Preview of the Flight Readiness Firing
United Launch Alliance (ULA) is preparing for the Flight Readiness Firing (FRF) of the Vulcan rocket as a validation of the fully integrated vehicle at Cape Canaveral Space Force Station, Florida.
FRF demonstrates the day of launch timelines and procedures, propellant loading operations and the entire countdown through ignition of the twin booster engines at Space Launch Complex (SLC)-41.
The firing will generate a roar of nearly a million pounds of thrust, but Vulcan will remain held to the launch pad by restraining mechanisms. The software program running in the rocket's flight computer will command engine shutdown to complete FRF.
The two BE-4 engines underwent extensive acceptance testing at Blue Origin before delivery to the ULA factory for installation into the Vulcan rocket. FRF will verify engine operations while coupled together with Vulcan to demonstrate engine start, throttle up, steady-state firing and shutdown. The entire sequence lasts approximately 6 seconds.
"The engines will execute a nominal terminal count, then ignite and throttle, holding thrust before the engines begin throttle down to simulate in-flight throttling prior to booster engine cut off (BECO), then execute a flight-like shutdown," said RJ Sansom, ULA's Vulcan chief engineer.
This milestone gives the opportunity to observe critical elements of Vulcan as a complete rocket in the launch environment. It provides a rigorous performance check of the vehicle, pad systems and the launch control team. The objectives include assessing the integrity and function of the main propulsion system, propellant feed systems and engines.
"FRF is really about confirming the operational readiness of the integrated system: launch vehicle, ground systems, facilities and the associated software. In addition, we will demonstrate the ability to successfully execute the engine start sequence and validate our hot-fire abort response procedures," said Dillon Rice, ULA's Vulcan launch conductor.
Extra instrumentation is placed at strategic locations in addition to the normal vehicle sensors as an enhancement of the data collection during FRF.
Engineers will study temperatures, pressures and other parameters while controllers monitor vital signs from Vulcan and send commands to the rocket and pad systems from the launch control center at the Advanced Spaceflight Operations Center (ASOC). The countdown matches normal launch day timelines and activities except the Certification-1 (Cert-1) mission payloads are not aboard nor involved.
FRF is one of the most dynamic ground tests performed at the launch site. The team will complete post-abort safing procedures and begin detanking operations following the test.