This isn't really a surprise to anyone familiar with him and his history, but Newt Gingrich is continuing to promote prizes for space achievements. I agree with commenters that his proposal of twenty billion for a human Mars mission is a prize too far, not just for all the reasons stated (too much money to raise privately, too long-term a proposition, too little faith in the government to keep its word) but also because I'm not sure that there would be adequate public support for the goal itself. A more incremental approach is indeed required--going from a ten million dollar prize to a twenty billion dollar prize is just too much of a leap.

I also agree with this comment, with a caveat:

IMO, we should start with smaller prizes. I would create three (3) prizes, in the following order: 1) orbital RLVs, 2) LEO propellant depots, and then 3) Processing oxygen on the Moon, and 4) Delivering the oxygen from the lunar surface to a LEO prop depot.

I suspect that it will be a long time before it's economically viable to deliver lunar LOX to LEO, at least directly. What I would envision happening is a LEO depot, an EML1 depot, and a continuous parade of low-thrust tankers (which might also serve as the depots themselves while in place) moving back and forth between the two locations, delivering propellant to wherever the price dictates. If the tankers could deliver lunar LOX to LEO at a lower cost than delivery from earth, then they would do so. If it only made sense to use lunar LOX one-way as propellant to leave the moon, and it was cheaper to refuel at EML1 for the return using LOX delivered from earth, then that's what should happen. The important thing is to establish the propellant supply infrastructure, regardless of the source of propellants. Building roads and a gasoline-delivery infrastructure was critical to making reusable cars (as opposed to the one-way Conestoga wagons) practical, and we need to do something similar in space.

EML2 works even better than EML1 for a propellant depot:

NASASpaceflight.com thread

EML2 works even better than EML1 for a propellant depot.

That depends on your criteria. It makes for much longer trip times. It's not unreasonable to trade off propellant versus time, particularly if propellant becomes affordable. But again, if we had enough activity going up there, the market could decide.

Twice the trip time for half the delta-V. That's a pretty good trade.

In your opinion. It depends on what you value, and how you weight the criteria. Time is money, too.

Here here on the propellant depots. I'd love to see a market-driven solution on that one.

I think we'll eventually be producing propellants on the moon, but I haven't seen an analysis that takes the return capsule/tank mass (and heat shield if you're going to aerobrake back to LEO) and propellant requirements (to get you off the surface and back to LEO...yes I know a rail gun would be the best solution) into account. If anyone has a link to something including such factors, I'd like to give it a read.

Currently in LEO we are transferring no LOX, and less than a tonne of GOX per year.

When the other alternatives are RLV's and mass produced BDB's, I don't see this scheme being economic until we start talking in gigatonnes.

Hey vanilla,

I read the main post and clicked comment to type "EML-2 would work better" and there you were, already there. Well done :-)

Robert Farquahar proved the essential point back in the 1960s and even Paul Spudis is now saying that L points are critical to moving mass back to Earth from Luna.

Deploy L point station(s) (EML-1 and EML-2) and a fully resuseable lunar lander leveraged with lunar LOX and the cost to access the lunar surface falls through the floor.

If it only made sense to use lunar LOX one-way as propellant to leave the moon, and it was cheaper to refuel at EML1 for the return using LOX delivered from earth, then that's what should happen.

At a minimum, lunar LOX could be used to power both legs of a journey between an L point transfer station and Luna. And if we harvest LOX rather than look for water at the poles we can access all of Luna and still use in situ fuel sources.

But, we still need a revenue stream from lunar access and PGMs (if Dennis Wingo is correct) combined with tourism strike me as the most likely near term possibilities.

I know that NASA's timidness is the reason we are talking about private ventures and space prizes. But NASA is a participant in the International Space Station, and couldn't NASA be doing some of this stuff, even if it is in their expensive, plodding manner?

What is a space station supposed to do anyway? Back in the day, it was supposed to be a manned platform for Earth observation (civilian or military); it could also be a radio relay (Clarkes' original communication satellite idea). Both of these functions, owing to improvements in microelectronics, have been performed unmanned quite well.

The other thing a space station was supposed to be was a staging depot for exploration of the Moon, Mars, and other Solar System destinations. The idea was that you would have some kind of shuttle bringing up fuel and supplies, both to operate the station as well as to stage operations outward. The final thing that a space station was supposed to do was train crew members for operating and working in space for those outward voyages.

What does the International Space Station even do in this day and age? My impression is that the resource available in space in low-Earth orbit is microgravity, and that much of the numerous "high school science project" level of experiments conducted aboard Mir and later ISS are aimed towards the eventual exploitation of Earth orbit microgravity as a resource for industrial and scientific purposes. A second objective of the ISS is the astronaut training one. Even though we are stuck in Earth orbit, it seems that having people "up there" for long periods of time is long-term thinking in terms of what it takes to keep people in space for voyages to Mars and the asteroids.

But what happened to the idea of the space station as a depot? If the space station is meant to be port on the route to another destination, ISS activities should include engineering experiments into 1) propellant transfers, especially of higher-energy cryogenics such as LOX or LH2, 2) some kind of manufacturing of structures in space related to assembling space craft in orbit. Either of those activities could be done on a small pilot-plant scale to investigate what is required and if this is even possible.

It goes to the fundamental problem of making an economic case for a single-stage-to-orbit reusable space launcher. A SSTO RLV is supposedly possible, but then what? All of the interesting destinations are farther out, starting with geosynchronous orbit, going to the lunar surface, and beyond. There is no technical possibility of single-stage to geosynchronous orbit let along single-stage to the surface of the Moon.

In the absence of the ability to transfer rocket fuels and oxidizers, SSTO doesn't make any sense, and what does make sense are the ELV designs with upper stages optimized for placing lighter payloads beyond Earth orbit rather than heavier payloads in Earth orbit. So why isn't propellant transfer and space structure assembly bigger elements of ISS activities?

::what is required and if this is even possible.

Everything is possible, the question, often, is price. Getting to ISS right now is expensive, or ITAR-restricted, and its at the wrong inclination. About everything you'd want to do, propellant transfer and docking tests are better done with free-flying automated platforms ( ASTRO/NextSat ) at sensible inclinations.

But yes, cryo propellant transfer and storage ought do be done sooner rather than later. LOX/Propane or Lox/Methane would work, if Lox/LH2 is too difficult/too much to ask for.

Has anyone looked into the economics of using nuclear pulsed reaction engines (like the real Orion) with the propellant/fuel lofted from ground?

The specific impulse (if I have the right term) is huge, and the fuel and engine mass is tiny compared to the power available. And the vehicle doesn't have to be enormous, either - I have seen hints that the lower limit for nuclear device yield is very small, maybe about 0.5kt.