Shuttle Extension 2015, the buzz Options

[PDP8E]

http://www.al.com/news/huntsvilletimes/ind....xml&coll=1

This is instead of 2010 -- still preliminary though.......hmmmmm....

[dvandorn]

Leaving politics and funding issues aside, I think it's worth discussing the safety aspect of any decision to extend the Shuttle fleet's operational lifetime past 2010.

The 2010 date was not set for political or even budgetary reasons. It was one of those very strong recommendations-cum-orders that came out of the Columbia Accident Investigation Board (CAIB) report.

The CAIB set the bar very, very high in terms of safety -- essentially, to reduce the possibility of another loss of crew and vehicle (LOCV) accident to such a remote level that one could confidently predict that we would never lose another Shuttle crew. In this regard, they studied not only the sequence of events leading up to the loss of Columbia, they also studied the engineering history of the orbiter fleet.

The general trend of the observations was that the fleet was flying fewer total flights per vehicle than it was designed for, but over a longer period of time. So while the process of refurbishing between flights was doing a decent job of catching and fixing flight damage, there were far fewer processes in place to catch and fix issues of senescence -- of aging components and wiring that could be developing fatal flaws.

This was reinforced by the late 1999 launch of the first Shuttle flight commanded by Eileen Collins, during which deteriorating wiring harnesses throughout the orbiter caused several short circuits which brought the Shuttle stack one electrical failure away from losing from one to all three SSMEs during the first few seconds of climb-out.

The CAIB studied this and other incidents, looked at all of the (at least partially) applicable data from the aircraft industry, and concluded that one of two things needed to happen:

1) The entire fleet needed to be completely rebuilt, checking and replacing every wiring harness, avionics box, and even high-stress portions of the airframe, if it was to be safe to fly beyond the end of the decade, or

2) The entire fleet needed to be retired by 2010.

Since option 2 is one heck of a lot less expensive than option 1, NASA decided to retire the fleet and redirect post-2010 Shuttle operational funding into CEV development.

Now, you can easily debate the political and funding issues surrounding a decision to abandon the 2010 retirement date. But I find it very difficult to ignore the original driving force behind that date -- the aging condition of the orbiter fleet.

I do understand that we have a corps of astronauts who will take the risk of flying a vehicle that may not be 100% safe. But, solely from a safety standpoint, do we *really* want that to be our national policy?

-the other Doug