On Tuesday 19th March 2013 a United Launch Alliance Atlas V rocket successfully deployed the US Air Force’s SBIRS GEO 2 infrared surveillance spacecraft on the fourth Atlas V to launch in four months.
At 2121 UTC the Atlas V ignited its RD-180 main engine and took off from Space Launch Complex 41 at Cape Canaveral Florida beginning the mission to deploy the SBIRS GEO-2 into its initial parking orbit.
The Atlas V lifts off with 860,000 pounds of thrust to start the ascent into space. The boosters first stage burns RP-1 Kerosene and Liquid Oxygen in its Russian designed RD-180 engine. After four minutes and five seconds the boosters RD-180 engine shuts down, completing stage one of the flight. After around ten seconds the first stage separates and the retro rockets pull it away from the Centaur upper stage as the RL10 engine readies itself for ignition.
At the 4 minute 25 second mark the RL10 engine on the Centaur ignites. The RL10 engine burns Liquid Hydrogen and Liquid Oxygen to produce around 22,300 pounds of thrust. The first Centaur burn lasts about 11 minutes to put the spacecraft into orbital velocity and to set itself up for the second burn of the upper stage that puts the satellite into a geosynchronous transfer orbit.
After 24 minutes, 12 seconds from liftoff the Centaur RL10 engine re-ignites to put the spacecraft into the correct orbit. The burn lasts about 4 minutes and puts the spacecraft into an orbit of 22,233 miles (35781 km) apogee by 115 miles (135 km) perigee on an inclination of 22.2 degrees.
The completion of the second Centaur burn didn’t mark the end of this mission, the payload deployment was held until the spacecraft was over until the rocket crosses Africa and Madagascar, flying within communications range of the Diego Garcia tracking station on an island in the Indian Ocean for live telemetry coverage of the deployment.
When the spacecraft was in range of the tracking station at 2204 UTC the Centaur started a 1 degree per second roll to prepare for payload deployment and at 43 minutes, 20 seconds after liftoff the Space Based Infrared System Geosynchronous satellite was deployed into orbit. The satellite will use its own propulsion to bring its perigee up into a circular orbit over the next week, before being moved into its permanent geosynchronous position in the sky.
All Image Credit: United Launch Alliance