Re: [twuug] Space Shuttle Columbia blows up on reentry!

[kjmck@xxxxxxxxxxxxxxxx]

I believe I heard someone from NASA say the remote manipulator arm wasn't installed for this mission -- other equipment took its place.

Kevin

On Sun, 2 Feb 2003 21:48:10 -0500
Dave hamby <Dave.Hamby@cox.net> wrote:

> Back in the mid-80's ACM Communications had a nice article on the  
> Shuttle Flight Software. My recollection was that everything was in 4  
> channels from sensor to actuator. IBM Federal Systems developed the  
> computers and flight software for the application. The idea was that if  
> a channel went bad, the happy machines would out-muscle the sick one  
> and the bird would fly correctly. My recollection is that the flight  
> software is customized for each mission.
> 
> On several occasions, one channel failed in flight, usually hardware  
> but the vehicle was able to complete the mission and return home.
> 
> There was a fifth computer on board of independent manufacture and  
> programming (Rockwell, I believe)  that could be used to reenter and  
> land.
> 
> The article described the validation and verification procedure used.  
> The Shuttle flight software is probably the most carefully tested code  
> on the planet.  They were very careful about correctness and  
> reliability.
> 
> Columbia had just been through a major overhaul or upgrade including  
> new glass cockpits. This is a rolling upgrade and it is my  
> understanding that the code has flown on other missions on other  
> vehicles. I have no idea how much hardware or code was replaced. My  
> understanding was that the flight deck display devices and software  
> were updated to have functionality similar to that in a jet transport.
> 
> NASA is still reviewing telemetry and piecing together a sequence of  
> high temperature indications and instrument failures on the left side  
> of the vehicle.  Still too early for a hypothesis confirmation. One is  
> that shed debris (insulation or ice) from the liquid fuel tank damaged  
> the insulation of the left side of the vehicle. This came from post  
> launch review of video footage. The flight rules check the ice build-up  
> and won't allow the flight if ice accumulates to the point were the  
> windows or insulation would be threatened if  ice were shed during the  
> ascent.
> 
> The press conference said that the film of the ascent had been  
> reviewed. Some debris were shed and struck the left side of the  
> vehicle. Whatever happened, there were no indications of damage until  
> the vehicle had begun reentry and was over California. From an analysis  
> of the film (frame by frame) NASA concluded that things were OK and  
> that there was nothing they could do differently  if there had been  
> significant damage to the insulating tiles or wing. The reentry  
> attitude and trajectory already minimize the heat and stress absorbed  
> by the vehicle. It couldn't be made lower.
> 
> I'm somewhat surprised that they did not try to inspect the vehicle  
> using the TV on the remote manipulator arm. One would think they could  
> look at the upper surfaces but the external tank and are on the bottom  
> of the vehicle and out of reach. The presenters mentioned that they had  
> tried to photograph a shuttle in orbit  once before but that the  
> results were of too low a quality to be useful.
> 
> WHRV has been carrying the NASA press conferences. One ran at around  
> 1700 Sunday that gave good detail.  Can't find it at NPR.ORG or  
> NASA.GOV.
> 
> Dave
> 
> On Sunday, February 2, 2003, at 05:27  PM, Anthony VanCampen wrote:
> 
> >     I got a call from my sister in-law, who wanted to know if it was
> > possible to reprogram the flight control computers on the shuttle.  My
> > recollection is that there are three independent computers running the  
> > same
> > program and that they are dedicated to the flight management tasks.  I  
> > old
> > her that anything was possible, but that I didn't think that it was  
> > likely
> >     Does any one know what OS the flight comp(s) use?  My guess is  
> > that it
> > is an embeded OS with a very limited set of functions?
> >
> > Tony
> >
> >
> > -
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