WASHINGTON — Separate investigations into two high-profile commercial launch accidents six months ago are entering their final phases and will be completed in the next few months or, in some cases, weeks.
George Nield, head of the Federal Aviation Administration’s Office of Commercial Space Transportation, said April 21 that he expected to soon receive a report on the Oct. 28 failure of an Orbital ATK Antares rocket launched from Wallops Island, Virginia.
“We expect to get their final report on that incident in the next several weeks,” Nield said at a meeting of the National Research Council’s Aeronautics and Space Engineering Board (AESB) here. He added the focus of the investigation remains on the AJ-26 engines used on the Antares first stage.
Orbital ATK is leading that investigation with FAA oversight. During a panel session at the 31st Space Symposium in Colorado Springs, Colorado, April 14, Ronald Grabe, president of the flight systems group of Orbital ATK, offered a faster timeline, saying that report would be submitted to the FAA “within days.” Grabe said that there was “excessive bearing wear” in the AJ-26 turbopump that caused the engine to fail, but did not disclose what cased that wear.
In addition to the Orbital-led report, NASA is wrapping up its own independent review of the accident. Aerojet Rocketdyne, which provided the AJ-26 engine, has also been performing its own assessment of the accident. Company officials said at Space Symposium that their review should be completed in the next few weeks.
The National Transportation Safety Board (NTSB) is leading a separate investigation into the Oct. 31 crash of Virgin Galactic’s SpaceShipTwo suborbital vehicle near Mojave, California. The vehicle broke apart seconds into a test flight, killing the vehicle’s co-pilot and injuring the pilot.
Nield indicated that the NTSB investigation should conclude within a couple of months. “We expect to see their final report in the next month or two,” he said April 21. “The final board decision from NTSB will be later on this summer.”
NTSB Chairman Christopher Hart, speaking to a joint meeting of the AESB and the Space Studies Board here April 22, did not give as specific a schedule for completing the investigation, only saying that the report would be completed later this year.
The NTSB has disclosed few details about the ongoing investigation, with its last formal public statement about it issued Nov. 12. At that time, the focus of the investigation was on the co-pilot’s decision to prematurely unlock SpaceShipTwo’s feather mechanism, which is designed to raise the vehicle’s tail section for re-entry.
In the early phases of the investigation, NTSB said they were forming a group to study human-factors issues associated with the accident. Hart, while not directly discussing that work, did bring up human factors when asked at the meeting about any surprising aspects of the investigation to date.
“They basically opted against automation. Everything is going to be very manual,” he said of the design of SpaceShipTwo. “So when I looked at that cockpit, it was very much sort of out of the 1950s, almost.”
That lack of automation, he suggested, could pose issues when operating SpaceShipTwo, particularly when its rocket engine is firing and accelerating the vehicle at up to three times the force of gravity.
“It depends so much on humans doing the right thing under some fairly challenging circumstances, i.e., being in a three-g environment, wearing gloves, flicking switches,” he said. “I don’t think it’s very well understood because we just don’t have that much experience with it.”
Hart noted in his talk that NTSB reports usually provide recommendations, which he said are accepted more than 80 percent of the time. The SpaceShipTwo report, though, may include no recommendations given the limited regulatory authority of the FAA and actions by Virgin Galactic and SpaceShipTwo manufacturer Scaled Composites to correct vehicle issues.
“I will not be surprised if, by the time we finish this report,” Hart said, “everything we would have recommended was already in process because the parties don’t want this to happen again.”
The SpaceShipTwo accident is the first spaceflight accident investigation that the NTSB had led, and Hart acknowledged that it has been a learning experience for the agency. “We’re newbies at this,” he said.
The investigation, though, is informing the NTSB in other ways. Hart noted that they benefitted by having immediate access to a large amount of data that was transmitted from the vehicle, rather than having to recover “black box” data recorders and analyze them. That approach, he said, is something that could benefit aviation accident investigations.
“I told my staff that that accident is probably going to be a window into commercial aviation accident investigations in the future,” he said.