propulsion systems played a role in successfully placing the second of five Mobile User Objective System (MUOS-2
) satellites into orbit for the U.S. Navy. The mission was launched July 19 from Cape Canaveral Air Force Station in Florida aboard a United Launch Alliance (ULA) Atlas V rocket, with five Aerojet Rocketdyne AJ60 solid rocket boosters (SRBs), an RL10A-4-2 upper-stage engine, and multiple spacecraft attitude control thrusters.
Built by Lockheed Martin, MUOS-2 is a next-generation narrowband tactical satellite communications system designed to provide mobile U.S. forces with reliable and secure global communication, including, for the first time, simultaneous voice and data capabilities. It is part of a $6 billion program to replace the UHF Follow-On (UFO) satellites currently used by the U.S. Navy. The Navy's Program Executive Office for Space Systems and its Communications Satellite Program Office are responsible for the MUOS program. Lockheed Martin Space Systems Co. is the MUOS prime contractor and lead system integrator.
"Aerojet Rocketdyne's diverse propulsion capabilities are critical to missions like this, trusted to not only assist with delivering the spacecraft to its final orbital destination, but also to keep it there, properly oriented, for its full intended mission life," says Steve Bouley, vice president of Space Launch Systems at Aerojet Rocketdyne. "Our record of mission success enables assured placement of such a valuable payload like MUOS which is anticipated to stay in service well past 2025."
The five AJ60 SRBs were ignited at lift off, increasing the launch thrust of the Atlas V rocket by more than 1.9 million pounds. All Atlas V launches requiring extra boost performance have flown Aerojet Rocketdyne-produced SRBs and this particular flight includes the 49th SRB delivered to ULA last April. These motors have demonstrated a 100% success record in flight, having now flown 17 missions over the past 10 years almost to the day, since the first Atlas V launch with SRBs on July 17, 2003.
A single RL10A-4-2 engine delivers 22,300 lb of thrust to power the Atlas V upper-stage, burning cryogenic liquid hydrogen and liquid oxygen propellants.
In addition to the five SRBs and upper-stage engine, 12 Aerojet Rocketdyne monopropellant (hydrazine) thrusters in four modules on the Atlas V Centaur upper stage provided roll, pitch and yaw control as well as settling burns for the upper stage main engine.
Aerojet Rocketdyne manufactures the Atlas V SRBs at its Sacramento, Calif. facility. The two types of thrusters aboard MUOS were designed and manufactured at Aerojet Rocketdyne's Redmond, Wash., facility. The RL10 engine is designed and manufactured at Aerojet Rocketdyne's facility in West Palm Beach, Fla.