NASA fired up its new rocket for 499.6 seconds on Thursday
It has been a long, difficult, and expensive road for NASA and its Space Launch System rocket. But on Thursday afternoon, the space agency got to taste some success with what appeared to be a nominal ground test-firing of the vehicle’s core stage.
With brilliant spring sunshine blazing overhead, the four space shuttle main engines that power the rocket roared to life on a test stand in Mississippi. Then they burned for 499.6 seconds, exhausting the vehicle’s supply of liquid oxygen.
At about one minute into the test, the engines began rocking and rolling. Known as gimbaling, this process is what allows a rocket to change the direction of thrust in flight. This dynamic exercise lasted for about 30 seconds and appeared to proceed nominally as well.
After the test completed, engineers in the control room began clapping and cheering. Although days of data review lie ahead, that the vehicle made it through a complete eight-minute test without stopping and in apparent good condition represents a huge win for NASA, the Space Launch System program, and the core-stage primary contractor, Boeing.
Now, NASA will spend some time to assess the vehicle’s performance during the test and its overall health. If everything looks good, the core stage could ship by barge to Kennedy Space Center in April, where it will be integrated with its large side-mounted boosters as well as the Orion spacecraft. In the coming weeks, NASA is also expected to set a target launch date for this Artemis 1 mission to fly an uncrewed Orion around the Moon and back. Theoretically this could occur in 2021, but a much more likely date is the first quarter of 2022.
Thursday’s test came more than 14 months after NASA and Boeing moved the core stage onto the test stand at Stennis Space Center and two months after the first Green Run test was halted after just 67.1 seconds. The January test was stopped when pressure levels in the hydraulic system dropped below test parameters.
No such issues occurred on Thursday. Although the cork insulation around one of the engines caught fire and appeared to burn aggressively before the camera view cut away, NASA’s Green Run manager, Bill Wrobel, said engineers had expected some of it to burn away. The insulation did its job, as sensors beneath the cork never got above 100 degrees Fahrenheit.
This should not be an issue during an actual launch, during which the vehicle will be ascending into much lower air pressures while exhaust is carried away from the engines.
As always, it is difficult to design, build, test, and fly rockets, especially large ones like the Space Launch System. And although the design of this vehicle was foisted upon NASA by the US Senate in 2010, and the agency has spent more than $20 billion to reach this point, completing such a dynamic test after a decade of work is nonetheless a big achievement.
Ultimately, it remains to be seen what role the SLS vehicle will play in NASA’s next chapter of human exploration. It could serve as a backbone for Artemis missions to the Moon, or it could well be superseded by cheaper commercial rockets with the capacity to fly much more frequently.
For a day, at least, that matters not at all. Let the engineers take their victory lap.
Listing image by Trevor Mahlmann / Ars Technica