NASA announced January 30 that it planned to rerun the hot fire test of the Artemis I Space Launch System (SLS) core stage after the first was automatically aborted 60 seconds into an eight-minute burn.
The first SLS core stage to roll off the production line of prime contractors Boeing has been undergoing Green Run testing since January 2020. The Green Run test series is designed to progressively build to a full eight-minute hot fire test, representing the performance that would be expected from the stage during a mission.
NASA performed the maiden hot fire test of an SLS core stage on January 16. The test was expected to last for eight minutes and once complete, the stage would continue to the Kennedy Space Center to be prepared for the launch of the Artemis 1 mission.
Shortly after all four of the stage’s RS-25 engines were ignited, problems started to arise. Approximately 67 seconds into the eight-minute burn, onboard computers automatically terminated the test.
An investigation into the early abort found that conservative test parameters caused the early shutdown and not a fault with the stage itself. As a result, NASA has stated that the hot fire test can be rerun as early as the fourth week of February.
In preparation for the second hot fire test, NASA is completing the refurbishment of the four RS-25 engines, making minor repairs to thermal protection systems, and updating the conservative test parameters. The agency has also repaired a faulty electrical harness that resulted in a Major Component Failure alarm in Engine 4 seconds after ignition, an issue that NASA says had nothing to do with the early termination of the test.
The second hot fire test is again expected to last eight minutes. NASA, however, has stated that in order to collect sufficient data to certify the stage for flight, the test only needs to last a minimum of four minutes.
Despite adding additional delays to an already tight schedule, NASA has said that the launch of Artemis I is still expected for later this year.
Artemis I is an uncrewed flight test of the SLS launch vehicle and the Orion spacecraft. The mission is the first of NASA’s Artemis program which hopes to return humankind to the Moon by 2024.