Flight Over The Mojave
In 2004, I sat down in a flight simulator at Scaled Composites with test pilot and engineer Peter Siebold. He'd built the simulator—a precise replica of the cockpit in Scaled's radically unconventional SpaceShipOne (SS1). That ship was the predecessor of SpaceShipTwo (SS2), which broke apart over the Mojave Desert on Friday. Siebold was at the controls at the time of the accident, with Mike Alsbury as co-pilot
Visionary aerospace designer Burt Rutan invented these odd birds, and the revolutionary feathered-wing re-entry system that both test craft share. Ten years ago, Siebold was a key part of the team bringing the system to life. As he showed me how to fly in the simulator, we chatted about the stress of piloting such a novel and admittedly twitchy vehicle under the extreme circumstances of rocket-powered spaceflight—even if the "space" part was brief, lasting barely three or four minutes on each parabolic arc the spindly craft cut through the sky.
Siebold was torn. Being involved in the program was a privilege, but the experience became a surprisingly emotional roller coaster. He badly wanted to earn his astronaut wings and was in heated competition with the other pilots on Rutan's team for missions. When the time came for Rutan to select the pilots, however, Siebold opted out.
When the time came for Rutan to select the pilots, Siebold opted out.
By then he was a new father, and his conscience simply wouldn't permit it. Scaled test-pilots Mike Melvill and Brian Binnie instead piloted the craft on the two suborbital flights required to win the $10 million Ansari X-Prize—a carrot dangled in front of the few companies who could even come close to developing a commercial spacecraft.
Siebold stayed with the program, and became, again, a test pilot. This time it was for the larger, passenger-carrying SpaceShipTwo, which The Spaceship Company—a spinoff of Scaled Composites—built for Virgin Galactic, Richard Branson's new X-Prize–inspired venture. On Friday, Siebold, 43, and Alsbury, 39, took off from Mojave Spaceport, about two hours north of Los Angeles, slung underneath the mothership, the huge WhiteKnightTwo (WK2).
The companies arranged the flight to test the rocket's newly revised propellant system for the first time. A rubber-based fuel had served SS1 well, but engineers recently switched to a plastic-based fuel to produce greater thrust for the larger SS2. The latter craft had flown 54 times, but never higher than 71,000 feet, compared to its estimated operational peak altitude of 361,000 feet. Only 10 of the flights incorporated the craft's "feathered" configuration, in which the twin tail booms flip upward to stabilize the spaceship during re-entry. It had flown under rocket power only three times; most flights were glide tests back to the airport after release from WK2.
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On Friday, Oct. 31, 2014, the rocket-and-mothership combination flew to 45,000 feet, at which point SS2 separated from WK2 and ignited its motor for the test flight. What exactly transpired next isn't fully known, but ground-based images clearly show the spacecraft disintegrating after the motor fired. During a National Transportation Safety Board (NTSB) press conference last night, acting chairman Christopher Hart revealed the engine was found intact with no signs of a breached fuel system. Hart also said video showed Alsbury moving a lever that unlocked the feathering mechanism at about Mach 1, or 660 mph. Evidently, this wasn't supposed to happen until Mach 1.4.
Here's a potentially crucial detail: At Mach 1, the aircraft would have been lower and in much denser air than at Mach 1.4. Releasing the feathers at higher speed would have been safe because the air would be much thinner. The press conference didn't reveal what the flight plan was to be—how long the engine burn was to last, and at what stage pilots would begin and conclude the feathering. Another important detail is that Alsbury merely unlocked the feathers; neither he nor Siebold actually attempted to move them. The feather movement was "uncommanded," in aviation parlance.
The premature unlocking of the feathering mechanism might have contributed to the tragic turn of events, since the thick air at that speed could have forced the feather to move. But Hart stressed that this is not a statement of cause, just fact. That's a crucial distinction we'll get to momentarily.
The craft broke apart and fell out of the sky, with debris raining down to the desert floor over a five-mile radius. There are no ejection seats in SpaceShipTwo, so Siebold—whose numerous flights had yet to earn him his astronaut wings—either separated himself from the structure or was thrown from the wreckage. The NTSB hasn't disclosed whether or not he was conscious and on his own oxygen system, or rendered unconscious by the rapid depressurization at high altitude. Presumably, he was unconscious and injured, and his parachute deployed automatically at 10,000 feet. Siebold landed on the ground, where first responders found him shortly thereafter and then flew him to the hospital. (It's worth noting Siebold is the first person to successfully bail out of a firing rocketship. Investigators and aerospace engineers will undoubtedly study the specifics of his survival in the days to come.)
Virgin Galactic Press Conference
Christopher Hart, the NTSB's acting chairman for the Virgin Galactic investigation, addresses members of the press.
