Friday, January 28, 2011

25 anniversary of the catastrophe in the sky

Read why the catastrophe in the sky was also a disaster in the newsroom.
It's the 25th anniversary of the Challenger disaster. This was an event so shocking, so unexpected, so emotionally intense that most of us still can recall that day with rare clarity. Today I am linking to an earlier post that examined the disaster and why newspapers around the world had disasters of their own when it came to running the picture of the shuttle disintegrating high in the sky off Florida.

The linked post was inspired by an editorial by Paul Berton the former editor-in-chief of The London Free Press: Catastrophe in the sky.

As to the question of did or didn't Challenger explode, the following is from the Huffington Post comments accompanying the Huffington Post article on the 25th anniversary of the disaster. As you can see, the argument continues 25 years later.

jsarets   4 hours ago (4:26 AM)
After reading the comments below, it's worth noting that Challenger did not explode.

A jet of hot gas leaking from the aft segment joint of the right solid rocket booster burned through the aft attach strut between the SRB and the external tank. When the aft end of the SRB swung loose from tank, it drove the tank and orbiter into the oncoming airstream at a high angle of attack.

Aerodynami­c loads caused the near-immed­iate structural failure of the external tank, releasing a massive plume of hydrogen and oxygen that ignited in the wake of the left SRB. This is called deflagrati­on, which differs from detonation in that the propagatio­n of the flame front is subsonic.

The rest of the vehicle, including the wings and vertical stabilizer of the orbiter, proceeded to break up due to the aero loads, but the crew compartmen­t -- which is a self-conta­ined pressure vessel attached to the airframe at four points -- was flung from the vehicle and remained structural­ly intact until it crashed into the ocean at over 200 mph.

Three of the four Personal Egress Air Peaks (PEAPs) on the flight deck were activated and exhibited air consumptio­n consistent with the 2:45 ballistic trajectory between breakup and crash. These packs provide unpressuri­zed air and would not have kept the crewmember­s alive if the crew compartmen­t had lost pressure integrity at over 60,000 feet in altitude.

Additional­ly, several lever-lock­ed switches on the pilot's right-hand electrical power system control panel were thrown after the loss of telemetry downlink, which indicates a futile attempt to restore power to the crew compartmen­t (which had ripped free of its connection­s to the fuel cells).

Even if the crew had been equipped with full-press­ure ACES suits and parachutes as they are today, it is unlikely that they would have been able to successful­ly bail out the crew compartmen­t on a free-fall ballistic trajectory­. The emergency egress system designed in the aftermath requires that the orbiter is in stable controlled flight (but will not be able to make a safe landing).

The only thing that could have saved them would have been a parachute system for the whole crew compartmen­t, similar to those equipped on the F-111 fighter-bo­mber. This was rejected, ironically­, because of the perceived cost and complexity of separating the crew compartmen­t from the vehicle, when Challenger plainly demonstrat­ed that the crew compartmen­t is quite capable of being flung free of the vehicle in the event of a complete aerodynami­c breakup.

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