Wednesday, June 1, 2011

In Search of Excellence

I'm referring to the early eighties book.  I read that book, but there's no time to re-read the darned thing.  The reason that I mention it was something that I remember about it.  It is a principle called "stick to the knitting". I take that to mean that you don't deviate from what you do best.

It seems that with the Shuttle program coming to an end, and considering the failure of the Constellation program, the lessons from that book were either never learned, or were forgotten.  Why create an entire new launch system? Why not use SRB's and ET's along with the Shuttle's main engines in a new configuration which was only minimally different from the one they already had? This may still be done, and has already been decided upon, but is now in jeopardy because of budget constraints.

The failure to stick to the knitting led to this outcome. If the original plan would have been something like an Ares I which was of the same size of the one that is used with the shuttle, then the remaining design needed a second stage that would have gotten a crew to orbit. This was necessary anyway, but it may have been a little different in the final configuration than the one they came up with. The cargo lifter could have been a shuttle derived sidemount using the same configuration as the shuttle with minimal changes. This should have led to minimal design costs and minimal risks, while maintaining heavy lift capacity and gaining crew safety offered by the Ares I. Two rockets, but each building upon the strengths already demonstrated in the shuttle program. That would have been sticking to the knitting.

What they did was to decide upon heavier lift, which required a bigger rocket. This is where they went wrong. In my opinion, the shuttle derived sidemount was sufficient. It lifts the current shuttle and cargo, which is 125 tons into low earth orbit. Now, it wouldn't lift that much into orbit in this hypothetical configuration, but it could lift, say as a wild guess, about 100 tons. That's plenty of heavy lift without the need for a complete redesign, which was what they did. The Augustine Commission said that a sidemount configuration would have been sufficient for a Mars mission. The extra lifting wasn't necessary for that mission.

If the Senate wants to keep the Shuttle derived system, they'd better remember this lesson. If they haven't learned it in the first place, they had better learn it now. Here's what they could do: do a sidemount and fund the Spacex for crew. Spacex could continue developing heavy lift, but that is a few years off. Keeping the sidemount would allow for some margin against program risk if Spacex fails. If Spacex succeeds, you can then decide if you need the program anymore.

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