Two reusable solid rocket
motors manufactured by ATK’s (Alliant Techsystems) Aerospace Group
helped launch NASA’s Space Shuttle Endeavour from Kennedy Space Center, Fla.,
yesterday on a mission to the International Space Station (ISS).

Endeavour will deliver the Expedition Five crew to the ISS and return the
Expedition Four crew to Earth. Members of the Endeavour crew will also
perform three space walks to continue station construction and to do repair
work on the orbital outpost’s robotic arm. The mission is scheduled to end
with the landing of Endeavour at Kennedy Space Center on June 17.

Manufactured by ATK Thiokol Propulsion, Promontory, Utah — the world’s
leading supplier of solid propellant rocket motors — the Space Shuttle
reusable solid rocket motor (RSRM) is the largest solid rocket motor ever
flown and the first designed for reuse. Key facts about the RSRM:

  • Each RSRM consists of 11 case segments designed for reuse up to
    20 launches or static tests.

  • The RSRMs provide 71 percent of thrust at liftoff and during
    first-stage ascent.

  • From ignition to end of burn, each RSRM generates an average thrust of
    2.6 million pounds and burns for approximately 124 seconds.

  • Each motor is just over 126 feet long and 12 feet in diameter. The
    entire booster — including nose cap, frustum, and forward and aft
    skirts — is approximately 149 feet long. Of the motor’s total
    approximate weight of 1.25 million pounds, propellant accounts for
    approximately 1.1 million pounds.

  • By the time the RSRMs have completed their task, the Space Shuttle
    orbiter has reached an altitude of 24 nautical miles and is traveling
    at a speed in excess of 3,000 miles per hour.

  • With safety, quality, and reliability as their primary objectives,
    engineers from ATK Thiokol Propulsion direct approximately
    110,000 quality-control inspections on each RSRM flight set.

ATK is a $2 billion aerospace and defense company with leading positions
in propulsion, composite structures, munitions, and precision capabilities.
The company, which is headquartered in Edina, Minn., employs approximately
11,300 people and has three business groups: Aerospace, Precision Systems,
and Ammunition. ATK news and information can be found on the Internet at .