Moon Miners' Manifesto

#99 October 1996

Tourism - On the Level

Peter Kokh

[EDITOR scan in illustration from hardcopy]

The recent winner of the X-33 competition, LockheedMartin's VentureStar is an apparently well thought out paper study design by Lockheed's famed Skunk Works, a team determined to overcome the considerable head start of McDonnell Douglas (the Delta Clipper program, with an actual successfully flying prototype).

VentureStar has a number of distinguishing features like its linear aerospike engine. But as a prototype upon which a future personnel carrier might conceivably be based it has one very salient characteristic that presents some challenges to passenger cabin design. VentureStar will take off vertically on its tail like the Shuttle, and again like the Shuttle, it will land horizontally. While this was probably not the deciding factor in its choice, NASA's cozy familiarity and complacency with the Shuttle may have added the appeal of psychological frosting to Lockheed's design.

Will passenger cabins on vertical take off horizontal land craft be fixed, so that passengers are pushed into their seats through their backs during takeoff, effectively lying on their backs with legs up, but sitting on their buttocks during landing, seats and postures remaining the same?

[EDITOR scan in illustration from hardcopy]

How comfortable this take off posture will be for the general public is debatable. Given a choice for the same money, we think the above arrangement will prove disastrously unpopular.

Another possibility is a seat that unfolds into a berth for takeoff, and back into seat position for landing. This may work well enough.

[EDITOR scan in illustration from hardcopy]

Clusters of Seats could be in Gimbaled pods free to rotate so that gravity or powered acceleration is towards and through the pod floor, not the cabin floor in general. Force will at all times be felt, through the buttocks and feet. A model for this system are the little passenger pods that take tourists to the top of the St. Louis Gateway Arch.

[EDITOR scan in illustration from hardcopy]

As flights are short, the reconfiguration of seat backs and postures or the closing off of clumsy cramped crawl-space passageways and gimballing of pods are bound to be distracting, cumbersome, and annoying. Mere annoyance could change to trouble fraught with danger if a seat resists reconfiguration or a pod decides not to gimbal. It is curious that NASA which shrinks from tests of artificial gravity because of the engineering challenges, embraces a configuration which almost mandates one contrived Rube Goldberg accommodation or another. But there is a history of this, witness the Shuttle tile thermal protection system which is just as unnecessarily contrived (and expensive), mandated by an unneces sary choice of reentry attitude and angle.

In contrast, the VTOL, vertical take off and land, and HOTOL, horizontal take off and land, offer one simple unchanging configuration through-out both legs of the flight. "KISS", i.e. "keep it simple, stupid!" Fans of VTOL, the Delta Clipper's way of doing things, point out that a Clipper-configured craft could land on the Moon and take off again whereas a VentureStar-patterned craft could not.

VTOL would give us CATS and CATL (Cheap Access To Luna) in one craft. That is tempting. But is it the best route. Could their be cheaper craft specialized for LEO (Low Earth Orbit) to Luna runs just as VentureStar is best specialized for ground based shuttle operations to space on a thick atmos phere world? We must explore and test all the options. Only then can we have confidence in our choices. "God and Heinlein decreed that rockets should take off and land on their tails!" Maybe. Maybe not. I see problems with VentureStar's mixed mode operation. But it may just work MMM

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