Shuttle Replacement Parts

[sodengineer]

Hi

I'm a Civil Engineer, but just returned from a visit to KSC. Excellent tour, any engineer would be blown away with what has been done there.

Anyway my question requires some background:
On the tour, the statement was made that the only part of the shuttle that isn't reused is the External Tank. But soon after that, they told us about what occurs in the Oribiter Processing Facility, i.e. the parts that are changed out, new tires, etc.

My question:
Just how much and what parts of the shuttle are replaced on a "typical" turnaround? I realize a few of the tiles are replaced, and it would make sense to conduct a full inspection inside and out, including testing components. I also realize that the orbiters are 20+ years old, and have been constantly upgraded over the years. I'm just interested in the typical wear and tear on a vehicle.

No, I'm not an aero or anyting like that, just another curious engineer who is impressed with the products of NASA and their contractors.

Thanks

 

[gwolf2]

Well this was always the 'elephant in the room' for the 're-usable' shuttle program. This supposedly reusable spacecraft actually takes months and months of maintenance, replacement, and repair to get it ready for the next shot.

The early idea was just check the oil and tires, refuel, clean the windshield and re-launch. The reality makes it actually harder than using simpler, cheaper, disposable re-entry vehicles.

Nice try, but no banana.

 

[sodengineer]

WRT "Just check the oil and tires, clean the windshield and relaunch..."

That is pretty much beyond the capability of any hi performance machine. (See Dragster, Top Fuel)

I was just curious about what a typical turnaround is.

Thanks

 

[gwolf2]

Months, lots of people, lots of new parts, lots of expense.

 

[IRstuff]

> Whatever they do, it's still about 2 orders of magnitude cheaper than building a new one for every flight.

> Most of the reported launch problems are with the stuff that actually is new, each flight, namely the solid and liquid rockets. Note that the last few flight delays involved cryogenic valves and sensors that are new each flight.

> Unclear what's actually replaced in the Shuttle itself, each flight, except that I would expect that the engines and thrusters are >90% of the refurbishment work.

> The Shuttle flew for years with magnetic core memories for its mission processor, so interior stuff doesn't get changed much.

TTFN

FAQ731-376

 

[sodengineer]

Relax...I wasn't trying to start a fire. Save your flaming posts for elsewhere.

I was just curious what a typical turnaround involved.

I wasn't interested in the costs or the merits of one spacecraft versus another. Since you are unclear, please let someone with more insight resond.

Thanks

 

[btrueblood]

Flaming? He's just trying to give answers...it's a pretty big question. There's more info. at

http://en.wikipedia.org/wiki/Criticism_of_the_Space_Shuttle_program

and you can dig into the references there for more detail. I'd debate IRstuff's 90% figure, as probably closer to 60-70% on SRB and main engine refurb/rebuild, 25% or more on heat shield tile refurb, and the remainder on various other subsystem components. But I am more guessing than knowing.

 

[serker]

The tile system used to require a lot of touch labor during refurb. I've heard there have been some major improvements between the system as initially implemented and the current installation.

That was a major focus with some of the now defuncted follow on / replacement programs: to get a thermal protection system that wasn't so fragile and labor intensive between flights. I don't know if any of that work will ever see the light of day as most of it was probably ditched, shredded or buried when the programs were cancelled.