NASA has successfully completed the first of two tests designed to certify the massive solid fuel boosters which will form a part of NASA's next generation Space Launch System (SLS). Once completed, SLS will represent the most powerful launch vehicle ever constructed and will be responsible for, among other tasks, launching NASA's Orion spacecraft on humanity's first manned mission to Mars.
The booster measures an impressive 177 ft (54 m) in length and carries 25 percent more fuel than those used to service the now defunct US Space Shuttle program. Upon completion, SLS will be powered by two of these monster boosters as well as four R-25 engines, with the maiden flight scheduled to take place sometime in 2018.
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Today's test took place at the Orbital ATK test facility located in Promontory, Utah, with the rocket lain on its side, firmly secured to the ground via a purpose- built test stand. In the month preceding the hot fire test, a team of engineers steadily raised the temperature of the booster propellant to 90 ºF (32 ºC). This is significant, as the temperature of the rocket plays a part in the duration of the burn. A solid fuel booster is not like a liquid fuel engine, as once ignited it is not possible to limit the thrust or shut it off during flight.
A temperature of 90 ºF was selected for the test based on the temperatures endured by the similar but smaller boosters used to launch space shuttles, which were found to endure between 40 ºF (4 ºC) to 90 ºF of heat over the course of their service.
The rocket successfully ignited and burned for a full two minutes, during which time it produced around 3.6 million pounds of thrust. Over 531 instrumentation channels on the booster kept track of 102 design objectives, including the performance of the steering mechanism and the resulting nozzle fluctuations as the rocket was vectored, as it would during an ascent.
Before the booster is certified, it will have to undergo one more test designed to assess the booster's performance at the lowest temperatures at which the propellant may be expected to function.
A video of the test can be found below, courtesy of NASA.