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The real prize is not the 10M purse, but the tourists that will follow. Some estimates are that the global market is in the billions. Several studies have been done indicating that people would spend 10k-100k for a trip, among people financially able to pay that.

I look forward to the day when a flight to space is a mundane vacation activity for rich people, right there next to hang-gliding rides and zorbing. Of course orbital is much harder, but the X-prize lays the first brick on that path.

-- Bob

The only drawback I see to solar power stations on the moon is the expense in buying 1,000,000 of those bright orange 50' extension cords so we can run the power back down to Earth.

I Googled for a random reference discussing the subject.

It is yet another space possibility that won't be realized while it costs thousands of dollars to launch a kilo to orbit. That price won't go down while lots of jobs at NASA depends on the shuttle...

Feasible, even economical, but nobody wants to put up the gazillions of spondoolies needed to kick it off.

Starting haphazardly.


The delta-v quoted by your source is far lower than the delta-v needed to get into a Hohmann transfer orbit even from free space in a circular solar orbit at Earth's radius (which the C3=0 orbit is the equivalent of). As the Hohmann orbits are the lowest energy transfer orbits that don't require slingshots from other bodies, I question the values on that figure.

Ah, there's your problem. The C3=0 orbit is NOT a circular orbit at Earth's radius. It's a parabolic orbit with Earth at its focus, which necessarily can NOT be a circular orbit about the Sun at Earth's radius. A parabolic orbit means that at infinity, it will have no velocity relative to the Earth, which means, if the craft traveled to infinity, it would then have the equivalent orbital velocity of Earth. Problem is, it never reaches infinity, as it's not a two-body system, since the Sun's there.

If you want a spacecraft to be in a circular orbit at Earth's radius, well, it doesn't have to do anything - just stay home. It already is in one. :) After it lifts off, depending on the direction, it is doing two things - first, it is escaping from Earth's gravity, and second, it is changing its orbit. You don't have to "add" the escape velocities onto the necessary orbital delta-V. If you wanted it to actually reach a circular orbit, that takes a lot more work, actually!

This is the problem when you're doing "you need to add an extra 5.03 + 2.38 km/s" - you're adding the Lunar escape velocity and the Martian escape velocity, which you do not need to do, because you're not exactly going to infinity. On the return, you can easily aerobrake in Earth's atmosphere as well to enter lunar orbit.

Also don't forget about aerobraking! No matter what, any time you approach a planet (even entering lunar orbit! you can always place your perigee inside Earth's atmosphere with clever timing!) if you need to slow down, it's free.

And if you don't like that site, how about here, which shows that Deimos is more accessible than the Moon (and shows a delta-V from Mars surface to Lunar surface of 8.0 km/s, not 13.0 km/s).

Or here, where you'll note that "LEO to Mars" is a delta-V of 4.8 km/s, not the 5.6 km/s you're claiming - this is because, of course, it's in LEO, and therefore has some orbital velocity about Earth (and is therefore traveling at -greater- than Earth's orbital velocity at certain points).

I can continue to give examples if you want - the point is that from the Moon, it's easier to get to Mars and back than it is to get to Earth and back.

The easiest way to think about this is simple: You do not need to actually escape Earth orbit in order to reach Mars. A highly eccentric orbit can include both Earth and Mars (if both were stationary, obviously - they're not, so you can't orbit them, but you can of course use that path to transfer between them), and so must necessarily take less energy than the escape velocity of Earth+the escape velocity of Mars (which reaches Mars by going through infinity).

Interestingly enough, Hohmann transfers are not lowest energy. Google for "interplanetary superhighway", which is a relatively recent discovery. Really does suck that the 3-body system isn't analytically solvable...

Obligatory link to How The West Wasn't Won

the microwave spectrum is a limited resource jealously guarded by commercial and nonprofit users alike. Allocation of the spectrum must be addressed promptly and effectively to avoid preemption of space power technology before it's born.

If he wants to build a replacement, I'm all for it. There are better technologies that, if funded, could really open up space exploration at a much lower cost.

In the heavens' name, NO! Don't have NASA or government funding. Have them pay for success only. That way smaller (and more innovative) companies aren't forced out of business by NASA or politicians, as has happened in the past. NASA's track record over the past 20 years is an unbroken and extremely expensive history of failures, paper projects and politically terminated projects.

Cheers, Coward

One of the problems with current situation is that craft seem to be designed by committee according to specifications drafted by politicians eager to bring to their districts as much business as possible (and line their own pockets with 'campaign contributions'). Efficiency, cost and (unless people die and it hits the news) safety do not seem to be important.

The rest of this post is mostly about launching satelites, but it probably also applies to manned launches.

Another problem is that of economics. There currently aren't enough launches per year to allow economy of scale to play any role. If, for instance, one were to design, build and launch a particular booster type twice weekly for three years (ca. 300 launches total), the unit cost would be a lot lower than if that same booster type were launched every other month (18 launches or so) or even monthly (36 launches) over the same period. The former case makes an assembly line affordable, the latter would not. The higher schedule would also allow more opportunities to test and phase in new equipment like electronics, pumps and engines.

A (somewhat extreme) example of this can be found in the history of the World War II A4 missile, better known as the V2. At peak production it is estimated that the Mittelwerke produced hundreds of the things, even under wartime conditions. Of those launched, about 80% worked as designed. Without bombing and slave labor and with better materials, quality control and manufacturing methods, mass-building a booster capable of lofting 2 tons or more to low orbit for under $4 million apiece and with a success rate of 95% or better should be quite possible. Since it isn't designed for maximum throw weight (like an ICBM) somewhat cheaper (and heavier) materials can be used to keep costs down. More on the V2's history and its application to modern launches can be found at this location. Cheers, Coward

Legality and ethics disccusion and links about space exploration and mining here.

