A new report from a study panel details the causes leading to the Space Shuttle Columbia disaster in 2003, with the panel recommending many corrective and preventive moves to avert further tragedies, while also concluding that some factors in the tragedy will remain unknown.

As Columbia lifted off and headed to the International Space Station, a piece of foam insulation broke off from the external fuel tank and punched a hole in a wing of the orbiter vehicle.

Later, during an attempted return to Earth, searing hot gases of reentry entered the wing, melted structural components and caused the loss of the ship and crew of seven.

As we have reported in many previous issues, NASA already has taken many of the steps recommended in the report, such as removing foam insulation from the external fuel tank, using better materials to lessen chances of icing on the tank, and much more.

The final report includes 30 recommendations to improve spacecraft design and crew safety. The recommendations cover a broad range of subjects from crew training, procedures, restraints and individual safety equipment to spacecraft design methods and recommendations regarding future accident investigations.

NASA already has implemented some of the report’s recommendations and is evaluating others. A fact sheet describing actions that have been taken or are in work by both the Space Shuttle Program and Constellation Program as a result of the investigation is available at the same web link as the report.

This was the first-ever in-depth crew survival study of a spaceflight accident. The investigation was conducted by a multi-disciplinary NASA team based at Johnson Space Center. The study team also consulted experts outside of NASA for portions of its work.

To view the Spacecraft Crew Survival Integrated Investigation Team report in full, please go to http://www.nasa.gov/reports on the Web.

To view the report details on fault tree elements not closed, please go to http://www.nasa.gov/columbia/caib/PDFS/VOL2/D04.PDF on the Web.

These are some of the still-unanswered questions that the report panel was unable to resolve. ET means external fuel tank. RCC is reinforced carbon carbon, a material that can withstand the high heat of reentry, shielding the shuttle orbiter vehicle.

Table 1: Fault Tree Elements Not Closed, and Likely Contributed to the Accident.

The "likely contributed to the accident" entries address the release of debris from the ET and the impact of this debris on the orbiter wing RCC panels or T-seals. Although the Super Light Ablator has not been implicated in the foam release, it cannot be ruled out.

Table 2: Fault Tree Elements Not Closed, and Possibly Contributed to the Accident.

The "possibly contributed to the accident" include a number of different means to cause damage to the wing leading edge. The effect of aging (both operational and calendar) of the RCC is uncertain at best. Certain debris sources are listed here as they could lead to relatively heavy objects hitting the wing leading edge. Micrometeoroids and space debris can also cause a large enough hole in the RCC to allow superheated air to enter the wing