Courtesy NTSB
Alsbury perished in the crash. His body was found still attached to his seat with a large section of wrecked fuselage. The test pilot, himself a husband and father of two children—both under 5 years old—had been with Scaled Composites since 2001. The aerospace community in Mojave, a famously tight-knit crowd, was clearly shaken by the pilot's death, as was Richard Branson, who arrived in California later that evening.
Over the weekend, Branson and the NTSB, which arrived in Mojave on Saturday to investigate the incident, each began delivering statements during a meandering series of press conferences. The initial comments from Virgin Galactic and Branson betrayed the team's shock, and touched on the inherent and well-known risks of spaceflight, the human urge to explore and push boundaries, and the collective vision and dedication of everyone involved in the program. But neither party, at least initially, provided any actual insight or information.
However, we can infer a lot from Branson’s specific, measured, and ambiguous responses to questions about the future of Virgin Galactic on Saturday, Nov. 1, 2014, as well as the mere presence of the NTSB in Mojave in the aftermath of the crash.
Let’s start with the NTSB. Though it had a peripheral role in the Space Shuttle Challenger accident investigation (1986), the beneficial impact of that role—specifically in accident reconstruction—led the 1990s-era Department of Transportation to request NTSB involvement should there be any future commercial space mishaps. The NTSB was also involved in the Columbia accident investigation (2003), but this is the first time the board has led a spacecraft accident investigation itself. It's out in Mojave Desert because Virgin Galactic plans to be a civilian, passenger-carrying entity. The NTSB will take the lead in the investigation, and the Federal Aviation Administration, which holds the keys to Virgin Galactic's passenger-carrying license, will pay close attention to its progress.
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The NTSB's involvement is significant and potentially the best thing that could happen to the fledgling commercial space industry. Scaled Composites has maintained an exemplary safety record since Burt Rutan created it in 1982, with no test-pilot fatalities despite the long list of radical prototypes it has designed and flown, both civilian and military. (Scaled is wholly owned by aerospace and defense technology juggernaut Northrop Grumman. Rutan retired from the company in 2011.)
The high-tech firm executes measured, highly regarded test-flight programs that focus on safety. Any incidents that occur within its programs are typically investigated and resolved internally. A 2007 accident involving a rocket-motor test, which killed three Scaled technicians, was considered an industrial accident and investigated by the Occupational Safety and Health Administration (OSHA). The NTSB, similarly, is an independent, public agency that publishes detailed reports about what led to accidents, and provides safety recommendations to address any of the discovered problems.
The NTSB will perform an unscheduled, high-caliber safety audit—the first the commercial space industry has faced.
The scrutiny will be intense. Experts inside the accident investigation community, who chose to remain anonymous (in case they participate in the investigation), told Popular Science that Scaled/Virgin/TSC will be about as ideal of an investigation partner that the NTSB could hope for. However, the impact of the investigation could be more than the private program can bear.
The NTSB will take time to sift through details, interview staff up and down the personnel chain, review and re-review images, videos, and transcripts from the accident flight (as well as previous flights), and of course interview Siebold extensively. It will use its expertise in metallurgy, flight controls, structural stress, material fatigue, and composite construction to figure out precisely what happened to the spacecraft on Friday morning.
The unlocking of the feathering mechanism is a key piece of intelligence, but the crucial question the NTSB will pursue is why Alsbury unlocked it. Was it a simple error, or did he have wrong information in front of him, or being relayed to him? Were the airspeed indicators functioning properly? Was there an unknown cockpit emergency in progress that Alsbury thought could be resolved by unlocking the feather? Finally, did unlocking the feather result in the destruction of the aircraft and the co-pilot's death? Was that a likely and expected outcome at that speed and altitude, or one that surprised the crew? In either case, what measures could be taken to eliminate the possibility of premature feathering?
Separation!
An illustration of Virgin Galactic's SpaceShipTwo separating from its mothership, WhiteKnightTwo.
Virgin Galactic
Here is where the investigation will look for redundancies, which is a key term in commercial aircraft design. These are the backups and fail-safes that are designed to permit safe operation of an aircraft even in the presence of erroneous information, mechanical failure, or pilot error. What redundancies are present in SS2 to prevent premature feathering, and if there are none, what ones should be there?
The NTSB will also assess the flight-test program overall. They'll attempt to see if less-tangible factors, such as interpersonal dynamics, corporate culture, or assorted pressures, both internal and external, might have affected decision-making within the program. It might find other safety problems that aren't germane to the accident itself, but which could nevertheless benefit from additional scrutiny. The NTSB will, in essence, perform an unscheduled, high-caliber safety audit—the first the commercial space industry has faced.
Ultimately, it's possible the cause of Friday's accident will become readily apparent, i.e. that feather unlocking. But more likely the NTSB will find multiple factors in play. If the board's long history of thorough investigations of baffling transportation disasters has proven anything, it's that accidents usually result from a sequence of seemingly unrelated events. Maybe budgetary pressures contributed to the accident, since each test flight costs the program several hundred thousand dollars; perhaps tensions between contractor and client contributed, even if remotely. After all, the relationship between Scaled Composites and Virgin Galactic has proven an awkward pairing from the beginning. Branson's relentless proclamations of imminent, months-away passenger-carrying suborbital flights have rankled the Scaled Composites staff. The program was originally supposed to start revenue flights in 2007. It's now 2014. Infer from that what you will.
