What about the two stowed radiators on P6? Have they been decertified or are they too hard to get to? I bet they simply wouldn't fit. Darn it... just 300 feet away. To think there could be a whole extra shuttle mission, just because of a stray thruster cover.
Quote from: DaveS on 04/02/2009 08:37 amQuote from: Analyst on 04/02/2009 08:21 amNot the whole rotating assembly, just one radiator. No need to replace the whole thing. The radiator is maybe 2 x 3 meters / 1,000 kg max and would fit nicely on an ICC or another cross bay structure. No need for an extra dedicated flight. AnalystI think you're actually talking about the radiator beam assembly on which the three radiator wing assemblies are mounted on. I was talking about the actual radiator wings. They're the ORUs, not the individual panels.A radiator consists of 8 panels and is, as you say, an ORU in its own right. Folded up they measure about 11ft x 9ft x 2.5ft and weigh about 2,475 lbs (3.35m x 2.75m x 0.76m, and 1120 kg).I'm sure many have seen the attached photo, which gives some idea of scale of these radiators.
Quote from: Analyst on 04/02/2009 08:21 amNot the whole rotating assembly, just one radiator. No need to replace the whole thing. The radiator is maybe 2 x 3 meters / 1,000 kg max and would fit nicely on an ICC or another cross bay structure. No need for an extra dedicated flight. AnalystI think you're actually talking about the radiator beam assembly on which the three radiator wing assemblies are mounted on. I was talking about the actual radiator wings. They're the ORUs, not the individual panels.
Not the whole rotating assembly, just one radiator. No need to replace the whole thing. The radiator is maybe 2 x 3 meters / 1,000 kg max and would fit nicely on an ICC or another cross bay structure. No need for an extra dedicated flight. Analyst
So, do they have spares on the ground? And if not, how long will it take to build one?
Knowing the root cause would be nice.
Quote from: Analyst on 04/02/2009 06:49 pmKnowing the root cause would be nice.The article says that a micrometeorite collision is the current favorite explanation. I imagine it was something similar to the impact that buckled one of the HST's original solar arrays.
Knowing the root cause would be nice.Analyst
Quote from: Analyst on 04/02/2009 06:49 pmKnowing the root cause would be nice.AnalystRoot cause (how the radiator covering separated - possible/probable impact and how it became unstuck..etc) may indeed help in the design of more robust cooling radiators for future space stations. However, I think we will have to stick with the original design for the possible R&R .
Getting it on the ground so the engineers can take a close look at it will be the most useful thing that can be done as far as figuring out the root cause, as long as they can stow it without "damaging the damage" too much. That definitely means sticking with the original design, but at the same time, five other panels appear fine, and there is at least one known difference between that radiator and the other five: the contact with the jettisoned cover.Now for my own thoughts: Since that radiator is apparently an ORU, it can obviously be isolated, although based on the fact that they don't appear to be discussing doing that pre-emptively despite the risk of failure without immediate notice, I'm supposing it would require more than flipping a switch to do so. I'd expect that if they decided that radiator needed it before a replacement was ready, they could drain it and disconnect and cap the ammonia lines and get by with 17% less cooling capacity.
My guess is that any repair would probably take six months to a year to get into the manifest.
Quote from: Ben the Space Brit on 04/03/2009 08:57 pmMy guess is that any repair would probably take six months to a year to get into the manifest.If that turns out to be the case, hopefully it will remain operating normally that long.One other thing to consider is a procedure to jettison the array (throw it overboard) if it can't be returned.If it springs a leak in the panel there's no way they'd risk a return (contaminating the payload bay with ammonia residue and vapors). The same if the array can't be fully folded enough to engage and tighten the panel cinches and locks - otherwise they'd need to develop and carry along enough contingency hardware to lock a partially folded panel tightly in position for reentry.A jettison that large would be fascinating to watch (remember the old Hubble solar wing?), but tricky to implement and get it moving away in a safe direction.