United Launch Alliance Atlas V delivered to orbit yesterday latest Space Base Infrared System Geosynchronous Earth Orbit satellite under contract with Department of Defense and Lockheed Martin signed in 2012. Satellite will be third in new constellation of early warning system against Intercontinental Ballistic Missiles.
Originally planned for Thursday, 19 January (local time), mission was postponed for 24 hours due the delay exceeding launch window. First 40-minute delay was caused by problem with one from sensors of Atlas V next, three minutes before flight, aircraft violated security zone around Cape canaveral Launch Complex 41. It was not possible to launch Atlas V with SBIRS-Geo-3 during launch window and mission was postponed to Friday local time (Saturday 00:42 UTC).
Punctually at 00:42 UTC Atlas v in 401 configuration started to rise over LC-41. First stage, not supported by any Solid Rocket Booster, allowed rocket to pass 1 Ma at T+1'15". Fifteen seconds later rocket reached MaxQ point, where dynamic pressure reaches peak value during whole flight. Rocket already set its course to East and at T+4' first stage was cut off on altitude of 109 km. Five seconds later Centaur upper stage separated and ignited its single RL-10 engine. Few seconds later 4 meter payload fairing was jettisoned. After another ten minutes engine was cut off for the first time and Centaur entered into ballistic phase of flight after reaching parking orbit. Second burn, necessary to put payload on GEO orbit with altitude of 36000 km, was performed after around 35 minutes. Satellite was released at T+43' and started its lasting 12 years mission.
SBIRS-GEO-3 satellite was designed and manufactured by Lockheed Martin. It was based on A2100M satellite bus with LEROS-1C thruster (fueled with hydrazine/MON and generating 460 N of thrust) and two deployable solar arrays. Its main payload are two SBIRS sensors: for continuous scanning and additional special "staring" sensor. The scanning sensor seeks intercontinental ballistic missile launches ; the staring sensor has better sensitivity and is able to detect short-range theater ballistic missiles. Sensors are also able to detect and monitor high energetic natural phenomena like eruption of the Vulcano. Mass of the satellite was evaluated by independent sources for ~4500 kg.