Moon Miners' Manifesto

#99 October 1996

Editorial

IN FOCUS: VentureStar Looks Good, But We Need C.A.T.S. Options

Henry Vanderbilt, in Space Access Update # 67, 7/11/'96 (Moon Miners' Review # 19), compared the X-33 offering with that of an inexpensive Delta Clipper follow-on that the Air Force would like to see funded. That comparison is given below. That the wisest policy is to pursue both options is clear.

Meanwhile, NASA will explore other promi-sing cheap access, reusable vehicle designs:

• According to Space News June 10-16, '96, NASA intends to hold a competition for a dual-fuel, air-breathing reusable launch vehicle in the next 2-3 years, says Dan Goldin. Such a rocket would use oxidizer from the atmosphere during the first phase of its flight, reducing the amount of LOX it had to carry along, thus leaving more room for payload and increasing its payload mass fraction.

• Goldin also mentioned that "A few more RLV [Reusable Launch Vehicle] development programs that don't even have numbers yet are planned to start before 1999."

What about market forces? Lockheed Martin's expectations are high, that its vehicle, once opera-tional, could garner 80% of big load business! It is unlikely that other commercial players such as McDonnel Douglas and Arianespace would be happy with such dominance. We can look for competition, competition exploring other options. That's good.

Nor should we think that it is only a ques-tion of guaranteeing that we find the best combina-tion of features. Cheap Access To Space, CATS, is not a simple challenge with a single solution. It is a veritable tree of problems with both roots and branches spreading in different directions.

That the best CATS solution for large hard-ware payloads should by coincidence be the best CATS solutions for shipping materials to space that can be handled in any quantity, or that the best CATS solution for either should by some lucky quirk also be the best CATS solution for sending people, cabinsfull of people, to orbit - that coincidence would be bizarre.

More, Heinlein pointed out that once you are in orbit you are half way to anywhere, i.e. you may have solved only half your transportation problem. We need Cheap Access from LEO to GEO, from either to the Moon, from Earth and the Moon to Mars. These are all different sets of challenges that are likely to have unique solutions.

If all that the push for Cheap Access achieves is to make it easier and cheaper to put communications satellites in orbit, we will have spent a lot of energy without doing a thing to open the real space frontier.

In this issue, we take a look at just some of the many challenges and just some of the possible solutions. We're sure there are more problems and more good strategies - our purpose is to stimulate thought and vaporize the current simplistic hysteria over something that is more important and far-reaching than most CATS champions have let them-selves realize. In the end, CATS, the effort to insure ever cheaper access of everything we want to put in space to everywhere we want to go in space, will be an unending story. -- Peter Kokh

Space Access Society's analysis of relative merits of VentureStar X-33 and proposed Clipper follow-on:

X-33 does horizontal runway landing. DC-XB/C would pursue vertical wingless small-pad powered landing. X-33 uses medium-temperature metallic thermal protection. DC-XB/C would use new high-durability high-temperature tile TPS. X-33 tests new 'aerospike' rocket engines DC-XB/C would demonstrate use of multiple traditional bell-nozzle engines, engine-out redundancy. X-33 will pioneer use of complex multilobe composite propellant tanks DC-XB/C insures against manufacturing/durability problems with simpler geometry tankage. X-33 will test out low L:D low heat-load reentry profiles. DC-XB/C will explore high-maneuverability high hypersonic L:D flight. X-33 will need fixed operating bases, specialized ground-handling equipment for ship and payload DC-XB/C will be aimed at more mobile operations out of small austere sites. X-33 is a higher-risk higher-payoff approach, bundling new technologies into a complex package. DC-XB/C takes a much more incremental approach - "build a little, test a little."

Teaser

The "Tree of Cheap Access"

Contents of this issue of Moon Miners' Manifesto