From my recollection of the report, the sequence was:The hole in the wing leading edge allowed plasma to progressively destroy the inner structure of the wing, including some hydraulic lines.Normal operation of the hydraulic system (to move aerodynamic surfaces) leaked hydraulic fluid until the system was empty.This loss of hydraulic power meant the vehicle could no longer maintain a controlled attitude, and it pitched up, breaking up not long after.I think the APU's were working fine for some time after hydraulic power was lost, and were not a contributing cause.There is a full report on L2.
Quote from: A_M_Swallow on 02/01/2013 05:48 am In future similar procedures can be applied to other spacecraft.Don't want to keep going OT, but I think it is a very bad idea to always require a backup spacecraft ready to fly every time we send a manned mission up. Do any of the current visiting vehicles to the ISS get full vehicle exterior reviews before docking?
In future similar procedures can be applied to other spacecraft.
Quote from: rdale on 02/01/2013 01:27 pmQuote from: A_M_Swallow on 02/01/2013 05:48 am In future similar procedures can be applied to other spacecraft.Don't want to keep going OT, but I think it is a very bad idea to always require a backup spacecraft ready to fly every time we send a manned mission up. Do any of the current visiting vehicles to the ISS get full vehicle exterior reviews before docking?Colombia was destroyed by a special case of the general problem called hull breach. It does not matter whether the hull was breached by foam, iceberg or bird strike people onboard frequently get killed.The story of Titanic's hull breach, including similarities.http://www.cuug.ab.ca/~branderr/risk_essay/titanic.html
Quote from: Wayne Hale on 01/15/2013 02:21 amBen,The more pertinent question for the future is why was there not better ascent imagery?Keep digging.You know, I still don't think this point has been addressed or answered by anyone here, at least to any satisfaction I have seen.I think it requires more than just NASA.
Ben,The more pertinent question for the future is why was there not better ascent imagery?Keep digging.
Quote from: iamlucky13 on 02/02/2013 04:40 amIn addition to the resources on L2, the CAIB report is publicly available. Page 65 of this part of the report is a good place to start:http://www.nasa.gov/columbia/caib/PDFS/VOL1/PART01.PDFI don't see or recall reading about loss of hydraulics, except articles from the first few weeks after the accident. Sensors related to some of the hydraulics were the first things to fail, but the conclusion was that was due to burn-through of the sensor wiring, not actual loss of hydraulics..The report section referenced above discusses the telemetry that indicates the shuttle was experiencing progressively increasing drag on the left wing as it shed pieces that altered the aerodynamics, and then in the later stages, began to deform in bulk.There was initially a tendency to yaw left, and roll left, shifting later to a stronger left yaw, but RIGHT roll tendency. Reading that, my first speculation was the weakening forward spars allowed the leading edge of the wing to begin to deflect upwards, effectively increasing the angle of attack of the left wing. The CAIB working scenario (page 196 onward), however, suggested a large dimple-like "recession" of the lower wing skin due to failure of some of the forward ribs, with a comparable aerodynamic effect (increased left wing AOA).This left yaw, right roll effect abruptly increased a couple seconds before telemetry was lost. The RCS jets were still firing to counter the yaw, and the ailerons were countering the roll, which suggests hydraulics were still working, but at this point were losing ground.42 seconds after radioed telemetry was lost, the onboard data recorder stopped. 5 seconds later, the breakup of the airframe occurred.I'm having trouble finding any clear info in the reports about what happened in those 47 seconds. I had the impression Columbia was in a tumble or spin, but I've never even seen a confirmation NASA knows what happened in that window.Read the Columbia Crew Survival Investigation Report.http://history.nasa.gov/columbia/columbiacrewsurvival.pdf
In addition to the resources on L2, the CAIB report is publicly available. Page 65 of this part of the report is a good place to start:http://www.nasa.gov/columbia/caib/PDFS/VOL1/PART01.PDFI don't see or recall reading about loss of hydraulics, except articles from the first few weeks after the accident. Sensors related to some of the hydraulics were the first things to fail, but the conclusion was that was due to burn-through of the sensor wiring, not actual loss of hydraulics..The report section referenced above discusses the telemetry that indicates the shuttle was experiencing progressively increasing drag on the left wing as it shed pieces that altered the aerodynamics, and then in the later stages, began to deform in bulk.There was initially a tendency to yaw left, and roll left, shifting later to a stronger left yaw, but RIGHT roll tendency. Reading that, my first speculation was the weakening forward spars allowed the leading edge of the wing to begin to deflect upwards, effectively increasing the angle of attack of the left wing. The CAIB working scenario (page 196 onward), however, suggested a large dimple-like "recession" of the lower wing skin due to failure of some of the forward ribs, with a comparable aerodynamic effect (increased left wing AOA).This left yaw, right roll effect abruptly increased a couple seconds before telemetry was lost. The RCS jets were still firing to counter the yaw, and the ailerons were countering the roll, which suggests hydraulics were still working, but at this point were losing ground.42 seconds after radioed telemetry was lost, the onboard data recorder stopped. 5 seconds later, the breakup of the airframe occurred.I'm having trouble finding any clear info in the reports about what happened in those 47 seconds. I had the impression Columbia was in a tumble or spin, but I've never even seen a confirmation NASA knows what happened in that window.
