Posts Tagged ‘VSE’

I wrote this architecture proposal, FLEX, a few years ago. It analyzes NASA’s approach that the ESAS study picked and notices how most of the mass in a lunar exploration stack in LEO is actually liquid oxygen. By using a propellant depot, the LOX can be lifted with tankers and any launchers imaginable (I wouldn’t use a Pegasus though). The rest of the stack is also naturally divided into about 20 ton chunks: EDS with its hydrogen, the CEV crew vehicle (Orion) and the LSAM lander (Altair).

No new heavy lifters need to be developed, there is enough US, nevermind world launch capability to support a moon exploration program. Launchers can also be improved on the run, because they are not tied to the single use, nor is the use dependant on the single launcher, and because they can fly often, hence improvements are worth the investment. This all could be achieved much sooner and cheaper than the current approach, and is much more robust for the future.

Go read it if you haven’t.

There are some comments at an old Nasaspaceflight.com thread that deal with a lot of the common questions about it.

I really don’t have the faintest idea of the background knowledge level of the readership here so I don’t know how much basics I should give, so feel free to ask in the comments if anything is unclear.

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Nasaspaceflight.com’s Chris Bergin finally wrote the article on Ares I’s thrust oscillation mitigation options. There are three main ones: new pulsed brake rockets, a damper between stages and a tuned small mass damper in the SRB. All three could be applied. They also increase mass and thus reduce performance.

Ares I’s thrust oscillation coupled with the whole rocket’s already looming possible underperformance and the Orion spacecraft mass growth drives towards a possible no win situation. It’s a bit hard to know about the margins.

There is only one earlierdocument making a clear picture of the masses, performances, margins and
reserves out there:
Brian Muirhead’s presentation from 31 Jan 2008. (Thanks to Renclod on Nasaspaceflight’s forum for finding it.)

CEV mass and Ares 1 performance and margins over time

So it seems there could still be some good margins left. The whole information coming from NASA through unofficial channels is always somewhat garbled, although less so than through PAO.

It’s next to impossible to judge how grave the situation is. When some component (say, a stage) is over
target mass, some manager reserve can pop up and increase the allocated mass considerably. Thus the need for presentations like Muirhead’s which show everything: performance targets, absolute limits and margins and reserves, not only for the launcher but for the payload as well.

(Sorry for the broken line breaks, it’s Opera’s incompatibility with WordPress, I’ll use only Firefox for these posts from now on.)

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Okay, the topic of course is a pun of the current moon exploration approach chosen by NASA. It has been the subject of endless debate, and rightly so, but the various ideas for that are a subject for other days. Bush’s Vision For Space Exploration (VSE), NASA’s 90 day Exploration Systems Architecture Study (ESAS), the resulting Ares I and V and Orion. The engineering. And the politics…

George Low, from NASA Photo 70-26105

But this is a new approach to the whole problem that I haven’t seen applied yet:


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