October 16, 2007—Here we seem to go again.

NASA is presented with a technical problem on the Shuttle and the alternatives, again, are—fix it and delay the launch schedule, or risk flying because "it worked fine in the past".

Allow me to explain.

A NASA safety panel has insisted that Space Shuttle Discovery not fly on October 23^rd because of microscopic cracks in three of the heavy gray heat shields on the Shuttle’s wings. They’re similar to the ones pictured at the left with Scott Hubbard of the Columbia Accident Investigation Board in 2003, after Columbia was lost. NASA program managers are leaning toward launching Discovery this month because the vehicle has flown safely with the same panels in the past. The agency is also on a tight timeline to get the International Space Station completed by mid, to late, 2010 so the Shuttle fleet can be retired.

I don’t mean to be alarmist, but NASA has been criticized for making similar decisions in the past with deadly results. In 1986, Roger Boisjoly, of solid rocket booster builder Morton Thiokol, complained that NASA went ahead and launched Space Shuttle Challenger because he couldn’t "prove" that cold weather would make the rubbery o-rings on the Shuttle’s boosters stiff and unsafe. Following the Columbia disaster in 2003, NASA was again criticized for not testing the heavy gray carbon heat shields after it was proven that foam insulation was falling from the Shuttles’ external fuel tanks. Again, NASA lacked the knowledge of whether foam could break one of those shields. During Columbia launch in January of 2003, one shield did break, and the Shuttle was lost.

If you’d like to read up on this, I write about it extensively in my book "Final Countdown" which is officially released this Sunday.

If NASA replaces the heat shields on Discovery, the vehicle won’t fly until probably December at the earliest. If a launch is attempted and the cracked shields fail, the agency could lose another Shuttle and perhaps another crew.

It appears to be a tough call either way.

More to come.

Photos courtesy of NASA and University Press of Florida