The private space industry suffered a setback last Thursday when an explosion ripped through a rocket-engine test area in the California desert, killing three workers and seriously injuring three others.
The industry's first fatal accident is already becoming a defining event in the history of commercial spaceflight -- it's the private rocketeers' Apollo 1.
In 1967, NASA's first moon ship was swept by fire in a ground test, killing all three astronauts on board and forcing a re-evaluation of the Apollo space-capsule design. Thursday's accident will likely force a similar period of self-reflection for the new industry of commercial space travel.
The workers killed in Thursday's blast had been testing a nitrous-oxide delivery system for a commercial spaceship under construction by Scaled Composites for Richard Branson's Virgin Galactic. And while it's too early to tell what effect Scaled's accident will have on the industry as a whole, it's safe to say it will take more than this to put the commercial spaceflight genie back in its bottle.
Meanwhile, the three men who died -- Eric Blackwell, Todd Ivens and Charles Glen May -- are being remembered by others in the industry as heroes who died for a higher calling.
"We are reaching for the stars, and it is not easy," said space entrepreneur and Space Frontier Foundation co-founder Rick Tumlinson in a press release. "Accidents happen. Good people die. And we move on. We move on to reach the goal they died for, because to do less would be to dishonor them and their sacrifice."
Scaled Composites built and flew the first privately funded manned spacecraft, SpaceShipOne, and sent the first commercial astronauts out of the atmosphere in 2004. The company is still the favorite to win the race to send the first paying passengers on brief, suborbital jaunts with its SpaceShipTwo, though the accident is certain to delay the new ship's first flight. It may also give potential passengers reason to question the safety of travel by rocket.
The cause of the accident, which did not involve the firing of a rocket engine, won't be known until the just-begun investigation is complete. For now, Scaled managers won't publicly speculate on it. A shaken Burt Rutan, Scaled's CEO and the designer of many envelope-pushing air- and spacecraft, could only tell reporters the day of the accident, "We were doing a test we believe was safe. We don't know why it exploded. We just don't know."
Nitrous oxide, also called laughing gas for its intoxicating effects when inhaled, is nonflammable and safe to handle under most conditions. "Nitrous is manageable in the context of dentists, whipped-cream containers, hospitals, race cars, etc.," Tim Pickens, head of Orion Propulsion and one-time propulsion chief for SpaceShipOne told Wired News. "But we still have to respect it and remember that it has the potential to release lots of energy."
A 1974 study by the Air Force concluded that nitrous oxide can be handled safely in just about any conditions, as long as it stays in a supercold, liquid state, but warned that "great hazards exist in the gaseous condition at elevated pressure and/or temperature."