One small leap for Orion
by Jeff Foust
|All 12 recorders contained the same set of data, so that NASA needed to recover only one to get all the data. “It’s very thorough: 11 backups,” quipped NASA astronaut Randy Bresnik.|
The Orion that briefly took to the skies July 2 was a test of the spacecraft’s launch abort system (LAS), the escape tower designed to pull the Orion away from the SLS in an emergency. It lifted off not atop an SLS from Launch Complex 39B at the Kennedy Space Center, but instead on a refurbished Peacekeeper motor a short distance down the coast at Launch Complex 46, operated by Space Florida at Cape Canaveral Air Force Station.
The mission’s plan called for the motor, with a boilerplate version of Orion—the same size and mass of the actual spacecraft, but without many of the subsystems required to support crews—on top, to fly for about 55 seconds. At an altitude of around 9,500 meters and speed of Mach 1.3, the LAS would activate, pulling the capsule away from the booster at conditions similar to those Orion would experience during an abort at maximum dynamic pressure, or Max Q, on an SLS launch.
“That’s covering that corner of the box to prove out that the system can really handle the whole spectrum of what we need to put it through,” said Blake Watters, principal engineer for Orion abort and jettison motors at Lockheed Martin, in an interview prior to what NASA called Ascent Abort 2 (AA-2). The other corner of the box had been tested nine years earlier, in a pad abort test in 2010 at White Sands Missile Range in New Mexico.
Orion’s abort system has three separate sets of motors. The first is the abort motor itself, generating 400,000 pounds-force of thrust for several seconds to pull Orion away from the rocket. A second set of much smaller motors reorients the Orion and LAS after separation. A final jettison motor pulls the LAS away from Orion itself, allowing it to descend back to the Earth under its parachutes.
On AA-2, though, there would be no parachutes for the boilerplate Orion. The test was effectively done once the LAS jettisoned itself from the capsule. The capsule would then jettison 12 data recorders containing data collected during the test to be recovered from the ocean as a backup to the data intended to be transmitted directly from the Orion. (All 12 recorders contained the same set of data, so that NASA needed to recover only one to get all the data. “It’s very thorough: 11 backups,” quipped NASA astronaut Randy Bresnik at a briefing the day before the test.)
NASA officials said that other tests of Orion’s parachutes, such as drop tests done from aircraft at the Yuma Proving Ground in Arizona, were sufficient, and thus they didn’t need to include them on the AA-2 Orion. “They’ve already been tested really thoroughly,” said Jenny Devolites, NASA test conductor for AA-2, of Orion’s parachutes at that pre-test briefing.
Instead, the Orion would be allowed to plummet back to the ocean, hitting the water at a speed of about 500 kilometers per hour at the time of impact, just a few minutes after liftoff. “We are not expecting it to stay intact when it hits,” Devolites said. “We are absolutely expecting it to sink.”
The first-order success of the test would be obvious when the LAS engaged: did it pull Orion away from the booster, did it reorient itself properly, and did it jettison itself as expected? Months of analysis of the data, though, would follow to study the test in detail and compare it to models. “There will be a lot of data crunching that we do in the months after the test,” Watters said, such as the effects of the sudden acceleration and rocket plume impingement on the spacecraft.
On the morning of July 2, NASA gave itself a four-hour window to carry out the AA-2 test to deal with any weather or technical problems. But the countdown was trouble-free and the skies were clear, allowing the Peacekeeper motor to ignite right at the beginning of the window at 7 am EDT.
|“Everything we’ve seen so far looks great,” Kirasich said a couple hours after the flight.|
The test, as viewed by the media gathered on a rooftop of a building at Cape Canaveral Air Force Station several kilometers from the pad, or crowds that gathered at Cape Canaveral’s Jetty Park, appeared to go just as planned. Nearly a minute after liftoff, the LAS ignited, pulled the Orion away, then jettisoned itself. They then watched as the capsule, LAS, and spent booster separately plummeted back to Earth, splashing down the ocean more than 10 kilometers offshore. (One Air Force photographer captured a picture of the LAS shortly before impact, its tower pointed straight down and looking like, if nothing else, a giant golf tee.)
A couple hours later, NASA confirmed what viewers saw. “Everything we’ve seen so far looks great,” Mark Kirasich, NASA’s Orion program manager, said at a post-test briefing. He added, though, that a full review of the data from the test would take a couple months. Orion transmitted the data down to the ground, and recovery crews collected all 12 recorders within about an hour.
The only deviation from expectation was with the booster, rather than the LAS. “Different motors have different performance, and as it turns out, on this flight we got a motor that called a ‘hot motor,’ so higher performance,” said Don Reed, AA-2 project manager. That meant that the booster reached the “test box,” or the altitude and speed conditions planned for the test, 50 seconds after liftoff, five seconds earlier than planned.
The apparent success of the test was a relief to astronauts like Bresnik. They became acutely aware of the importance of abort systems last October, when a Soyuz rocket carrying NASA astronaut Nick Hague and Roscosmos cosmonaut Alexey Ovchinin manlfunctioned. The Soyuz’s escape system allowed the spacecraft to safely separate from the rocket and land a short distance downrange from the Baikonur Cosmodrome. Unhurt, the two got a second chance to fly to the station earlier this year.
