Saturday, October 20, 2007

This Is Starting to Sound Too Familiar...

A lot of hot air was expended the other day by the Emperor's minions discussing the viability of the RCC on Discovery. They claimed victory because they talked out loud about the problem, not because they could solve it. Instead of a incurring a one month stand-down to replace the panels, they also chose the path of least schedule resistance over the prudent answer.

Because NESC wrongly presented inconclusive evidence, the problem was put on the pile of risks list and Discovery was ok'ed for flight. Since the problem is not understood, and flight is allowed in light of its recurrence on many flights, the program has once slipped into the lackadaisical "its happened before, we didn't get hurt, so its routine now" mentality. Hopefully, the hot air will stay here on the ground and not be felt through the RCC like Columbia felt it on its ill-fated re-entry. But, least you think that's the only thing out of the ordinary on this flight, think again.

The External Tank that Discovery is flying was picked up from the used tank lot. You see, this tank was originally destined for STS-114, but was sent back to Michoud for an overhaul of some of its pesky foam. No big deal, you say, tanks have been repaired before and flown without incurring a major loss of foam. True, but those tanks have pretty much avoided multiple hot/cold/hot fill up cycles. When STS-120's tank is filled next time, it will be its third cycle.

The program has been trying to minimize tanking cycles to avoid stressing the foam that tends to break off and fly away, aiming for that delicate RCC. Should STS-120 not get off on the first attempt, the foam will have been doubly stressed over the desired number of times on the next attempt. Questionable RCC and stressed foam typically do not make for a good day. But we're sure that the Emperor will once again proclaim that only the shuttle asset is at risk, not the crew. And, sure, flying on top of millions of pounds of explosive fuel is risky from the get go, but shouldn't we try to minimize that risk best we can? Apparently not, if the cost is an extra month of schedule.

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