that after 2 years of development, Space Exploration Technology Corp ('SpaceEx') successfully test-fired their new LOX/Kerosene Merlin rocket engine for the 160 seconds required for orbit. SpaceEx was founded by Elon Musk from the proceeds of the 2002 sale of his prior start-up, Paypal, to Ebay. According to Musk, 5 Merlins bundled with the first stage of SpaceEx's powerful Falcon V booster will launch 5 people to orbit by 2010, thereby winning America's Space Prize which was endowed by Robert Bigelow."

Comments

Big rockets?

[chris098]

I'm surprised that with a $1.5 billion budget they couldn't find a better way to get people into space. Rockets don't seem like the "affordable" answer to me. Maybe a space elevator, or maybe some new technology that nobody's invented yet. ...but big rockets? They seem so dated...

Re:Big rockets?

[Anonymous Coward]

I'm surprised that with a $1.5 billion budget they couldn't find a better way to get people into space. Rockets don't seem like the "affordable" answer to me. Maybe a space elevator, or maybe some new technology that nobody's invented yet. ...but big rockets?

"To the moon, Alice! Bang! Zoom!"

They seem so dated...

just like some of us posters... sigh.

Re:Big rockets?

[cmowire]

Right, but the history of "let's do better than a standard rocket by .... because we've got $x billion" hasn't been so good.

Case in point, space shuttle.

The big thing to remember is that the Falcon boosters should be signifigantly cheaper than the current crop of launchers and at least partially reusable. So, even though it's not revolutionary, there's much jumpstarting of the launch biz with what he's got.

The problem is that most of the time, you don't need a revolution, just a little evolution.

Re:Big rockets?

[rastachops]

What are the limitations of building such an elevator? I'm guessing the stability of making such a structure would be difficult to achieve. Any chance of a self balancing computer controlled structure?

Re:Big rockets?

[Chairboy]

Rockets might not 'feel' right to you, but they exist, are a known technology, and there's over 60 years of large scale design and construction experience behind them.

$1.5 billion is a lot of money when you're looking at buying groceries, but it's peanuts compared to the cost of developing a whole new technology (carbon nanotube, for example which might be needed for space elevators), then testing and building the new technology (literally) from the ground up.

In regards to the 'some new technology that nobody's invented yet' comment, I'd rather take one rocket now versus a hundred ephemeral fairy dust ideas of things that may or may not happen in the future. This isn't the only money that will ever be spent on private aerospace. If new technologies become promising and affordable to develop, then other companies will do that in the future.

These guys may succeed, they may fail. That's a great thing about America, you can take risks with commensurate payback. If every company needed the public to vote on whether to let them do their thing, we'd be where the USSR is. Oh yeah, they don't exist anymore.

Re:Big rockets?

[snuf23]

"Case in point, space shuttle."

Um, on launch the space shuttle is pretty much a big rocket. That's what the big fuel tank and boosters are for. Rocketing it into space.
The Shuttle's innovation was in the landing stage and the reuse of the rocket boosters and shuttle vehicle itself. This also allowed for large payloads such as science labs that could be carried in the vehicle and returned to Earth. In the case of Apollo or Soyuz style vehicles, only the small crew compartment is returned.

Re:Big rockets?

[snuf23]

Considering they seem like they want to be a viable commercial company - going with a proven technology seems like a good bet.
The R&D to develop something like a space elevator is HUGE. What happens if you just can't make it work? It might sound simple enough on paper, but the engineering challenges are extreme.

Re:Big rockets?

[Tackhead]

> I'm surprised that with a $1.5 billion budget they couldn't find a better way to get people into space. Rockets don't seem like the "affordable" answer to me. Maybe a space elevator, or maybe some new technology that nobody's invented yet. ...but big rockets? They seem so dated...

Rockets are cheap.

Space elevator? Start thinking about building a space elevator when someone has built a carbon nanotube footbridge.

Something not yet invented? The probability of discovering a new physics is not directly proportional to the number of dollars spent.

So - we're back to rockets. Which are cheap.

NASA's rockets are expensive, because NASA doesn't care where the money comes from. (And NASA's funders in Congress don't care whether NASA's rockets even fly, so long as every district gets its piece of the pork pie.)

If you're Boeing or Lockmart, that's fine -- shuttling rich tourists to orbit and back will barely net you pocket change. So you build big expensive vehicles and you sell 'em to people who don't give a rat's ass about the cost of their ride, because they're using other people's money.

Thanks to Rutan, Bezos, and Musk, there's the possibility of a new market niche for those of us who prefer to use our own money.

Re:Big rockets?

[eclectro]

but big rockets? They seem so dated

Thankfully the promise of dilithium crystals to power a new generation of warp drives is just right around the corner.

That and transporter technology will finally free us from "big rockets."

Re:Big rockets?

[tuxter]

IF there was a more affordable, cost effective means of transport to space, don't you think it would have been done by now? It's gonna takes years to formulate and actually produce something like a space elevator. And it'll have to be placed somewhere with a distinct lack of nasty weather. Also, being kicked in the back by multiple G's is way cooler.

Re:Big rockets?

[WolfWithoutAClause]

Oh well, if they're "dated" then they must be bad. Sure hope your girlfriend has only gone out with you in her entire life. :-)

Seriously though, the reason rockets are expensive is because they aren't launched very much- mass production would slash the cost. But because the cost is high, production is low, and so nobody can afford to go, so the cost stays high.

If that sounds utopian, consider that the fuel to put somebody into orbit is only about as much as to send someone on a round the world trip by jet...

Rocket hardware, contrary to popular opinion, isn't very complicated, your car probably is about as complicated.

Incidentally, the projected cost of Space Elevators is likely to be about as high as rockets- it's only if the launch rate goes really high will the initial higher R&D costs of Space Elevators cancel out.

Then there's the Van Allen radiation belts around the earth- people would get radiation sickness and possibly die if they go up an elevator. Shielding is extremely heavy and expensive, but rockets go much faster so you get less dossage and rockets can do what Apollo did, steer around the worst of the belts- but elevators have to be above the equator where the belts are, so they can't do that.

Even then, there's another fly in the ointment, the power costs of a space elevator are much higher than you would expect- currently the costs per kg to orbit are thought to be higher than the cost of cheap rocket fuel to do the same thing. This is mainly because the laser power beaming system looks like it may turn out to be about 2% efficient for various reasons (and even that's optimistic- current tech is 0.5% efficient), and other techniques aren't practical for sending power 38000 km up a nanotube rope. It turns out that rockets are if anything more efficient, and may even be cheaper in the long term. :-(

[or :-) if you like rockets, personally I like all ways to get to space :-) ]

Re:Big rockets?

[BigGerman]

I always thought that it is just not right esthetically speaking:
Take 500 tons of explosives, pile them up skyhigh, put a person on top of it in a tin can and then set the whole thing ablaze.
You can smell government / military-indistrial thinking all over it. There MUST be a better way.

Re:Big rockets?

[Tx]

I think the point was it's not a "conventional" rocket, it's a kludgy hybrid lash-up which never worked all that well, and is fundamentally unsafe.

The Russians got it right with their shuttle - instead of a big main engine on the shuttle, have much more payload space in the orbiter, and launch the thing with a big-ass conventional rocket. Shame the Russians couldn't afford to run their shuttle.

Re:Big rockets?

[dabigpaybackski]

Couldn't agree more. The reason we're still using primitive vertical launch technology is in large part due to the U.S. military's choice of silo-based ICBMs for massive nuclear barrages, from which your typical space launch vehicle was derived. Werner von Braun advocated launching rockets from long inclined ramps in order to boost payloads and reduce costs, but didn't have the clout to make this happen. For full background, check out the link.

I find their arguments convincing. It's an incremental step using existing technology, but it's a big one.

Re:Big rockets?

[TK2K]

Big rockes are dieing.
NASA is getting their SCRAMJET system to work, if used on the space shuttle, it would drop its weight by 85%! That is a huge amount!
How it works, A scramjet works by extracting the oxygen required from the atmosphere is passes though, as long as it is travling faster then mach two (on earth's atmosphere) it can sustain flight. This gets rid of the need to cary liquid oxygen, allowing spacecraft to be much lighter, and to be able to go faster.
If the shuttle had a fuel tank the size of the moon, it still wouldnt even be able to get up to 1/10th the speed of light! (this is due to the mass of the liquid oxygen)

Re:Big rockets?

[snuf23]

Yeah they got it right. So right it flew only one test orbital flight and unmanned at that.
Ok so that's related to economics BUT you can't really judge a launch vehicle's performance and call it "right" if it never really got a chance to do its job.

Re:Big rockets?

[georgewilliamherbert]

I'm surprised that with a $1.5 billion budget

His actual budget was a fraction of the $1.5 billion he made on PayPal, not the whole amount.

There is no way that SpaceX would be profitable selling rockets for $6 and $12 million each if he spent $1.5 billion developing them. That's part of the reason why normal space launch rockets cost $40 to $250 million (or more...).

Re:Big rockets?

[mOoZik]

Are you really so naive that you think he invested the entire proceeds from the sale in developing a rocket motor? More likely, it's an investment of a few million dollars.

Re:Big rockets?

[Kiryat Malachi]

Hey, it could land automatically in Russian weather. Give them some credit, Buran looked to be a decent craft that died solely due to economics.

Re:Big rockets?

[TheKidWho]

No they never got it right.

The american's got it right, they got it almost perfect, but congress didn't give them enough cash so they had to take out a lot of things from the shuttle design to make it as cheap as possible and as safe as possible.

Re:Big rockets?

[ScrewMaster]

Actually, it's pixie dust. Soy-based, I understand.

Re:Big rockets?

[ScrewMaster]

Yeah ... like in that old George Pal flick "When Worlds Collide".

Re:Big rockets?

[Anonymous Coward]

I gather from this that you havn't looked up how much a jet costs, going around the world. Which while not being insanely expensive, certaintly isn't cheap either.

Re:Big rockets?

[WindBourne]

hummmm. if you have an efficient design, why change it? Consider that Linus borrowed a lot of ideas from Unix in Linux's early days. Then as time progressed, the insides have changed and improved.

Same with the rockets. Right now, they are taking a standard design and imporving its reliability and economics. Down the road, when we are back on the moon, is the right time to test the space elevator.

Re:Big rockets?

[LWATCDR]

Well there are is another reasons\ besides lack of clout.
In the US there are no convent mountains. The ideal place is as far south as possible and the rocket needs to fly over WATER to the east. IE where it can not come crashing down on a school. That is why they launch sites in Kansas. There are no sites that meet those requirements in the US. The only place that might work well for this would be in Hawaii. Any guess how the greens would scream if you tired to bulldoze that track in paradise?

Re:Big rockets?

[IgnoramusMaximus]

The american's got it right, they got it almost perfect, but congress didn't give them enough cash so they had to take out a lot of things from the shuttle design to make it as cheap as possible and as safe as possible.

Dude. What precisely did they "take out"? An anti-matter warp drive? An anti-gravity generator? That is what one could reasonably expect if the shuttle got any bigger budget. It probably will come as a shock to you but the insanely overpriced abomination that the space shuttle is, costs a cool 0.5 billion greenbacks each frigging launch! Never you mind all that contented squeeling of corporate pork feeding at the NASA troff during the design phase. If it were not for the Congress putting its foot down, they will be still spending 15 billion per design only to reject it in final phase to start over.

The parent poster is absoulutely right, for 1/1000th of the design budget of the Shuttle, the Russians would have the Buran flying like clockwork and each launch would have cost 1/100th of that of the Shuttle's.

Re:Big rockets?

[FleaPlus]

I think he's actually spending a pretty modest amount on development. From an older interview:

While Musk said he is not the company's sole backer, he said he is prepared to fund the development of the Falcon LV entirely out of his own pocket if he has to. He declined to say exactly how much he expects to spend developing the rocket, only that the figure will be "in the tens of millions" of dollars.

Re:Big rockets?

[wes33]

"If every company needed the public to vote on whether to let them do their thing, we'd be where the USSR is. Oh yeah, they don't exist anymore."

funny thing though -- the legacy of the ussr in this domain is the safest, cheapest and best "big rockets" in the world, while in America they can't remember how to build a Saturn V anymore :(

Re:Big rockets?

[Anonymous Coward]

Maybe a space elevator, or maybe some new technology that nobody's invented yet. ...but big rockets? They seem so dated...

Well, until that technology is invented (and that includes space elevators), it seems that rockets are still the way to go.

It is starting to look like the next step is a "hybrid" rocket using some alternative technology for the first stage. At this point, anything that can be done to reduce the amount of fuel (or other stuff) that the actual rocket has to lift is about as much as we can hope for.

