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Thursday, October 30, 2014

Russian Roulette

The malfunction and then detonation of the Antares/Cygnus cargo spacecraft at Wallops on Tuesday is now being tied to the use of refurbished 1960s Soviet vintage AJ26 rocket engines. I'm not going to speculate on whether or not this is the case; I suspect that the age of the engines had very little to to do with the accident, but I have no evidence to back this up either way.

What is more conclusive is that chemical rockets remain A) the only means we have of launching any payload into low earth orbit and beyond and b) dangerous as hell.

A little bit of sloppy number crunching, looking just at the space shuttle program. Five orbiters totaling some 130 launches, two of which failed catastrophically. That's about a 1.5% failure rate. Scaled up to commercial aircraft, that's about 20 major airline disasters every single day. At Seattle-Tacoma International Airport. By itself.

This is a serious problem for true commercial spaceflight. If the ground crew cheered every time a Boeing 737 took off or landed safely, nobody in their right mind would fly in Boeing 737s. For routine commercial spaceflight to be feasible, we need something which works reliably every time it flies. Highly volatile chemical rockets probably are not the answer.

One possible answer floating around (sorry) is lighter than air craft. The idea of riding a dirigible into space, at first glance, seems a little absurd. But John Powell of JP Aerospace has demonstrated how a hypersonic dirigible could reach the International Space Station, and beyond. Another possibility is using less volatile hybrid (HTPB/N2O "rubber and laughing-gas") rockets, but these have yet to reach the 100 km Kármán line, much less low earth orbit. But better propellants and/or oxidants may be found, which are still reasonably stable. Until then, what we have looks less like science than theology. And if part of your routine flight-plan includes "pray real hard," you're not yet ready to fly grandma to the moon.

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