Nighttime rocket test lights sky over Box Elder

PROMONTORY, Box Elder County — Hundreds of onlookers gasped when the brightest flare this side of the sun shot from a booster motor anchored to the ground across a small valley. Several seconds later, a continuous roar enveloped the spectators.

It was the first nighttime test by ATK Launch Systems of one of its immense solid rocket boosters since 1992. NASA officials, contractors and other experts stood amazed Thursday, as the gigantic flame stretched along the ground, brilliant white in the center, orange-red above. A nearby mountainside, dark seconds before, was bathed in bright light, every boulder and ridge etched in white with black shadows.

Spectators a mile and a half or two miles away from the test suddenly were illuminated as brightly as at a sunrise. Some winced at the amazing intensity of the flame as the test continued. Smoke rose ever higher, boiling heaps like those ejected from a volcano, and the clouds themselves were lit.

Two minutes after ignition, the flame dwindled, turning bright red, and then looked like a railroad flare. The roar died. Behind the motor, a red line of sagebrush burned for a moment. Then, carbon dioxide fountains cooled the engine and the flame ended. Soon the brush was extinguished, too.

"It was awesome, amazing," said Jessica Tandy, who works with Pratt and Whitney and Rocketdyne at Kennedy Space Center, Fla. "It just lit up the sky, just a spectacular view."

Among the spectators, officials said, was NASA's administrator, Michael Griffin.

The static (non-launching) test was dubbed "FMS-13." Not only was the typical space shuttle reusable rocket motor checked, but some special features were designed to improve understanding of the Ares rocket, which is to take Americans back to the moon and then to Mars.

The Ares I will use an expanded version of the booster motor as its first stage; it will have five linked segments, instead of the present four. The second stage will be a Saturn V engine. Crew quarters or cargo space will be on top of the assembly.

Shuttle motors are balanced, with one on each side of the vehicle. But when the single booster is used in Ares I, it will not have that balancing effect. Instead, retrorockets will help correct changes in direction.

An objective of Thursday's test was to check the amount of torque delivered during the motor's firing, and delicate instruments measured that effect.