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Forum:Exploration: Asteroids, Moon and Mars
Topic:Ares I five-segment solid motor test (DM-2)
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Initial test data indicated that the motor, which was chilled to a 40° F core temperature since early July, performed as designed, producing approximately 3.6 million pounds of thrust, or 22 million horsepower, and burned for just over two minutes. The test collected 764 channels of data to accomplish 53 test objectives. This is the most data ATK has ever collected in a static fire test.

"The information collected from this test, used together with data from DM-1 and the Ares I-X flight test, will help further validate the five-segment design leading to critical design review next year," said Charlie Precourt, vice president and general manger, ATK Aerospace Systems, Space Launch Systems. "The data will also confirm the performance and reliability of this solid rocket, which can be configured for use on multiple launch vehicles."

The five-segment rocket was designed to maximize astronaut safety while providing the United States with an affordable and reliable launch capability for both crew and cargo missions. For example, a single five-segment solid rocket motor first stage, coupled with a liquid upper stage, would be able to lift more than 55,000 pounds of payload directly to Low Earth Orbit.

The main test objectives from today's static motor firing were measuring the first-stage rocket's performance at cold temperatures, and verifying the performance of new materials in the motor joints at the lowest range of operational temperatures.

"Testing at these extremes aids us in fully understanding all operating conditions for this motor," said Precourt, a former shuttle astronaut. "This data, along with information we have collected over the past three decades, confirms that this is the most powerful and reliable solid rocket motor ever designed, and it is the right motor to ensure the safety of our astronauts."

DM-2 is the largest human-rated solid rocket motor built today, measuring 12 feet in diameter and 154 feet in length. The five-segment motor is based on the design heritage of the flight-proven Solid Rocket Boosters on the Space Shuttle Program, and has been upgraded to incorporate 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.

The five-segment cases remain the same as those used for more than three decades on the Space Shuttle Program. Just like shuttle cases, the cases for this rocket are designed to be recovered and reused. This enables NASA and ATK to collect vital post-flight information and performance data, confirming a safe and robust design. The cases used in this ground test have collectively flown on 59 previous shuttle missions.

As the prime contractor, ATK continues to perform on schedule and on cost in support of NASA's space exploration programs. The next test for the program, Development Motor-3, will be a hot temperature test conducted next year.

Robert PearlmanNASA release
NASA and ATK Successfully Test Five-Segment Solid Rocket Motor

With a loud roar and mighty column of flame, NASA and ATK Aerospace Systems successfully completed a two-minute, full-scale test of the largest and most powerful solid rocket motor designed for flight. The motor is potentially transferable to future heavy-lift launch vehicle designs.

The stationary firing of the first-stage development solid rocket motor, dubbed DM-2, was the most heavily instrumented solid rocket motor test in NASA history. More than 760 instruments measured 53 test objectives.

Prior to the static test, the solid rocket motor was cooled to 40 degrees Fahrenheit to verify the performance of new materials and assess motor performance at low temperatures during the full-duration test. Initial test data showed the motor performance met all expectations.

"For every few degrees the temperature rises, solid propellant burns slightly faster and only through robust ground testing can we understand how material and motor performance is impacted by different operating conditions," said Alex Priskos, first stage manager for Ares Projects at NASA's Marshall Space Flight Center in Huntsville, Ala. "Ground-testing at temperature extremes pushes this system to its limits, which advances our understanding of five-segment solid rocket motor performance."

The first-stage solid rocket motor is designed to generate up to 3.6-million pounds of thrust at launch. Information collected from this test, together with data from the first development motor test last year, will be evaluated to better understand the performance and reliability of the design.

Although similar to the solid rocket boosters that help power the space shuttle to orbit, the five-segment development motor includes several upgrades and technology improvements implemented by NASA and ATK engineers. Motor upgrades from a shuttle booster include the addition of a fifth segment, a larger nozzle throat, and upgraded insulation and liner. The motor cases are flight-proven hardware used on shuttle launches for more than three decades. The cases used in this ground test have collectively launched 59 previous missions, the earliest being STS-3.

After more testing, the first-stage solid rocket motor will be certified to fly at temperature ranges between 40-90 degrees Fahrenheit. The solid rocket motor was built as an element of NASA's Constellation Program and is managed by the Ares Projects Office at Marshall. ATK Aerospace Systems, a division of Alliant Techsystems of Brigham City, Utah, is the prime contractor.

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