Engineers have been prepping NASA's Space Launch System (SLS) rocket with a warm up so the booster will be the right temperature for Wednesday's two-minute firing - or, as NASA put it, "Steam me up, Scotty."
At Orbital ATK's test facility in Promontory, Utah, on Tuesday, the booster was heated to 90 degrees Fahrenheit. "The space shuttle propellant mean bulk temperature ranged from approximately 55 to 83 degrees on the launchpad, so the 90-degree mark does a good job representing what we expect to see for SLS," said Mat Bevill, deputy chief engineer in the SLS Boosters Office at NASA's Marshall Space Flight Center in Huntsville, Ala., according to NASA.
"The booster is so large at 177 feet long, and other than the metal case around the propellant, it's basically made up of mostly rubber-like materials," Bevill added. "With that much mass, it takes about a month to affect the temperature and get it uniform all the way through."
The hotter the booster's propellant gets, the faster it burns, so the burn rate will affect booster performance. In order to achieve the 90-degree mark, the thermostat is turned up inside the test stand where the booster awaits its big day. Sensors inside the booster gauge the temperature. The test stand cover will be removed on the day of the hot fire testing.
"Outside temperatures are something we have to watch, but just like it takes a long time to heat the booster, it takes a long time to get the temperature back down," Bevill said, according to NASA. "That's why we target the highest temperature condition for testing. This isn't a new concept - we've always conditioned to a certain temperature. We basically know ahead of time how the booster will respond, but we still watch and make sure it performs the way we think it will."
A second booster test is planned for 2016. That test will measure the other end of the temperature parameter - a cool 40 degrees.
"These two qualification tests are major steps in getting the booster certified for the first two flights of SLS and another step closer on the journey to Mars," said SLS Boosters Office Manager Alex Priskos, according to NASA.
To access the live stream of Wednesday's 11:30 a.m. EDT test fire, click here.