The reentry is an area where there is lots of room for innovation even with current tech. The shuttle was designed the way it is mostly for military and political reasons (it is relatively easy to direct its landing and it gives the pilot something to wrap his left hand around). I'm a fan of a rotary wing design myself but then I'm not an aerospace engineer.

Re:Big rockets?

[dabigpaybackski]

The only place that might work well for this would be in Hawaii. Any guess how the greens would scream if you tired to bulldoze that track in paradise?

Check the website. There's are good arguments in favor of candidate sites, which include Vandenburg, White Sands, which both have acceptable mountain slopes, and yes, Hawaii. Carlton Meyer of skyramp.org thinks building a ramp on the barren slope of Mauna Loa may not be as big a deal with environmentalists as detractors think, and there is also the jobs issue in favor, as there aren't a lot of high-paying jobs on the big island.

Now, with respect to your point about launching rockets over water rather than land, don't space launches from Vandenburg AFB in California cross the continental United States? And now that Bezos guy from Amazon intends to start launching rockets from West Texas; those will spend at least some portion of their flight over land.

As for the old argument in favor of siting spaceports as far south as possible, what we have learned since building the installation in Cape Kennedy is that launching from sites with a lower air density (as in higher altitude) is more important than getting a little boost to velocity from a more southerly location's better angular momentum. This is why the Russian launch site in Kazakhstan is arguably better than Cape Kennedy, even though it's at like 40 degrees north. Of course, best of all would be a mountainside in Ecuador, but politics would never allow for a U.S.-funded site to be built there.

Re:Big rockets?

[iocat]

That's 'cause the Russians don't really care if they lose a few ships or cosmonauts, so they under-engineer stuff. Perversely, NASA, which over-engineers stuff for safety, then has way more go wrong.

Although it's hard to talk up the Russians when their oxygen generator keeps balking up on the ISS. Of course, NASA mission control probably won't let them thump it, which would probably work (given that it's problem seems to be bubbles sticking in the plumbing).

Re:Big rockets?

[Ohreally_factor]

Why would a space elevator need to be positioned at the equator? I'm not being facetious, I'm truly curious.

Re:Big rockets?

[Anonymous Coward]

Good one - congratulations

Re:Big rockets?

[Repran]

"The probability of discovering a new physics is not directly proportional to the number of dollars spent."

Not so fast... You may want to check out the Theories of Burkhard Heim and its applications to space propulsion.

Why care what he has to say? Well - for one Heims theory apparently is the only theory which yields remarkably exact theoretical values for the masses, the resonances, and the mean lifetimes of elementary particles, as well as the Sommerfeld fine structure constant.

If his calculations are correct a flight over 10 light-years could be done in roughly 80 days - 160 days roundtrip.

Extraordinary claims that require extraordinary proof indeed. However, if I got US 1.5 Billion and would be thinking about exploring space I would not mind spending a few million to go about proving/disproving them...

Re:Big rockets?

[Anonymous Coward]

wow, 5million a launch? I didn't know they could launch 30,000kg for 5million. $166 per pound, interesting.

Re:Big rockets?

[CaptDeuce]

I'm surprised that with a $1.5 billion budget they couldn't find a better way to get people into space. Rockets don't seem like the "affordable" answer to me. Maybe a space elevator, or maybe some new technology that nobody's invented yet. ...but big rockets? They seem so dated...

Oy! Where to start?

1. The $1.5 billion is how much Musk made from his sale of PayPal to Ebay, NOT RocketX's development budget.

2. Rockets are the best and only way to get people -- or anything else -- to space and will be for the foreseeable future. Consider that ...

3. The space elevator concept is very cool but the materials required to build one do not exist. So you could say a "way" has been found but it's currently impossible to build. The materials could be developed in the not too distant future, say, 10-25 years, but they are still at the basic research phase. Cables made using bucky tubes hold promise but still hasn't been demonstrated.

4. SpaceX is not developing "big" rockets. A "big" rocket is something like the Saturn V or the Energia which can lift about 120 tons to LEO (Low Earth Orbit) whereas SpaceX's Falcon I will lift about one ton to LEO and the Falcon V about 5 tons.

5. Rockets are incredibly efficient in terms getting the most power (work? I ain't no engineer) from chemical fuels.

And ultimately,

6. There is nothing intrinsically unaffordable about rockets. You are assuming that "rockets" are necessarily expendable since virtually all current space launcher rockets are expendables. A well designed reusable rocket would be extremely "affordable" to operate but, alas, very tricky and expensive to design and develop. Note that the Space Shuttle is not well designed, not truly reusable, and most certainly not affordable to operate on a commercial basis.

In conclusion, there is little wonder that you are surprised since you know not of what you speak.

Re:Big rockets?

[Cyberax]

Well, only 3 Russians died during a real space mission: Soyuz 11, but shuttles have a pretty large death-toll: Challenger, Space Shuttle...

Old Soviet rockets are pretty reliable and cheap, mostly because they are quite simple in comparision with overcomplicated shuttles.

Re:Big rockets?

[CaptDeuce]

The Russians got it right with their shuttle - instead of a big main engine on the shuttle, have much more payload space in the orbiter, and launch the thing with a big-ass conventional rocket. Shame the Russians couldn't afford to run their shuttle.

Well, no, the Russians did not get it right.

Their first -- and therefor arguably their last -- mistake was to build a shuttle system that even resembled the US Shuttle which is exactly what they did.

Why? There is essentially no good reason to build a large multipurpose winged reusable orbiter. In particular:

* A reusable orbiter has no business hauling cargo. It just forces the orbiter to be larger and therefor heavier and therefor able to carry less cargo. Carrying passengers and small load of equipment would be OK ... sorta -- and that is what NASA wanted to do originally.

* While debate still rages, wings on a reusable space craft are a Bad Idea®; they're heavy, don't help the spacecraft get into orbit, are useless in orbit, and ultimately drastically reduce payload. Alternatives are good ol' ballistic capsules (Soyuz, Apollo, etc) and parachutes or powered vertical landing like you see in old sci-fi movies. Check out the DC-X.

The closest anybody could have gotten to getting it right, would have been to develop reusable boosters; those are the things that the Russian design threw away! The advantage of putting the engines on the US Shuttle is that those expensive engines live to fly again and again. The rest of the US Shuttle stack is largely propellant tanks which are relatively cheap.

Ultimately, there is no "right" way to design, build, and operate and affordable rocket launcher that can provide CATS (Cheap Access To Space). If anyone is interested in actually learning more, they should check out the usenet newsgroup sci.space.tech.

Re:Big rockets?

[tsotha]

Yeah they got it right. So right it flew only one test orbital flight and unmanned at that. Ok so that's related to economics BUT you can't really judge a launch vehicle's performance and call it "right" if it never really got a chance to do its job.

It was a proof of concept. After they built it the political leaders realized something the engineers had said all along - "hey, it really is fundementally stupid to put wings on a rocket."

You see, they had a perfectly servicable, safe, and cheap way to get people into space already. The Soyuz was the most successful space vehicle from any perspective. Still is. The Russians didn't have enough money to use their space program as a giant welfare program for big aerospace companies and critical congressional districts. They had a job to do and they did it with a tenth of NASA's budget.

The exciting thing about commercial space is the financial discipline it provides. We should have solar power satellites and a permanent base on the moon for the money we've squandered on the Space Shuttle and ISS.

Re:Big rockets?

[azuretek]

I'm not really sure on this but I think it has something to do with that being where the most force is?

like kinetic energy... when it's spinning that's where the most power is.... though I could be completely wrong but I allways figured that was the reason.

Re:Big rockets?

[Retric]

Ok say you want something in space to point at some point on earth all the time. Well the closer to the earth the more gravity some the faster you need to go so in LEO you need to go mach 23. But if your far away say where the moon is go can go slower ~27days. In between those two point's there is an orbit that's 24 hours which means if your over the equator and that high up your orbiting the earth.

So if you built a tower from that point you would hit orbit no problems. You could aso build down from that orbit and hit earth now problems and when those poin'ts are connected you how your elevator.

Now over the north pole you would never hit orbit al speed becasue you would never circle the earth.

Now if you where a little closer to the equator but not on it you could build something that's not strat up and down that would be do the same thing but it would not work untill it was compleated as the orbit would not be stable untill it was connected to the ground. It would also need to be longer ect. Hell if you had a realy big rock orbiting the earth just outside of geo sinc orbit and tied it with something realy strong to a point on the north pole you could have a space elevator but it would be a hell of a lot harder and longer than building over the equator.

Re:Big rockets?

[cheekyboy]

Shame the japaneese with billions of dollars they have couldnt have done a deal, but japan probably has rules in it that prohibit technology transfer in that domain.

So therefore, China/India should have bought it or done a combo deal.

Pitty the Russians werent such good negotiators/business people to follow on with their shuttle program and turn it in into a global enterprise with 10-50 shuttles. It chould have been done, but too many people have NO BALLS.

People should stop thinking of space as something mysterious and magical, and think of it as just another ocean to cross and place to exploit business wise.

Re:Big rockets?

[Retric]

Also think of it like this if you have a rock on a string some of that string close to your hand is moving a lot slower than the string close to the rock. But the whole thing is spinning around your hand the same number of times a second. If your standing over the equator and you put up a pole it's going to aproach orbital speed and be in the right path. If you do the same thing over DC it's going to aproach orbal speed but not an orbital path.

Re:Big rockets?

[Anonymous Coward]

Since when is 0.5 billion equal to 5 million?

Re:Big rockets?

[Anonymous Coward]

Nah, stability's easy. You just build it out way past GEO, and hang a weight off the end. The main problem is that we don't have any material remotely strong enough in tension to support its own weight.

Re:Big rockets?

[imsabbel]

and where, smarty, do you get the oxygen from above 50km or so?

Re:Big rockets?

[amorsen]

Extraordinary claims that require extraordinary proof indeed. However, if I got US 1.5 Billion and would be thinking about exploring space I would not mind spending a few million to go about proving/disproving them...

I would mind. I have read the talk page related to his article. While Burkhard Heim may not have been a complete crank, his supporters are certainly not sufficiently versed in physics.

Re:Big rockets?

[amorsen]

Why would a space elevator need to be positioned at the equator? I'm not being facetious, I'm truly curious.

Do the experiment. Take a ball, attach a string with a weight at the end. Now try spinning the ball. You will notice that if you put the attachment on the equator of the ball, you will be able to reach further with the same length of string.

Re:Big rockets?

[Anonymous Coward]

At 50 kilometers the scramjet still works, above that, how about small oxygen tanks onboard (the whole point of the scramjet being not to carry no oxygen, just less)

Re:Big rockets?

[Anonymous Coward]

I think the point was it's not a "conventional" rocket, it's a kludgy hybrid lash-up which never worked all that well, and is fundamentally unsafe.

Putting a human being outside of the atmosphere is fundamentally unsafe. It ain't nerfworld up there, buddy...

Re:Big rockets?

[Anonymous Coward]

Affordable, this engine runs on Kerosene and smoked salmon!

Re:Big rockets?

[mangu]

Rocket hardware, contrary to popular opinion, isn't very complicated, your car probably is about as complicated.

But the rocket is stressed to the limit. If the rocket had the same power/weight ratio as your car, it would be able to fly only as high as your car does. Space hardware isn't expensive because it's made in small quantities; it's expensive because it must be extremely lightweight and at the same time very strong. Independent of the production scale, carbon-fiber honeycomb is more expensive to make than stamped steel plate. Otherwise, cars would be made of carbon-fiber honeycomb.

Also, space hardware must be extremely reliable, because it's so difficult to go there and repair it, and that raises the cost.

Re:Big rockets?

[mangu]

launching from sites with a lower air density (as in higher altitude) is more important than getting a little boost to velocity from a more southerly location's better angular momentum. This is why the Russian launch site in Kazakhstan is arguably better than Cape Kennedy, even though it's at like 40 degrees north.

The advantage in launching from sites near to the equator isn't the velocity boost, which is, as you say, relatively small. The problem is when you want to use geosynchronous orbits. Cancelling the resulting orbit inclination, which is always at least as large as the latitude of the launch site, is the big problem. Suppose you had a polar orbit, with 90 degree inclination, and wanted to turn it into an equatorial orbit. If the orbit velocity is v, you would need a 2*v velocity change. The only reason why they can launch from Baikonur is that the Russian rockets are so large. Their fourth stage is big enough to zero the orbit inclination.

Re:Big rockets?

[LWATCDR]

"don't space launches from Vandenburg AFB in California cross the continental United States"
Nope. Vandenburg is ONLY used for polar launches. That kind of orbit is only used for recon and EOS that is why most launches are out of the cape. They do launch ICBM tests out of Vandenburg as well but those are suborbital.
Bezos is going suborbital. I would bet all of the flight path is over unoccupied land. West Texas is empty and since this is straight up it will likely go less than 100 miles downrange.
White Sands and Vandenburge are total non-starters for anything going into a normal orbit because of the population centers that you would have to over fly in boost phase. You might. And I do mean might get premission to lauch from those sites if you where using a "Proven" single stage to orbit system or a system with proven flyback boosters. But that would be a big maybe.

