AEHF 5 lights up the sky atop ULA Atlas V 551
CAPE CANAVERAL, Fla. — United Launch Alliance completed its third flight of the year on Thursday, Aug. 8. The flight got off the pad and soared into the early morning sky a little later than planned.
ULA used an Atlas V 551 rocket to send the fifth Advanced Extremely High Frequency (AEHF-5) satellite on its way to geosynchronous orbit. The launch window was slated to open at 5:44 a.m. EDT (09:44 UTC), but ULA needed a little more time to work issues that they encountered in the lead up to launch. When all was said and done, the satellite was sent into the sky at 6:13 a.m. EDT (10:13 UTC).
At T-0, the RD-180 main engine and 5 SRBs ignited, sending the Atlas soaring away from the pad. At 1 minute and 46 seconds into flight, the first pair of solids were jettisoned. Then a second and a half later, the last three AJ-60A boosters were also jettisoned.
At about 3 minutes and 23 seconds into the flight, the payload fairing separated. This will expose the $1.1 billion satellite to its intended environment – the vacuum of space. After burning for approximately 4 minutes and 26 seconds, the first stage shut down and separated from the Centaur upper stage six seconds later.
A few seconds after stage separation, the Centaur ignited for the first of three burns. This initial burn placed Centaur and AEHF-5 into a circular parking orbit. The Centaur shut down at 11 minutes and 42 seconds after leaving the pad and begin a coast phase. After coasting for a little bit more than 11 minutes, Centaur reignited over Africa and begin a six-minute burn that placed both vehicles into a transfer orbit.
Centaur and AEHF-5 will now coast for about five hours up to the apogee of the spacecraft’s orbit. After the long coast, Centaur will reignite for the third and final time for a three-minute burn that should circularize the spacecraft’s orbit. At T plus 5 hours and 40 minutes, Centaur is scheduled to release AEHF-5 into orbit.
After separation, AEHF-5 will begin orbit raising maneuvers. It will use its on-board liquid apogee engine in a series of three burns to raise its apogee. After those burns, AEHF-5 will use electric Hall-effect ion thrusters to place itself in its final orbit. These thrusters will burn continuously for almost 70 days.
“We are thrilled to return to the Cape to launch AEHF-5 less than a year after launching AEHF-4, showing an accelerated pace to support the Air Force Space and Missiles Systems Center,” said Mike Cacheiro, vice president of Protected Communications at Lockheed Martin Space said via a release issued in May. “AEHF-4 arrived to its on-orbit operational position a month early, where it demonstrated Extended Data Rate (XDR) connectivity. This is an exciting time where we are witnessing the deployment of critical capabilities of the current four AEHF satellites in geosynchronous orbit, which provide ten times greater capacity than the original Milstar constellation. The AEHF system is essentially a high capacity data network in the sky, and this is a complete paradigm shift for the future of protected communications.”
The Atlas line of rockets can trace its lineage back to the earliest days of the Space Age. Atlas was the first rocket to send U.S. astronauts to orbit. In 1961, John Glenn’s Friendship 7 lifted of from Canaveral’s SLC-14 atop Atlas LV-3B 109-D.
Patrick Attwell is a native of Houston, Texas but he currently resides in Austin, Texas where he studies accounting at Concordia University Texas. Atwell has had a passion for all things pertaining to aerospace, rocketry, and aviation. Atwell has worked to cover these fields for more than a decade. After he attended and watched the launch of NASA’s OSIRIS-REx mission it gave him what is known in the space community as “rocket fever.” Since that time, Atwell has followed his dreams and has covered events dealing with NASA’s Commercial Crew flight assignments at NASA’s Johnson Space Center and other space-related events in the Lone Star State.