fisher@star.DEC (Burns Fisher ZKO1-1/D42 DTN 381-1466) (12/09/85)
<If you can't see this line, please tell me> Many moons ago, in a completely separate discussion, I posted something which said approximately, "I am always amazed at how spacecraft are designed so closely to their environment, without a great deal of leeway". Examples: Apollo CSM had to rotate all the way to the moon in order to distribute heat; comsats can't hang around in LEO/shuttle/xfer orbit for long because that is not the environment they were designed for. This is not criticism, just fact. (I don't want to get ames!eugene all upset at me again!) I think that this same stuff applies to the ET schemes I have seen discussed. To most of us, the ET is a source of kilo-cubic feet of space, perhaps with only a tiny mod to make it work just right. But think of all the relationships that any tiny mod would mess up! So we need the tank a bit thicker, to hold the air pressure, huh? Yes, but what of the extra mass? What of the change in resonant frequency? What of the strain on the ET/Shuttle coupling? etc etc etc. Oh, we just need to put in a "wet workshop"? How do you test it? Run power through the components while the ET is full of LH2? Etc. My point is this: In most of the discussion I have seen, we are assuming that the benefits are obvious and the costs are low. I suspect that the benefits of having an UNMODIFIED ET in orbit are not obvious in the short term, and the costs of modifying an ET to be useful are not necessarily low. Burns ...decwrl!rhea!star!fisher