miller@uiucdcsb.CS.UIUC.EDU (02/04/86)
Two parts here: first a reply & then reasons why I do not think we should build a replacement space shuttle. > He called the director of flight safety for the SRBs in Florida > shortly after the explosion and was told that the pilot knew there was > a problem and had made the decision to jettison both the SRBs and the ET > and abort back to ground, but that the thing exploded before he could > accomplish any of this. Having recovered one of the nosecones of the SRBs (which was lowered by a parachute) examinations reveal that the separation motors were not fired, indicating that neither the computer nor the copilot initiated separation procedures. Unless someone could read the copilot's mind, there is no indica- tion that he suspected anything was wrong. > Also, from a (possibly) less reliable source: The thing that came down on > a parachute that took forever (almost 20 mins.) to fall was supposedly > the "black box"; just like the flight recorders used on airliners. I don't > know if it was successfully recovered. NASA stated that the orbiter does not carry a similar "black box" flight recorder. Most of the data is fed from PASS (Primary Avionics Software System) via downlink to mission control in real-time. ****************** On another subject: CNN (quoting NASA and Rockwell sources) claims that the orbiters, which were originally designed to be reused 100 times, are now estimated to be good for only 25 flights. It seems that the stresses are causing more fatigue than the simulation models said they would. Challenger already had 10 flights, or almost half its realistic lifespan. Estimated replacement cost by Rockwell is 2.2 billion dollars. Cost/pound, which was supposed to decrease under the shuttle program, has actually increased (even adjusting for inflation). My question: should we really build a replacement shuttle, or would it be better to get by with the three we still have (plus the Titan booster for launching satellites) until the next generation space shuttle design is completed? After all, while some activities definitely require the shuttle, launching satellites with it is overkill. (Please don't flame me for being antispace - it's just that we have to ask ourselves if only 25 (!) flights is a system we want to stick with.) A. Ray Miller Univ Illinois