The space shuttle Columbia Accident Investigation Board (CAIB) has released what it’s calling “a working scenario” to explain the February 1 tragedy that claimed the lives of seven astronauts–three of them Amateur Radio licensees.

Preliminary findings, based on three months of “intense investigation,” suggest that just over a minute into the January 16 launch, a piece of foam insulation from the shuttle’s external fuel tank struck and damaged the lower left wing reinforced carbon-carbon (RCC) panels. The CAIB says its evidence indicates that a breach in the same area of the left wing allowed hot gases to flow into the wing during re-entry into Earth’s atmosphere, eventually leading to the spacecraft’s destruction.

“The CAIB is continuing testing and analyses to refine the working scenario,” NASA said. The independent investigation board–headed by retired US Navy Adm Harold Gehman–will issue its final report this summer. Gehman told reporters earlier this month that his panel has been careful not to say that the piece of insulation knocked a hole in the leading edge of the orbiter’s wing “because we can’t prove it.”

In an effort to pin down that probability, investigators at Southwest Research Institute in San Antonio has been using a gas-fired cannon to shoot pieces of insulating foam at actual shuttle RCC and insulating tile components.

Lost in the February 1 disaster were Columbia Commander Rick Husband; Pilot Willie McCool; Mission Specialists Kalpana “KC” Chawla, KD5ESI; David Brown, KC5ZTC; Laurel Clark, KC5ZSU; and Michael Anderson; and Payload Specialist Ilan Ramon–an Israeli astronaut.

The Columbia started to break up over the southwestern US as it entered the earth’s atmosphere on the return leg of its 16-day science mission. Many Amateur Radio volunteers provided communication support during the early days of the shuttle debris recovery effort. NASA and Amateur Radio have a longstanding relationship through the Shuttle Amateur Radio EXperiment (SAREX) and Amateur Radio on the International Space Station (ARISS) programs.

More information is available via the NASA Human Spaceflight Web page