Dribs & Drabs
The Orlando Sentinel has certainly done everyone a big favor in printing a leaked schematic of NASA's thinking on the architecture for the return to the Moon. In many regards it bears an uncanny resemblence to the Apollo architecture, especially in the end stages when pieces are being discarded.
There's no permanence to this architecture. The Earth departure stage is jettisoned. The descent stage is discarded on the Lunar surface. The ascent stage is jettisoned in Lunar orbit. The Earth return stage is jettisoned. It's all being thrown away.
No mention is made of the ISS, or its possible use as a staging point for leaving LEO. No mention is made of any capabilities at EML-1 or at least in LLO (Low Lunar Orbit). No mention is made of harvesting the ET (external tank) after orbit.
Is a disposable Moon program really what we want to pay NASA to do?
There's no permanence to this architecture. The Earth departure stage is jettisoned. The descent stage is discarded on the Lunar surface. The ascent stage is jettisoned in Lunar orbit. The Earth return stage is jettisoned. It's all being thrown away.
No mention is made of the ISS, or its possible use as a staging point for leaving LEO. No mention is made of any capabilities at EML-1 or at least in LLO (Low Lunar Orbit). No mention is made of harvesting the ET (external tank) after orbit.
Is a disposable Moon program really what we want to pay NASA to do?
posted by murphydyne at 8:16 PM
5 Comments:
Ken,
It is kinda sad, but ends up being a "logical" result of trying to avoid all on-orbit assembly, refueling, and rendezvous/docking operations, while simultaneously trying to do a much larger surface payload with a not much bigger launcher. But it was pretty apparent that NASA doesn't want a cost effective lunar program, so I can't say I'm shocked.
The big problem for NASA is that if you want to reuse elements, you need to make the elements reusable and develop on-orbit refueling capabilities. If you do that, there's no longer a real need to launch everything in one big shot, and in fact a reusable architecture prefers smaller vehicles. But that wouldn't provide welfare for aging rocket nerds in Huntsville, Houston, and Titusville.
~Jon
Of course, the plan can always be updated in the future. If lunar propellant depots are established from ice deposits, a reusable lander could be substituted for the expendable one. If we develop better heat shielding and lighter structural materials, it might be possible to build a vehicle that combines the functions of the command and service modules with true reusability.
In the long run, on-orbit refueling is the way to go (just as the Air Force does with combat planes to extend the range of smaller vehicles.) But until we can achieve high flight rates with reusable RLV's, a sustainable lunar architecture will have to wait.
MJ,
The problem is that the current design choices make it very difficult for them to upgrade to a reusable lander in the future. A reusable, single-stage lander would be so completely different from the expendable two-stage version they're doing now that it would be a completely new development task. And for NASA, that means $5B or so (though a private company could probably make something pretty nice for $50M or so). Same with making the CEV/EDS combo into reusable hardware. None of them are being designed at all with reusability in mind, so if they actually try to upgrade at some future point, it will pretty much be a complete replacement vehicle.
Seeing how long NASA kept flying shuttle in order to avoid developing a new system doesn't give me warm fuzzies about NASA being able to upgrade to better systems when they become available.
I don't think that high-flight rate RLVs are 100% required for a sustainable lunar architecture. We can get started with existing boosters if NASA went with a drylaunch architecture. With SpaceX's current and planned vehicles, that would be a really good start (while proving out a large market for future RLVs) on sustainability/affordability.
Looking at what NASA's proposing, it's clear that their lunar flight profile isn't economically viable. But NASA's rationale for going back to the moon is to develop operational experience for a future Mars mission (and perhaps build a support infrastructure for the Mars mission on the moon, but I feel that would be impractical.)
If I understand Mike Griffin, he wants to transfer the lunar program to the private sector once it has fulfilled its mission. At that point you'll start to see some real innovation. If it doesn't come from the Boeings and LockMarts, it will come from the smaller firms like SpaceX and Scaled Composites. I think the shuttle-derived rockets will be retained (at least until Musk can build a heavy lifter,) but the lunar spacecraft will be replaced with new designs.
MJ,
I'm not sure how much of what NASA is developing is even worth transfering to the commercial sector. See the point Chris Miller of CSI made in the "In-Space Business Models" panel I reported above. If an infrastructure is designed to meet political needs, it isn't going to be economical to operate, even if it were given away for free after NASA's done with it.
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