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Glenn Urges Direct-to-Mars Trip
Geno Z Heinlein writes "Reuters reports that astronaut John Glenn testified March 4 before the President's Commission on Moon, Mars and Beyond, saying that Bush's plan 'pulls the rug out from under our scientists' and that 'It just seems to me the direct-to-Mars [route] is the way to go.' Referring to the Moon as an 'enormously complex' Cape Canaveral, Glenn said that NASA might spend all the money getting to the Moon and never get to Mars."
The ISS budget is not 2.5 million, but 2.5 BILLION! Plus there is an additional ~3 BILLION that is spent on shuttle launches that service ISS. He of all people should know that...
Isn't it obvious why $800billion of stuff sitting on the moon is better than $800billion of stuff sitting on Mars?
No, it's not. Military-related paranoia aside, the potential for long-term residency is far better on Mars because of the higher gravity and existing atmosphere--even if it's not breathable, it still provides some protection from solar radiation.
Wasn't John Glenn one of the Keating 5 ? ...
(savings & loan scandal)
Talk about the WRONG stuff
From His NASA Bio Page
He attended Muskingum College in New Concord and received a Bachelor of Science degree in Engineering.....
When astronauts were given special assignments to ensure pilot input into the design and development of spacecraft, Glenn specialized in cockpit layout and control functioning, including some of the early designs for the Apollo Project.
Great ideas often receive violent opposition from mediocre minds. - Albert Einstein
Just like Antarctica you cannot own the moon.
And just like Antarctica you can have a base there and thereby stop others from having a base on top of yours. Just like the US base on the very south pole itself.
And there is one particularly strategically important point on the moon. I wrote about it in detail on an earlier thread and got it modded to zero so I am not wasting more time on it. Look for it.
You missed a big physics fact. The orbit that the ISS sits in is totally wrong for launching anything. Originally the orbit was to be just off the equator, but in order for the Russians to help and launch from the Cosmodrome in Khazakstan, the orbit was changed to 51 degrees. That meant a change in the mission of the ISS from a "jumping off point to outer space" to an international scientific outpost. Here's a NASA quote: "NASA spokesperson Phil West says the ISS' inclination of 51 degrees was chosen as a compromise to accommodate all of the international partners who will be launching from different latitudes. For example, Russia's launch site in Kazakhstan is further north than the Florida site, making lower inclinations difficult to achieve."
ISS History article
Space Station History
Here's a page that describes the international treaty covering Antarctica:s /Internationa l/ATCM.msa
http://www.antarcticanz.govt.nz/Page
Here's part of it:
" The key elements of the treaty are:
1. Antarctica is to be used for peaceful purposes only. All military activities are banned, although military personnel can be used to support scientific programmes in such things as transportation of people, and equipment to Antarctica
2. There is freedom of scientific investigations and discoveries. Scientific plans, information and staff are regularly exchanged. This scientific cooperation has been genuinely successful among the treaty nations. The Cape Roberts Drilling Project is an example of successful collaborative scientific work.
3. All political claims for territory are frozen for the duration of the treaty and no new claims or enlargements can be made
4. Nuclear explosions or dumping of nuclear waste in Antarctica is banned
5. All stations/bases and equipment are open to inspection be observers appointed by Antarctic Treaty nations."
In "The Case for Mars". Moon bases and space stations increase cost and complicate missions and crucially will push back the date by which we get there. Direct to Mars is clearly the best approach but who is going to convince Nasa? Or Bush?!
I don't read your sig, why do you read mine?
I think the "useful source of material resources" is kind of key. Using a space station for interplanetary vehicle construction means that the vehicle, the station, the scaffolding, the blast shield in csae the fuel goes up, etc. all have to be hauled up from Earth, at huge cost.
With a moonbase, you have space, a stable framework, and ample supplies aluminium silicate dirt, from which you might be able to refine something useful. Even if you can't, you can pile it up to provide bracing, shielding and the like.
If you just want to dock three or four pieces of Mars mission together you might as well just do it, in LEO with no station. If you really want to start building, you want to be somewhere with some ground to lean on.
Of course if Earth->orbit costs come down by a couple of orders of magnitude, for instance with an elevator, then it's a different game entirely, but I think we're probably 20-30 years away from that, if we're lucky.