Re:Big rockets?

[merlin_jim]

Why would a space elevator need to be positioned at the equator? I'm not being facetious, I'm truly curious.

It's not about the force... at least not directly as another poster said.

There is no compression material that can support its own weight for that distance. There are a few tensile materials though. Meaning that the things center of gravity has to be on the midpoint of the elevator, with both ends pulling outward.

Which means its in orbit, not fixed to the ground. There's only one class of orbits that would allow it to stay over the same spot on earth; geosynchronous orbits.

All of those orbits are 22,000 miles up... over the equator.

So to build a space elevator, it's center of gravity has to be 22,000 miles directly above the equator.

Re:Big rockets?

[IgnoramusMaximus]

That's 'cause the Russians don't really care if they lose a few ships or cosmonauts, so they under-engineer stuff

This is absoultely false, the Russians are just as concerned about safety as NASA is, their method is different. While NASA tries to use primarilly bureaucracy the Russians try to use an incremental system whereby they use proven and tested stuff with small modifications. Your assertion that NASA is "over-engineering" is laughable: the Shuttle has virtually no workable astronaut escape system, while the Soyuz has an emergency escape rocket on top of the launch stack that can be used from the moment when the cosmonauts are in the capsule all the way to the point where capsule has enough altitude to land on its own in case of the booster explosion or malfunction. In other words for the most dangerous part of the launch sequence the Shuttle has no safety mechanism. And then there is the unprotected heat shielding and overcomplicated system whith the main engine in the shuttle itself etc etc. At this point in time it is Soyuz and its launch system that are "over-engineered" for safety in a good sense of the word.

Although it's hard to talk up the Russians when their oxygen generator keeps balking up on the ISS.>

ISS' main function is to be a political boondogle and I am certain that the Russians would probably have replaced the thing long time ago if it was their decision to make (and if they had funds to do so). Also banging the thing with a wrench is an acceptable solution if the unit was made to accommodate such treatment from the get go, which, being Russian it probably was.

Re:Big rockets?

[CrimsonAvenger]

If the shuttle had a fuel tank the size of the moon, it still wouldnt even be able to get up to 1/10th the speed of light! (this is due to the mass of the liquid oxygen)

Umm, no. It is due to the specific impulse of chemical fuel.

If the Shuttle had a fuel tank the size of the moon, and were using a scramjet (yes, it's impossible, but we can play what-if games), and the fuel tank had zero empty mass (it's a big ball of LH2, supported by our goodwill), then the deltaV of the Shuttle would be on the order of 0.33% of lightspeed.

Note that that 1/3 of 1% (of c) deltaV only required three impossible conditions to achieve.

Re:Big rockets?

[Anonymous Coward]

space elevator...stupidest thing to come out of the mouths of moronic, volvo-driving californians.

Re:Big rockets?

[Anonymous Coward]

"troff" ?!??? Hahahahaaa!!! What a dork, it's "trough" you fool.

Re:Big rockets?

[Anonymous Coward]

So, you don't go swimming much, I take it?

Re:Big rockets?

[WolfWithoutAClause]

The elevator is positioned by a combination of centrifugal force acting directly outwards from the rotation axis of the earth, and the earths gravity.

It turns out that if you add the two sets of forces together you get a force that pushes the cable towards the plane above the equator as well as the force acting away/towards the earth.

It's easiest to see at the poles. If you imagine swinging a long cable around the north pole the rotation pulls it out in a long line, but the earths gravity would pull it down towards the equator. It would probably drag along the ground in fact; although if you built a tall tower you might be able to stop that.

Whilst you can fix the lower end of the cable somewhat north or south of the equator, the geosynchronous orbit part of the cable ends up pretty much in the equatorial plane (it will move a bit as you move the fixture point, but not much, since the cable is fairly flexible.)

If the fixture point goes too far north or south, the cable will actually drag along the ground.

If you stick a massive counterweight on the cable then the cable becomes taut and can be pulled off the ground somewhat, but you're ultimately limited by the strength/weight of the cable- making the cable tauter needs it to be stronger, which makes it heavier. So there's a limit how far north/south you can go in practice.

Re:Big rockets?

[WolfWithoutAClause]

But the rocket is stressed to the limit.

That's not actually so. The Russian Proton rocket engines for example, uses a safety factor of 2.

i.e. they worked out the stress on each of the parts and then made them twice as strong as they needed to.

Re:Big rockets?

[WolfWithoutAClause]

If you had a 200 km high tower and spun the ends of the string at orbital speed and you let something go, it indeed would be in orbit.

The difficult/expensive bits are building something 200km high, and having the ends of the string being at orbital velocity :-)

But it is theoretically possible, particularly if nanotubes are used for the 'string'.

Re:Big rockets?

[danila]

Good points. I'd add that a rocket is a rocket (looks like a rocket) because it's the most functional form for using propulsion. Since you need a lot of propellant/fuel to launch into orbit, you need to store it somewhere. And since that propellant/fuel is usually much heavier/larger than the payload, the form of the vehicle is determined by the need to store the fuel. And what better way to do it than with a huge cylinder? Add a cylindrical (since it's going to fly through air for some time) capsule for the payload and you have a traditionally looking rocket. Adding wings, while sexing up the craft, doesn't really help something which flights straight up through the air and after that basically flies in vacuum.

Re:Big rockets?

[cmowire]

I think it was also there because the Russians didn't want to let the US be able to do stuff that they weren't able to.

Like space war. The shuttle would have been able to fly up, retrieve a Russian spysat and then land again, after 1 orbit.

But, after the US wasn't plotting to do such things to Russia, they didn't necessarily need to do those sort of things to us. Therefore, because Soyuz still worked just fine, there was no point in having a shuttle-equivelent because it would be even less useful than the US's shuttle.

Re:Big rockets?

[cmowire]

See, the Russians are perfectly capable of making safe, well-engineered stuff. It's just that we don't always recognize it.

A F-16 has a jet intake under the cockpit. Thus, it's awfully easy for it to suck up any debris on the ground while taxing or taking off. Therefore, debris control is important. They need to scout the airport every morning. Our jets need a whole mobile maintenence facility to keep them flying.

A Mig-29? It's got a screen that deploys in front of the engines and auxiliary upward-facing intakes. So they don't need to wory about operating from poorly-prepared fields. They make it such that everything needed right now for an aircraft fits on a single truck. If it's more important than that, you make sure it won't need to be replaced in the middle of your campaign.

The Soyuz has primitive components, yes. But they've got stuff that won't stop working. Like a primitive optical periscope that gives you enough margin to do a re-entry without guidance. They make sure that the systems that are important just won't fail.

Re:Big rockets?

[Anonymous Coward]

Also, if you want to use it for more than bulk materials, things like changes in acceleration. Humans can get rather squishy when expossed to rapidly changing accelerations, and most finished or semi-finished goods would have potential problems as well.

Re:Big rockets?

[WolfWithoutAClause]

No biggie, you just have to make the bolus section long enough- like 1000km long enough :-)

Re:Big rockets?

[WhiplashII]

While true, your car uses a safety factor of at least 10, and normally near 100...

Re:Big rockets?

[WhiplashII]

This is not really true, in order to change your orbit 90 degrees you need about 0.5 v change (or so, I forget the exact number).

Essentially, you first change the orbit from circular to extremely eliptical. Then you change directions when you are farthest from Earth. The you circularize the orbit. It works because the energy required to change directions is a lot less when you are at the extreme edge of an elliptic orbit, because you are so much slower.

Re:Big rockets?

[WolfWithoutAClause]

You obviously have never driven a Ford :-)

Re:Big rockets?

[cheesybagel]

The closest anybody could have gotten to getting it right, would have been to develop reusable boosters; those are the things that the Russian design threw away! The advantage of putting the engines on the US Shuttle is that those expensive engines live to fly again and again. The rest of the US Shuttle stack is largely propellant tanks which are relatively cheap.

Not quite. The Zenith first stage was meant to be retrieved by parachutes + retro-rockets, as well as the second stage. While the second stage was never recovered using this mechanism, the engines of the second stage, below the main tank, were recovered in one of the test flights for inspection. But it seems the whole thing was uneconomic.

See more information here and here. Quote:

...By contrast the RD-170 engine for the booster stage was a purely Soviet design and experienced a slow and difficult development program. These were exactly the kind of closed-cycle liquid oxygen/kerosene engines that Glushko had opposed developing in the 1960's. In addition the TTZ required that they be reusable for ten missions...

...The Block A 11S25 booster stages were the responsibility of KB Yuzhnoye in the Ukraine, F Utkin, General Constructor. They were to be reused ten times, and were therefore fitted with parachute containers. Solid fuel soft landing rockets in the parachute lines provided a soft landing downrange. It's not clear how the 35 tonne boosters were to be transported back to base for reuse...

Just another dot com trillionaire

[Anonymous Coward]

Fulfilling his childhood fantasies.

Re:Just another dot com trillionaire

[Anonymous Coward]

$1.5 B won't even by a B2 plane these days...

Begalke

Re:Just another dot com trillionaire

[Rosco P. Coltrane]

$1.5 B won't even by a B2 plane these days...

Because owning a B2 bomber is your childhood fantasy?

Frankly, mine involves bras and suspenders and don't cost remotely as much.

Re:Just another dot com trillionaire

[Anonymous Coward]

You'd prefer a 48DD to a B52?

Re:Just another dot com trillionaire

[Anonymous Coward]

Yes, and what you wear in the privacy of your own home is entirely your own business.

Re:Just another dot com trillionaire

[Kiryat Malachi]

Mine involves bras and suspenders... in the cockpit of a B2.

Obviously, mine is superior.

Bigelow Aerospace is located..

[dustinbarbour]

.. not 10 minutes from my front door! Craziness!

and hey, if it doesn't work...

[zonker]

he can just sell the thing on ebay...

Re:and hey, if it doesn't work...

[ackthpt]

he can just sell the thing on ebay...

Shhh!!! I'm planning to sell fragments of it when it comes down over my state ;-)

Re:and hey, if it doesn't work...

[birdman17]

he can just sell the thing on ebay...

...and have the buyer deposit the price into his PayPal account...

Re:and hey, if it doesn't work...

[merlin_jim]

and hey, if it doesn't work...
[snip]
he can just sell the thing on ebay...


Look at it this way, he's probably the one guy in the world that can trust PayPal with his money...

Re:Karma Pit

[Anonymous Coward]

Paypal me $5, I'll fix it asap.

Wow!

[TheOriginalRevdoc]

Amazing! They managed to get sixty-year-old technology to work!

This is great news. Now, if only they can get their valve radios to work, they'll be in business.

Re:Wow!

[ugmoe]

My valve radio is still working fine

Re:Wow!

[Anonymous Coward]

Paypal uses valve radios?

Re:Wow!

[VanillaCoke420]

Yes, it's just crazy that a new rocket engine actually would be tested before being used for launching people into space. Whatever were they thinking? We've had solid fuel rockets since ancient China, surely we don't need testing any new rockets built since then. Just build them, attach them to the spacecraft and off you go in a most spectacular way.

Re:Karma Pit

[Anonymous Coward]

Paypal who? you twit.

The 'insightful' moderator missed 'troll'

[Chairboy]

The parent post is clearly a troll. PayPal isn't perfect, nobody is, but making the paypal slam AND the 'up in smoke' comment in the same sentence, that's straight up under the bridge, 'gonna eat some billy goats' type trolling.

Re:The 'insightful' moderator missed 'troll'

[ackthpt]

The parent post is clearly a troll. PayPal isn't perfect, nobody is, but making the paypal slam AND the 'up in smoke' comment in the same sentence, that's straight up under the bridge, 'gonna eat some billy goats' type trolling.

I bet you feel all warm and fuzzy when you've lost (or spent poorly) hard earned money, when you see the mogul who received a chunk of it, having fun while you struggle with Windows Security, Ebay's Enigmatic Policies or PayPal's Inattention to Customers. I loved it when someone with a 'Power' account forwarded on to me special email addresses and phone numbers that get actual human beings employed by eBay/PayPal, while little fish get form replies or overtaxed volunteers...

Seriously, it takes the fun out of it unless I visualize some of these same people being on that 5-man rocket and hitching a ride on a wayward asteroid.

Re:The 'insightful' moderator missed 'troll'

[Chairboy]

1. Paypal is not a bank.
2. Sometimes people lie.
3. I've done almost 100 transactions through paypal knowing #1 and #2, and I've been lucky enough not to get hit. If I want absolute security, I'll pay through the nose for an escrow service. If I want convenience for small purchases, I'll use PayPal.

