Tolerance for testing
by Jeff Foust
|“Rocket made it to drone spaceport ship, but landed hard,” Musk wrote. “Close, but no cigar this time.”|
Many, though, paid more attention to what happened after the Dragon’s first stage completed its mission and separated. SpaceX, which previous had tested “landing” that first stage on the ocean surface as part of efforts to eventually recover and reuse it, this time planned to bring the stage down on the deck of an “autonomous spaceport drone ship,” about 90 meters long and 50 meters wide. If the stage successfully landed, it would be a major step forward towards SpaceX’s goal of reusability, and the promise of less expensive space access.
Only the test wasn’t a complete success. Taking place far out of sight in the ocean, the public had to instead rely on updates company CEO Elon Musk that he posted to Twitter. “Rocket made it to drone spaceport ship, but landed hard,” he wrote. “Close, but no cigar this time.”
Musk later wrote that the problem appeared to linked to “grid fins” mounted on the stage that are used to provide precision steering as it returns to earth. “Grid fins worked extremely well from hypersonic velocity to subsonic, but ran out of hydraulic fluid right before landing,” he wrote. He didn’t elaborate on why the fins, primarily used for steering, would have contributed to a hard landing, but some speculate that without the fins, the stage would have had to rely on gimbaling of its main engines for steering.
On Sunday, the ship retuned to port in Jacksonville, Florida, tracked by interested people both in person and remotely, monitoring webcams at the port and on bridges. The ship appeared to be in good condition, although with some damaged and singed cargo containers on its deck. There wasn’t much in the way of a rocket on the ship, other what appeared to be some debris under tarps.
Musk indicated they already planned to add more hydraulic fluid to the grid fin system for its next test. “Upcoming flight already has 50% more hydraulic fluid, so should have plenty of margin for landing attempt next month,” he wrote on Twitter. He didn’t indicate which mission would be the next test of recovery. The next Falcon 9 launch, of the Deep Space Climate Observatory spacecraft, is currently scheduled for January 29, followed by the launch of two commercial communications satellites in February.
SpaceX was trying something no one else had attempted before, and prior to the flight had cautioned the odds of success were not necessarily high (although Musk backed away from earlier statements of a 50-perecent chance of landing the stage on the ship: “I pretty much made that up. I have no idea,” he wrote in an “Ask Me Anything” question-and-answer session on Reddit last Monday evening.)
|“SpaceX Stumbles in Test to Show Reusable Rocket Technology Advances,” was the Wall Street Journal’s headline, followed by “Rocket Booster ‘Landed Hard’ in Botched Attempt to Return to Floating Platform.”|
“There’s at least a dozen launches that will occur over the next 12 months,” he said in an on-stage interview at MIT in October, when he first announced plans to land the stage on a ship. “I think it’s quite likely—probably 80 to 90 percent likely—that one of those flights will be able to land and refly.”
Given what SpaceX was able to achieve, one might think the company would be celebrated for at least a partial success on its first attempt. Not so much, at least in part of the popular media. “SpaceX rocket recovery test fails,” declared the original BBC.com headline about the test (later amended to “SpaceX launches cargo ship but rocket recovery test ends in crash”). “SpaceX Stumbles in Test to Show Reusable Rocket Technology Advances,” was the Wall Street Journal’s headline, followed by “Rocket Booster ‘Landed Hard’ in Botched Attempt to Return to Floating Platform.” And the New York Times: “Private Rocket Fails to Stick the Landing.”
Tough audience. To be certain, all those headlines are accurate: SpaceX tried to land the first stage on the ship but failed to bring it back in one piece. That, though, doesn’t mean the test itself was a failure. The company, by Musk’s account, already has an idea of what went wrong and what it plans to do to address that problem for its next test. But by failing to achieve complete success—a stage standing intact on the ship’s platform—many perceived it as a failure.
One person who would likely sympathize with SpaceX regarding that media coverage is another aerospace executive who has gone through arguably an even worse experience.
“The last couple of months have certainly been difficult for our company,” said Virgin Galactic CEO George Whitesides in a speech the day before SpaceX’s launch at the AIAA’s SciTech 2015 conference in Kissimmee, Florida. “They have also been a continued exercise for me in explaining the concept of aerospace development, design, ground and flight test to the media and public.”
Whitesides was, of course, referring to the October 31 crash of his company’s first SpaceShipTwo vehicle during a powered test flight in the skies above Mojave, California. That accident, which killed the vehicle’s co-pilot and injured its pilot, was arguably far more visible than SpaceX’s landing test, dominating the news for the first day or so.
