A massive solid-fuel booster designed to help lift NASA's Space Launch System super rocket out of the lower atmosphere was test fired Tuesday in Utah, generating a spectacular torrent of fiery exhaust and nearly 3.6 million pounds of thrust, enough energy to power more than 46,000 homes during the two-minute six-second burn.
Mounted horizontally on a massive concrete test stand at Orbital ATK's Promontory, Utah, test facility, the 154-foot-long motor ignited with a torrent of fire 11:05 a.m. EDT (GMT-4), one hour late because of problems with a ground systems computer.
Made up of five fuel segments bolted together -- one more than the boosters used by NASA's space shuttles -- the giant rocket consumed 5.5 tons of propellant per second at some 6,000 degrees Fahrenheit before burning out, generating the equivalent of 1.15 million kilowatts of power.
Hundreds of spectators watched the firing from a viewing site more than a mile away, cheering and applauding as the rocket ignited with a ground-shaking roar, sending a towering plume of churning exhaust high into the sky.
As the propellant burned out, the horizontal jet of exhaust turned into a billowing cloud of orange flame before a swing arm rotated into the nozzle, flushing the interior of the booster with carbon dioxide to quickly quench any residual flame.
"We've had a chance to look at just some very, very preliminary data (and) everything looks great so far," said Alex Priskos, manager SLS booster office at NASA's Marshall Space Flight Center in Huntsville, Alabama.
During a test firing in March 2015, the 1.5 million pounds of propellant packed into qualification motor No. 1, or QM-1, was heated up to around 90 degrees Fahrenheit to test the booster's performance at the upper end of its operating range.
For Tuesday test, the booster's propellant was cooled to 41 degrees, a process that took more than a month using 25-degree air pumped into a roll-off hangar from multiple refrigeration units. The goal was to collect performance data at the lower end of the allowable temperature range.
Other major objectives included tests of a new insulation and a redesigned nozzle, along with SLS computer commanding for motor ignition and steering. Some 530 channels of telemetry were recorded.
"What an absolutely amazing day today!" said Bill Gerstenmaier, NASA's director of space operations. "It's not just a test firing, it's a qualification motor test firing, which fits in a sequence that essentially says this design is ready to go fly."
Engineers will "get a lot of data, there are over 500 channels of data on this rocket," he said. "They'll be poring over that data to make sure it performed exactly the way we intended it to perform at these cold conditions. And that data will be really important to go ahead and say things are certified."
Assuming no major problems surface during data analysis, the next time an SLS solid-fuel booster fires will be during launch of Exploration Mission 1 in the Fall of 2018, the first full-up flight test of the gargantuan 322-foot-tall SLS booster.
Using two five-segment SRB's and four upgraded shuttle-vintage main engines at the base of the rocket's first stage, the initial version of the SLS will generate a combined 8.8 million pounds of thrust at liftoff, 15 percent more than NASA's fabled Saturn 5 moon rocket.
For the EM-1 fight, an interim second stage engine and uncrewed Orion capsule also will be put through their paces. All told, the Block 1 version of the SLS will tip the scales at 5.75 million pounds at launch and be capable of putting 77 tons of payload into space.
Three of the 10 segments needed to make up the two EM-1 solid-fuel boosters are already loaded with propellant and all 10 are expected to be shipped by rail from Utah to the Kennedy Space Center by the Fall of next year. NASA has enough shuttle-vintage booster segments to support eight SLS launches.
The first crewed flight of an Orion capsule atop an SLS rocket -- EM-2 -- is tentatively planned for 2023. During that flight, four astronauts will venture beyond the orbit of the moon for a critical shakedown mission.
NASA plans to develop an upgraded version of the SLS rocket in the 2020s that could generate 9.2 million pounds of thrust to launch large spacecraft into deep space and, eventually, Mars.
"If you look at the continuum of this program, it may not be optimum from anyone's particular standpoint ... but if you want a robust program that camn keep this nation as a leader in spaceflight, this is a human spaceflight program that I think any country would be lucky to have," Gerstenmaier said. "Hopefully, the political (establishment) will see that and recognize what we have."