rjn@hpfcla.UUCP (02/15/86)
re: tidbits from Aviation Week & Space Technology, Feb. 10, 1986 Lead article: "Ruptured Solid Rocket Motor Caused Challenger Accident" The following are answers to questions I have had since the accident, but which have not been answered (or even asked) by the mass media. I suspect some of you may have been asking also. There are also some facts I have not heard or seen elsewhere. None of this is direct quotes. The abbreviations are expanded as footnotes. * AWST states that the ET explosion was caused by the right SRB separating at its lower attach point, then rotating outward. The upper portion of the SRB (above the upper attach point) ruptured the ET. The as yet unexplained "plume" may have caused the lower detachment, but evidently did NOT cause the explosion by blowtorching the ET at that point. Rate gyro telemetry data supports this. Also, the right SRB was trailing its recovery parachute immediately following the explosion (and prior to destruction by the RSO), consistent with the nose cone having been knocked off by contact with the ET. Meanwhile, a TV report has it that the SRB "burned through the external tank and ignited the liquid oxygen". [no comment] * These SRBs were the current seamless steel design. The filament-wound cases were not planned to go into service until the first Vandenberg launch. * At 40 sec. into the flight, the vehicle flew through a wind shear. Both SMEs and SRBs pivoted to compensate. There was no comment on whether this shear was typical and/or significant. The SRB leak was first detected by cameras at 59 sec. The explosion was at 73 sec. * There is concern about stresses on the SRBs. The entire weight of the launch vehicle rests on them on the mobile launch platform. The whole vehicle rocks as much as 20 inches forward and back during the time between SME ignition and prior to SRB ignition. These stresses were designed for. * As other posters to net.columbia and net.space have stated, NASA confirmed that there is no survivable way to separate from firing SRBs. Analysis revealed that the orbiter would likely pivot around the umbilical connection aft. This would cause structural failure of the wings due to the rapid increase in angle of attack and/or would cause an explosion due to fuel line rupture. The article didn't state, but this seems to presume that the SMEs would have to be operating; that shutting them down before an ET/SRB separation would have other destructive consequences. Presumably a premature SRB sep would also have problems. * Although the SRBs were destroyed by the RSO, NASA expects them to be sufficiently intact to provide significant data. They also carry cameras. The article did not indicate whether or not the cameras would have been destroyed by the ordnance, nor whether the film could survive sea immersion after destruct. * There was some discussion in the net.* groups about what a shuttle ride would be worth, and more recently about whether you'd still be willing to go in light of the accident. This AWST has an article about Japanese reaction. They have some payloads (and payload specialists) planned for the shuttle. The specialists said they are still willing to go. * The spares (potential fifth orbiter) program is nearly complete. This is by no means a complete vehicle. There has also been some confusion about the number of orbiters. Here's the breakdown: Enterprise: not spaceworthy - currently at Dulles Columbia: recently returned to operational status after mods Challenger: lost Discovery: operational Alantis: delivered last year Spare parts: program (not orbiter) to complete in 1987 Wouldn't it be nice if there were NEWS on TV and radio? Regards, Hewlett-Packard Bob Niland 3404 East Harmony Road [ihnp4|hplabs]!hpfcla!rjn Fort Collins CO 80525 ET External Tank RSO Range Safety Officer SME Shuttle Main Engine (on the orbiter) SRB Solid Rocket Booster