Penny Wise, Billions Foolish

As Clark Lindsey notes, even if we can believe the Probabilistic Risk Analysis that declares Ares “twice as safe” as an EELV (of course, to do that, we’d have to first actually see it…), that’s a pretty pathetic safety improvement considering the billions of dollars and many years that it will cost us. Considering how high the operational costs will be, it’s not likely to fly very much, anyway (I can’t see more than a four lunar missions a year, given the the budget likely to be available at the outrageous per-mission cost for the Constellation architecture). So the difference between, say, 0.999 and 0.995 is likely to be academic. Particularly when most of the hazards in a lunar mission occur after orbit has been attained. I am increasingly less and less impressed by Mike Griffin’s vaunted intelligence, and don’t miss him as administrator, even if he’s never replaced.

Speaking of which, this is indicative either of how disconnected with policy the president’s press secretary is, or how low a priority space policy is (and perhaps some depressing combination of the two):

“Q: Robert, the James A. Baker Institute is recommending that the Obama administration defer another lunar shot, and instead focus on energy and climate change. Does the White House have a reaction on that?

MR. GIBBS: I don’t have anything particularly from — I would point you to folks over at NASA. I don’t have any particular guidance on that.”

What would the “folks over at NASA” know about it? Policy has to come from the White House, but so far, it seems lacking. Clearly the administration is (over)interested in energy and climate change, but to set that up as an alternative to a “lunar shot” is a false choice. Of course, characterizing VSE as a “lunar shot” is simply a display of ignorance on the part of the questioner, but I suspect that this will be representative of the clueless quality of the space policy debate to come. If there is one.

[Update a couple minutes later]

Oh, and just in case you thought that Ares 1 didn’t have enough technical problems, here’s a new one — post-staging recontact:

This so-called recontact problem could end an Ares I mission – possibly catastrophically – during ascent. Failure could come seconds after firing of the separation pyrotechnics, if the upper stage’s J-2X engine does not provide enough power fast enough to stop it from slowing down and colliding with the first stage and its motor, which would still be providing residual thrust.

This is what caused SpaceX’ third failure. It will be a lot harder for NASA to solve, though.

SpaceX had the problem because they made a change to their first-stage propulsion that resulted in a slightly longer thrust tailoff than they expected. It was solved by simply decreasing the delay between separation and upper-stage ignition.

NASA doesn’t have this option, necessarily, because there are relatively large dispersions in thrust tailoff for an SRB, so it may be hard to find an optimal and reliable delay duration between separation and ignition. This wasn’t a problem for Shuttle because it doesn’t actually stage — it does a parallel burn, and the SSMEs are already at full thrust when the solids separate, and it can easily outrun them. But now, since they’ve come up with the brilliant concept of a solid first stage with an air-start second, they have a new serious risk in the program. And Ares-1X will tell them absolutely nothing about how to solve it.

[Update a few minutes later]

One more point. I’d like Dr. Griffin to tell us what he thinks an astronaut’s life is worth. Because clearly it’s not infinite. He has decided that making it twice as safe is worth billions, but even then, it’s not “safe” in absolute terms (because nothing is, this side of the grave). So we’ve established what he is — one of those heartless bastards who are willing to kill astronauts to pinch pennies. Now we’re just haggling over the price. I’d like to know what it is, though clearly, it’s a lot higher than my own estimate.

4 thoughts on “Penny Wise, Billions Foolish”

  1. From the department of useless nitpicking: the delay was increased, not decreased.

    Indian PSLV has 2nd hyperholic stage sitting on top of a solid stage and seems to work fine, for varying amounts of “fine” (GSLV bypasses this problem by having the core solid buring out before liquid strap-ons).

    Anyway, what’s the big deal? They’ll just have Shaft to coast and tumble a bit until the solid calms down enough to separate safely, at which point the upper stage will just fly away (assuming the whole thing does not tumble so the upper needs to make a full U-turn).

  2. Anyway, what’s the big deal? They’ll just have Shaft to coast and tumble a bit until the solid calms down enough to separate safely, at which point the upper stage will just fly away (assuming the whole thing does not tumble so the upper needs to make a full U-turn).

    No problem, other than the performance hit from the increased gravity loss (and of course, they have so much performance margin that it’s no big deal at all…)

  3. I have an even better idea: allow J-2X start before separation (like they do on Soyuz). All is needed is to have the the conical adapter to have holes in it. Heck you can make it so the thrust actuates the separation (again it works like that on Soyuz).

  4. I’m sorry for the sarcasm above. But in a sense exactly this kind of inexact and handwaving engineering produced Shaft in the first place: let’s use the SRB and piece it together with a vaguely defined second stage (with air-start SSME, no less), and voila! Surely the same approach should be used to fix the problems.

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