It seems that in quite short time PSLV and Ariane 5 will lose their supremacy in being equipped with largest solid fueled rocket engines. Please welcome the SLS solid fueled rocket booster motor by Orbital ATK!

Second (first was performed in Utah in 2015) fire test was planned by Orbital ATK at 14:05 GMT but in the last moment was postponed for 15:05 GMT due the problems with computers installed to collect data from booster during the fire test. Test was prepared for a long time as one of the milestones of Space Launch System program. SRB (Solid Rocket Booster) were designed by Orbital ATK for next generation Space Launch System launch vehicle; they  are generally based on boosters (designed as consisting 4 stages) used for Space Shuttle. Elements of the boosters were transported many months before test to Orbital ATK’s Promontory Propulsion Systems facility in Northern Utah. Many parts, which were used during today’s trial, were in fact already used during Space Shuttle missions; engineers in Orbital ATK facility carefully performed many tests during and after assembling motor. Finally, today at 09:05 GMT special container which was covering booster was rolled out. Weather was favorable and it was decided to start preparing to second and last qualification motor test (QM-2). Motor of SRB was chilled to the lower temperature then last year (5°C instead 30°C). It is worth to mention that in spite of planned thrust, SRB motor is biggest solid fueled booster in the world, long for 50 m and with diameter of 4 m. Its motor is able to provide thrust of 16000 kN burning 5.5 tons of APCP every second (test was planned to last 126 seconds). At T-4′ everything was set for “go” and at T-1′ siren gave last warning signal.  At T-45″ SRB motor was armed. Punctually at 15:05 GMT QM-2 started. Impressive view of fire and smoke coming from slightly moving nozzle (during QM-2 Orbital ATK tested also thrust vector control system) was combined with loud noise. Computers started to collect 600 GB data regarding thrust pressure, dynamic of burn process, temperature and nozzle behavior. Long fire and clouds of smoke covered almost all hill on the opposite of testing station.


At T+2’6″ engine was cut off. At T+2’20” robotic boom was extracted to extinguish motor completely. After 30 minutes service teams approached to motor and started to collect pieces of the nozzle plug, which seals engine before start (and launch in future) for further analysis and performed general inspection of the motor. Last fire test before first mission of the SLS finished with success!