Buzz Aldrin's plan for NASA

[LunarOrbit]

http://www.huffingtonpost.com/buzz-aldrin/spaceships-worthy-of-the_b_473452.html

• Replace the Shuttle with another vehicle capable of runway landings
• Extend the Space Shuttle program by a few additional flights
• Use the Shuttles to bring a "Exploration Module" to the ISS

[DonPMitchell]

Did you see the thing Buzz wrote last summer for Popular Mechanics?

http://www.popularmechanics.com/science/air_space/4322647.html?page=1

[DonPMitchell]

I added a comment about Aldrin's XM concept to a blog entry on the Soviet TMK project.  Now this would be interesting!

http://donpmitchell.blogspot.com/2010/02/heavy-interplanetary-ship.html

[LunarOrbit]

I don't know if I'm allowed to put it online, but I recorded a video at a presentation by Buzz in Toronto in 2008. He talked about the Constellation program and what he would do differently. It was basically the same as his Popular Mechanics article.

[DonPMitchell]

I believe, if you're going to promote manned spaceflight, you have to do something new.  Building XM would be forward progress.  It builds new infrastructer that can be reused and expanded.  I don't think repeating an Apollo style mission to the Moon gets us anywhere new.

Landing a man on Mars or Venus is a tough one, because gravity is so great.  The landing craft would have to be huge.  But it seems immediately feasible to orbit around Mars or Venus, and to land on smaller bodies.  The Moons of Jupiter and Saturn would be nice, although you'd have to get people safely through Jupiter's powerful radiation belt.

[LunarOrbit]

For a "space taxi" the Orion capsule design wouldn't have been my first choice, but it was my belief that it was the fastest way to replace the Shuttles with the fewest lost jobs. But I agree with Buzz Aldrin that ocean recoveries slow things down and don't make any sense.

I was (and still am) very fond of the Venture Star (X-33) design, I was really disappointed when it was cancelled. I don't know if they're any closer to solving it's problems, but apparently Lockheed-Martin is still working on a similar design (a scaled model was launched as recently as October 2009).

I would love to see something like the Exploration Module get built. It makes perfect sense to build a spacecraft that only operates in space and is completely reusable. I'm not sure I like abandoning the Moon, but getting to Mars should be our main goal.

[ijuin]

If the XM is a vacuum-only craft, then it would be possible (and probably preferable) for it to have VASIMR propulsion, which would reduce the amount of propellant needed for it by an order of magnitude as compared with hydrolox combustion., and could also make a 2-3 month (instead of 6-8 month) Earth-Mars transit possible.

[DonPMitchell]

Chemical rocket engines are certainly out of the question.  VASIMR seems very intriguing.  Right now, the best working ion engine technology seems to be the Hall effect thrusters used on SMART-1.  Work on thermionic/thermoelectric nuclear reactors would also be essential to get the necessary energy.  Of course, using nuclear power means adding a $100 million to your budget to cover lawsuits from the eco left.

[ijuin]

VASIMR allows something like one hundred times more thrust than electrostatic ion engines (with a correspondingly high electric power demand) because ion engines are limited by the high voltage required--if you increased the voltage high enough to match VASIMR thrust levels, then you would get vacuum arc discharges. Also, its ability to be run in both "low gear" mode (higher thrust but lower ISP, though still higher ISP than nuclear-thermal) for orbital capture and "high gear" mode (ISP even better than the current best electrostatic ion engines, but thrust just as low as ion engines), as well as anywhere in between, is a very useful feature. I think that VASIMR is the best that we can do with present engineering, until we can develop such futuristic stuff as fusion plasma engines.

[DonPMitchell]

That's less of a concern with hall-effect ion engines, but there are still lots of problems.  Nobody has come close, even by a factor of 1000, to building an 8 ton thrust ion engine like the Russians planned for TMK.  That may be impossible.

VASIMR is a cool concept.  I worry that it has been talked about it for several decades, so how close are we to a working prototype?  How close are we to a finished product that can work in space for years at a time?

I have little faith in fusion.  Where is it?  After decades of expensive research, still nothing.  I think even if fusion ever works, the reactor technology will be too heavy and bulky for space.  You can build a very compact fission reactor, and it's technology that exists and is proven.  But the direct fusion stuff, just pictures people draw with no scientific or engineering study.

I mean, look at diagrams like this, it's just bull****.  Like NASA advanced concepts group bull****.  None of the technology works, if it did, the thing would vaporize itself in a microsecond.