Just Barely Unacceptable Risk

June 27th, 2006

Posted by: Roger Pielke, Jr.

The Space Shuttle is set to launch on July 1, 2006. According to NASA officials, this is the first flight being launched in which the risk has been deemed “unacceptable”:

NASA’s top safety official and the agency’s chief engineer said today they opposed the shuttle Discovery’s launch July 1 because of concern about so-called ice-frost ramps on the ship’s external tank that could shed foam and cause catastrophic impact damage. In fact, Discovery’s flight will be the first in shuttle history with a system formally classified in the “unacceptable risk” category.

Bryan O’Connor, director of Safety and Mission Assurance at NASA headquarters in Washington, and Chris Scolese, the agency’s chief engineer, both declined to concur with the decision to launch when signing an official Certificate of Flight Readiness, or CoFR, following a flight readiness review that ended Saturday.

But both men said today they viewed the issue as a threat to the vehicle – not a direct threat to the crew – and as such, they accepted NASA Administrator Mike Griffin’s decision to press ahead with launch.

Here is how O’Connor characterized his thinking:

O’Connor today acknowledged a perception problem with the seemingly contradictory positions, but said it was the result of the flight readiness review process and the engineering community’s classification of the ice-frost ramps as “probable/catastrophic” in NASA’s integrated risk matrix.

“When this first came up, most folks were pretty concerned about it,” he said. “That concern level has been going down as we learn more about it, as we refine the models, we look at the data. We haven’t changed the design, but there’s a little bit of a shift toward more comfort than the other direction.

“I think we’re just barely into the unacceptable risk area. I think it’s unacceptable to the program to go fly in this condition. But I also believe if it’s elevated to the right authority, an administrator (Griffin) who looks at it and with his understanding and his position in the agency who can accept it, then I felt like I was not going to lie down in the flame trench or throw my badge down.”

Is NASA playing Russian Roulette with the future of the space program?

3 Responses to “Just Barely Unacceptable Risk”

  1. Roger Pielke, Jr. Says:



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  3. Jim Angel Says:


    There was a related story on that same yahoo link (under most viewed – science) about the recent firing of director of engineering at the Johnson Space Center. Not much was revealed in the story but it makes you wonder if it was related to the decision to launch July 1.


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  5. Robb M Randall Says:

    I’m not sure I understand the gray area here. In my experience, risk matrices are created to make decisions based on risk. If the risk is unacceptable then it’s… unacceptable!! Why have an unacceptable part of the matrix if it is not going to be used? And how can “a threat to the vehicle – not a direct threat to the crew” be possible. If it is a catastrophic risk to the vehicle then it has to be catastrophic to the crew–period. I must be missing something here. If NASA is truely making the decision as presented in the media then they are wrong, no matter how it is stated.