I'm not trying to be a jerk, but.. c'mon.

Re:The 'insightful' moderator missed 'troll'

[ackthpt]

1. Paypal is not a bank.
2. Sometimes people lie.
3. I've done almost 100 transactions through paypal knowing #1 and #2, and I've been lucky enough not to get hit. If I want absolute security, I'll pay through the nose for an escrow service. If I want convenience for small purchases, I'll use PayPal.

So ... when it goes badly for you, that's OK, eh? Hmm never thought of it like that. Kind of charity for the rich.

I'm not trying to be a jerk, but.. c'mon.

Oh, sure, exuuUUuuse me. I'll just put on my brave face and overlook these things. If it weren't for the Hong Kong (Tsuen Wan) Police I'd have gotten nowhere.

Re:The 'insightful' moderator missed 'troll'

[Anonymous Coward]

1. Paypal is not a bank.

BZZZT thank you for playing. Paypal was ruled to be a bank by the feds.

Re:The 'insightful' moderator missed 'troll'

[Chairboy]

No, they weren't. An AC that posts misinformation? Why, I never!

Re:The 'insightful' moderator missed 'troll'

[Anonymous Coward]

For that matter: A slashdot poster who posts misinformation? Why, I never!

Re:Karma Pit

[Anonymous Coward]

Come on slashdot, I have "-1 Terrible" karma for no apparent reason, and I have posted lots of comments recently that have been modded up.

Most likely, you have offended one of the petty, small janitors that work at Slashdot and have been bitchslapped to permanent -1 land. Don't worry, some of Slashdot's best content lives there.

Re:Karma Pit

[Anonymous Coward]

you twit

Think I found your problem, grennis.

Conventional but exciting

[Spy Handler]

See, you don't need exotic new technologies for cheap(er) space access... just cut the NASA fat.

Re:Conventional but exciting

[Anonymous Coward]

See, you don't need exotic new technologies for cheap(er) space access... just cut the NASA fat.

Since every government department tends to accomplish the exact opposite of it's stated purpose (i.e., Dept. of Education, Dept. of Defense,) you're probably right. Hear that, everyone? Let us finally enter the space age by abolishing NASA!

SpaceEx

[Anonymous Coward]

That just screams a FedEx lawsuit.

Re:SpaceEx

[georgewilliamherbert]

Even better.

It's not even the right name for the company.

See www.spacex.com

Someone's got an itchy E key.

Re:SpaceEx

[Anonymous Coward]

hmm...Universal Parcel Service

What can Brown do for You?

Getting up is only the first part

[Shadow Wrought]

Any word on how they get the lucky orbiters back down? I thought NASA had great difficulty with heat shield design, implementation, etc.

Re:Getting up is only the first part

[Chairboy]

NASA had trouble making cheap, low cost, light weight re-usable heat shields.

For each of those requirements you scrap, you save a boatload of money. If you equip your capsules (no need for big wings like the shuttle) with one use heatshields, you might incur a weight penalty, but you can use 40 year old Apollo or Soyuz technology. If you can squeeze an extra half a percent of efficiency from your engines or start with more boost then you think you'd need, you can chuck the light weight requirement.

Commercial space flight will be different from government in a few important ways. I suspect that being able to design your craft without congressional 'input' will help. A lot of the things that make the shuttle complicated and expensive to run are leftover from 1970s requirements that it serve everyone, from civilian NASA to the NRO (spy sats) to the Air Force (dropping bombs on USSR using once around orbits and landing back at Vandenburg).

Re:Getting up is only the first part

[BradleyUffner]

wait.. isn't "cheap" one of your requirments? Are you saying that if you scrap that one you can build it for less? :)

Re:Getting up is only the first part

[NardofDoom]

Water, sprayed at high pressure, stored in a pressure vessel would provide a low-weight, high efficiency, reusable, heat shield.

Re:Getting up is only the first part

[rewt66]

Low weight? Water? Are you nuts?

Water is heavy. Seriously.

Re:Getting up is only the first part

[DerekLyons]

Commercial space flight will be different from government in a few important ways.

Yes. High on the list is economics... And tossing your heatshield after each flight is not economical at all.

I suspect that being able to design your craft without congressional 'input' will help.

When we have a spacecraft designed with Congressional input, we'll have a data point to compare to. As it is, all Congress contributed was a budget cap... Which pretty much everyone has to live with inside and outside the Beltway.

A lot of the things that make the shuttle complicated and expensive to run are leftover from 1970s requirements that it serve everyone,

Umm... No. It's complicated and expensive because Congress declined to produced Saturn's for cargo delivery and then declined to fund a space station in paralell with the Shuttle. This forced the Shuttle to become a cargo craft (as opposed to the passenger craft it originally was) and then forced it to have a far higher degree of self-sufficiency to support free-flight missions. It's also complicated and expensive because in many ways it's a first generation system. It's also complicated because it operates in a series of harsh enviroments. It's also expensive because NASA kept trading R&D costs for operational costs - rather than admitting the thing could not be done and that a massive redesign and delay was in order.

The Shuttle was never *required* to 'serve everyone', that was a NASA creation in order to build political support for the craft. The only real impact of that was the wing (for high cross-range) and to some extent the tiles. (A tile system was already baselined long before the design was mutated from a short duration passenger taxi into the ungainly thing it became.)

Re:Getting up is only the first part

[wes33]

and it does not compress into small packages

Re:Getting up is only the first part

[georgewilliamherbert]

wait.. isn't "cheap" one of your requirments? Are you saying that if you scrap that one you can build it for less? :)

No, he's saying that "reusable" is one of the requirements, and if you scrap that one then you can build it for less. And lighter, too.

The Space Shuttle tiles aren't lighter than a good ablative heatshield would be. The shuttles have about 18.5 metric tons of tiles and thermal blankets and leading edge RCC panels, out of a total gross weight of 104 metric tons (18%).

Apollo, which was re-entering at a higher velocity coming back from the moon, has a thermal protection system weight of 850 kg out of 5,800 kg total mass (15%).

The proposed British Multi Role Capsule re-entering from low orbit had 666 kg of thermal protection system mass, out of 6,200 kg total mass (11%).

Re:Getting up is only the first part

[qbwiz]

Yes. High on the list is economics... And tossing your heatshield after each flight is not economical at all.
That depends upon what your heatshield is made of. If it's made from the same tiles that make up the space shuttle, it would be expensive. If it's made from carbon phenolic, or a similar material, it would most likely cost less to replace it every time than to boost a more durable material into orbit. That's not to mention the fact that a tile system or similar would still have to be inspectedand partially replaced after every flight, reducing any gains in cost.

Remember that for every pound you put in orbit, you just spent thousands of dollars. Those thousands of dollars could provide for a lot of work making a heat shield on the ground.

Re:Getting up is only the first part

[Profane MuthaFucka]

The space shuttle has a higher surface area compared to it's mass than an Apollo capsule too. Your rough calculations don't seem to take that into account.

Re:Getting up is only the first part

[FleaPlus]

It's interesting to note that the Chinese made cheap, disposable wooden heatshields. It's certainly not the most glamorous thing around, but it gets the job done.

From the link:

The Chinese had developed another novel but usable "low tech" solution. They glued up wooden blocks, appropriately contoured, with the end grain facing the reentry air stream. The wooden heat shield would char and ablate during reentry, just like the caulk material on the Apollo capsules. The fact that you could build a serviceable heat shield for reentry from space out of wood certainly showed that the basic problem was not insurmountably difficult, so Tom had always regarded this too as a rather straight-forward challenge. ... Wood can't withstand directly the temperatures of reentry, but for that relatively short time, it can resist those temperatures by gradually eroding. ... As the wood heated, a carbon ceramic char formed on the outer surface, and the volatiles, or fluids, in the wood behind the char flowed up through cracks in the char. Heat was radiated away from the charred surface, and the interior was kept cool by the outward movement of the cooler heat-absorbing volatiles flowing towards the hot side.

Re:Getting up is only the first part

[georgewilliamherbert]

The space shuttle has a higher surface area compared to it's mass than an Apollo capsule too. Your rough calculations don't seem to take that into account.

That's because they don't have to. To a first order approximation, thermal protection total heat capacity for orbital re-entry is proportional to the vehicle mass only, not the vehicle's surface area. Denser vehicles with less surface area need more thickness of heat shield per unit area. It all comes out very nearly equal, with some slight advantage for lower density, higher surface area vehicles due to secondary effects.

Lower density, higher surface area vehicles will decellerate more quickly at higher altitude. Lifting re-entries, where you use hypersonic lift due to wings or capsule shape to keep the altitude higher and extend the decelleration time, decellerate more slowly over longer time but still at high altitude.

In all cases, the direct energy transfer into the vehicle depends on the vehicle shape (blunter is better, you want a detached shock wave to keep the highest temperature gases away from the vehicle) and its orbital kinetic energy, which is dependent on its mass and velocity. The energy dissipated in ablative heatshields is fairly constant whether it is a quick high intensity exposure or a longer low intensity exposure.

The only difference with longer reentries is that you have to worry more about heat soakthrough on the back surface of the heatshield. Normally the back surface is a lighter, low density insulating foam, which is a small faction of the total heatshield mass. For some designs the whole heatshield is made of that material. Depends on the conditions, etc.

Re:Getting up is only the first part

[georgewilliamherbert]

Low weight? Water? Are you nuts? Water is heavy. Seriously.

And it has a huge heat capacity and heat of vaporization. Seriously.

The technique is known as active transpiration cooling, or just transpiration cooling.

It has never been flown, but it has better (lower) mass than other reusable thermal protection system options according to the engineering studies done to date.

Re:Getting up is only the first part

[georgewilliamherbert]

And tossing your heatshield after each flight is not economical at all.

I have to disagree... I have proprietary pricing info from ablative heatshield vendors about historical projects and ranges for new ones which indicates that ablative TPS systems should be dirt-cheap. First unit prices under a megabuck cheap.

Re:Getting up is only the first part

[DerekLyons]

I have proprietary pricing info from ablative heatshield vendors about historical projects and ranges for new ones which indicates that ablative TPS systems should be dirt-cheap.

*Should* be, that's a long, long step from *are* George.

First unit prices under a megabuck cheap.

First unit prices are utterly meaningless. It's bulk prices over time (x shields per y time) that matter. (Not to mention labor costs in the swap, schedule impact of the same, the costs of storing the spare shields, and the disposal of used ones.)

Re:Getting up is only the first part

[Anonymous Coward]

I'm assuming they didn't use a balsa heat shield. Perhaps oak? Or were they using chinese elm, perhaps?

Maybe they should make a heat shield out of mesquite and start launching cattle into orbit.

I'll just be waiting here with my knife and fork poised.

Re:Getting up is only the first part

[NardofDoom]

You don't need thousands of gallons to do it, and you don't even have to ship it up as water. Send it up as hydrogen and oxygen for the fuel cells and store the excess water in a chamber. Hell, use the urine from the crew! Any water-bearing-liquid would do.

Pressurize the container using air (which does compress) from the cabin. The water would spray out of nozzles on the leading surface of the craft and vaporize, turning into steam and insulating the craft from the heat of reentry. Since it's a passive system it's very safe, won't chip or crack, is reuseable, doesn't need to carry anything up with it and is at least comparable to the weight of an ablative heat shield if not lower.

Re:Getting up is only the first part

[DerekLyons]

It's interesting to note that the Chinese made cheap, disposable wooden heatshields. It's certainly not the most glamorous thing around, but it gets the job done.

Actually... It's not noteworthy at all. The first wooden heatshields were used (IIRC) by German experimenters pre-WWII, and they were also used by the US during the 40's and 50's. It's a well-known method of constructing low performance heatshields.

They aren't as cheap as believed however as they require extremely regular and tight grain in the wood... Which is scarce and expensive. They require careful attention in the selection of the wood and the glue, and great care in construction. At the end of the day they are very heavy and unpredictable in performance.

There's a reason why they were abandoned.

catch 22

[Spy Handler]

Building a space elevator requires that you haul lots of mass into orbit. That's very expensive so it will never get built until orbital launches become cheap. But when we do have cheap access to space, you lose the whole point of building a space elevator in the first place.

Uh oh

[Rosco P. Coltrane]

SpaceEx was founded by Elon Musk from the proceeds of the 2002 sale of his prior start-up, Paypal, to Ebay.

Now here's one person who hasn't left the proceeds of his sale into his PayPal account. I mean, imagine that, buying rocket and space stuff like that, they'd have frozen his account immediately, for no reason, without any explanation besides "what goes on looks strange".

Well done Elon! (and when you have time, please tell your former employees to f*)(*&@$ing give me back my $150 in my account they locked up about, oh, 5 years ago...)

Re:Uh oh

[Anonymous Coward]

If PayPal were open-source, you wouldn't have this problem.