It was also a far more serious accident. In addition to its tragic human toll, the crash destroyed the company’s first vehicle just months before it was expected to begin commercial flights. “Our test flight accident in October of last year was really the toughest thing that our business could undergo,” said Whitesides. “After years of work, we had felt that we were finally getting close to the start of commercial operations… But it was not to be.”
But that October 31 flight was still very much a test flight, something that he claimed that the media and the general public didn’t properly appreciate. “Many members of the press and public seem to fundamentally misunderstand the nature of test,” he argued. “Failure, in the context of test, while unfortunate and, in our case, tragic, is essentially part of the deal.”
“We as an aerospace community are at a frontier of discovery, the frontier of test, and thus the frontier of failure,” he told an audience of aerospace professionals, academics, and students. “Our failures improve the safety and the lives of people on and off the planet, and thus we should be active and forward-footed in our efforts to communicate the challenges of our business and the way that progress is truly made.”
|“Parenthetically, I would highly recommend just turning off television if any of you are unfortunate enough to have a failure that cable news decides to cover,” Whitesides said.|
He said that “proactive communications” with the public about tests can help address what he perceives as an increasing intolerance to risk, something that he acknowledged Virgin Galactic could have done better prior to its test flight accident. “Setting context, and probabilities of success and corresponding potential failures, can help the public and the press understand the range of outcomes more fully,” he said.
“I was certainly disappointed with some of the more hyperbolic coverage of our accident, which speculated on the failure of subsystems that were generally cleared early on by the NTSB investigation,” he said.
That was an apparent reference to early speculation that focused on SpaceShipTwo’s hybrid rocket motor as the cause of the accident. Investigators with the National Transportation Safety Board said a couple days after the accident that there was no evidence of problems with the motor, and that the failure appeared to be linked to the premature unlocking by the co-pilot of the vehicle’s feathering system.
“Parenthetically, I would highly recommend just turning off television if any of you are unfortunate enough to have a failure that cable news decides to cover,” he told the audience. “That helped me a lot, certainly.”
Whitesides’ comments about risk tolerance were as close as he came to talking about the accident itself, saying he couldn’t talk much about it beyond what the NTSB has disclosed in its investigation—and NTSB has not released any details since mid-November. Instead, he focused on the company’s future.
That future includes a relatively rapid return to flight. Virgin Galactic had already been working on a second SpaceShipTwo, which the company said at the time of the accident was nearly two-thirds complete. Construction has continued, and Whitesides said structural fabrication of the vehicle is more than 90 percent complete, and other systems are two-thirds complete.
“We have a lot of work to do over the coming months, but ‘weight on wheels’ is now in sight,” he said.
Virgin’s goal, Whitesides said, is to get that second vehicle completed and to begin test flights this year. “As we start 2015, we are focused on finishing the build of this vehicle during this year and getting back to flight test as soon as we can do so safely and responsibly,” he said. Later in his talk, he said, “I expect that we will be back into test flight this year.”
|“We’re shooting to have our first test launch of LauncherOne in 2016,” he said, “which will be the year we expect our spaceship to go into commercial service.”|
That flight test program will differ from the one that Virgin used for the first SpaceShipTwo, he said. “We will be able to take the lessons from the flight test program for that first vehicle and apply them to the second,” he said. He didn’t disclose what differences in the type or number of test flights the company was planning.
His comments, though, suggested a fairly aggressive test schedule for that vehicle. Later in his talk, he discussed the company’s work on LauncherOne, a smallsat launch vehicle. “We’re shooting to have our first test launch of LauncherOne in 2016,” he said, “which will be the year we expect our spaceship to go into commercial service.”
That schedule, he said, does allow the company to make any modifications to the vehicle or other changes that may come out of the NTSB investigation when it is completed later this year. “Our team has organized the final steps of the build schedule to accommodate any learnings from the NTSB investigation,” he said, “and we’re committed to making any modifications or improvements that we feel are necessary to improve the safety of the vehicle.”
Whitesides, in what he said was one of his first public speeches since the accident, said the company was putting the crash behind it. “Today, nine weeks after this fairly traumatic event, the company is turning the corner and looking to the future,” he said. “Our team and our investors remain committed to the goal of opening space for all. We will recover, we’ll learn the hard lessons from the accident, and return to flight.”
Given that neither the SpaceShipTwo crash nor SpaceX’s hard landing on its landing platform are likely to be the last accidents the two companies, or others in the emerging aerospace business, will experience in test flights, that ability to recover and learn from failure could be as important a lesson as any engineering knowledge gained from those test failures.