The National Transportation Safety Board opened its investigation today into Friday's loss of Virgin Galactic's SpaceShipTwo following an in-flight explosion during a test flight over the Mojave Desert. One crew member was killed and a second seriously injured, according to local law-enforcement officials.
Only two days earlier, Orbital Science Corporation lost an unmanned rocket and cargo destined for the International Space Station to an explosion just seconds after launch. No one was injured in that incident.
The probe is a first for the federal safety agency, noted Christopher Hart, the NTSB's acting chairman, during a brief press conference Saturday morning. It marks the first investigation the NTSB has led involving a human-occupied spacecraft.
As a result, the investigation team is somewhat larger than usual – between 13 and 15 investigators.
“Because this has some new aspects for us, we wanted to make sure we covered all of the bases,” he said.
Because the loss occurred during a test flight, investigators anticipate they will have a wealth of information to help them track down the cause of the tragedy and offer recommendations for correcting them, he added.
The back-to-back tragedies underscore the challenges of safely launching cargo or people into space, aerospace specialists say. But the two companies are so different in experience levels, technological approaches, and objectives that lumping the two incidents together as an indicator of the state of commercial-space efforts in the United States may be premature, especially with accident investigations in such early stages.
“I don't think this spells doom for so-called commercial space,” notes Ann Karagozian, a professor of mechanical and aerospace engineering at the University of California at Los Angeles.
“Many different companies are developing concepts that are experiencing a lot of success,” she adds, with Space Exploration Technologies Corp. (SpaceX) a prime example.
But progress in spaceflight has seldom been smooth. Over the years “the country has seen a number of launch failures,” she adds.
No sector – government or private – has a monopoly on them.
NASA lost seven astronauts when the space shuttle Challenger broke up some 70 seconds after launch, killing the crew. The agency lost three astronauts to a capsule fire in the run-up to the Apollo 1 mission in 1967, and another seven to the breakup of the space-shuttle Columbia on re-entry in 2003.
Among the relative newcomers to spaceflight, SpaceX has had its teething issues. Its first rocket, the Falcon 1, caught fire within a minute after its first test launch. Only with its fourth launch could the company chalk up a fully successful lift-off. Its fifth Falcon 1 launch, also successful, was the model's last as the company fielded its newer Falcon 9 rocket.
As tragic as these failures have been for the people and institutions directly involved and for the nation, each one brings additional technical knowledge, understanding, and expertise that launch providers put in place for future systems, observes Dr. Karagozian, who has served on advisory groups for the country's military and civilian space programs.
SpaceShip Two is a prototype for the craft Virgin Galactic plans to use for its commercial suborbital flights. More than 700 people have paid as much as $250,000 each for eventual rides on the six-passenger craft. In addition, the Southwest Research Institute, a non-profit research-and-development company based in San Antonio, signed a contract with Virgin Galactic in 2011 for eight seats, with an option for 17, to suborbital space.
Virgin Galactic was hoping to loft its first paying customers next year.
If the back-to-back launch tragedies don't spell doom for commercial space, Scaled Composite's loss is likely to be closely scrutinized, not only because of the accident's human toll, but because demand for suborbital flights will be a useful gauge of the market for wider access to space in general.
SpaceShip Two's designer and builder, Scaled Composites, adopted an approach for Virgin Galactic's suborbital craft that hearkens back to the days of the Bell X-1 and later the X-15 – rocket-powered craft that test pilots rode to high altitude beneath a mother ship. After the mother ship released the craft, its motor would ignite to complete its flight. Orbital Sciences had used a similar technique to launch its Pegasus unmanned rocket.
Scaled Composites considers the craft it lost on Friday a prototype. The test flight was the fourth time SpaceShip Two ignited its motor after release from its mother ship, the White Knight Two.
The motor uses solid fuel and a liquid oxidizer – the source of oxygen needed for the fuel to burn. Such hybrid motors are said to be simpler, safer, and less expensive than propulsion systems that use liquid fuel or solid fuel alone.
Earlier this year, Scaled Composites switched the type of solid fuel it used in the rocket motor from one based on rubber to another that uses plastic pellets. The new configuration had completed successful test firings on the ground, according to company officials. This was the first flight test using the new configuration.
WhiteKnight Two took off at 9:20 Pacific Standard Time Friday from the Mojave Air & Space Port, about 18 miles northeast of Edwards Air Force Base, long the site of test flights for the US military and NASA.
Some 50 minutes later, the mother ship released SpaceShip Two. Two minutes later it became clear something was wrong, according to Stuart Witt, the chief executive officer for the space port. Confirmation came quickly, along with reports that wreckage had been spotted about 25 miles north of the space port.
“Our primary thoughts at this moment are with the crew and family, and we're doing everything we can for them,” said George Whitesides, Virgin Galactic's chief executive officer, during a press conference late Friday. “Space is hard, and today was a tough day…. The future rests in many ways on hard days like this. But we believe we owe it to the folks flying these vehicles as well as the folks who have been working so hard on them to understand this and to move forward.”
[Correction: This article has been updated to correct the title of Ann Karagozian, a professor of mechanical and aerospace engineering at the University of California at Los Angeles.]