NASA completes ‘summer of testing’ for SLS and Orion
NASA and its contractor team have completed what they call their “summer of testing” for the Space Launch System (SLS) and Orion spacecraft. This included testing of the five-segment solid rocket boosters and core stage engines, fabrication of the SLS core stage propellant tanks, and multiple tests of the Orion crew module. NASA is pressing on toward a first uncrewed flight for SLS/Orion—Exploration Mission-1 (EM-1)—beyond the Moon in 2018.
Prepping for flight
The SLS five-segment solid rocket boosters (SRBs) contain 25 percent more propellant than the Space Shuttle SRBs upon which they are based and will generate 3.6 million pounds (16,013.6 kilonewtons) of thrust—300,000 pounds (1,334.4 kilonewtons) more thrust than the Shuttle variety. Orbital ATK conducted a full two-minute qualification test of the SRB in Utah on June 30. Unlike the Shuttle, the SLS boosters will not be recovered and reused, reducing their complexity.
At its center, the SLS will have a 212-foot (64.6-meter) tall, 27.6-foot (8.4-meter) wide core stage, which will be fueled by liquid hydrogen and liquid oxygen and powered by Aerojet RS-25 engines. Originally situated at the tail end of Space Shuttle orbiters in a three-engine cluster, four RS-25s will now be located at the bottom of the SLS core stage, creating additional heat and vibration loading than the engines had experienced in the Shuttle environment. The 1970s-era engines are also receiving a new controller unit to interact with updated flight computers.
In July and August, Aerojet conducted static of a development engine at NASA’s Stennis Space Center in Mississippi, including a full 650-second static test that ran the engine all the way up to 109 percent of its rated thrust (500,000 lbf / 2,224.1 kN). The development engine has now racked up 1,263 seconds of test time dedicated to the SLS development.
To reach lunar orbit, Orion will rely on the SLS Interim Cryogenic Propulsion Stage (ICPS), which is essentially an upper stage adapted from the Delta IV rocket. NASA Marshall Space Flight Center received the ICPS in June.
Building big things
While the SLS engines, upper stage, and boosters are relatively known quantities, the core stage is a new development being built by Boeing at Michoud Assembly Facility in New Orleans. Once fully assembled, the qualification version of the stage will be shipped to Marshall Space Flight Center for structural load testing in a new stand built just for the SLS. NASA has also been making modifications to the Pegasus barge—previously used for the Space Shuttle external tanks—to transport the massive stage by river and sea.
All of this testing is standard operating procedure for a new vehicle and is absolutely necessary if NASA is going to launch astronauts aboard the SLS in 2021. Tony Antonelli, Lockheed Martin’s chief technologist for civil space exploration programs, said, “Crew safety is the highest priority as NASA prepares to send astronauts into deep space and eventually Mars. A rigorous flight test program is critical to ensuring all systems are ready for the journey.”
Orion is Rising
Meanwhile, on the spacecraft side of things, Lockheed Martin engineering teams have finished proof-pressure testing of the EM-1 crew module at Kennedy Space Center in Florida. Langley Research Center in Virginia has been conducting a variety of drop tests for the capsule’s splashdown phase. Additionally, NASA Glenn’s Plum Brook Station in Sandusky, Ohio, has been conducting acoustic, vibration, and solar array deployment tests. Perhaps one of the most important safety features—the parachutes—were tested earlier this year, with development chutes completing their tests in January of this year. This fall, the parachutes will be tested using capsule mockups instead of weighted “darts”.
Lastly, on the pointy end of the rocket, Aerojet Rocketdyne successfully test-fired the jettison motor for Orion’s Launch Abort System (LAS) in Sacramento, California. The jettison motor, which generates 45,000 pounds (200.2 kilonewtons) of thrust, is used to move the LAS away from Orion after a successful launch.
“NASA and the SLS and Orion industry team remain on schedule in executing a highly successful test program as the U.S. maintains space leadership through the Journey to Mars,” said Julie Van Kleeck, vice president of Advanced Space and Launch at Aerojet Rocketdyne. “All of this testing adds up to lowering the risk for astronauts to ensure they arrive and return safely from their destinations.”
What the future holds
NASA remains committed to the long-term goal of sending humans to Mars in the 2030s, with SLS and Orion as the initial pieces of an incremental path toward the Red Planet. The SLS got a secondhand vote of confidence, as Congress approved preliminary work on a mission to Jupiter’s moon Europa, a mission NASA has touted as being a suitable mission for the massive launch vehicle. Beyond the 2018 EM-1 flight, the future of the SLS and Orion will depend on the funding and policy priorities of the next U.S. president.
Video courtesy of NASA Marshall
Bart Leahy is a freelance technical writer living in Orlando, Florida. Leahy's diverse career has included work for The Walt Disney Company, NASA, the Department of Defense, Nissan, a number of commercial space companies, small businesses, nonprofits, as well as the Science Cheerleaders.