“We have to prepare for this even though it’s a low likelihood of happening,” Bresnik said of abort scenarios prior to the test. He credited the Russians for extensive testing of and training for the Soyuz abort system, which prior to last year had not been needed for 35 years. “That was definitely a good message to all of us that, hey, this is serious stuff.”
The Orion’s launch abort system (top) pulls the capsule away from its booster nearly a minute after liftoff. (credit: J. Foust)
The outcome of AA-2 left people like Kirasich optimistic about the future of NASA’s exploration program. Prior to the test, he said he saw renewed enthusiasm for the effort after the March speech by Vice President Mike Pence that called on NASA to land humans on the Moon by 2024, four years earlier than the agency’s new plans.
“We were extremely excited about the announcement,” Kirasich said of Pence’s speech. “You might imagine that we have a very focused team. It elevated our focus.”
|“Obviously, everything has to go perfectly” to maintain that 2020 launch date, Hill said, “but there’s a shot.”|
He was already looking ahead to the first SLS/Orion mission, formerly known as Exploration Mission (EM) 1 but recently renamed Artemis-1 to reflect the designation of the overall lunar return effort as the Artemis program. “The next big checkmark is the Moon. It’s our Artemis-1 mission,” he said. That mission, he claimed, will fly “a little over a year from now.”
That seems unlikely. NASA has been aiming for a mid-2020 launch of Artemis-1, but delays with the SLS—specifically, its core stage—have pushed that schedule back, with doubts now that the mission can take place before the end of next year.
At a meeting of the NASA Advisory Council’s Human Exploration and Operations Committee in late May, Bill Hill, deputy associate administrator for exploration systems development, still clung to a 2020 date for Artemis-1, provided everything went well through the rest of the core stage’s assembly and testing. “Obviously, everything has to go perfectly” to maintain that 2020 launch date, he said, “but there’s a shot.”
An open question remains for SLS whether to perform a “green run” test of the core stage. In that test, the core stage would be shipped from the Michoud Assembly Facility in New Orleans to nearby Stennis Space Center and placed on a test stand there. Its four RS-25 main engines would then fire for eight minutes, simulating a complete burn of the core stage on an actual SLS mission. If the test went well, the core stage would then go to the Kennedy Space Center for integration with the rest of the SLS components—its solid rocket boosters and upper stage—and Orion for Artemis-1.
NASA administrator Jim Bridenstine suggested earlier this year that the green run test could be shortened or skipped entirely, cutting the development schedule by months. That concept, though, has been criticized by some, who argue that the test is the best way to ensure the core stage can operate as planned.
“There is no other test approach that will gather the critical full-scale integrated propulsion system operational data required to ensure safe operations,” Patricia Sanders, chair of NASA’s Aerospace Safety Advisory Panel (ASAP), said at a meeting of the safety group in April. “I cannot emphasize more strongly that we advise NASA to retain this test.”
ASAP reiterated that recommendation at its latest meeting June 6, as it awaited a decision by NASA on whether to cancel or revise the green run. “We provided the agency with a recommendation. The agency is contemplating it,” Hill said in late May, not stating what that recommendation was. NASA has yet to announce its decision about the green run, although industry sources said one possibility would be to streamline the test in some way to save some schedule while still testing the core stage.
Orion itself is not without problems. Its development has suffered delays because of challenges with the European-built service module. A recent report by the Government Accountability Office also highlighted problems with Orion’s avionics.
|“We are really excited about this mission,” Kirasich said, “and Orion is on track to support the administration’s challenge.”|
The Orion built for Artemis-1 is nearly ready for a final series of tests. Later this month the crew module, built by Lockheed Martin, will be integrated with the service module for the first time. After a couple months of testing at the Kennedy Space Center, the integrated Orion will be flown to Ohio for thermal vacuum testing at NASA’s Plum Brook Station.
Kirasich said in an interview last week that those tests at Plum Brook should be completed, and Orion returned to KSC, by early January. At the May advisory committee meeting, Hill estimated that Orion would return from Plum Brook in November.
Work is already underway for the Orion that will fly Artemis-2, the first crewed mission, likely in 2022. The crew module is taking shape at KSC, while Airbus is building the service module in Germany. Kirasich noted that the work is going more smoothly for these vehicles, particularly the service module. “Their second build is going much better, much faster,” he said of the service module.
Some long-lead items are already being procured for the Artemis-3 Orion, such as aluminum panels that require precise machining as well as radiation-hardened electronics. That Orion, under NASA’s current plans, will transport astronauts to the lunar Gateway in 2024 for the first human lunar landing since Apollo.
Recent experience suggests those schedules should be taken with a grain—or many grains—of salt, but Kirasich believed that, at the very least, Orion would be ready to achieve that 2024 lunar landing goal. “We are really excited about this mission, and Orion is on track to support the administration’s challenge.”
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