While its first test flight may be 3.5 years out, NASA is hard at work developing its successor to the Apollo era’s mighty Saturn V, which launched a generation of astronauts beyond Earth’s confines to the Moon.
NASA’s newest launch vehicle, which will take the next generation of astronauts and space explorers to destinations such as Mars, asteroids, and deep space, continues to come together. On Wednesday, March 11, Orbital ATK will conduct a a full-scale test fire of the company’s Space Launch System (SLS) booster test article, Qualification Motor-1 (QM-1), at its facilities in Promontory, Utah. The company announced last week that a “flight-like” set of avionics will be part of the QM-1 test article, which will mark the first time in spaceflight history that this kind of system will be included in a booster firing test.
During this upcoming booster test, the avionics system will be as close to flight conditions as possible in order to sort out any unknowns that may occur during ascent, and, according to NASA, “further validate the design and test the system performance in the conditions the boosters will experience on the pad and during flight.” NASA and Orbital ATK engineers discussed the motivation behind this rigorous kind of testing.
Video Credit: NASA’s Marshall Center on YouTube
Eric Corder, avionics system manager for the SLS Booster Element at Marshall Spaceflight Center in Huntsville, Ala., stated: “We are designing a system for a human-rated vehicle that has to be at a minimum single-fault tolerant, which means no one failure on a critical system can result in a big problem for the mission. We don’t want the rocket to just operate the way it’s supposed to. Our team intentionally implements failure scenarios to the electronics to make sure, for example, a shorted circuit or faulty box doesn’t compromise mission success. That’s even an issue that may have a one-in-10,000 chance of occurring.
“We’re going through millions of possible failure scenarios all the way down to the individual circuits within the boxes. It’s not easy to do. We may think we have everything right in the design, and then a failure occurs during testing that we weren’t expecting at all. We have to go back and figure those things out. That’s why it takes so long to develop and test a human-rated avionics system.”
Jennifer Graham, Orbital ATK systems integration test engineer, added, “We are really starting to look through the microscope, so to speak, at the parts that make up this system to ensure they function properly.”
The avionics system, which according to NASA is “responsible for igniting, steering and jettison of the solid rocket boosters for SLS,” was delivered to Marshall (where SLS is being developed) in early February from Orbital ATK’s Avionics Lab in Clearfield, Utah. The system was developed by NASA, Orbital ATK, and L-3 Cincinnati Electronics of Mason, Ohio.
A previous AmericaSpace article detailed the history of SLS’s booster development. Mike Killian wrote: “ … Booster avionics and control tests were complete in December 2013. Booster avionics testing was completed in April 2014, and completion of a significant structural test of the booster’s main attachment mechanism, the forward skirt, was completed in May 2014. Final validation testing of the booster aft skirt avionics command and control system was successfully completed in August 2014 with an off-motor aft skirt hot-fire test, which represented the last phase of testing for the final validation that planning, engineering, scripts, equipment, and people are all ready for the upcoming QM-1 static test fire.”
Killian added, “[Orbital] ATK expects to conduct a second QM booster test fire, QM-2, a year after QM-1, and booster avionics qualification efforts are in work and will be incorporated into the vehicle qualification effort, the Design Certification Review, which is scheduled for completion in 2016.”
The SLS launch vehicle will be powered by two of the boosters and four RS-25 engines—the same kind of engines used during the space shuttle program (albeit with several modifications). In January, the first successful static test fire of a development RS-25 engine took place at NASA’s Stennis Space Center in Mississippi.
The first test flight of SLS integrated with the Orion Multi-Purpose Crew Vehicle (MPCV), and the European Space Agency’s Service Module (ESM), Exploration Mission-1 (EM-1), is slated to take place in late 2018. This flight, which will be powered in part by two of the world’s largest boosters, measuring at 177 feet long, will take an Orion capsule beyond low-Earth orbit to a trans-lunar trajectory. It will be the first time a spacecraft meant for humans has been to the Moon since the Apollo 17 mission, which launched and returned to Earth in December 1972. NASA’s recent Exploration Flight Test-1 (EFT-1) mission, which took place on Dec. 5 last year, has been described as a nearly “flawless” test of the Orion capsule’s systems.
NASA’s next “big shot” will certainly be one for the history books, and March’s booster test will aid in further propelling SLS to space.
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