NASA attempted an important ground test of the Space Launch System (SLS) last weekend, aiming to fire the vessel’s main engines for eight minutes to simulate a real launch. Unfortunately, the test ended after barely a minute. NASA has now analyzed the test and says there’s no physical problem with the rocket. It may even re-run the test, which is one of the final pieces of the puzzle before NASA begins assembling the first flight-ready SLS stack.
The SLS has been in development for more than a decade with a total bill of more than $17 billion so far. NASA will eventually use the SLS to return to the moon for the Artemis program, as well as to launch large payloads into the outer solar system. The core stage sports a quartet of RS-25 engines, the same model used on the Space Shuttle. Last weekend’s test called for the core stage to be locked to a B-2 test stand while the engines ran for the full duration of a launch. The flight control team announced a “major component failure” after 67 seconds, which is when the SLS automatically shut down.
NASA set to work investigating the cause of the error — if the SLS core had a physical defect, that could mean months of costly redesigns. Luckily, NASA now says the hardware is in “excellent condition.” The shutdown was apparently a result of the conservative abort threshold for hydraulics in place for the test. The team believes the rocket would have performed perfectly with a more permissive test protocol.
An update on the Jan. 16 Green Run test: Data and inspections indicate the #Artemis I core stage is in good condition. The team has determined the shutdown after firing the engines was triggered by intentionally conservative test parameters. MORE >> https://t.co/MNigZBlIYJ pic.twitter.com/kmeL6bfs8H
— NASA_SLS (@NASA_SLS) January 19, 2021
The question remains, should NASA make absolutely certain the rocket would have passed the test? NASA administrator Jim Bridenstine is on the way out as the Biden administration takes over the government, but before his departure, he told reporters NASA was undecided about re-running the test. “We might be able to take the rocket down to Kennedy and get it ready for launch,” Bridenstine said.
If NASA reruns, the team can simply change the thrust vector control to prevent another shutdown. That would allow engineers to gather even more data on the rocket’s performance, but former administrator Bridenstine said the team got a wealth of data even from the shortened test. Boeing, the primary contractor for SLS, apparently wanted at least 250 seconds of data. The final decision will probably depend on what the Biden administration plans for NASA. The previous administration was firm that it wanted humans on the moon by 2024, but the timeline might be less pressing now.