PROMONTORY, Box Elder County — A long jet of flame seemingly as bright as the sun, a loud throaty roar that continues for more than two minutes, a huge clump of gray and brown smoke boiling toward the cloud cover — it could only be the test-firing of a space shuttle booster engine.
Officials of ATK Thiokol, which builds the rockets, and NASA, which uses them to power the shuttle into space, declared Thursday's static firing a success. In a static firing, an engine mounted horizontally burns propellant just as it would when lifting into space, but it remains grounded on the test bay.
The purpose was to check modifications to the motor that are supposed to improve safety and make the engine more powerful. According to NASA, a slight change in the shape of the solid fuel propellant in the motor's forward segment is intended to increase the rocket's power.
Flight safety should be enhanced by the new design because it will reduce risk of cracks in the propellant during storage and transportation, according to a NASA statement quoting Jody Singer, manager of the Reusable Solid Rocket Motor Project in Huntsville, Ala.
A siren sounded at the test complex, across a valley from the observation site. Then a voice on a loud speaker counted down. After, "Two, One, Fire," the searing yellow-white flare shot from the end of the distant rocket tube. The complex was so far from the viewing site that five or six seconds passed before the sound waves arrived, bringing the otherworldly whooshing, roaring rumble. Most of the flame was yellow-white, but more distant flickers were red amid the smoke.
After 123 seconds, the roaring died and the brief flame shrank to a small concentration at the end of the tube, black smoke rising. Then it went out. NASA representatives, Thiokol employees and members of the media cheered and clapped. The top of the smoke cloud merged with the natural cloud cover.
"It's always exciting to see 15 million horsepower come out," said Michael A. Kahn, vice president of Space Programs at ATK Thiokol. "It was excellent."
A full-scale motor was used in the static firing, he said. "This is the same motor we fly on. Even though we were verifying some changes for the future, it demonstrates the configuration we actually fly.
"So it was very exciting, and we're ready to keep flying. . . . Everything went well."
Wendy Lawrence, an astronaut who had been into space three times on shuttles boosted by these engines, said the shot went "Great."
In an interview before the firing, she noted that she is to be on the next space shuttle flight, that of Discovery. In March 2005, more than two years after Columbia exploded on reentry, the shuttle should again rocket into space.
"This is my first opportunity to actually see a static test firing," said Lawrence, who is a Navy captain. "So I'm pretty excited about it. I've watched several launches and I've obviously been on the top of the orbiter when three pairs of these things have lit off.
"And I can say that it's a pretty spectacular ride. You definitely know when the solid rocket booster have lit off, because you're immediately thrown down into your seat and you're experiencing about seven million pounds of thrust."
Lawrence added that the importance of Thursday's test was that even though the shuttle has been grounded for a year and a half, it shows Thiokol still has "really good processes in place and they're still developing solid rocket boosters that are performing flawlessly."
NASA is working hard to get back into space, she said. "We want to make sure that we're doing everything correctly. We've learned a lot over the last year and a half and we're starting to make some significant progress."
Lawrence added that she feels good about where the program is headed.
Also thrilled to watch the firing were a group of Boy Scouts from Salt Lake City, Varsity Scouts of Troop 44. They watched from the west parking lot near Thiokol's Promontory offices.
"I thought it was cool," said Vincent Schaaf, 15, who is working on his Space Exploration merit badge. He enjoyed "hearing the sound wave hit after it launched."
Parker Chapman, also in Troop 44, said the test was awesome. "I've never seen anything like that. I've launched little small rockets," he said.
The small rockets were "not quite as cool," he conceded.
E-mail: bau@desnews.com