Tether, iron pellets, or vapor, energy of position is possibly the first lunar marketable resource.

Probably as many variants on momentum transfer launch as we can think of means of transferring momentum without destroying the spacecraft or cargo.

Check out the link Sjv supplied. Dr Walthelm worked this idea over years ago with hundreds of robotic spacecraft shepherding the snowballs to the precise trajectories.

I got a nice reply from him describing some of his viewpoint.

When I first read this, I was thinking that it would be nearly impossible to hit a moving target (on a suborbital trajectory) with a stream of snowballs (LOX balls, whatever) hurled from the moon several days earlier. I guess it would be the responsibility of the pilot of the suborbital vehicle to be in the right place at the right time to get in the way of the incoming snowballs.

Then I started thinking about the Bussard ram scoop. It might be possible to generate a magnetic funnel to collect the snowballs as they are approaching the vehicle. The snowballs themselves would probably have way to much kinetic energy/linear momentum to be captured in such a way. However, if they were to be vaporized (as you suggest) and also ionized, then it may be possible to channel the material into a nozzle/thrust chamber (either in a muzzle loading or perhaps a ram-scoop configuration).

Chances are good that this idea has also already been considered. It’s new to me, though, so take it for what it’s worth (about $0.02).

Most of the criticism of it was directed at two-launcher architecture, with claims that autonomous planetary rendezvous has never been done before hence it being too risky.
Well, Orbital Express ASTRO/NextSat pair, with the expertise of Boeing, Ball Aerospace and MDA combined performed a near flawless coreography of mutiple hydrazine transfers last summer.

Now with all this in mind, can anyone propose a cheaper or more capable MSR ? I believe they have competitions and prizes for that by the way.
See the iMARS_Report_July2008.pdf linked above.

http://www.islandone.org/LEOBiblio/SPBI1CT.HTM

The very high speed gas impacts can be done as in project Orion. Another that is mentioned at times is Medusa, which is a spaceship with ‘parachute’ which spreads the nuclear blast over a much larger area and is a lighter shock absorber. There would be a lot less ‘fuel’ required at solar escape velocities is all. I think this might be the seed of a method of exploring the outer solar system economically.

His Hydrogen would be in the rocket chamber just before LLOX impact so that it would operate as a pulsed combustion rocket with external LOX supply. His numbers assumed a perfect rebound instead of the 50% that I did. So that 2,200 m/s LLOX impact would have the same net impulse as a 4,400 m/s LOX/H2 rocket exhaust velocity per pound. At 1 km/sec impact, on board Isp would be ~3,500.

I never picked up on the higher level directories trick, thanks. I think I could win a pool for least formal education on this site.

One last crazy idea to apply to this whole concept.

You mentioned Dr. Walthelm’s idea for spraying fuel into the incoming rain of LOXballs to add chemical energy to the applied impulse when the vehicle has speeded up and the kinetic energy differential has dropped. How about the opposite problem? What if you wanted to exchange momentum with a stream of volatiles that was moving hundreds of km/s relative to your vehicle.

This is way out there, but I can think of several potential sources of volatiles at these energy levels. Maybe we’ll spot an asteroid transiting the solar system from interstellar space, or find ways of speeding masses up to these levels using mass drivers, or use high acceleration very close to the sun.

Firing a plume of really high speed rocket exhaust into the oncoming impulse gas might lower the speed of the gas that hits your vehicle from an energy level that would destroy you down to usable levels. You would do this until the velocity differential dropped to tens of km/s, then start injecting fuel when you get down to single km/s.

I got this idea from a past discussion of adding rocket thrust to aerobraking to slow down faster. It turns out that it wouldn’t work, the plume of exhaust partially lubricates your passage through the atmosphere and the deceleration methods do not add up to the sum of the methods. This is a similar principle to the “supercavitation bubbles” that allow russian skval torpedoes to fly through water at 200 knots by firing a rocket plume ahead of themselves and then flying through the hole in the water so opened. A better space example would be to approach a planetary atmosphere at a relative velocity of 100 km/s and try aerobraking. Normally you would die, but if you fly behind a hard enough rocket plume you would get some deceleration from your passage through the atmosphere and survive.

Like I said, a crazy idea. I wonder if it could ever work in practice?

I always check the higher level directories of links that interest me. Old habit. Dr. Walthelm’s thermal storage paper is here: http://www.walthelm.net/NightTimeEnergyStorage.pdf

Independent rediscovery of ideas happens all the time. As a callow undergraduate I once invented the shift register. My Professor told me to do the reading next time…

If possible, I would like to avoid the appearance as well as the reality of wrong doing. I intend to do business in this field sooner or later. If I reach that point, trust becomes an issue.

There may be perfectly valid reasons to share a room with your secretary at the conference, and nothing wrong happened. That will be a cold comfort as you search for a new job while going through a divorce.