A United Launch Alliance Delta 4 rocket will deliver the U.S. Air Force’s second GPS 3-series navigation satellite into an elliptical transfer orbit nearly two hours after liftoff from Cape Canaveral.
Liftoff is scheduled during a launch window opening at 9:00:30 a.m. EDT (1300:30 GMT) Thursday. The window extends to 9:27 a.m. EDT (1327 GMT).
The United Launch Alliance Delta 4 rocket takes off powered by an Aerojet Rocketdyne RS-68A main engine and two solid rocket boosters built by Northrop Grumman Innovation Systems. The hydrogen-burning main engine ignites at T-minus 5 seconds, following by ignition of the two boosters at T-minus 0, the release of four hold-down bolts and retraction of the launch pad’s three swing arms.
T+00:00:58.5 — Max-Q
Heading northeast from Cape Canaveral on an azimuth of roughly 60 degrees, the Delta 4 surpasses the speed of sound at T+plus 42 seconds, then experiences the most extreme aerodynamic pressures of the mission at T+plus 58.5 seconds.
T+00:01:40.0 — Solid Rocket Motor Separation
The Delta 4’s two GEM-60 solid rocket boosters are jettisoned in two pairs around seven seconds after consuming all their propellant.
T+00:03:55.9 — Booster Engine Cutoff
The Delta 4’s RS-68A main engine shuts down after burning its supply of super-cold liquid hydrogen and liquid oxygen.
T+00:04:02.4 — Stage Separation
The Delta 4’s Common Booster Core separates from the rocket’s second stage.
T+00:04:16.9 — First Second Stage Ignition
The Delta 4’s second stage Aerojet Rocketdyne RL10B-2 engine ignites and powers up to 24,750 pounds of thrust in the first of its two firings to place the GPS 3 SV02 satellite into a MEO transfer orbit.
T+00:04:26.9 — Payload Fairing Jettison
The Delta 4’s composite bisector fairing jettisons from the rocket once the launcher reaches a safe altitude above the dense lower layers of Earth’s atmosphere.
T+00:13:33.1 — First Second Stage Engine Shutdown
The second stage’s RL10B-2 engine shuts down after placing the GPS 3 SV02 satellite in a preliminary parking orbit, beginning a 53-minute coast before the engine reignites.
T+01:06:47.3 — Second Stage Engine Restart
The RL10B-2 second stage engine ignites again for a three-and-a-half-minute burn to send the GPS 3 SV02 spacecraft into a higher, elliptical transfer orbit.
T+01:10:14.6 — Second Stage Engine Shutdown
The Delta 4’s second stage engine shuts down after placing the GPS 3 SV02 spacecraft in a transfer orbit ranging between 745 miles (1,200 kilometers) and 12,542 miles (20,185 kilometers) above Earth, with an orbital plane tilted 55 degrees to the equator.
T+01:55:26.6 — GPS 3 SV02 “Magellan” Separation
The Lockheed Martin-built GPS 3 SV02 spacecraft, nicknamed “Magellan,” separates from the Delta 4’s second stage.
NASA’s InSight spacecraft, the next lander to head for Mars, lifted off Saturday from Vandenberg Air Force Base in California aboard a United Launch Alliance Atlas 5 rocket. Launch occurred in a blanket of fog at 4:05 a.m. PDT (7:05 a.m. EDT; 1105 GMT).
The U.S. Space Force announced Tuesday that it awarded $384 million in contracts to United Launch Alliance and SpaceX, giving each company two missions to launch military satellites in 2023.
The nation’s existing Atlas and Delta launch sites are vying for a future when United Launch Alliance completes its modernization with a new rocket system and downsizing to one pad on each coast.
