Part 10: Conclusion – Shuttle Crew Safety Could Be Improved
The Shuttle's replacement: the Orion capsule
Some things have changed for the better. Debris from the Space Shuttle Challenger was dumped into an abandoned missile silo. Out of sight, out of mind, perhaps. Even the data was not catalogued for use in further investigations. The Spacecraft Crew Survival Integrated Investigation Team (SCSIIT) lamented that, “The lack of debris for comparison and methods of data preservation made the Challenger data essentially unavailable for this investigation.”
Not so with the debris and data from Columbia. Both have been preserved to allow further investigation and research into the development of future spacecraft and crew survival equipment. Given the timing of the Columbia Crew Survival Investigation Report, the SCSIIT members might not have had any other option to make their work meaningful. Design of space vehicles for the Constellation program, which are to take astronauts to the Moon and possibly to Mars, has already begun.
On the other hand, as a result of the Challenger accident, NASA made some substantial changes to improve the survivability of a Space Shuttle accident. Unfortunately, the Columbia accident does not appear to have initiated much in the way of further improvements, despite a demonstrated need to do so. Following the report of the Columbia Accident Investigation Board, the Shuttles were returned to service, not waiting for the Columbia Crew Survival Investigation Report.
SCSIIT does not seem to have harboured any illusions that their report would impact the Shuttle program. In fact, SCSIIT maintained confidentiality until they had published their report, although apparently they did release some interim directives internally. It's not possible for me to say if any of their findings benefited the first eleven missions after Columbia, except for the replacement of the seat belt inertial reels.
NASA’s conclusion from the Columbia accident seems to be, “We’ve identified the problem and made changes so it probably won't happen again. If it does, we'll find it and fix it.” They’ve increased inspection of the external tank prior to launch, increased the quantity and quality of surveillance during ascent, developed repair kits, implemented a thorough in-orbit investigation of the Shuttle, and have a contingency plan for a second Shuttle to mount a rescue mission.
Foam fell off the external tank as the Space Shuttle Endeavour headed for orbit on July 15th, 2009, so the threat of catastrophic damage from that remains, even if NASA is better at detecting it. But what if there are other unknown threats? I think a different approach is in order.
ADDENDUM
The Summary Report of the Review of U.S. Human Space Flight Plans Committee was published on September 8th, 2009. The Committee was set up to provide the Obama Administration with an evaluation of NASA's current plan versus its budget. In the words of the Committee:
“The Committee noted that the projected flight rate is nearly twice that of the actual flight rate since return to flight after the Columbia accident. Recognizing that undue schedule and budget pressure can subtly impose a negative influence on safety, the Committee finds that a more realistic schedule is prudent. With the remaining flights likely to stretch into the second quarter of 2011, the Committee considers it important to budget for Shuttle operations through that time.”
In other words, the Committee is concerned that the budget set by the Bush Administration, which retires the Shuttle fleet in 2010 so that NASA can concentrate on the next generation of space vehicle, has resulted in an overly compressed schedule for the remaining Shuttle flights. The Challenger accident may be seen as an example of past reluctance to delay the program (until the known O-ring flaw could be rectified). The Obama Administration has already allowed NASA to extend the Shuttle program into Fiscal Year 2011, but it hasn't budgeted any additional funding. I hope the Administration acts on the Committee's recommendation to provide sufficient time and money to operate the Shuttles safely.