Rockets are cheapest.

[reality-bytes]

And 1.5 billion USD is not all that much when it comes to getting to LEO.

Todays current regular human launch vehicle, the Soyuz, costs around $30m and that is a fully developed and very well tested system.

In terms of rocket development, with a new design, you could expect to spend your first 1bn USD on getting to the 'Manned rated' stage.

As for orbital tethers or 'space elevators' we're talking a whole different order of magnitude for cost. 1.5bn USD in this case would probably pay for about half of the raw materials for the ground tether station. Certainly, space elevators are theoretically cost effective for getting things to orbit but only once they are built.

Rolls Royce?

[StarTux]

Never knew that the famous RR Merlin engine was a rocket...Oh wait...

StarTux

Financed by PayPal?

[DogDude]

Does that mean that they used all stolen credit cards and "frozen" account assets to pay for this ridiculous thing? That gives me a warm fuzzy feeling...

DOD Sat launch?

[crunk]

FTA:

In March, once the final checkouts are completed -- akin, said Musk, to software beta testing -- Falcon I will lift a Department of Defense satellite called TacSat-1 into orbit from Vandenberg Air Force Base in California.

Do commercial entities normally do DoD satellite launches? That doesn't seem right to me.

Re:DOD Sat launch?

[TheOriginalRevdoc]

TacSat-1 is a small experimental satellite:

http://space.skyrocket.de/doc_sdat/tacsat-1.htm

The interesting bit is that the second stage is derived from the lunar module descent motor.

Re:DOD Sat launch?

[VoidWraith]

Commercial entities usually haven't had the resources to do DoD satellite launches. The US military is rather privatized: they buy most of their stuff, they don't produce it themselves, why should they launch their own satellites? It seems like a logical trend.

Re:DOD Sat launch?

[That's Unpossible!]

Do commercial entities normally do DoD satellite launches? That doesn't seem right to me.

Why not? The DoD pays companies to build its weapons, vehicles, planes, etc. Why on earth wouldn't they pay companies to launch their satellites?

Re:DOD Sat launch?

[iamlucky13]

You mean companies that operate for profit like Boeing or Lockheed? The real difference is this company doesn't have a reliability record yet. I'm sure they satellite didn't cost much and isn't terribly important, but it's good to see a young company getting it's foot in the door.

WWW -- Space

[Eric Hysen]

What is it with all of these .com executives entering the private space industry? First Bezos and now this. Do they think that since they got lucky with their investments in the web, they now are obligated to spend millions in another obscure industry? If I had the type of money these guys have, there's no way I'd waste it on something as risky and untested as private space travel.

Re:WWW -- Space

[pinkocommie]

Most of these guys are presumably geeks just like you and I n love the idea of human space travel and moving beyond our planet etc. Half the people on slashdot would be doing the exact same thing if they had ungodly amounts of money to burn.
To infinity and beyond? ;) :)

Re:WWW -- Space

[ScentCone]

2 <> all of these .com executives

And, if all of those that entered into early aviation, using the money they made in other industries (see, for example, Howard Hughes), thought the way you do, we'd be way behind and probably would have lost WWII.

Re:WWW -- Space

[Prophetic_Truth]

shoot for those stars!

Re:WWW -- Space

[TK2K]

But dont you see? that is the beauty of this, Privit companies spending money on space exploration! This is EXACTLY the kind of thing that was invisioned when NASA was created. The space industry is likly to be a huge economic forfrount in the coming years, from tourist attractions to manufacturing. The main reason it has not become that yet, is that it takes billions of inital money to start off. Companies cannot risk this amount of money, but if you already have a thriving company like Paypal, you can spend this amount of money without worrying about not having any more money.

Re:WWW -- Space

[randall_burns]

Just because someone has money, doesn't mean they have a lot of respect from anyone except other folks with money. Musk is young enough, he probably wants to do something _memorable_ with his life.

I'd also be curious to know if his interest in space predated his dotcom activities. One early microcomputer pioneer is reputed to have motivated his employees with claims that if his company was successful, they'd intest in space development. He even invested in a couple of rocket companies-and then retreated to other interests. The technology has improved since then, but frankly, I think a lot of folks are less trusting of the rich and powerful now than they were then.

Quite a few rich folks find their money brings them neither happiness or satisfaction.

I personally have a strong distrust of concentrations of wealth or political power. However, I would suggest that if humanity doesn't develop real, physical frontiers, the future for humanity is pretty dim-maybe just a high tech replay of ancient Egypt--a highly developed but stagnant culture that gradually drifts into oblivion.

The future for humanity with frontiers could be quite an interesting adventure.

Re:WWW -- Space

[Peter Cooper]

I agree, but I'm glad someone's doing it, even if I wouldn't. This is why I have some respect for what Gates is doing with his money. He's helping people get educated and manage to stay alive to actually experience space travel in the future ;-)

Re:WWW -- Space

[John Miles]

If I had the type of money these guys have, there's no way I'd waste it on something ... risky and untested

Wait. I think I see why you don't have the type of money those guys have.

Re:WWW -- Space

[Anonymous Coward]

Really? So give me all your money. That's risky and untested, and by your "logic" you should be rolling in it! Uh, yeah. Back to your day job, Mr. Buffett.

Re:WWW -- Space

[sadomikeyism]

If I had the type of money these guys have, there's no way I'd waste it on something as risky and untested as private space travel.

Which explains why you are not a dot com billionaire....

Big Al's pest control is located...

[Anonymous Coward]

.. not 10 minutes from my front door! Even crazier!

Soyuz vs. anything else

[dingDaShan]

The soyuz costs on average $40 million per launch. This is not what NASA is charged, NASA is charged more than this. Bigelow aerospace hopes to take advantage of this. NASA currently depends almost entirely on the Soyuz. If a private sector competitor can lower the cost to about 25 to 30 million, then a huge step can be made. NASA will have another option, which will drive the price of the Soyuz down. Nothing like a little competition...

Re:Soyuz vs. anything else

[ravenspear]

Your line of reasoning is moot because the space shuttle will be back in operation before any option other than the Soyuz becomes viable.

Re:Soyuz vs. anything else

[QuantumG]

The shuttle will be back in operation by the end of the year? WooHoo! Wanna buy a LongHorn?

Re:Soyuz vs. anything else

[ThogScully]

I seem to recall reading in a recent article posted here that the next shuttle launch is scheduled for March or April.
-N

Re:Soyuz vs. anything else

[QuantumG]

and thus the LongHorn reference which was scheduled for last year.

Re:Soyuz vs. anything else

[dingDaShan]

No because the shuttle costs about the same as the Soyuz. Any competition here is healthy. The antiquated space shuttle can not continue to be the backbone of NASA. It is old and expensive. A newer, cheaper, option is a necessary next step.

A company doing this??

[TK2K]

It seems to me the original idea of NASA is actualy going to work! NASA was created in the begining to combine all of the branches of the government's space research in one location, to pionere new technologies, then, after a few decades, transfer the exploration of space over to the privite sector. Needless to say, NASA is stil in existance. What is impresive about this is the fact that someone from a company is doing a project like this. The problem with the idea of space being exploited by companies is that the inital cost is too great, and the payoffs too little. So what if it is 60 year old technology? They are still financing something that has little or no consivable payoffs for them in the short OR long run, appart from getting Paypal's name out there. True, a big rocket isnt that creative or inovative, but its better then nothing right? (also, the comparitive size of the rocket is much smaller then the older ones) Just the fact that he could actualy use that much (1.5 bill)money on something like a space flight is impresive. Its a good thing money from companies is going towards space, dont complain that its just a rocket, remember, NASA makes the new stuff! (scramjet)

Re:A company doing this??

[LiquidCoooled]

He sold Paypal didn't he?

I think this is more about boys and their (very expensive) toys.
We never grow up, and admit it, if you were as rich as these guys, you would want to do something "cool" :)

Re:A company doing this??

[Gewis]

Little or no conceivable payoffs? Do you have any idea how much our economy depends on and has been enhanced by space-based assets? Elon Musk has stepped in with really cheap ground-to-orbit launch capability which is likely to make him a lot of money as he fairly quickly gains market dominance. He's gone from concept to near-launch in a very short amount of time, less than 3 years, where typically it's ten years or more.

Paypal is only mentioned because Musk happened to get his money from it. He has no real association with it anymore, and Paypal has nothing to do with SpaceX.

Anyway, yes, they are building on NASA's (Boeing's, Lockheed's, Ariane's) successes. However, SpaceX is doing it for far less, with potential for real returns.

And NASA makes the new stuff? They've run two (or three?) scramjet tests since the start of that program, and they've already axed it. NASA is a black hole.

Re:A company doing this??

[Anonymous Coward]

And NASA makes the new stuff? They've run two (or three?) scramjet tests since the start of that program, and they've already axed it. NASA is a black hole.

It is not NASA's job to make "ready-for-market" applications. However, since they were the first, and so far only ones, to develope not only a scramjet, but also one that is capable of speeds Mach 5, I think that qualifies as making new stuff. They succesfully proved it was possible, and now it is up to someone else to make scramjet powered commercial airplanes.

Re:Frist

[Anonymous Coward]

Yes, yes, no. Respectively.

Space Exploration Technology Corp ('SpaceEx')

[Anonymous Coward]

SpaceEx? Sounds a bit like Space Sex. I think I might know their secret mission statement.

One key point you missed

[Nomihn0]

The environmental impact of a space elevator is far less than that of the convential rockets. A space elevator could be powered in part by alternative energy sources that are both energy efficient and clean when compared to rocket fuel. The space elevator's effective footprint would be the size of its anchor facility (which amounts to far less space, in a very remote location).

Isn't this just an RD-180 in disguise?

[Anonymous Cowherd X]

First he sells PayPal and now he's wasting his money on this? It's not that the project is not worthwhile, it's just that there are more economical and efficient ways of achieving what he set out to do.

We'd like Merlin to be the best performing engine of its class (LOX/Kerosene, GG cycle turbo-pump) ever made and it looks like we have a decent shot at getting there.

Just how is their Merlin engine different from the Russian RD-180? It sounds like a rip-off which they are trying to improve and claim they invented something radically new. Renting Baikonur and hiring Russian specialists would have cost him half as much and the results would be much better, IMHO.

Re:Isn't this just an RD-180 in disguise?

[georgewilliamherbert]

Just how is their Merlin engine different from the Russian RD-180?

Other than being completely different?
Such as 10 times smaller?

RD-180:
RD-180 info at astronautix.com

Propellants: Lox/Kerosene
Thrust(vac): 423,050 kgf.
Thrust(vac): 4,152.00 kN.
Isp: 338 sec.
Isp (sea level): 311 sec.
Burn time: 150 sec.
Mass Engine: 5,393 kg.
Diameter: 3.00 m.
Length: 3.56 m.
Chambers: 2.
Chamber Pressure: 257.00 bar.
Area Ratio: 36.87.Oxidizer to Fuel Ratio: 2.72. Country: Russia/USA.
Status: Hardware.
First Flight: 1999

Merlin:
SpaceX page on Merlin via flash link

Sea Level Thrust 71,500 lb
Vacuum Thrust 85,000 lb
Sea Level Isp 261
Vacuum Isp 310
Thrust to weight (fully accounted) 94

Re:Isn't this just an RD-180 in disguise?

[FleaPlus]

Just how is their Merlin engine different from the Russian RD-180?

An individual RD-180 costs $10 million. The price-per launch that Musk is charging for the entire Falcon I is $6 million. Putting a $10 million engine on a rocket that you're charging $6 million for doesn't seem particularly economical.

Renting Baikonur and hiring Russian specialists would have cost him half as much and the results would be much better, IMHO.

Yeah, and make it impossible for him to launch US satellites.

NOT PayPal founder

[Anonymous Coward]

Elon Musk is not a founder of PayPal. Elon Musk founded X.com. PayPal was founded by Max Levchin and Peter Thiel. PayPal and X.com were joined "in a merger of equals" afterwards.

Re:NOT PayPal founder

[Anonymous Coward]

Peter, Peter, Peter.. You have better things to do than post on Slashdot!

Re:NOT PayPal founder

[Anonymous Coward]

Don't we all...

It just occured to me...

[Anonymous Coward]

It just occured to me that the guys doing these space ships are like the rich guys a few centuries ago mounting ocean expeditions, as much for the exploration and adventure as for profit. We all complain about rich people, but many of them tend to be philanthropists and use their money for some kind of public good.

Re:It just occured to me...

[FleaPlus]

Yup.

In the wake of the dot-com days, we have a odd situation where we have a large number of very rich individuals who are also quite clueful and interested in technology. Many of them read lots of sci-fi books when they were kids, and are hoping to make a mark on the future by funding space endeavours.

