RS-25 Engine Test

NASA is conducting a hot fire of an RS-25 engine as part of certification testing for future SLS (Space Launch System) rockets. The test of developmental RS-25 engine No. 10001 is planned to run for almost eight-and-a-half minutes (500 seconds) and throttle up to 111% of its rated power level. Location: Fred Haise Test Stand, NASA’s Stennis Space Center.

Saturday, October 31, 2026

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Countdown Timer - RS-25 Engine Test

Get ready for an exciting milestone in space exploration! On Saturday, October 31, 2026, NASA will conduct a hot fire test of the RS-25 engine, a critical component in the development of the Space Launch System (SLS) rockets. This countdown event will feature the testing of developmental RS-25 engine No. 10001, operating at an impressive 111% of its rated power level for nearly eight-and-a-half minutes (500 seconds). Join us as we track the countdown timer leading up to this groundbreaking moment at the Fred Haise Test Stand, located at NASA’s Stennis Space Center. Witness history in the making as we propel humanity's quest for deeper space exploration! Be sure to mark your calendars and stay tuned for updates as the countdown to this monumental test begins!

Frequently Asked Questions

There are exactly 15 days left until RS-25 Engine Test, which is 376 hours or 22591 minutes.

RS-25 Engine Test will take place on Saturday, October 31, 2026.

Use our real-time countdown to precisely track the time remaining until RS-25 Engine Test.

There are 2 weeks and 1 day left until RS-25 Engine Test.

Before RS-25 Engine Test, there are 2 Sundays left, along with 2 Saturdays and 3 Fridays.

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