Orion service module completes testing at NASA’s Plum Brook Station
SANDUSKY, Ohio — The European-built Orion service module is progressing successfully through its campaign of testing in preparation for Exploration Mission-1 (EM-1), scheduled for late 2018. Engineers and technicians at NASA’s Plum Brook Station testing facility in Sandusky, Ohio, carried out an exhaustive series of tests on the service module test article throughout 2016.
The tests were done with the assistance of engineers from the European Space Agency (ESA), who are providing the service module for Orion. Major portions of that testing included the service module’s exposure to high decibel sound pressures in the Reverberant Acoustic Test Facility (RATF) chamber and vibration tests atop the Mechanical Vibration Facility (MVF). Those tests simulated the tremendous sound and vibration loads that the service module will endure during its liftoff atop the mighty Space Launch System (SLS) rocket.
November and December brought a final series of tests for the service module.
“We went into two pyroshock tests,” Carol Ginty, Plum Brook’s Energy Systems Test Area campaign manager, told Spaceflight Insider. “Those were conducted by Lockheed Martin (prime contractor for Orion). The first one was simulating the mechanism used to separate the fairing. We conducted that test on November 2. Two days later, we did our test on the separation of the adapter from the service module.”
The lower part of that adapter was part of the stack assembled in the high bay of Plum Brook’s Space Power Facility (SPF). The stack included the service module test article, a mass simulator that was attached to the top of the service module to simulate the mass of the Orion crew capsule, and the adapter which will connect the service module to the SLS rocket. During the test, the pyroshock bolts detonated and the adapter dropped a few inches into a catch mechanism.
“The pyrotechnics worked and it was a nominal test,” Ginty said.
Video Courtesy of NASA
Following the pyroshock tests, the stack was reconfigured to conduct a solar array deployment test. The NASA engineers and technicians at Plum Brook conducted the test in cooperation with test engineers from Airbus Defence and Space, the European contractor for the Orion service module. The SAW Deploy 2 test (Solar Array Wing Deploy 2 test) was the second deploy test for the Orion solar array, following a previous deploy test conducted on February 29, 2016, before the acoustic and vibration testing campaign began on the service module test article.
“We needed to see if it could survive that environment (vibration, acoustic, and pyroshock environments) and it did,” Ginty said. “Airbus was able to validate their design, and that is the design they will be using for the four arrays that will be used to power the service module for Orion.”
After the testing was completed, ESA and Airbus conducted an inspection of all their systems and subsystems. Next, a hardware acceptance review, which is part of the agreement that NASA has with ESA in their overarching implementation plan, was conducted on December 12, 2016. Through this review, the hardware was charted and turned over from Airbus to ESA, then ESA turned it over to NASA, which officially accepted the service module before turning it over to Lockheed Martin, the prime contractor for the Orion spacecraft. This was required because the next set of testing involving the service module is scheduled to take place with Lockheed Martin test engineers at Kennedy Space Center (KSC).
However, the location of that first test appears to have been changed. The first tests that were to be conducted were the Direct Field Acoustic Tests (DFAT). They were supposed to take place at KSC, but it was decided through a series of Orion boards to conduct those tests at Plum Brook.
“Engineers had an objection to breaking the stacked configuration to do this DFAT,” Ginty said. “They want to compare the data they get from a DFAT to the data we had from conducting it in our Reverberant Acoustic Test Chamber here. They thought there were too many variables if we broke the configuration, packed and shipped all these components to Kennedy Space Center, and reassembled there to do the test. So the Orion boards made the decision to conduct the first DFAT test here at Plum Brook, and that is scheduled to begin on February 1.”
The upcoming DFAT test is designed to help verify DFAT as a proof-of-concept alternative for future acoustic testing applications. Lockheed Martin subcontractor, MSI (Maryland Sound International), will bring gigantic banks of speakers into Plum Brook’s assembly high bay and surround the Orion test articles with the stacked speakers to produce the acoustic loads.
“The reason you can use speakers instead of our acoustic chamber for this test is that the fairing that surrounds the service module will not be installed,” SPF Manager Rick Sorge told Spaceflight Insider. “Therefore, the attenuation that we got from outside to inside the vehicle in our acoustic chamber will not be there. The speakers won’t have to overcome that attenuation. Even though the speakers put out 143 decibels or so, that may be sufficient because the fairings aren’t attenuating the sound pressure.”
Plum Brook’s RATF chamber, with its nitrogen gas-driven horns, is capable of producing a sound pressure of 163 decibels. The test articles were shrouded by the fairings during those tests in the acoustic chamber, partially blunting the effect of the sound pressure. However, with the fairings no longer in place, the DFAT speakers hitting the exposed test articles with 143 decibels should be sufficient to provide verification testing for the DFAT testing concept.
Following the DFAT tests, engineers at Plum Brook will conduct testing on the ogive panels for Orion. The ogive panels are the panels connected to Orion’s launch abort system (LAS) that will surround and protect the Orion crew module from sound and vibration pressures if the LAS system is activated on the launch pad or during ascent. The ogive panels will undergo testing in Plum Brook’s acoustic test chamber.
The service module test article is scheduled to arrive at KSC after the DFAT tests and be integrated with a test version of the Orion crew capsule. They will then be flown to the Lockheed Martin facility in Denver for further testing.
The EM-1 flight hardware is scheduled to arrive at Plum Brook sometime later this year, with the service module and crew capsule arriving fully integrated. Testing will continue into 2018, with the Orion flight hardware undergoing tests in Plum Brook’s giant thermal vacuum chamber.
Video courtesy of NASA / Space Exploration
Michael Cole is a life-long space flight enthusiast and author of some 36 educational books on space flight and astronomy for Enslow Publishers. He lives in Findlay, Ohio, not far from Neil Armstrong’s birthplace of Wapakoneta. His interest in space, and his background in journalism and public relations suit him for his focus on research and development activities at NASA Glenn Research Center, and its Plum Brook Station testing facility, both in northeastern Ohio. Cole reached out to SpaceFlight Insider and asked to join SFI as the first member of the organization’s “Team Glenn.”