Space Forum / Shuttle / August 2004

I'm currently working my way through _From Runway to Orbit: Reflections of a
NASA Engineer_, and am a bit over 1/2 of the way through it.  It's doing well
as I'm putting lots of dog ears in it and lots of good sections to discuss.

Now, I remember STS-1 and some issues with tiles, as I'm sure many of us do.  
Here's a section from Ken I.'s point of view, from the inside, which I found
interesting both from the point of view of reflecting on my memories and the
events of last year.  This is from pages 202-203 (I have the hardcopy edition,
don't know if there is any other).  Note that issue of slideslip is addressed
further on page 215.

{Iliff+}

The next exciting thing that happened on the flight was the opening of the
payload bay doors. If they didn't open right away, the astronauts were coming
back to Edwards at the next opportunity. I don't think the doors opened as
smoothly as I thought they would. There was probably uninformed concern at
Dryden about all of the activities, because although we knew roughly what
should happen, none of it had anything to do with our specialty. Once the
payload bay doors were open, they had video coverage of the Shuttle. They
could see damaged tiles on the orbital maneuvering system (OMS) pods, as well
as what looked like dings on various parts of the vehicle.

The astronauts on STS-l were launched wearing space suits so they were
prepared to use their SR-71 ejection seats if something happened at Mach 3 or
below. I think Mach 3 on the Shuttle occurs around 90,000 to 100,000 feet, so
that probably would have been okay for using the SR-71 ejection seats.
However, I remember some talk at the time that there might be some way, once
in orbit, that the crew could go outside and take a look to see if anything
was damaged on the bottom of the Shuttle, where the greatest heating and
aerodynamic forces were going to be if any tiles there had been damaged.

Otherwise, things seemed to be going fairly well, despite little gripes about
things that would be fixed before the next flight. I remember being very
concerned about whether the Shuttle had significant tile damage on the bottom.
Depending on what the damage was, the vehicle could reenter with a significant
sideslip. If there were very much more than one degree of sideslip, the
thermal protection nosecap would not be the highest heating point, so we would
get a burn-through on the vehicle. There were also concerns that if a large
enough group of tiles was missing, the heating would get into the wing's
aluminum structure and damage it to the point where the vehicle could no
longer fly.

I don't know how Young and Crippen felt about it, but to me it did seem risky.
There was talk of using our classified military cameras to take pictures and
see if there was significant damage to the tiles. Information about our
capability for taking pictures of things in orbit was classified. At any rate,
I remember hearing less talk as we approached the time for the Shuttle to do
its deorbit burn. I assume that they got enough verification with those
classified cameras that there wasn't a significant bunch of tiles missing,
although I never heard directly that they were no longer concerned.

{Iliff-}