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William E. Haynes

Bill Haynes (R) tests the engine the Wright Flyer model that he and friends built in Torrance, California.

8/3/2005
The Space Shuttle: Safety, Risk and Reward, by Bill Haynes

Safety is not a binary function. You are not either "safe" or "unsafe", as you are well aware. You are "safer" or "less safe". Reliability analyses are attempts to determine where on a distribution curve a given system lies. The statistics say that one Shuttle out of about 57 has failed disastrously. If we flew another 113 completed Shuttle missions and none blew up or crashed, it would be lowered to about one in 114. I think Dennis Tito is aware of this, and that is why he said on Fox News that he would not fly on the Shuttle "if they paid him $20 million to do so". The Crew has little choice but to fly anyway ... that's the bargain they made to become members of a very select group.

I would not be enthused about flying on a Shuttle mission, even to break John Glenn's age record! But my perception is less driven by fear than by a lack of enthusiasm for the Shuttle as a space vehicle, per se. I would (as I told a group that was discussing "risk") jump at the chance to participate in a one way trip to Mars. After all, my life expectancy at the age of 81 is probably less than ten years in any case. If I spent those years on such a mission and then died as my expendables were all consumed, what a way to go! As I pointed out to the group, it is not the risk that is important. It is the ratio of risk to reward! And that is true for the Shuttle and for flights to the Moon or Mars. The trouble is that because current NASA manned space flight has degenerated into a make-work project, the rewards are no longer adequate for justifying the risks.

Pat Kelley comments:

I realize there is also a tendency to wax poetic about how much better things were in the golden era of Apollo, but as you and I have discussed, there was the same willingness to ignore or accept unquantified risks during that program. This is the problem with nationalized systems. They tend to be driven by image - national pride and sacrifice.

The question has to be whether the profit motive and stockholder pressure would drive a commercial venture in a similar direction. All of us in the commercial space venture community need to take a sober look at that issue. Traditionally, for example, commercial construction of skyscrapers tended to be extremely high-risk, with safety features added only when the publicity from excessive loss of life became too much. Even now "high iron" workers are considered one of the most at-risk tradesmen.

Anyone who has seen the documentary about Rutan's SpaceShip One, "Black Sky" can see that this venture was as risky as any of the X-plane or NASA ventures. Too late the team recognized that selection of a hybrid propulsion system was not good for a horizontally-launched vehicle, due to the potential for CG problems. The first full-load flight exemplified this problem, when the pilot reported inadequate control right after drop. As the team went over their options as the ship dropped like a stone, they realized there were no good options: either they fired the engine and hoped that as speed built up control would return; or have the pilot try to land heavy, which would have resulted in an impossibly high landing speed, which would have undoubtedly resulted in a fatal crash; or dump the liquid propellant, which would have shifted the CG too far aft, resulting in an unrecoverable stall and an attempt to get the pilot out safely using the crude bailout system. They got lucky after going with the first option, but a catastrophic failure could have easily been the outcome.

The brutal fact is that any form of high-speed transportation is not risk-free. The best we can hope for is that our risk assessment and management team is really thorough. Gratuitous NASA-bashing (or astropreneur-bashing by NASA in retaliation) serves no one's interest. The public needs to be educated that there are still many uncertainties about space flight, and as with air travel the more we fly the better we'll get at it.

Bill Haynes responds:

I think you are trying to squeeze the Shuttle accident rate into a comparison with, e.g., super sonic aircraft safety records .. "no high speed flight is risk free". As one with considerable time in super sonic (capable) aircraft, that is a real stretch! In my mind there is absolutely no excuse for NASA to still be flying the technology of the '70's in 2005, and on 'til 2010. Face it: NASA is forced to do that because every effort they have made to develop a Shuttle replacement, and there have been several that cost billions (Venture Star, Aerospace Planes, etc.), and all have failed! In the case of, e.g., the F-100, crashes not attributable to pilot error usually involved equipment failures or maintenance procedures that had enjoyed many thousands of hours of successful operation. But I venture the guess that maintenance errors share the absolutely lowest contribution to accidents in such aircraft with weather and enemy action. One of the two pilots I lost in Vietnam died because he tried to turn too hard at low altitude to check a report of a (false) fire warning light in his flight leader's aircraft just after take off. That was pilot error brought on by an equipment failure. But no one repeatedly made decisions to ignore indications of dangerous conditions in order to fly the aircraft. Not even at Edwards do they do that.

William E. Haynes is an aerospace systems analyst who worked in senior positions at major systems firms in California until his retirement. He is a fighter jet pilot and flew numerous missions in the Vietnam War.