From: kjenks@gothamcity.jsc.nasa.gov
Subject: Re: Deployable Space Dock..
Organization: NASA/JSC/GM2, Space Shuttle Program Office
X-Newsreader: TIN [version 1.1 PL8]
X-Posted-From: algol.jsc.nasa.gov
NNTP-Posting-Host: sol.ctr.columbia.edu
Lines: 42

: In article <1993Apr30.000050.1@aurora.alaska.edu> nsmca@aurora.alaska.edu writes:
: >Why not build a inflatable space dock.

Henry Spencer (henry@zoo.toronto.edu) wrote:
: If you're doing large-scale satellite servicing, being able to do it in
: a pressurized hangar makes considerable sense.  The question is whether
: anyone is going to be doing large-scale satellite servicing in the near
: future, to the point of justifying development of such a thing.

That's a mighty fine idea.  But since you asked "Why not," I'll
respond.

Putting aside the application of such a space dock, there are other
factors to consider than just pressurized volume.  Temperature control
is difficult in space, and your inflatable hangar will have to 
incorporate thermal insulation (maybe a double-walled inflatable).
Micrometeoroid protection and radiation protection are also required.
Don't think this will be a clear plastic bubble; it's more likely
to look like a big white ball made out of the same kind of multi-layer
fabric that soft-torso space suits are made out of today.

Because almost all manned space vessels (Skylab, Mir, Salyut) used
their pressurization for increased structural rigidity, even though
they had (have) metal skins, they still kind of qualify as inflatable.

The inflation process would have to be carefully controlled.  The
space environment reduces ductility in exposed materials (due to
temperature extremes, monotomic Oxygen impingement, and radiation
effects on materials), so your "fabric" may not retain any flexibility
for long.  (This may not matter.)  Even after inflation, pressure
changes in the hangar may cause flexing in the fabric, which could
lead to holes and tears as ductility decreases.

These are some of the technical difficulties which the LLNL proposal
for an inflatable space station dealt with to varying degrees of
success.

-- Ken Jenks, NASA/JSC/GM2, Space Shuttle Program Office
      kjenks@gothamcity.jsc.nasa.gov  (713) 483-4368

     "Good ideas are common -- what's uncommon are people who'll
      work hard enough to bring them about." -- Ashleigh Brilliant