Any NTSB investigation is intended to determine causes of major accidents so they can be prevented in the future. The process will be well-executed and efficient. As with the loss of the prototype spaceship itself, this will delay the program, just as Scaled's own internal investigation would even without the NTSB. But the former will undoubtedly generate information to make space tourism safer. Which leads us back to the question of Virgin Galactic's own future.
During Saturday's press conference, Branson said the following: "We owe it to our test pilots to find out what went wrong. And once we find out what went wrong, if we can overcome it, we will make absolutely certain that the dream lives on." If.
Virgin Galactic's Founder
Sir Richard Branson speaks at a press conference on Nov. 1, 2014, about the fatal SpaceShipTwo incident.
Courtesy Virgin Galactic
For Branson—a typically rabid enthusiast about Virgin Galactic—to even insinuate, by his lack of strenuous affirmation otherwise, that the future of the program may indeed be in jeopardy after just one crash, albeit a fatal one, suggests strongly that he already knows what the final decision will be. Virgin claims it has taken more than 800 payments for suborbital tourist flights, at $200,000 each. This might sound like an extraordinary haul, but at $160 million, it represents barely one-third of what Branson has already reportedly invested in the program. The company can't access that passenger money, however, until it starts actually flying people into space.
If a half-billion-dollar aerospace enterprise can't sustain a single flight-test setback, particularly in an industry with a century's worth of flight-test setbacks, then either Branson is nearing the end of his willingness to sustain the long-delayed project financially or the program itself may just be too complicated and dangerous to be viable. You can possess all the support in the world, but that doesn't mean your spaceship will work.
The investigation will yield considerable insight into how practical SpaceShipTwo actually is. If it points to a need for increasingly complex and expensive safety mechanisms, or a broader design flaw, the challenge might be insurmountable. SpaceShipOne was a brutal ride for the test pilots, with a re-entry that was a brain-scrambling ordeal on both of its suborbital flights. (In 13 years since the SpaceShipOne program began in 2001, the effort has only successfully gone to space twice.) The engineers worked to smooth out the ride with the upscaled concept, but the program had yet to go far enough in test to see if they succeeded. SpaceShipTwo, by any reasonable measure, is still a small ship. It's hard to imagine that things are that much improved, and many of the hundreds of well-heeled, would-be space tourists presently lining up for rides won't have the stomach for a hard-core ride the likes of which certifiably freaked out Binnie, Melvill, and Siebold.
If the statistics of human spaceflight are any indicator, more people will die if flights continue.
What's even more troubling is the notion that this won't be the last accident in this nascent industry. It won't be. To have a catastrophic failure in such an early stage of flight raises questions about what will happen once these vehicles start reaching space, then feathering for the heavy buffeting of re-entry. (And then doing it over and over, several times a day, for years.) Like its predecessor, SpaceShipTwo is designed to be three vehicles: a rocket, a spacecraft, and a glider. As a result, it struggles to do any of these well. Each stage of flight includes compromises necessary to permit the other stages to exist. Rutan has frequently acknowledged this, but even this was new turf for him. The concept is genius, and it could work brilliantly. Nevertheless, it likely won't be the ride people are expecting—and its final form won't come easy at all. If the statistics of human spaceflight are any indicator, more people will die if flights continue.
Part of SpaceShipTwo
Screenshot, ABC 23 Kero Bakersfield live feed
Now, the good news. Even if Virgin Galactic folds in the wake of Friday's accident, commercial space exploration, and space tourism in particular, will continue. Interest is simply too high, and the dreams and visions that fuel the industry itself are too powerful, compelling, and worthwhile to ignore. Space tourism isn't simply a party for rich people: The systems developed to facilitate it—from economical strategies to innovative designs and materials—move the ball forward, even if the benefits don't trickle down for decades. Furthermore, having this kind of scrutiny on the effort raises the standards across the board for safety and reliability. Whatever the NTSB and Scaled Composites learn during the investigation will have positive implications across the industry, just as every accident in the history of aviation has contributed to making it the safest form of transportation known to man.
There are others in the private spaceflight game who can help. SpaceX (created by PayPal co-founder and Tesla Motors honcho Elon Musk), Blue Origin (created by Amazon.com founder Jeff Bezos), and XCOR Aerospace, among others, are all developing commercial rocket systems that use different strategies—some new, others familiar—that could make access to space practical and affordable.
What is poignantly clear now, however, is that this bold vision of the future won't happen on Richard Branson's schedule.
Eric Adams, a Popular Science contributor, has covered the aviation and space industry for 20 years. Follow him on Twitter and Instagram.
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