Installation of World's Largest Solid Rocket Motor for Ground Test completed

Engineers and technicians at Alliant Techsystems and NASA have completed installation work on the second Ares I First Stage five-segment Development Motor (DM-2), in preparation for its static-fire, which is currently scheduled for early September.

The Ares I First Stage is the largest solid rocket motor ever built. It was designed to maximize astronaut safety while providing the nation with a reliable launch capability for both crew and cargo missions. As the prime contractor, ATK continues to perform on schedule and cost in support of NASA's space exploration programs.

The motor, which is 154 feet in length and 12 feet in diameter, has been installed horizontally in a specialized test stand in Utah. Results from this test will be compared with data from the ground test of the first five-segment motor and Ares I-X test flight both successfully completed last year.

"A robust ground and flight test program is a critical part of human-rating to ensure reliability and safety when launching crew into any orbit," said Charlie Precourt, VP and GM of ATK Space Launch Systems. "This test is a vital milestone in further growing the performance database for this new five-segment solid rocket motor."

Although the five-segment motor is based on the design heritage of the flight-proven Solid Rocket Boosters on the Space Shuttle Program, it was upgraded utilizing modern technologies and materials. These include the addition of a fifth segment, changes to the propellant grain, a larger nozzle opening and upgraded insulation and liner.

"We designed this motor using a knowledge base gained from over three decades of operations, during which we constantly monitored and improved our design," said Precourt.

ATK technicians are in the process of instrumenting the five-segment rocket with sensors and gages to collect measurements on more than 750 data channels. This information will be used to evaluate performance, roll control, acoustics, motor vibrations, oscillations, nozzle modifications and insulation upgrades. The full-scale motor test will advance the safety, technology and knowledge of solid rocket motors.

When fired, the motor will produce 3.6 million pounds of maximum thrust or 22 million horsepower. Utilizing the in-line configuration with a single five-segment solid rocket motor first stage and liquid upper stage, this launch vehicle is designed to lift more than 54,000 pounds of payload directly to Low Earth Orbit.

"The combination of a solid propulsion first stage and liquid propulsion upper stage provides optimum payload capability, reliability and lowest cost," said Precourt. "These motors were designed not only to carry humans to orbit but also for use on a heavy lift vehicle where performance and reliability are key requirements."