AEHF Orbit Raising Making Progress, Air Force Says


The U.S. Air Force’s newest secure communications satellite is nearly halfway through a yearlong orbit-raising process devised after one of its thrusters failed shortly after the spacecraft reached its initial orbit, the service announced Feb. 10.

The Advanced Extremely High Frequency (AEHF)-1 satellite, built by Lockheed Martin Space Systems of Sunnyvale, Calif., was successfully launched Aug. 14 into a highly elliptical orbit ranging from 230 kilometers above Earth at perigee to 50,000 kilometers above Earth at apogee. The satellite was designed to use its hydrazine-fueled liquid apogee engine to raise its perigee to 19,000 kilometers over 30 days, and then use its xenon-ion electric thrusters to circularize its orbit at 36,000 kilometers over 90 days.

The liquid apogee engine failed on orbit, and operators devised a contingency plan to lift the satellite with smaller on-board thrusters fueled by the same hydrazine tank. That phase of the plan is now complete, and the satellite’s perigee is now 13,350 kilometers, according to an Air Force press release. The satellite is now using its electric thrusters expected to carry it to its final orbit by late summer, the press release said.


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