Quote from: Wayne Hale on 01/15/2013 02:21 amBen,The more pertinent question for the future is why was there not better ascent imagery?Keep digging.You know, I still don't think this point has been addressed or answered by anyone here, at least to any satisfaction I have seen.
Quote from: robertross on 02/02/2013 02:34 amQuote from: Wayne Hale on 01/15/2013 02:21 amBen,The more pertinent question for the future is why was there not better ascent imagery?Keep digging.You know, I still don't think this point has been addressed or answered by anyone here, at least to any satisfaction I have seen.I think it requires more than just NASA....Now in any organization you have to make trade-offs on budget, even on safety issues. There's not enough money to fully fund everything. Do you buy better tracking cameras or do you buy an X-ray machine for examining the TPS on the orbiter?There were other similar issues. We had a Nobel Prize winner on the board who was really into digital cameras and he was really peeved to learn that NASA was operating film cameras both on the orbiter and on the ground when digital technology was available. Yeah, there's a cost issue, but he did have a point that for things like tracking and vehicle health assessment you want the data as soon as possible. But again, it's money. And it's also management. They go hand in hand.
Quote from: robertross on 02/02/2013 02:34 amQuote from: Wayne Hale on 01/15/2013 02:21 amBen,The more pertinent question for the future is why was there not better ascent imagery?Keep digging.You know, I still don't think this point has been addressed or answered by anyone here, at least to any satisfaction I have seen.From page 60-61 of the CAIB pdf.Imaging IssuesThe image analysis was hampered by the lack of high resolution and high speed ground-based cameras. The existing camera locations are a legacy of earlier NASA programs, and are not optimum for the high-inclination Space Shuttle missions to the International Space Station and oftentimescameras are not operating or, as in the case of STS-107, out of focus. Launch Commit Criteria should include that sufficient cameras are operating to track the Shuttle from liftoff to Solid Rocket Booster separation.Similarly, a developmental vehicle like the Shuttle should be equipped with high resolution cameras that monitor potential hazard areas. The wing leading edge system, the area around the landing gear doors, and other critical Thermal Protection System elements need to be imaged to check for damage. Debris sources, such as the External Tank, also need to be monitored. Such critical images need to be downlinked so that potential problems are identified as soon as possible....
The image analysis was hampered by the lack of high resolution and high speed ground-based cameras. The existing camera locations are a legacy of earlier NASA programs, and are not optimum for the high-inclination Space Shuttle missions to the International Space Station and oftentimes cameras are not operating or, as in the case of STS-107, out of focus.
I agree with all you say (and grateful for your work with CAIB, no doubt a diffcult task).
I'm seeing safety tradeoffs, with money at its center, as a big hole in the 'plan' to flying a safe vehicle.
That's not the original. It was a highly enhanced version, made painstakingly during the months after the accident.
Quote from: robertross on 02/02/2013 11:42 pmI agree with all you say (and grateful for your work with CAIB, no doubt a diffcult task).Not sure what you mean by "difficult." It was a good job, they paid me well, and it was important work. I'm glad I was there.
Quote from: Jorge on 02/03/2013 12:39 amThat's not the original. It was a highly enhanced version, made painstakingly during the months after the accident.I know that. All I'm saying is that the out-of-focus tracking camera wasn't the only one shooting the launch with high resolving power.
Quote from: Blackstar on 02/03/2013 12:03 amQuote from: robertross on 02/02/2013 11:42 pmI agree with all you say (and grateful for your work with CAIB, no doubt a diffcult task).Not sure what you mean by "difficult." It was a good job, they paid me well, and it was important work. I'm glad I was there.The emotional aspect.