ULA Atlas V 411 lights up the night with SBIRS GEO 4 launch
CAPE CANAVERAL, Fla. — United Launch Alliance (ULA) saw its launch window open at 7:48 p.m. Eastern (00:48 GMT on Jan. 20) and soon thereafter sent its Atlas V rocket thundering into the Florida sky. The payload, the fourth geosynchronous satellite in the U.S. Air Force (USAF) Space Based Infrared Sensor (SBIRS) program, is now headed for geosynchronous orbit.
Once its there, it will help enhance USAF’s missile early warning, missile defense, battlefield awareness, as well as technical intelligence.
Launching by the numbers
The Atlas V 411 used for this evening’s launch was an ideal choice for the GEO 4 flight based on its performance (up to 12,323 pounds / 5,590 kg to a geosynchronous transfer orbit / GTO). The 411 variant of the vehicle is comprised of the Atlas common core booster stage and a single Aerojet Rocketdyne-provided asymmetrical solid rocket booster (SRB) for liftoff as well as a four-meter payload fairing and a single RL10C-1 engine on the Centaur upper stage.
At approximately T-3 seconds, the Russian-built NPO Energomash-built kerosene/liquid oxygen RD-180 rocket engine ignited its 860,000 pounds (3,825 kilonewtons) of thrust, followed by the Aerojet Rocketdyne AJ60 SRB, pushing the rocket rapidly away from Space Launch Complex (SLC) 41 at T-0, 7:48 p.m. Eastern Time.
Eighteen seconds off the pad, the Atlas V began its pitch/yaw maneuver to point it in the proper direction for its eventual placement over the Equator. Just over 80 seconds after liftoff, Atlas V powered through Mach 1 and then maximum dynamic pressure ten seconds later.
The Atlas Booster Engine cut off some 243 seconds into flight, with the booster separating from the Centaur upper stage six seconds later. The Centaur’s RL10A upper stage engine ignited ten seconds after booster separation, with the payload fairing jettisoning eight seconds later.
Afterward SBIRS GEO-4 will begin transitioning to its its planned final location in geosynchronous orbit, approximately 22,000 miles (35,406 kilometers) above our world. If everything goes as mission planners hope, the satellite will deploy its solar arrays, antennas and its light shade before it undergoes testing. The spacecraft will join its ‘siblings’ SBIRS GEOs 1, 2 and 3, which were launched in 2011, 2013 and 2017 respectively and continue to meet or exceed performance expectations.
“Meeting the challenge of launching two critical national security missions from opposite coasts within a week, the entire ULA team once again demonstrated its unwavering dedication to 100 percent mission success,” said Laura Maginnis, ULA vice president of Government Satellite Launch via a release issued by ULA. “Thank you to our U.S. Air Force and industry teammates for their outstanding partnership in successfully delivering SBIRS to orbit today.”
While there is no official word on when GEO-4 will begin operations, GEO-3 spent around 65 days circularizing its orbit before reaching its station and starting to collect images of Earth. This positioning effort was followed by a commissioning campaign lasting several months before the USAF declared the satellite operational. The previous two satellites (GEO-1 and -2) took 16 and 35 days, respectively, to circularize their orbits.
The contract for the next two geosynchronous elements for SBIRS, GEO-5 and -6, was signed in 2014. These two spacecraft will use a more advanced Lockheed Martin A2100M spacecraft bus. According to a Space News report, Lockheed Martin expects to have the two satellites completed by 2022.
“SBIRS is the nation’s 24-7 global watchman, with infrared eyes ready to detect and deliver early warning and tracking of ballistic missiles. A cornerstone of the nation’s missile defense system, SBIRS is proving even more precise and powerful than expected,” said Tom McCormick, vice president of Lockheed Martin’s Overhead Persistent Infrared systems mission area. “Space is a place to do great things, and we’re already improving on SBIRS, upgrading our fifth and sixth SBIRS GEO satellites to our modernized LM 2100 satellite bus at no additional cost to the Air Force. On SBIRS 5 and 6 the Air Force saved $1 billion through improved production and management efficiencies.”
The launch had been scheduled to take place on Thursday, Jan. 18. However, due to a ground issue associated with the booster liquid oxygen system, the flight was pushed back 24 hours to this evening.
The weather conditions for tonight’s flight – simply could not have been better with clear, albeit chilly, temperatures providing favorable conditions calculated at being around 90 percent. With weather and no other issues cropping up, Atlas’ lone RD-180 and its lone solid rocket booster cleaved a bright arc through the early evening skies, signaling a successful start to the mission.
“The SBIRS satellites help safeguard the nation’s homeland and deployed forces against the threat of ballistic missile attacks. It is critical to have reliable propulsion systems on every satellite to ensure they maintain a watchful eye and are able to detect a threat at a moment’s notice,” said Eileen Drake, CEO and president of Aerojet Rocketdyne, which provided the Centaur’s rocket engine as well as the AJ-60A solid rocket strap-on motor that was attached to the rocket’s core stage.
ULA’s next scheduled flight is, at present, the flight of an Atlas V 541 with the GOES-S weather satellite for the National Oceanic and Atmospheric Administration (NOAA). That mission is slated to launch on March 1.
Video courtesy of SpaceFlight Insider
Bart Leahy is a freelance technical writer living in Orlando, Florida. Leahy's diverse career has included work for The Walt Disney Company, NASA, the Department of Defense, Nissan, a number of commercial space companies, small businesses, nonprofits, as well as the Science Cheerleaders.