NASA conducted a full-duration RS-25 hot fire Feb. 29 on the Fred Haise Test Stand at NASA’s Stennis Space Center near Bay St. Louis, Mississippi, continuing a key test series for future Artemis flights of NASA’s SLS (Space Launch System) rocket. The hot fire to certify new production RS-25 engines for SLS marked only the second ever Leap Day engine test. Fourty-four years ago on Feb. 29, 1980, before the first space shuttle launch, a test-fire occurred for RS-25 engine #0009. Both tests were conducted on the Fred Haise Test, previously known as the A-1 Test Stand at NASA Stennis. The Feb. 29, 2024, hot fire is the second test following installation of a second production engine nozzle that will provide additional performance data on the upgraded unit. It also marked the eighth in a 12-test series to certify production of new RS-25 engines by lead contractor Aerojet Rocketdyne, an L3Harris Technologies company, to help power NASA’s SLS rocket on Artemis missions to the Moon and beyond, beginning with Artemis V. The current series is the second and final series to certify restart production of the upgraded engines. NASA completed an initial 12-test certification series with the upgraded components in June 2023. Four RS-25 engines fire simultaneously to help launch each SLS rocket, producing up to 2 million pounds of combined thrust.