Mar 8, 2019During the Space Shuttle program, the Flight Readiness Firing (FRF) tests were primarily done to test all three of the Space Shuttle Orbiter's RS-25 main engines by igniting them and letting them run until the Shuttle's onboard computers detects an error in the main engine system, which will force an Redundant Set Launch Sequencer (RSLS) Abort in order to shutdown all 3 engines. There has only been 7 FRF tests that are known. The majority of the Shuttle FRF tests were performed prior to the maiden voyage of each Shuttle orbiter, except for STS-26, which was the Return-to-Flight mission after the Challenger Disaster. These tests were also performed at the John C. Stennis Space Center in Hancock County, Mississippi.
