Photo Of The Day

Photo: Associated Press

Photo: Associated Press

Space Shuttle Challenger

Exploded 29 Years Ago?

The intact crew cabin was seen exiting the cloud by a tracking camera after its trajectory carried it across an adjacent contrail. The Red Circle on the photo is indicating the crew cabin.

NASA has paid tribute to the crews of Apollo 1 and space shuttles Challenger and Columbia on its annual Day of Remembrance. Jan. 28, it marks the 29th anniversary of the space shuttle Challenger disaster that left seven astronauts dead. Challenger’s launch had been delayed several times. Ultimately, its mission lasted just 1 minute and 13 seconds. It traveled 18 miles.

The crew cabin, made of reinforced aluminum, was a particularly robust section of the shuttle.?During vehicle breakup, it detached in one piece and slowly tumbled into a?ballistic arc. NASA estimated the load factor at separation to be between 12 and 20 g; within two seconds it had already dropped to below 4 g and within ten seconds the cabin was in?free fall. The forces involved at this stage were likely insufficient to cause major injury.

At least some of the astronauts were likely alive and at least briefly conscious after the breakup, as three of the four recovered?Personal Egress Air Packs?(PEAPs) on the flight deck were found to have been activated. Investigators found their remaining unused air supply roughly consistent with the expected consumption during the 2 minute 45 second post-breakup trajectory.

While analyzing the wreckage, investigators discovered that several electrical system switches on Pilot Mike Smith’s right-hand panel had been moved from their usual launch positions. Fellow Astronaut?Richard Mullane?wrote, “These switches were protected with lever locks that required them to be pulled outward against a spring force before they could be moved to a new position.” Later tests established that neither force of the explosion nor the impact with the ocean could have moved them, indicating that Smith made the switch changes, presumably in a futile attempt to restore electrical power to the cockpit after the crew cabin detached from the rest of the orbiter.

Whether the astronauts remained conscious long after the breakup is unknown, and largely depends on whether the detached crew cabin maintained pressure integrity. If it did not, the time of useful consciousness at that altitude is just a few seconds; the PEAPs supplied only unpressurized air, and hence would not have helped the crew to retain consciousness. If, on the other hand, the cabin was not depressurized or only slowly depressurizing, the astronauts may have been conscious for the entire fall until impact.

NASA routinely trained shuttle astronauts for splashdown events, but the cabin hit the ocean surface at roughly 207?mph (333?km/h), with an estimated deceleration at impact of well over 200?g, far beyond the structural limits of the crew compartment or crew survivability levels.

On July 28, 1986, Rear Admiral?Richard H. Truly, NASA’s Associate Administrator for Space Flight and a former astronaut, released a report from?Joseph P. Kerwin, biomedical specialist from the?Johnson Space Center?in Houston, relating to the deaths of the astronauts in the accident. Kerwin, a veteran of the?Skylab 2?mission, had been commissioned to undertake the study soon after the accident. According to the Kerwin Report:

The findings are inconclusive. The impact of the crew compartment with the ocean surface was so violent that evidence of damage occurring in the seconds which followed the disintegration was masked. Our final conclusions are:

  • The cause of death of theChallenger?astronauts cannot be positively determined;
  • The forces to which the crew were exposed during Orbiter breakup were probably not sufficient to cause death or serious injury; and
  • The crew possibly, but not certainly, lost consciousness in the seconds following Orbiter breakup due to in-flight loss of crew module pressure.

Some experts believe most if not all of the crew were alive and possibly conscious during the entire descent until impact with the ocean. Astronaut and NASA lead accident investigator Robert Overmyer?said “Scob fought for any and every edge to survive. He flew that ship without wings all the way down… they were alive.

NASA is hosting special content on its site to pay tribute to the fallen astronauts.?View the content here.?