WASHINGTON — An initial analysis of data from Orion’s first test flight last month indicates that the spacecraft performed better than expected in many respects, although NASA officials confirmed that this success won’t accelerate its next test flight, still planned for 2018.
In presentations at a meeting of the NASA Advisory Council’s Human Exploration and Operations Committee Jan. 13 at the Stennis Space Center in Mississippi, officials also said that plans for the first crewed Orion mission will depend on which upper stage is available in time for that 2021 flight.
William Gerstenmaier, NASA associate administrator for human exploration and operations, told the committee that the Dec. 5 test flight of Orion, designated Exploration Flight Test 1 (EFT-1), was “tremendously successful.” On that four-and-a-half-hour flight, Orion made two orbits of the Earth before successfully splashing down in the Pacific Ocean.
“The data review so far looks really, really good,” he said. “We haven’t seen anything in the data that’s really off-nominal.”
In a later presentation to the committee, William Hill, NASA deputy associate administrator for exploration systems development, said that Orion achieved 85 of 87 objectives during the EFT-1 flight. “The bottom line is that EFT-1 was extremely successful,” he said.
The two objectives the mission did not meet both involved the Crew Module Uprighting System, airbags in the nose of the capsule that are designed to inflate after splashdown to flip the spacecraft upright should it come to rest upside down. Several of the airbags did not inflate or stay inflated, although they were not needed as the capsule remained upright. “We’ve got some redesigning to do on that,” Hill said.
Other systems on Orion, though, performed better than expected. The spacecraft used significantly less hydrazine propellant than planned, Hill said. The spacecraft carried 180 kilograms of hydrazine, and engineers planned for it to use 55 kilograms, with the rest as contingency. Instead, Orion used only 42 kilograms.
“We need to understand why that’s the case,” Gerstenmaier said of Orion’s propellant use, although Hill said later it was likely linked to Orion being placed into orbit very accurately by its Delta 4 Heavy launch vehicle.
NASA and the Orion prime contractor, Lockheed Martin Space Systems, are continuing to review data from the EFT-1 test flight, Hill said. A final post-flight briefing on the mission is scheduled for March 4.
Analysis of the data will support work on the next Orion mission, which will also be the first launch of the Space Launch System heavy-lift rocket. Hill told the committee that this mission, called Exploration Mission 1 (EM-1), still had an official planning window for launch between December 2017 and September 2018, leading to questions from the committee about whether a 2017 launch was indeed possible for the mission.
Gerstenmaier, who told the House Science Committee at a Dec. 10 hearing that EM-1 would slip to 2018, repeated that revised schedule at the meeting. “We’re in the process of re-baselining our plans for some time in 2018,” he told the advisory committee.
EM-1 will send an uncrewed Orion spacecraft into a distant retrograde orbit around the moon, the same orbit that NASA plans to use as the destination for its Asteroid Redirect Mission. On EM-1, SLS will employ a temporary upper stage called the Interim Cryogenic Propulsion Stage (ICPS), based on the upper stage used by the Delta 4.
Hill said that NASA would like to repeat this mission on the first crewed Orion flight, called Exploration Mission 2 and tentatively scheduled for 2021. However, he said the ICPS would not be powerful enough to send a crewed Orion into a distant retrograde orbit, and instead NASA would need to use the more powerful Exploration Upper Stage under development.
It’s unclear, though, whether the Exploration Upper Stage will be ready in time for a 2021 mission. “We will make a decision this year on the upper stage,” Hill said. If NASA decides to use the ICPS for the mission, he said, Orion would instead fly into a more conventional lunar orbit.
Gerstenmaier told the committee that if NASA receives more funding for SLS than currently planned in future years, as it did for fiscal year 2015, it would use the money to accelerate development of the new upper stage. “If we get additional funding in 2016 and 2017, we will apply much of that to the Exploration Upper Stage,” he said.