The next launch of United Launch Alliance’s Atlas 5 rocket with the U.S. Air Force’s fifth Advanced Extremely High Frequency communications satellite, previously scheduled for Thursday, has been delayed to no earlier than July 9 to replace a failed battery on the vehicle.
In a statement Sunday, ULA said the launch was delayed “due to a vehicle battery failure discovered during final processing.”
ULA crews at Cape Canaveral were preparing for liftoff at 8:27 a.m. EDT (1227 GMT) Thursday with the Lockheed Martin-built nuclear-hardened, jam-resistant
AEHF 5 spacecraft designed to provide secure communications for the U.S. military and the president.
“Additional time is needed for the technical team to complete the evaluation of the issue and replace the battery,” ULA said in a statement.
A launch window for the Atlas 5’s earliest launch opportunity July 9 has not been announced, but the window is expected to open at approximately 7:45 a.m. EDT (1145 GMT).
The Atlas 5 rocket is fully assembled inside the Vertical Integration Facility, or VIF, at Cape Canaveral’s Complex 41 launch pad. Since the Atlas 5’s first stage arrived at the VIF last month, workers have installed the rocket’s Centaur upper stage, five solid rocket boosters and the Atlas 5’s payload shroud containing the AEHF 5 spacecraft.
The AEHF 5 satellite’s launch comes after the launch of four previous AEHF spacecraft in 2010, 2012, 2013 and 2018, all on Atlas 5 rockets.
The Atlas 5’s Centaur upper stage will fire its RL10 engine three times to send the AEHF 5 spacecraft into an elliptical “high-energy” geostationary transfer orbit ranging from 8,970 miles (14,435 kilometers) to 21,933 miles (35,298 kilometers) in altitude, with an inclination of 9.95 degrees.
The rocket will deploy the AEHF 5 spacecraft around 5 hours, 40 minutes, after liftoff. The satellite’s own engine will guide the craft into a circular geostationary orbit more than 22,000 miles over the equator, where AEHF 5 will join its predecessors in the secure communications network.
After AEHF 5’s launch, ULA plans to begin stacking its next Atlas 5 rocket inside the VIF at Complex 41 for the first unpiloted test flight of Boeing’s CST-100 Starliner crew capsule, which is scheduled for liftoff in September.
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