Five 'lethal' events doomed the crew of space shuttle Columbia almost six years ago, including ill-fitting helmets and 'lack of upper body restraint,' NASA said in a report released today. The Feb. 1, 2003 re-entry accident was not survivable for many reasons, investigators said.

The 400-page report, published suddenly before a major holiday, details the timeline and events that led to the tragic loss of Columbia and commander Rick Husband, pilot William "Willie" McCool, flight engineer Kalpana Chawla, physician Laurel Clark, payload commander Michael Anderson, physician David Brown and Israeli astronaut Ilan Ramon. The investigation, the second to look into the Columbia accident, is also intended to provide guidelines for improving astronauts safety, NASA officials said.
One the key elements in the report: the astronauts had only about 40 seconds of conscious knowledge of something going wrong during the landing attempt. The analysis showed that the crew did not suffer as their vehicle came apart, shattering debris across areas of Texas.
The lethal events and the ensuing recommendations include:
1. Depressurization of the crew module at or shortly after orbiter breakup.

The pressure suit used by space shuttle crews on ascent and entry was not a part of the initial design of the orbiter. It was introduced in response to the Challenger accident. While it protects the crew from many contingency scenarios, there are several areas where integration difficulties diminish the capability of the suit to protect the crew. The Columbia depressurization event occurred so rapidly that the crew members were incapacitated within seconds, before they could configure the suit for full protection from loss of cabin pressure. Although circulatory systems functioned for a brief time, the effects of the depressurization were severe enough that the crew could not have regained consciousness. This event was lethal to the crew.

.... Space shuttle crew training should include greater emphasis on the transition between problem-solving and survival operations.

Future spacecraft must fully integrate suit operations into the design of the vehicle and provide features that will protect the crew without hindering normal operations.

2. Exposure of unconscious or deceased crew members to a dynamic rotating load environment
with a lack of upper body restraint and nonconformal helmets.When the orbiter lost control, the resultant motion was not lethal but did require crew members to brace against the motion. The forebody, which is made up of the crew module and forward fuselage, separated at orbiter breakup. The forebody continued to rotate. After the crew lost consciousness due to the loss of cabin pressure, the seat inertial reel mechanisms on the crews’ shoulder harnesses did not lock. As a result, the unconscious or deceased crew was exposed to cyclical rotational motion while restrained only at the lower body. Crew helmets do not conform to the head. Consequently, lethal trauma occurred to the unconscious or deceased crew due to the lack of upper body support and restraint.

Crew procedures must be re-evaluated in light of the findings regarding the motion of the intact orbiter and the forebody after separation.

Future spacecraft should be evaluated for loss of control motion and dynamics for adequate integration into development, design, and crew training.

Future spacecraft seats and suits should be integrated to ensure proper restraint of the crew in off-nominal situations while not affecting operational performance. Future crewed spacecraft vehicle
design should account for vehicle loss of control to maximize the probability of crew survival.

3. Separation of the crew from the crew module and the seat with associated forces, material
interactions, and thermal consequences. The breakup of the crew module and the crew’s subsequent exposure to hypersonic entry conditions was not survivable by any currently existing capability. It was an extremely significant event, but it was very difficult to characterize because many events appeared to happen in a short period of time.

The actual maximum survivable altitude for the crew module following a breakup of the orbiter is too
complex to compute because it depends on the altitude and velocity at release as well as rotational dynamics that are understood only in a general way. The lethal-type consequences of exposure to entry conditions included traumatic injury due to seat restraints, high loads associated with deceleration due to a change in ballistic number, aerodynamic loads, and thermal events. Crew circulatory functions ceased shortly before or during this event. The ascent and entry suit had no performance requirements for occupant protection from thermal events. The only known complete protection from this event would be to prevent its occurrence.

Future vehicle design should incorporate an analysis for loss of control/breakup to optimize for
the most graceful degradation of vehicle systems and structure to enhance chances for crew survival.
Operational procedures can then integrate the most likely scenarios into survival strategies.

4. Exposure to near vacuum, aerodynamic accelerations, and cold temperatures. The ascent and entry suit system is certified to a maximum altitude of 100,000 feet and velocity of 560 knots equivalent air speed. It is uncertain whether it can protect a crew member at higher altitudes and air speeds.

Crew survival suits should be evaluated as an integrated system to determine the various weak points (thermal, pressure, windblast, chemical exposure, etc.). Once identified, alternatives should be explored to strengthen the weak areas.

5. Ground impact. The ascent and entry suit system provides protection from ground impact with a parachute system. The current parachute system requires manual action by a crew member to activate the opening sequence.
Future spacecraft crew survival systems should not rely on manual activation to protect the crew.
Columbia's end began shortly at about 81.7 seconds after liftoff on Jan. 16, 2003. A piece of foam insulation from the external tank broke off, and flew under the left wing. KSC cameras showed a sudden cloud of debris.
One of the most tragic decisions of that flight was an engineering and management determination that the debris cloud did not indicate a need to photograph the underside and wing area of Columbia. What they missed was a hole, about four to six inches across, that the briefcase-sized foam chunk had carved into the wing's carbon compound leading edge.
After the Columbia accident, a full camera scan of the shuttle's underbody is routinely performed once the orbiter is on orbit. NASA believes that there are still lessons to be learned from the loss that can help protect future space flights.
....the investigation was performed with the belief that a comprehensive, respectful investigation could provide knowledge that would improve the safety of future space flight crews and explorers. By learning these lessons and ensuring that we continue the journey begun by the crews of Apollo 1, Challenger, and Columbia, we help to give meaning to their sacrifice and the sacrifice of their families. It is for them, and for the future generations of explorers, that we strive to be better and go farther.
The report builds on the 2003 accident study. As NASA builds its new Ares rocket and Constellation components, a further understanding of risks to crew are essential. The report includes technical evaluation and 30 specific recommendations to improve flight safety in upcoming generations of spacecraft and missions.

NASA has a portal to honor the Columbia astronauts.

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