"SpaceShipTwo" won't get off ground

[astebbin]

The linked article mentioned the "rebel billionaire" buying a new fleet of SpaceShipTwos for commercial trips to the upper stratosphere and back, which in my opinion is a prety foolish way for him to waste his accquired wealth. Unlike the Concords, which were also expensive and could actually transport you to useful places in small amounts of time, no celebrity or politicial figure would ever want to spend a couple thousand dollars just go up high in a potentially unsafe civilian spacecrat for the sole purpose of floating around in their seat and coming back down. There are easier and cheaper ways to obtain the thrills of floating in null-g that have been around for years, and not many people have expressed much interest in those, so why would anyone feel differently about the SpaceShipTwos? Don't get me wrong, I am excited about SpaceShipOne and the X-Prize (which it won), I just don't feel that this would be the correct application of the current technology.

I want to hear everyones' thoughts... please post comments!

Re:"SpaceShipTwo" won't get off ground

[Anonymous Coward]

Make a bazillion dollars and then I'll tell you how to spend it.

Re:"SpaceShipTwo" won't get off ground

[Kiryat Malachi]

no celebrity or politicial figure would ever want to spend a couple thousand dollars just go up high in a potentially unsafe civilian spacecrat for the sole purpose of floating around in their seat and coming back down

Dennis Tito. Mark Shuttleworth. Lance Bass (well, sort of.)

Evidence does not bear out your assertion.

Re:"SpaceShipTwo" won't get off ground

[astebbin]

Lance Bass fell into legal trouble with the Russians from whom he recieved expensive Cosmunaut training in preparation for a flight that *never happened*. Also, two or three customers is never enough to support a commercial enterprise that is doomed to failure, whether it be condemned by a shoddy product (ex. the N-Gage) or lack of public interest (ex. EQ II getting wiped by WoW, despite EQ II having better... never mind, I don't need to go off topic and get flamed to death :)

Re:"SpaceShipTwo" won't get off ground

[Kiryat Malachi]

That's why I added the "sort of" comment to the Lance Bass naming.

Let's also note that those two or three had to pay significantly more than "a couple of thousand".

Hell, look at skydiving. Lots of people pay a few hundred dollars in fees and equipment in order to ride a plane and then jump out of it. You think people wouldn't pay a few thousand to ride up to space?

Re:"SpaceShipTwo" won't get off ground

[hyperstation]

Unlike the Concords, which were also expensive and could actually transport you to useful places in small amounts of time, no celebrity or politicial figure would ever want to spend a couple thousand dollars just go up high in a potentially unsafe civilian spacecrat for the sole purpose of floating around in their seat and coming back down. There are easier and cheaper ways to obtain the thrills of floating in null-g that have been around for years, and not many people have expressed much interest in those, so why would anyone feel differently about the SpaceShipTwos?

you know, today i thought to myself, "why the fuck not", and actually RTFA. i'm glad i did, cuz i a) learned a few things, and b) realized that space may suddenly going to be very important once capitalism moves in, which it inevitably will do.

people pre 1903 (and just post) said things similar to what you wrote. i think there will be many failures, but over time (and if the time it's taken to develop electronics and computer technology and aviation to their current states of the art is any indicator, spacecraft and the technologies necessary to move and support masses of humans in space will be developed quickly.

call me romantic or whatever, but it's total destiny and very inevitable at this point.

and i am baked...

Re:"SpaceShipTwo" won't get off ground

[FleaPlus]

Unlike the Concords, which were also expensive and could actually transport you to useful places in small amounts of time, no celebrity or politicial figure would ever want to spend a couple thousand dollars just go up high in a potentially unsafe civilian spacecrat for the sole purpose of floating around in their seat and coming back down.

Every year, a great many people shell out upwards of $60,000 to be given an attempt to climb Mount Everest. Many of these don't make it all the way, and a large number actually end up losing their lives in the process. I think it's safe to say that a large number of the climbers go through an immense amount of misery. Despite this, there is a constant demand to climb the mountain.

Re:"SpaceShipTwo" won't get off ground

[fimbulvetr]

I would, in a heartbeat.

Think about it...

I know if I had a choice of ways I could die, I would always choose space over just about anything else.

Sure as hell beats getting hit by that drunk driver tomorrow night. I don't wanna die in no friggen car after coming home from some meaningless place. And I don't want to die in some jet some religous fuck decides to run into a building. I'm gonna die in space, dammit.

Re:"SpaceShipTwo" won't get off ground

[Dieppe]

I'm not certain that it's a waste of money for the "rebel billionaire"... but an investment.. in the future...

First off.. people will pay for the priviledge. People making more money than me, for sure, and maybe only people who get $10 million per movie... with an extra $200k sitting around. But they'll pay, and they'll into space, and they'll enjoy it.

Secondly... SpaceShipTwo.. far from being a dangerous rocket or space shuttle is... basically an airplane attached to another airplane. All fights are dangerous, from a you-never-know-what's-going-to-happen standpoint... but you're not going to blow up on the launchpad, and you're not going to run out of fuel on landing. Once they figure out that wierd shimmy... it'll be all good.

Thirdly.. imagine these wealthy people taking a flight from Palmdale... to Vegas... Who says they have to land back in the CA desert. Why not have a flight that just happens to end up in Vegas, or San Francisco, or Phoenix... Hey, an expensive one-way flight, but they get to end up somewhere else..

Fourthly... It's an airplane dammit. Not the Hindenburg!

Fifthly. Godwin's Law.

Re:"SpaceShipTwo" won't get off ground

[Anonymous Coward]

People don't pay "a couple of thousand" to fly first class across the globe. They pay between ten and twenty thousand. Spaceship Two could function as a kind of super concorde, transporting people anywhere on earth within a couple of hours.

Re:"SpaceShipTwo" won't get off ground

[Anonymous Coward]

Sixthly, ???
Seventhly.. Profit!

Re:"SpaceShipTwo" won't get off ground

[QuantumG]

Well obviously Richard Branson, multi-billionaire is completely unaware of the risk that he is taking and desperately needs your advice as soon as possible. I suggest you go into your local virgin megamart and tell everyone wearing a Virgin polo shirt this important news!

Re:"SpaceShipTwo" won't get off ground

[pavon]

Which is why over 10,000 people are already on the waiting list to pay $190,000 for a ride when it comes out. That is over $2 billion of potential revenue, and they expect the initial investment to be around less than $150 million. Unless they screw up and have a crash that scares everyone away, they are practically garenteed profit.

You are talking about a generation that grew up watching the first people to land on the moon and who were "promised" flying cars and space colonies were just around the corner, and now they are finally getting a chance for the first step into that future. Considering that people have spent $15 million dollars for a ride in the Soyuz, all the other ways celebrities throw away money, and how popular risking exotic "x-activities" are I am not surprised at all by the response.

Re:Karma Pit

[Caydel]

Wow.. no bitterness there...

Re:Karma Pit

[Anonymous Coward]

Yes, that's right. Send the PayPal to you@tw.it

Fires up?

[DarthWiggle]

"Paypal Founder's Merlin Rocket Engine Fires Up" ... shouldn't it be firing down? *rimshot!

Like eventually...

*ahem*

(NB, 'rimshot'!='rimjob')

Is that why pay pal emailed me?

[agent]

Is that why pay pal emailed me?
Yahoo filtered it as spam.
Good thing I check those messages as well.
Do not forget about the freenet.
http://freenet.sf.net
Peace.

So...

[Jozone]

So thats where my 1.9% + $0.30 go...

Musk Should Talk To Maryniak

[Baldrson]

Of his motivation Elon Musk says:

"I think it's very important that we become a spacefaring civilization, and that we eventually become multiplanetary."

Although I didn't want to encumber the story's synopsis with it, I really think Musk needs to discuss his vision of space migration with Gregg Maryniak who was the head of Space Studies Institute for sometime after Gerard O'Neill's death.

It was Gerard O'Neill who put forth the vision of space settlement after challenging his Princeton physics class with the question:

"Is a planetary surface the right place for an expanding technological civilization?"

His conclusion, backed up by much subsequent research, is that the answer is a resounding, "No!"

A better statement would by Musk would be:

"I think it's very important that we become a spacefaring civilization, and that we eventually become heliocentric."

Elon is not founder of PayPal

[Anonymous Coward]

I work at PayPal. Elon Musk is not the PayPal founder. He founded another company (X.com) that merged with PayPal. Ultimately, the PayPal product succeeded, and X.com was scrapped.

160 Seconds?

[Will_Malverson]

To get into orbit, you need at least 9000 m/s of deltaV, or about 15 g-minutes.

To do that in 160 seconds (2.67 minutes), you need an *average* acceleration of over 5.5g. You're also not going to get that at launch without a ridiculously overpowered engine that will crush your passengers at the end, when the ship has burned out all of its fuel and weighs a lot less. Most rocket engines aren't all that throttleable, with min thrust usually >.5 x max thrust.

For comparison, a Space Shuttle launch goes something like this:

(launch)~2g

(just before booster burnout)~3g

(just after booster burnout)less than 1g

(just before main engine burnout)~3g

The average acceleration is about 2g, meaning that the Shuttle takes around 8 minutes to go from ground to orbit.

5.5g? Average? I doubt it.

Re:160 Seconds?

[Anonymous Coward]

Its two stages though. The first stage Merlin runs for 160 seconds, then the second stage does the rest.

Re:160 Seconds?

[Anonymous Coward]

Nice maths but you have missed a couple of things:

* This engine is for the falcon 1 vehicle which is unmanned, the payload could take 5.5g

* The falcon 1 is a two stage vehicle, this means that the max g is going to be a lot less that 5.5

Re:160 Seconds?

[Kiryat Malachi]

First off, these engines are only part of a two-stage process, making your whole point wrong. Using them for two stages gives a total burn time of 320 seconds, yielding an average acceleration to LEO of more on the order of 3g, which is quite reasonable.

Second, even on a single stage rocket, an average acceleration of 5g is almost acceptable; witness certain NASA studies (about halfway down the page) which concluded that 5g for two minutes is sustainable for most all humans.

Re:160 Seconds?

[mj_1903]

5.5g for the Falcon I is fine as it only launches satellites. Have you seen the diagrams for the Falcon V though? It is a much larger rocket and has a much larger first stage that I can only assume holds more propellant.

Re:160 Seconds?

[Will_Malverson]

Original poster here...

I didn't realize it was a two-stage rocket. I should have R'd TFA more carefully.

While your passengers might be able to handle 5g+ for a couple of minutes, there would still be engineering problems. A single stage to orbit (SSTO) rocket runing LOX/Kerosene needs to be at least 12:1 fuel:(everything else). That means that at burnout, the acceleration will be as much as 13x what it was at launch, because the same engine is now pushing 1/13 as much weight. Most rocket engines are not very deeply throttleable; Minimum stable thrust is typically 50% or more of maximum thrust. Because of that, a single-engine rocket will be exerting easily 5x as much force on the passengers at burnout as it was at launch.

Of course, you can get around that by using multiple engines and shutting some of them off as you get lighter. However, that means you're hauling dead weight for part of the trip, never a good idea on an SSTO.

Anyway, I stand corrected on my initial point.

Re:160 Seconds?

[serutan]

When they say 160 seconds I wonder if they are talking about Specific Impulse? The definition of specific impulse has never been clear to me, but it has something to do with the amount of thrust you get per amount of fuel burned, and is expressed in seconds. For example, the space shuttle main engines have a specific impulse of about 450 seconds.

Re:160 Seconds?

[birdman17]

Specific impulse has always been a bit fuzzy to me too, and I do have some physics background. But I always think of VASIMR whenever someone mentions specific impulse. That's gotta be just about the coolest engine ever.

Obligatory Wikipedia links

[FleaPlus]

http://en.wikipedia.org/wiki/SpaceX
http://en.wikipedia.org/wiki/Falcon_I (their $6 million, 670 kg payload rocket, being launched in March)
http://en.wikipedia.org/wiki/Falcon_V (their $12 million, 6020 kg payload rocket, scheduled for a November launch)

Space Prize is fake!

[nrlightfoot]

I sent for a starter package on the America's Space Prize 2 months ago, and I never recieved a reply of any sort. I don't think it actually exists.

Re:Space Prize is fake!

[georgewilliamherbert]

I sent for a starter package on the America's Space Prize 2 months ago, and I never recieved a reply of any sort. I don't think it actually exists.

If you're serious, contact them again.

For their own reasons, they did early announcements before the whole rules and signup packages were ready.

However, as someone who contacted them before they even officially announced it, I can assure you that they are responding to potential competitors that they believe are credible, and they are in the process now of recontacting people and sending out the full official info packets.

I only had to make two phone calls on my side, and have received a number of responses over the last month-plus, including one yesterday.

Why SpaceX is a big deal

[FleaPlus]

First, read this article.