This article on spacefuture.com has a pretty good analysis of what centripetal forces we should be looking for in deciding to build a rotating space station. It takes into account not only the physics, but also the effects of this artificial gravity on humans (since there is a significant effect due to Coriolis forces that make it behave differently from natural gravity).

This is one of the most on-target criticisms of NASA's operations that I've seen.

Perhaps it is time to move this effort to the private sector. On the other hand, I would really like to move to Mars (assuming I can get Internet access there), and I don't see a profit-driven operation accomplishing that anytime soon.

We can only guess at the author's credentials:

Resume for I M Patient -- (References available upon request.)

2001 - Won third-best fiction story in Mrs. Parson's seventh grade English class, section B. Accuracy of content and knowledge of NASA, economics, and politics was unimportant for this assignment. We intend to submit the final draft for publication at spacefuture.com

2001 - Successfully launched "Honest John" model rocket with 2-stage thrusters.

2000-2001 - School hall monitor. Responsiblities include wearing a badge and maintaining alertness.

This 1998 market study claimed a civilian space travel industgry was feasible. Lots of graphs.

On the same subject, Discovery or TLC ran a documentary last year that said commercial airliners within the next 30 years will be designed to fly to about 40-50,000 feet, refuel from a tanker, then climb steeply out of the atmosphere and coast to a landing. Passengers will be strapped in, no snacks, no potty break. Max trip time to anywhere in the world: 45 minutes. Now that's my kind of space travel.

So think twice before shelling out $98K for a suborbital flight. You'll be able to get your 20 minutes of weightlessness on a routine flight to Hawaii.

The same research that is shrinking cell phones has a higher purpose: an exhaust-free electric car.

Would somebody please stick a note to that author's forehead - you recharge your exhaust-free car by plugging it into a radioactive and/or hot'n'smoky power station...

I'm still hanging out for that orbiting solar collector/microwave beam thingie!!

In response to your questions...

1. How will they focus the beam on receptor antenas?
I'm not gonna pretend I can explain it, but I am gonna pretend I can use google. This is an artice on spacefuture.com written by a boeing engineer.
2. How will they keep airplanes from flying across the beams?
Getting air traffic to steer clear should be a monumentally easy task. Do you realize the amount of "restricted airspace" that already exists? It is simply a matter of designating the land, and getting the air traffic controllers to say "hey, don't go there."

3nd, I have to believe that the fact that there are hundreds of communications sattelites in geosynchronous orbits that don't collide, it wouldn't be excessivly difficult to add one more to the list. Admittedly it would be inconvenient due to the fact that nothing could fly underneath it, but again inconvenient does not mean impossible.

For those of you interested in Darwin Awards, here is the X-Prize site. Here is Robert A. Braeunig's page on how to do it, orbital mechanics and the like. Space.com usually carries the X-prize news. For those of you wondering about the difference between an Ariane and a Proteus, here is the glossary

1Alpha7

It's important that any design is comfortable.

--

For what its worth, here are some decent sites containing current NASA and other country's position, and progress on civilian space travel:

http://www.reston.com/nasa/tourism.html
http://www.spacefuture.com/archive/general_public_ space_travel_and_tourism_volume_2.shtml
http://www.nss.org/alerts/releases/release36.html
http://dir.yahoo.com/Science/space/civilian_space_ travel/

MODS: Don't mod me because of age/sex/religion/creed/color/name. If you must criticise, please post contstructively rather than zealously. thanks

It gives the facts and figures on an 860 mile long elevator as opposed to the accepted idea of a much longer elevator.

Interesting.

The one engineering problem I forsee is the ground platform which would have to be a minimum of 50Km tall to adequately serve the elevator. This is a huge obstacle to overcome. The current tallest buildings are a little over .5 KM IIRC. This presents a major construction problem that no one has found a solution to yet.

Any idea's? ;-)

• We'd prospect for the kind of asteroid we want. Metal or fluff, depending upon whether we need metal framework or acoustic tiles.
• Any part of the surface is "a place to land". Low gravity. Harpoons probably needed to stay in solid contact.
• Smelt with mirrors. On Earth we can melt metals with mirrors. A lot easier when we don't have to hold mirrors in place against gravity.
• Space colonization is not a population growth measure. Not enough people can be moved...unless we can build space elevators. Colonists would be a few people and their children. Population growth can happen off-planet also.
• Space is enormous. Plenty of room for some humans.

"...It was a stepping stone to later developments - either an X-15 launched atop Navaho G-26 boosters, an X-15 scramjet version, or the X-20 - that would lead to manned orbital spaceflight. This stepping-stone approach was abandoned and the crash programs of Mercury and Apollo initiated instead..."

Imagine a zero-G water park...fountain jets, water balls floating around, coriolis fountains, sheets of water sweeping across broadside, people surfing a rotating fountain...and oversize foot fins for flapping at the air...

• Space Tourism Initiative
• SpaceFuture's Tourism page
• Space Markets: Tourism
• The Prospects for Space Tourism
• Zegrahm Space Voyages (wait until 2002)
• Artemis Project: Recreation (mostly lunar)

• Map of Lunar private property.
• Map of Apollo landing sites.
• Moon Handbook, a travel guide.
• Robotic Exploration: LunaCorp, CMU Lunar Rover
• How to get there: The Artemis Project, GSC, Spacetopia
• What to do on the way there: Enjoy Low Earth Orbit
• What to do there:
  • Fun: Lunar golf and javelin throwing
  • Work: Mine oxygen