I remember, a few years ago (5?) that the various Mars programs being fronted by the U.S. government were in direct opposition to the way Zubrin and his Mars Society were proposing we do it - with the "Mars Direct Program".
... and thats good news.
Now, it seems that there are a significant number of Washington players who are getting behind the scientific thinking that Zubrin's program has produced for us
When I think about where we are currently at, evaluating the Mars situation, and where we've come as a result of an independent organization, it warms my heart. The Mars Society have done a lot to get humans thinking about going to Mars properly, and finally it seems like their momentum is having a great effect.
; -- the corruption of government starts with its secrets. a truly free people keep no secrets. --
There is a UN treaty banning the militarization of space. I'm pretty sure the US signed on as well.
Support the First Amendment. Read at -1
Um, John Glenn never went to the moon. His only flights were on Friendship 7 (as part of the Mercury program) and on STS-95.
blog |
The Apollo spacecraft made the trip there in three days. Six days is a round trip.
A NYC lawyer blogs. http://www.chuangblog.com/
now...Kyoto...well, that's a different story. Its all hypocracy anyway. The plane flights to Egypt do terrible damage to the atmosphere. Maybe they should meet online instead, so they can be taken seriously. The promoters of it care for nothing other than widening the trade deficits in the US, bleeding us dry until we collapse. All about jealousy.
History. Awareness. They are your friends.
I can see you aren't an astrophysicist. The dark side of the moon is called that because it faces away from the Earth, not from the Sun. It gets the same semi-lunar worth of daytime as the near side.
Doing some sums (and wouldn't it be nice if someone checked them - don't trust me to remember where the decimal point goes...):
1 kg of iron going at 2/3 * c has 2E16J of kinetic energy (about 4.8 megatons of TNT) and will take approx 2s (1.925s by my calculation) to cover the distance from the Moon to Earth. Most 'battlefield' nuclear weapons are about 25 kilotons, so you'd probably only need a mass of about 0.5g (plus whatever you expect to burn up in the atmosphere) to enable a very, very capable artillery battery.
Nuclear reactor + big-ass capacitors + -155 deg C in the shade = superconducting electromagnetic projectile launcher capable of taking out cities. 4-minute warning?! Bwahahahahaha!
One of the penalties for refusing to participate in politics is that you end up being governed by your inferiors - Plato
2 seconds? Dude, the lightspeed delay between earth and the moon is just over 1 second. How the heck are you going to launch a projectile at 50% of c?
At this point, the military believes they can build an EM-cannon that will (in a vacum) give a muzzle velocity of about 2 miles (3.2km) per second. Not counting accelaration, that's 34 hours.
I'll leave it to someone else more motivated than I to calculate the velocity added by the rock 'falling' to the earth.
I'm not crazy,I'm actively irresponsible.
Quick note about silly consitutional matters : The president cannot "fund" anything. The US Constitution expressly gives that power (funding) to Congress alone. Given that, perhaps you should write your congress-critter and ask them to fund any space ambitions.
Of course the president could divert existing funds to a space program, but such a plan as this would require more funding that could easily be diverted.
Finally, many think such a program will not be funded, and normally I would concur, but China is now looking at a similar program and this, from a government standpoint, is the greatest motivation. Too bad that kind of motivation leads to flag and footprint missions....
Dean G.
OK,
. ......6.0.........4.5
I keep hearing this idea of using the moon as a refueling station. If you haven't looked at the numbers, t seems like a good idea. However, a quick look at the actual orbital mechanics shows that the Moon is a big waste of time. Here's the breakdown for ow much Delta V is needed to get to the Moon and Mars:
Moon.........Mars
LEO to Moon/Mars..3.2.........4.0
Orbital Insertion.......0.9.........0.1
Orbit to Surface.......1.9.........0.4
Total.............
Yes, it actually takes LESS fuel to get to Mars primarily because it has an atmosphere you can use to aerobrake. The Moon has no atmosphere and so you have to carry fuel to bleed off your transorbital speed. Furthermore, Landing on Mars is assited by being able to use the aerobrake to bleed off speed on the way down unlike the Moon. Those figures even assume that you don't use a parachute and rely upon retrorockets to come to a stop.
OK, what about the idea of the Lunar refuelling station? You now lose the 1.9km/s of energy you need to get back off the lunar surface. (you still pay for it but the refuelling barge now pays that cost) The problem is that the cost of getting to the Moon and in and out of Lunar orbit is as expensive as getting to Mars to begin with. Sure, you now havea refuelled ship that can go to Mars from lunar orbit which is cheap BUT you just spent as much fuel getting to the Moon as it would have taken to go to Mars without stopping!
