NASA has been grounded since the Space Shuttle program was ended a few years ago. The agency has partnered with private companies like SpaceX and Boeing to develop low-Earth orbit launch and resupply vehicles, but NASA wants to go beyond orbit. The Space Launch System (SLS) will be used to send the Orion capsule to more distant places in the solar system. To get off the ground, SLS will need new rockets, and one of them was just tested in Utah. The solid SLS rocket booster fired by Orbital ATK is the largest and most powerful ever built.

Rockets like the Falcon 9 carry liquid fuel reservoirs, but solid rocket boosters are different. A rocket motor powered by liquid oxygen, refined kerosene, or liquid hydrogen can be turned on and off and provide variable thrust. A solid rocket booster fires and cannot be shut down — they just burn all the way through. SRBs have been used on a variety of larger launch vehicles over the decades, as they provide very high thrust and don’t require refrigerated fuels. For example, the Space Shuttle had two SRBs mounted on either side of the main orange fuel tank.

NASA’s new booster is a more advanced version of the one used to get the shuttle into orbit. The SLS qualification motor (QM-1) can put out 3.6 million pounds of thrust, which is roughly equal to 14 Boeing 747s at maximum power. The QM-1 uses many parts from past shuttle missions, but it has an extra segment that allows it to hold 25% more fuel than NASA’s old SRB. That brings the total height to 177 feet. There will be two solid rocket boosters on the SLS at launch, along with the four main engines, which are also being adapted from the shuttle program. However, the SRBs will provide about 75% of the thrust needed to escape Earth’s gravity. They’ll be jettisoned after use.

This first full-scale test of the SLS booster design went off without a hitch. The booster burned through 1.3 million pounds of propellant in a little more than two minutes (5.5 tons per second). This was a ground test, meaning the booster was bolted down so it didn’t go anywhere. Engineers will evaluate the booster itself and the mountain of data gathered during the test to see how it performed.

Another test of the SLS booster will take place in early 2016 with the booster (QM-2) cooled to 40 degrees F, which is the low end of the ignition range. The QM-1 test was actually conducted with the booster conditioned to 90 degrees Fahrenheit to test performance at the top of the propellant temperature range.

It will still be several years before engineers complete the final design for the SLS system. This ambitious program aims to land humans on an asteroid in the 2020s and on Mars a decade later. NASA is already well into the testing phase of the Orion crew capsule, which had a successful test flight in December.