Right now, launch costs are the biggest barrier to having lots of cool things (orbital hotels, factories, lunar bases, etc.) zipping around in space. According to this interview, Musk was previously planning on self-funding a mission to put an experimental greenhouse on Mars, but decided to start SpaceX when he realized that the overall mission cost would be dominated by the launch price.

SpaceX's Falcon I is designed to compete with the Pegasus rocket, which currently dominates the "low-cost" launch market. The Pegasus costs around $20 million to launch 375kg into space. The Falcon I will cost $6 million to launch 670kg into space. Stated differently, the Pegasus costs around $53,000 per kg, while the Falcon I will cost around $9000 per kg.

Things change even more with SpaceX's larger Falcon V rocket, scheduled for a launch this November. This will compete directly with the Delta IV Medium, which costs $90 million to lift 8600kg to LEO. The Falcon V will cost $12 million to lift 6020kg to LEO. That's around $10000 per kg for the Delta IV Medium and around $2000 per kg for the Falcon V.

One of SpaceX's goals is to reuse as much in terms of engines, components, and software as they build larger and larger rocket. As they benefit from economies of scale and build larger rockets, the costs will only drop.

Re:Why SpaceX is a big deal

[FleaPlus]

If anyone's curious, here's a little more info on his old "Life to Mars" project:

MarsNow 1.9 Profile: Elon Musk, Life to Mars Foundation

Someone is putting his money where my mouth has been. Describing permanent settlement of Mars as "a positive, constructive, inspirational goal" capable of uniting humanity at a critical time," dot-com entrepreneur Elon Musk has pledged a substantial portion of his personal fortune to realizing that goal, beginning with a proposed $20 million technology-demonstration Mars lander to be launched perhaps in 2005. Calling his "victory condition" seeing NASA's top priority change to establishing a permanent human presence on Mars, he said in an interview last week that "the path by which I hope to get there is to get the public enthusiastic about the possibility, then translate that into legislative pressure so that Congress hands us a Mars mandate." Musk's plans are invigorating, finally matching for Mars the initiative and boldness recently displayed in Low Earth Orbit by Dennis Tito's flight and the recent MirCorp announcement of a private "MiniMir" orbiting facility. I hope his entrepreneurial directness will bring a new effectiveness to the Mars effort. I hope also that he can avoid being brought down by the Byzantine politics of space: on the Hill, in the scientific community and in the space movement.

NASA wants to know whether there ever was life on Mars. Musk - and I, and many more - want to know if there ever can be.

Musk's "Mars Oasis" project is a small robotic lander intended primarily as a mini-greenhouse, growing samples of food crops in an enclosed chamber filled with treated Martian regolith (soil), to test the feasibility of humans living off the land. Other experiments may include test units for the production of oxygen and rocket fuel from the Martian atmosphere, and radiation sensors. In a radical departure from the missions scheduled by NASA, each experiment would focus on developing data critical to human habitation, rather than on pure planetary science. While the project's centerpiece is essentially the project long advocated by NASA planetary scientist Chris McKay, Musk stated that he had only met McKay in passing and had not discussed the project with him. ...

His goal of moving Congress to declare a human presence on Mars to be a priority implies substantial legislative action, at the very least putting forward a legislative program to be advocated to Congress by citizen supporters.

Re:Why SpaceX is a big deal

[QuantumG]

Ya know the best way to get all these interesting things into space is to not lift them. Use lunar materials (bwahahaha, as if a Falcon V could get to the moon) or use asteroids (mehehehe, yep, cause going into a solar orbit and sending a few 100,000 tons back earth's way is really doable) or, (really this time I promise) use the vast amount of abandoned space junk that is already sitting up there in earth orbit. We know what it is made from. We know where it is. Why not cut it up and do something useful with it. Hmm, now I wonder if I could make a fully autonomous orbital scrapyard robot for under 670kg.. it could float around and cut up old launch tanks, weld em together and make me a space hotel (with hookers and blackjack), yeah.

So?

[RM6f9]

Who's up for building an induction catapult launcher?

Re:So?

[QuantumG]

Well actually I was looking into this today. Are you aware of any electro-magnetic propulsion system that has been shown to be capable of even putting 1kg into orbit? It's one thing to get a bunch of engineers together and make a rocket engine using technology that is 40 years old, it's another to sit down and design something that has never been done before. Personally I see think about the whole hitting-the-air-at-mach-8-at-sea-level and that's about the end of that plan. What's your idea?

Re:So?

[m50d]

Hell yeah. If you've got big enough capacitors or whatever you're planning to use, I'm there.

Re:So?

[sadomikeyism]

I am. I assume that you intend on building it at as high an altitude as possible, preferably on a mountainside somewhere?

Might I suggest a combination of scramjet and laser launcher for the second stage? I have a nice conceptual design.

Re:So?

[RM6f9]

I didn't say it had been built, or even designed on paper - to be honest, I was attempting to redirect those who were complaining about these companies using "40-year-old technology". Verne thought we'd be going to the moon by way of cannon. Heinlein made popular the idea of magnetic catapult ("The Moon is a Harsh Mistress"), though to be fair, he described it solved from Luna to Earth first.
I don't happen to have the fund$ it would take to build/test a launch rail, and going up would definitely be the easier portion of the up-and-down problem to solve, but I *would* be interested in seeing a meaningful collation of investigations done into the *possibilities* surrounding it. Any mathematicians wanna jump in and describe the length necessary for a launch rail providing 3.5-4g acceleration long enough to assure high orbit or better? If multi-ton bullet trains can run at 200+mph, the rest of the problem is magnitude and release mechanism..
Rambling, maybe, but where would *you* start?

Re:So?

[QuantumG]

Well honestly I'd start with completely different technology. Rail guns have been made by thousands of college students but none of them have reported the construction of even a remotely large enough unit. Personally I think that technology is awaiting some breakthrough that hasn't happened as yet (room temperature semiconductors maybe).

Have you heard of Lifters? Basically you take an asymetric capacitor, put a shitload of DC power through it and you get lift. The biggest lifter I have seen was 250g (60g of that was payload) and required 257W of power to lift. None of that 250g was power supply, and obviously you couldn't fit such a high power supply into it. The only way to get power to it is via microwave or optic power transmission. Microwave is the more mature technology and it's also cheaper. So adding a rectanna to a lifter would be an interesting design for a launch vehicle. Back in 1975 it was demonstrated that 30 kW can be transmitted over a mile. If we could transmit over 60 miles that would be better, and I'm sure with correct experimentation we could do it. That's 60 miles of continuous accelleration. That'd put your lifter outside the atmosphere moving at a pretty damn high speed.. orbital velocity? maybe.

Re:So?

[RM6f9]

Rail guns at scale would be interesting - what would it take to propel a 5Kg mass from surface to extra-orbital, maybe with a transponder package for data feeds wrapped in an impact-resistant hull... Though I wonder how to protect the egg from the mega-gauss fields launching it...

Room-temperature super-conductors?

Do you have any links for these lifters? How would signal attentuation rate be dealt with in terms of acceleration control? What would one use for any *lateral* accelerations needed? (problem applies to both models)

Re:So?

[QuantumG]

The Lifters Experiments home page. It's well known technology but I'm not aware of anyone who has used microwave power transmission to power them. Presumably you could put tilt control electronics on the lifter which would vary the voltage to the four quadrants so it stays flat. From what I've read of rail guns at scale the track actually bends and is damaged by the high power throughput. It's an interesting idea but I think that whole mach-8-at-sea-level thing is the killer.

What if you used simple physics instead...

[Nefarious Wheel]

...basically build the elevator on the ground, make it long enough (say, would 500 miles long do it? 1000? I'm thinking in terms of Pak Protector scale projects here) -- presupposing you could get that much land to lay it out, etc. could you just anchor one end, weight the other, shorten the cable and let the change in the moment of intertia fling the sucker up?

Re:What if you used simple physics instead...

[JQuick]

Building from the ground up would not work. It would need to be supported by compressive forces.

A space elevator would be a bundle of cables (or ribbons) built from an artificial satellite, lowered into the atmosphere, captured, and then anchored to structures on the ground. Actually to provide balance, the orbital structure needs to be in geosynchronous and as building proceeds on the tether which grows toward the ground, additional mass needs to grow outward into higher orbit to balance it. The tensile strength of the material must be enormous, and though cables grown from carbon nanotube are theoretically capable of use for this purpose are far beyond current capabilities.

Basically once the first filaments is in place, capable of supporting itself against the stress of both gravity and atmospheric buffeting, light robots would travel up and down repeatedly for years, adding more strands until the cable could support useful payloads.

Thus, power, huge amounts of mass, and a lot of space infrastructure needs to be in place before the elevator could be built. Once operational, however, it would be by far the most effective way of getting to and from space.

Using only compressive forces, e.g. building a tall skinny tower is not possible. Even carbon nanotubes would collapse under their own weight before reaching only a small fraction of the required height. Worse, even given an infinitely rigid structural material they would crush the foundation on which they rested (basically punching through the crust).

Re:What if you used simple physics instead...

[CrimsonAvenger]

..basically build the elevator on the ground, make it long enough (say, would 500 miles long do it? 1000?

30,000 miles. That's a good starting guesstimate. You might be able to do it in 25,000, you might not - depends on how large the mass that you use as a tensioner at the upper end is. It can't be less than (longer than geosynchronous orbit) though, which puts the absolute minimum over 22,000 miles.

Re:What if you used simple physics instead...

[merlin_jim]

(say, would 500 miles long do it? 1000? I'm thinking in terms of Pak Protector scale projects here)

It's called a space elevator, and they're working on it.

There's no known material with a compression strength that could go the distance... which by the way is most likely to be significantly longer than GEO. But there are several candidate materials with tensile strengths up to the job, which is a good thing if you think about tides (in this case, more inertial than gravitational) for a minute...

The point is, you make a ribbon, you put it's center of gravity at Geosynchronous earth orbit, and you make sure one end is just barely long enough to touch down. Then you (presumably) anchor that end, and build giant elevator cars that can climb the ribbon material, and power beaming stations to drive them, and ticket booths and friendly receptions and... well you get the idea. Point being that the ribbon is balanced by equal masses on both sides of GEO (22,000 miles)...

A couple quick observations and I'll finish this post hahaha. First off, the two ends of the cable are pulling outwards due to tidal forces. What that means is that the point of highest tension is the center of gravity. Most materials, this means that you need to make this part thicker than everything else.

I once read that in order for a steel cable to support its own tension over that distance, you have to gradually widen it as you move inward from the ends. And as a result, you have to widen it faster as you move inwards, because each section is adding more weight than the section previous. I read that the diameter of the cable in the middle would be LARGER than the length of the cable.

And more steel than exists in the solar system.

The great part of all this? Run it like an elevator; descending passengers from GEO create electricity to power ascending passengers. Which makes a great argument for a space mining industry, if only to provide ballast! If you want to do a deep space launch, move to the other side of GEO, put a ring or other stabilizing element around the ribbon, and just wait for the proper time and let go. And if you don't need all that speed, then you pay for part of your ascent with the other part of your ascent!

Re:What if you used simple physics instead...

[Nefarious Wheel]

I meant a tension lift, not a compressive lift ... think Tibetan prayer drum, spinning between hands, the little clapper swinging up as the drum begins to spin... a change in the moment arm of a sufficiently long weighted cable stretched out across the equator should lift the end of the cable into orbit without compressive structures or direct thrust to orbit.

Re:What if you used simple physics instead...

[Nefarious Wheel]

You could start the thing out as a very large kite to get the initial velocity going. By the time it reached the outer atmosphere shortening the cable could do the rest. Perhaps a deep ocean current could act as the source of energy for shortening the cable.

Re:What if you used simple physics instead...

[WhiplashII]

Weirdly enough this is not true - you can build a compressive structure to Geo! It would be insanely expensive, but two things make it possible.

1. Using tension strength as compressive strength - you essentially use "balloons" sitting on top of each other, giving you a compressive strength equal to 1/2 tensile strength.

2. The taper works much better with a tower - most of the structure is at very near zero G, and so only needs to support the very thin low G structure above it. Conversely, a tension structure has to be thickest at the top.

To really understand the impact of #2, a compressive structure will have a HUGE base, but 500 km up will be a thin spike going the rest of the 30,000 km. A tension structure will be a thin thread for the first 500 km, and a thick structure for the rest of the 30,000 km.

Weird yes, but a compressive structure may be easier!

Re:What if you used simple physics instead...

[merlin_jim]

a change in the moment arm of a sufficiently long weighted cable

That would work if the earth was flat. Which it isn't.

And the cable is WAY too long to put any leverage on it. Do the physics; no matter how you do it, you've still gotta put enough energy into the system to hoist the center of gravity up to GEO...

Oh and why does it matter if the earth is flat?