To use an analogy, I want to drive to New York from Seattle. Now, would it a be a good idea to send a bunch of my friends out to Washington DC to build a gas station for me so that I can drive there, gas up and then drive up to New York? NO! The only way it would make sense is if we were building a spaceship in lunar orbit which is simply insane - we can't even do that in LEO right now. Hell, we have enough trouble doing it on the ground right now.
Furthermore, as the other respondant mentioned, you can't make fuel on the Moon. All rockets that aren't ion drives (which have no need to refuel at the Moon anyways) need an oxidizer and fuel. There's plenty of O2 on the moon in the form of metal oxides. The Moon's something like 70% oxygen. There's plenty of metal and O2 if we want to expend the energy to get it. However, O2 is the oxidizer - we still need the fuel. All our fuels use (to my knowledge) carbon, nitrogen or hydrogen. That includes everything from gasoline and candle wax to hydrazine and liquid H2. The moon has no large supplies of H2, C or N. You'll have to haul all of those in anyways. It really makes no sense to refuel there.
There's plenty of good reasons to go to the Moon, refuelling on the way to Mars is NOT one of them.
It doesn't even make much sense to build the thing in orbit. Especially not for the first few exploratory missions. Orbital construction costs are still exorbitantly expensive. In a few decades, when it's significantly cheaper, it might make sense. But it doesn't right now.
In his book The Case For Mars, Dr. Robert Zubrin explains his plan for Mars exploration, called Mars Direct. Zubrin does a much better job of explaining it than I could, so I'll just say this: he figures that getting to Mars is doable with a low-earth-orbit mass of 70-100 tons. This is in the same range as the Saturn V's heavy lift capabilities, so it's achievable using common rocketry knowledge.
Y'know, you blow up one sun and suddenly everyone expects you to walk on water.
Of coarse the length of a space elevator depends on two things. The mass of the planet it's orbiting, and the rotational period of that planet. The moon has 1/5 the gravity of the earth, but it has a rotational period 30 times as long. So an elevator on the moon may not be that feasible.
I found a link in First Science, The Audacious Space Elevator
Later, Jerome Pearson thought about building a tower on the Moon. He determined that the center of gravity needed to be at the L1 or L2 Lagrangian points, which are special stable points that exist about any two orbiting bodies where the gravitational forces are balanced. The cable would have to be 291,901 kilometers long for the L1 point and 525,724 kilometers long for the L2 point. Compared to the 351,000 kilometers from the Earth to the Moon, that's a long cable, and the material would have to be gathered and manufactured on the Moon.
I highly suggest starting with wikipedia's information on propulsion. It should give you enough knowledge to plug into Google. After that, visit my topic on the Nuclear Space message board to find out why heavy lifters aren't a big deal.
I started with the, "we can barely get to LEO" idea as well. Turns out we can put as much tonnage into LEO as we want. Once LEO is achieved, that acts as the staging point for more advanced engine designs.
I've heard of bomb-rates in the 60/sec, which clearly doesn't square with the descriptions of intermittent back-slamming in Lucifer's Hammer, but even a good strong 60Hz buzz in the butt would get tiring, fast. (How well can it really be absorbed?)
If you're referring to "Footfall", I haven't had the chance to read it. You would not be getting a 60hz buzz however. You have to remember that the pusher plate moves so that the acceleration to the rest of the craft is gradual. Thus you'd feel just a constant push. M2P2 Orions would be similar. The M2P2 field "gives" a bit, and basically would accelerate the craft as if it were inside a water balloon.
Javascript + Nintendo DSi = DSiCade
The Reagan administration's massive increases in military spending had no impact on Soviet spending at all. They tied their military budget growth rate to their GDP growth. When economic growth slowed, so did military spending increases.
It is cowardly, and a betrayal of whatever it means to be a Jew, to act as a white man
-James Baldwin
The president cannot "fund" anything. The US Constitution expressly gives that power (funding) to Congress alone. Given that, perhaps you should write your congress-critter...
Indeed, I should. So should we all. In addition, I believe the president should ask the congress-critters to fund it. They will, one hopes, pay more attention to what he says than to what I say.
