In answer to
wes_wall, the debris detached when the Shuttle stack was some 82 secs into launch, at ±65,860ft and passing Mach 2.46 (±1620 mph) according to the best analysis. The relative speed of impact of the primary piece of foam on the leading edge was estimated at 775-820 fps (528-559 mph) from high-speed film frames. The time from foam release to impact was 0.2 secs. These figures are from the official investigation's
Working Scenario released on 8 July but have been widely publicised for months. . . . . Also, (elsewhere) this is not a "tile" or "stalactite" issue. I hope this clarifies some of the confused posts above. The pic below shows the analysed debris path.
For the benefit of those without broadband, I'll quote (in blue) a couple of relevant extracts from the report, as it is a 12mb pdf of 189 pages!
The damage was most likely equivalent in size to a 6 to 10 inch diameter hole or area broken from the RCC panel or an adjacent Tee seal. (and referring to the tests)
The exact flight damage is unknown but is believed to be bracketed by these two tests* . . . . . The testing is important in that it confirms that the ET bipod foam can catastrophically damage the RCC.
This photo shows the result of the final test on actual RCC panels referred to by
brockenspectre in her post above - the "Wow" factor. It is probable that the actual damage to Columbia was not this dramatic (re:
* ).
The report also includes ascent data on the leading edge post-impact:
The temperature sensor on the leading edge spar behind RCC panel 9 showed a slightly higher temperature rise than seen on any previous Columbia flight. . . . . STS-107 had a 7.5 degree Fahrenheit rise that started very early during ascent (five to six minutes after launch). Although the data do not prove that the RCC was breached during ascent, the data are consistent with a possible flow path into the RCC cavity via damage in the RCC panels 6 through 8 area.
Re: various posts: personal messages of that nature are quite normal between crew and ground on all missions. The crew were routinely informed of the impact, were assured that it was not an issue ("
in family" - a vile piece of NASA management speak on past damage) and were not expecting anything abnormal on re-entry. The video recovered shows this aspect with grim clarity.
Finally,
avioniker, at this stage of the investigation, I remain convinced that Adm Gehman and his team have a firm handle on the situation you refer to. It seems unlikely that we will see a Challenger whitewash this time. As Sally Ride and others hinted a while back, 107, like 51L, was an avoidable accident where top-level complacency overrode professional engineering concerns. There will be major structural (
sic) changes. Unfortunately it took the lives of another seven good people and an irreplaceable ship to achieve it.