NASA’s Space Launch System (SLS) is dubbed as the biggest, most capable rocket ever built for human exploration. It is getting a lot of attention given its ambitious, deep space, human exploration goals and the estimated $10 billion investment in rocket technology alone.

As with every rocket program, the heavy lifting starts on the ground, where development and qualification motors are thoroughly tested before first flight. SLS development followed a five-test protocol that began in 2009 and culminated with the final, successful qualification test of the QM-2 in June. This final test included 82 qualification objectives. Among the most important of these was the evaluation of solid rocket motor performance at its low-temperature range of 40°F, ±2°F.

Orbital ATK, a manufacturer of aerospace and defense technologies, relied on Aggreko to provide the cold-conditioning system to reduce propellant mean bulk temperature (PMBT) from its initial 73°F down to a test-ready PMBT of 40°F.

 To meet testing requirements, Aggreko helped Orbital ATK design a temporary, portable solution for temperature control and power generation. At the heart of the system were two, 200-ton, low temperature mechanical chillers and two pumps used to deliver a 50 percent propylene glycol solution to the air-handling units (AHU). Three sets of two, 120-ton AHUs circulated cold air to the enclosure. The tandem arrangement allowed one AHU to deliver chilled air while the other operated in defrost mode. An additional AHU dehumidified and cooled outside air to maintain positive pressure in the enclosure.

 QM-2 was the final ground test before Exploration Mission 1—the first planned flight of the SLS scheduled for late 2018. According to Orbital ATK, the test provided critical data that demonstrated nozzle, ballistics and other design performance parameters met requirements at the design temperature of 40°F. The previous qualification test, QM-1, validated motor performance at its high-temperature range of 90°F. The QM-1 test, as well as the design motor tests — DM-1, DM-2 and DM-3 — also employed Aggreko temperature and power generation systems.