Plus, he has ready-made opportunities to do this. As I suspect you know, the U.S. budget process begins each year with the executive submitting his budget proposals to congress, where the respective budget committees debate them, negotiate them into bills, pass the bills through the houses, reconcile them into one, submit it to the executive, and then hope he doesn't veto it. (Somewhat oversimplified, but close enough for the moment.) In many respects, the budget is a congressional bill like any other -- i.e., it has the usual executive involvement. All of which leads to this: the executive "funds" something by proposing funding for it to congress. To announce a space initiative and then not to propose adequate funding is something of a hollow gesture.
Of course, the power to lay and collect taxes resides in congress (Art. I, Sec. 8) and such bills begin in the House of Representatives (Art. I, Sec. 7). However, the budget isn't a tax bill, and even tax bills require the usual executive interaction: signature, veto, or override. So they're not all that different.
"We reject as false the choice between our safety and our ideals." --The American President (20.1.2009)
The formula for escape velocity is Ev = sqrt((2*G*m)/r). Given the moon's mass and radius, we have to be certain your hypothetical rail gun has enough oomph to even achieve escape velocity.
In MKS, G is 6.67e-11 m^3/kg-s^2, the mass of the moon is 7.349e22 kg and the radius is 1.736e6 m. Plug and chug gives us about 2.4 km/sec from the moon's surface. So, it would be feasible as long as the direction of launch is within about 41 degrees of zenith (acos(theta) = (V/Ev)).
The problem of accurately striking the earth remains a three-body problem, though it's easier to approximate since the projectile mass is insignificant next to the mass of the earth and moon. There is no neat numerical answer to flight time, since there are a variety of paths that could be used to reach the earth, in addition to some trajectories that would never get you to earth. You could also put things into lunar orbit, earth orbit, or leave the earth-moon system entirely. The escape velocity of earth at the moon's perigee is about 1.4 km/s.
So, no matter how motivated one could be, the correct answer to your problem is "not enough information to answer".
Just to put the kinetic strike weapon concept to bed for now, accurate strikes would be a difficult problem to solve at best, especially since there's no mid-course correction available. Vagaries of the system's gravitation, perturbation by other celestial bodies, and atmospheric contact would all work together to increase the uncertainty of the problem.
Now, that railgun has some real potential to launch guided spacecraft cheaply (well, once the cost of construction has been amortized!), but as an unguided weapons platform, it's not too useful. Now, if you *could* accelerate something to .5c like the grandparent post suggested, you're onto something.
Apologies to the parent; I'm going to be a bit brutal...
You were going to get this 25 kT of energy to put into the system from where? And you're going to give it to the projectile how?
Two thirds of the speed of light is pretty damn quick. You'll get a few miles per second of that from falling down the gravity well, but that leaves you short by two hundred thousand kilometers (~120,000 mi.) per second.
Let's assume that your launcher is a linear accelerator a hundred miles long, built on the moon. If we assume a roughly linear acceleration, our rock will spend 0.001 second from rest to launch. On average over each mile of the launcher, you need to transfer to a half gram of material the energy equivalent of 250 tons of TNT, and you need to do it in ten microseconds. Roughly, that's ten to the sixteenth watts flowing, delivering ten to the eleventh joules.
Using as-yet-undeveloped capacitors with diamond dielectric, you might get an energy storage density of 2.5E4 J/kg. To store 1E11 J comes out to 4E6 kg, or four thousand tons of capacitor. (Existing technology is probably about an order of magnitude worse.) Per mile of accelerator. I haven't worked out the mechanical stresses on the accelerator imposed by Newton's third law, but you can bet they'd be brutal, too.
So...to store the energy to fire once will require four hundred thousand tons of capacitors. At best. To charge them, let's say we have a good-sized nuclear power plant churning out 2000 MW. To collect 1E13 joules will take 5000 seconds, or about ninety minutes...assuming no losses.
What does that give us? A weapon located inconveniently on the Moon that costs a fortune to build and maintain, and can fire a 25 kT 'bomb' once every hour and a half. Oh, and it's useless at least twelve hours per day when the targets are on the opposite side of the Earth.
By the way, did you think any country is going to stand by and let any other country build one of these things? Yeah, I know--it's a fun idea...but totally impractical unless we have some real engineering miracles. And you'd probably be better off militarily building smaller versions for use on the battlefield.
~Idarubicin