GEO = 22,282 miles above the equator

Circumference at the equator = 24,901 miles

If you laid it flat it would encircle the globe at least once. And if you don't have a huge counterweight on it, it'll be goin around twice.

Re:What if you used simple physics instead...

[Nefarious Wheel]

I'm not comfortable that the question is closed yet. Would slowing down the Earth's rotation a nanosecond or two provide enough energy? Could ocean currents provide the necessary energy for launch?

What if you could control the effective length of the cable so you could launch it with a shorter length, then unreel it to geostationary orbit after escape velocity is reached? What if the cable was built in two pieces, one on the ground and a spinning section dropping down from orbit?

Maybe I should go back to fly fishing and flying my kite, but I can't help thinking that when our descendants use their elevators they'll know that the ultimate solution was something clean and elegant, if colossal.

Interview with Elon Musk about SpaceX

[FleaPlus]

I've mentioned it elsewhere in this discussion, but a couple years ago HobbySpace's RLV News had a very good interview with Elon Musk.

Here's a quote:

HS: Private rocket development by startup companies in the post-Apollo era includes projects such as Truax's Volksrocket in the late 70s, Conestoga I and AMROC in the 80s, Beal Aerospace and several other ELV and RLV companies in the 1990s. They all came up short of space and many see their history as nothing but a tale of woe and failure. To me, though, they each appear to build on what was learned before them and to provide significant advancements in the technical and strategic knowledge needed to develop a rocket business from scratch.

It looks like SpaceX will be the startup company that finally makes it to orbit. When you studied prior efforts, what were some of the lessons [you] learned on what to do and, perhaps most importantly, what not to do?

Musk: Well, I have tried to learn as much as possible from prior attempts. If nothing else, we are committed to failing in a new way :)

The ones I'm familiar with failed on one or more of the following:

1. Lacked a critical mass of technical skill.
2. Insufficient capital to reach the finish line, particularly if an unexpected setback occurred.
3. Success was reliant on a series of technology breakthroughs that did not happen.

The above modes can obviously cross-feed one another.

HS: John Carmack has said something to the effect that the gap between what could be done versus what is being done is bigger in aerospace than in any other industry. Gary Hudson said that he was "amazed by how much easier the job of getting to orbit is today than even a few years go"..."Software, avionics and manufacturing technology have all improved measurably" and drastically reduced the number of people needed to design a launcher.

Now that you've gone through the rocket vehicle design phase and are well into construction, does your experience support their views or has the Falcon development perhaps been more difficult than you initially expected?

Musk: Well, hard and easy are somewhat nebulous terms. I think I have high standards and would classify getting Falcon to orbit as quite difficult. Overall though, I think we have had quite a smooth development so far, which is a credit to the hard work of the SpaceX engineering team.

The design tools, such as solid modeling and finite element analysis software are substantially more powerful than ten years ago, so that's a clear advantage. Obviously, most electronics have improved a lot too, except gyroscopes and flight termination systems.

Big Price tags

[Mulletproof]

1.5 billion? So I guess there was no "buy it now" option, huh?

Spending the Good Spend

[handy_vandal]

If I had the type of money these guys have, there's no way I'd waste it on something as risky and untested as private space travel.

I know what you mean -- if I had that kind of loot, I'd spend it on hookers and Chivas Regal. And a plasma TV set, wall-to-wall. And my own private submarine.

-kgj

Space Flight: the new millionaire hobby

[Cainjustcain]

Richard Branson, Jeff Bezos, Paul Allen, John Carmack, and now this PayPal dude... Is there any super rich person who doesn't have his own pet space project going on somewhere?

Re:Space Flight: the new millionaire hobby

[Yanray]

They all have to beat out Howard Hughes.....

I want to see a space ship built out of spruce. It only has to fly once...

Obviously

[Anonymous Coward]

Well, he's too stupid to realize religious people can be smart too, why think he would have any ability to chain logical thought together regarding water and weight?

That's just the kind of guy that really turned me off Kerry. Superior but ignorant.

No Crew Vehicle at Present?

[iamlucky13]

I scanned through the Spacex website and didn't see any mention of a crew vehicle or their plans of putting 5 people into orbit by 2010. While I'm sure they are somewhat serious about this plan, and there is probably a news update or two that I missed, it definitely appears that Spacex is (sensibly) focusing much more heavily on making their rockets a commercially viable lift vehicle.

I have seen no discussion at all of a crew vehicle, so it seems logical to assume that they have not addressed that detail yet. There is still a lot of work to be done, then.

Re:No Crew Vehicle at Present?

[m50d]

The Falcons - and I'm pretty sure that's both of them - have been man-rated from the ground up.

Re:No Crew Vehicle at Present?

[iamlucky13]

Good to hear. So they are taking this goal realistically.

After I posted my first comment, I found out that their first customer for their Falcon 5 launch vehicle is none other than Bigelow Aerospace, with one of their inflatable spacehab modules. Way cool.

I think I can tell you why.

[StarKruzr]

Just looking at your post history, you have a "-1, Interesting" which caught my eye. Turns out you were spamming your (closed-source, paid) software on Slashdot. The editors probably don't like that very much.

I'm certainly not condoning their action, but it would help explain the bitchslap.

Blah blah

[Anonymous Coward]

Paypal sucks!

Re:Low Environmental Impact unless it goes splat

[Rubyflame]

Nope. If it's 30 meters thick, yes, but if it's one centimeter thick, it will just burn up in the atmosphere.

Merlin Engine?

[slashnik]

How can this guy call this a Merlin Engine.
Doesn't Rolls Royce have the trademark on this?

Is this an animated story, or live-action?

[Fantastic Lad]

Is it just me or does this article read a lot like the kind of plot excuse a hack sci-fi writer might come up with to populate and propel a story? "Genius industrialist founds well known public company, sells it off and uses proceeds to build a giant space-based laser, time machine, moon colony or other such cheesy crap from the seventies."

"What's going on!? Talk to me, lieutenant!"

"Sir! A signal is coming through now, Sir!"

[All the staff at Earth-Command look up at the giant monitor. The towering image of a bald-headed man fills the screen. It is LEX LUTHOR.]

"Greetings, General. . . By now your instruments will have. . .", etc. etc.

This reality is becoming increasingly more like a weird fever dream with each passing week.

Funny part is that I think it was always like this, but the veils were pulled down tighter than they currently are.

I'm going to sleep now. Wake me up if it starts to rain. Space rocks.

-FL

Re:Is this an animated story, or live-action?

[sail4evr]

Fortunately social misfits don't have the diverse skills required to manage a successfull space venture.
However replace rich industrialist with rogue nation such as N Korea...

Frankenstein

[mrshowtime]

I know I sound like the ultimate troll, but this guy's rocket "empire" was built via paypal's "dirty" years, when paypal froze (i.e. stole money) accounts for no reason to make it seem like they had more money on hand to lure poetential investors. Also don't forget the money laundering and federal investigations which Ebay had to buy themselves out of. Paypal ruined a lot of honest people's lives during the time period when this guy was in charge.

Falcon I

[dpilot]

Sor according to the AWST article, Falcon I was supposed to have flown several times last year. The top-level subject is the engine test for Falcon V. Once I thought I read that both launchers used the same base components, just that the V had more engines and bigger tanks, etc.

Has SpaceX flown anything?

Re:Falcon I

[FleaPlus]

They were planning on flying last year, but problems with getting the engine working properly prevented that from happening. Hopefully this latest news means those problems have been resolved.

The engine which was tested will be used on both the Falcon I and Falcon V.

Re:Falcon I

[cheesybagel]

This is the more complex first stage engine, which uses a turbopump. They had some problems with it, but I guess they fixed them. The second stage engine is simpler and pressure fed. They did not find any major problems with it.

Whenever doing something new there is an element of uncertainty attached. Elon said before that teething problems could happen, but that there was enough funding to cover them. Even with the delays, this project has developed a launch vehicle in record time, just a couple of years, on a tiny budget. Often in the old days it took 10 years just to design and prototype an engine.

Boeing or Lockmart

[dpilot]

You've all missed the real problem with Boeing and Lockmart. It's the nature of government contracts, and has NOTHING to do with NASA.

Government buys launches on a cost-plus basis. They pay the cost of the launch, and grant the "plus" so that Boeing and Lockmart get to make some sort of profit.

There's absolutely NO incentive to reduce launch cost. In fact, there's every incentive to keep launch costs as high as possible, because that maximizes the flow of dollars in.

Another way to reduce launch costs would be to adopt a different cost/profit structure. Adopt a launch-cost curve, to be fixed for some number of years, and pay that cost. That curve starts at today's cost, and then declines at some rate. Companies that can launch cheaper, make more money. At the end of X years, negotiate a new declining launch-cost curve.

Re:Boeing or Lockmart

[WhiplashII]

It's even worse than this - all rocket development is done as a funded research project. Research projects that choose the easiest way to do something do not get funded! Research into hard things gets funded - so given the choice between making an existing rocket engine more reliable (easy) and making an existing rocket engine 0.0001% more efficient (hard), they choose efficiency.

By the way, the theoretical maximum efficiency of the space shuttle's engines is about 2% less than the actual - they obviously spent too much time on those engines...

Re:Boeing or Lockmart

[dpilot]

>the theoretical maximum efficiency of the space shuttle's engines is about 2% less than the actual

Don't you mean that the other way around, that they're just 2% under the maximum theoretical efficiency? Or are they overachieving theory?

But you know, as far as that goes, if someone has worked WAY too much on those engines, shouldn't we be doing more with them? Shouldn't we be using them, or a cost-reduced version everywhere we can, if they're THAT good?

Re:Boeing or Lockmart

[WhiplashII]

No, I said it right - they beat the theoretical maximum. (Of course, that just means that the theory doesn't account for everything, but even so no other engine has ever come close to that!)

The real problem is that in order to do that, they made an engine that really is not reusable. The engine has to be completely ripped down and refurbished between flights - thats why everything costs so much. The engine also is started via a magic process with hundreds of steps - so in orbit restart (or restart without hours of prep for that matter) are impossible.

The opposite is true of most of its predesesors. The RL-10 can be restarted as many times as necessary, and can run for hours with multiple restarts with no maintainence. (The X10 never had to do maintainence on its engines during the whole life of the program!)

Everyone now tries to make a shuttle engine copy - and they normally end up exploding (see Japan's J4 (I think)). Simple is good, people!

ah! That's why ebays fees just doubled

[Blitzenn]

That explains why ebay just doubled all of it's fees. The had to pay for their rockets! Perhaps if they bought them off ebay instead...

Don't sass the spaceman

[PeanutGallery]

I wondered how long it would take somebody to say that!

...Almost as much as I wondered how log it would take to comment on the unfortunate grammar: "According to Musk, 5 Merlins bundled with the first stage of SpaceEx's powerful Falcon V booster will launch 5 people to orbit by 2010"

I would've hoped for "a spacecraft containing 5 people", but sometimes you just get these thrillseekers...

*Foom* Aiiiiiieeeeeeeee...

John Walker

[Baldrson]

John Walker doesn't have one (to the best of my knowledge). Maybe he got conned by Jack Sarfatti? It certainly is an interesting coincidence that the date of Walker's essay on UFO's mentioning Sarfatti is a few months after Walker had started considering support of a rocket engine developed by Roger Gregory and I.

...and get defrauded

[Sagarian]

...by someone using a stolen credit card via Paypal.

Specific Impulse

[Will_Malverson]

Basically, specific impulse (Written Isp) answers the question:

If I ran this engine with the throttle set so that it was generating one pound of thrust, how long would one pound of fuel last?

It only works in the USA, because the metric system doesn't use the same units for force and mass. GO USA!

Interestingly, Isp is always equal to (exhaust velocity) / (force of gravity). So, if the SSME gets a specific impulse of 450 seconds, then the exhaust velocity is (450sec * 32 f/s^2), or around 14,400 feet per second. For the rest of the world, that's (450sec * 9.8 m/s^2), or around 4400 m/s.

Because of conservation of momentum, the faster you shoot stuff out the back, the less stuff you have to shoot out in order to generate the same thrust, so the Isp gets higher. However, the faster you want to shoot each kilogram you shoot out, the more energy per kilogram you need. The most energetic chemical reactions top out with enough energy to get themselves moving at around 5500 m/s, but that involves nasty stuff like Lithium or Flourine. You can also get really exotic by using things like monatomic Hydrogen, which when it combines with other H atoms gives off enough energy to result in a theoretical Isp of around 1600s (!). The problem of keeping individual Hydrogen atoms from combining until they reach the combustion chamber is left as an exercise for the reader.

The Redneck Side Of Me...

[johnshirley]

...really, really wants to mount a smaller one of these on my truck. Tailgaters would never be a problem again. Brakes, on the other hand, would probably need to be replaced daily.