Technology Status of Hydrogen Road Vehicles

A1.4 The Challenger Accident
Certainly the space industry, and the Shuttle program in particular, cannot be compared with the more
mundane activities of traditional industries, including a future hydrogen vehicle industry. Yet when such a
common factor as safety of human life is involved, we must ask ourselves whether the chances of failure
cannot be similarly high.
Feynman (1986), an eminent scientist who formed part of the Presidential Commission that investigated the
accident, stated:
If a reasonable launch schedule is to be maintained, engineering often cannot be done fast enough
to keep up with the expectations of originally conservative certification criteria designed to guarantee
a very safe vehicle. In these situations, subtly, and often with apparently logical arguments, the
criteria are altered so that flights may still be certified in time. They therefore fly in a relatively
unsafe condition, with a chance of failure of the order of a percent (it is difficult to be more accurate).
Official management, on the other hand, claims to believe the probability of failure is a thousand
times less. One reason for this may be an attempt to assure the government of NASA perfection and
success in order to ensure the supply of funds. The other may be that they sincerely believed it to be
true, demonstrating an almost incredible lack of communication between themselves and their
working engineers.
This indictment may be peculiar to the space industry, but a skeptical public may not be so persuaded.
The cause of the accident was simple enough. A rubber O-ring, intended to prevent hot gases from escaping
through a joint between two lower segments of the solid rocket booster, could not expand properly at the cold
ambient temperature of this launch. The escaping gases from the aluminum-based fuel booster acted as a
torch, breached the LH 2 tank and ignited the hydrogen, resulting in the destruction of the vehicle.
The psychological and other pressures on NASA differ from those on the automotive industry. But public
relations, the strife of competition, and so on, can stifle the automotive engineer’s voice. If hydrogen with its
new--not necessarily increased--risks is to become the fuel of the future, the safety culture in the organizations
involved may need to be updated.
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