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Re: Columbia's safety margins misread, expert tells panel




On Wednesday, Mar 26, 2003, at 20:52 US/Central, Scott Avery WA6LIE 
wrote:

> From what I have seen, it appears clear that the foam most likely with 
> some
> heavy ice attached to it had an impact that might have been enough to 
> create
> damage.

It sure looked like it.  The chunk of foam looked like natural foam 
color before it hit the wing, but whatever fell behind the wing after 
impact looked noticeably whiter, like it might have had a lot of tile 
fragments in it.  I don't have the footage with me to go over it frame 
by frame, but I'll probably find an .mpg of it somewhere I can take a 
closer look at.  It might just be that whatever it was fell down 
further to where it was backlit by the SRB's a little more, which might 
have caused something of a color shift, but it sure looked like what 
fell down after impact was a different color and appeared to be 
somewhat more mass.  It could have potentially been several dozen or 
even a few hundred tiles affected.

> It would have been nice if an EVA could have been done, seeing this
> was a concern of NASA. Maybe in the future there will be EVA's or 
> maybe a
> remote camera that can be sent around the vessel.

I thought about that.  I also thought that it would be prudent on 
future missions to carry an emergency docking adaptor that could allow 
crew transfer to the ISS or a rescue shuttle flight, in case the damage 
to the HRSI tiles is found to be outside safe reentry limits.  The 
shuttles can autoland if need be, I think, and it might be a good 
safety option to be able to bring the shuttle down unmanned and bring 
the crew down on a rescue flight.

The main problem would be the weight of the docking adaptor, plus the 
turnaround time in the OPF and the likelihood of having to keep a crew 
on-orbit for a couple of weeks while a rescue mission is configured, 
plus the impact on a shuttle fleet that's already down one bird and 
would need another to standby for rescue under the new mission rules 
that would undoubtedly be required.  And if a rescue flight in turn 
ends up with *its* heat shield in an unsafe condition, then you're 
really in a jam.

> It is a shame, but an awakening too.
> These Shuttles are considered old, but there is a lot of old military 
> and
> civilian aircraft still in service. With new technologies available,
> maybe we can have a space plane that launches off a 747 and get rid of 
> one
> of the potential dangers of space flight. That is the violent masses of
> energy produced to get the Shuttle from ground to space.

I've often thought about that, considering that the part of ascent from 
SRB ignition to SRB sep could conceivably be replaced with an aerial 
launch at high altitude and airspeed.  A separate automated launch 
aircraft could even allow a launch to be aborted before 
ignition/separation and simply fly a powered return flight to KSC, and 
the entire system could be made to use a major runway at almost any Air 
Force base or large airport as a contingency.  It's an *attractive* 
solution.  But, still runs into the same laws of diminishing returns ..

IIRC, at one point there *was* some serious talk of a crew-only vehicle 
that could be launched on top of a Titan.   There's a finite supply of 
Titans, but it would certainly be an alternative if we can find a good 
heavy-lift booster for the cargo .. we lose the ability to bring a 
satellite to earth, but aside from LDEF payloads, when have we ever 
used that? ..

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