Two European-made communications satellites destined to serve the Brazilian government and commercial customers across Asia are set to ride an Ariane 5 rocket into orbit Thursday.
Standing nearly 180 feet (55 meters) tall, the Ariane 5 is scheduled to lift off from Kourou, French Guiana, at 2031 GMT (4:31 p.m. EDT; 5:31 p.m. French Guiana time) Thursday. The launch will mark the 92nd Ariane 5 flight since 1996, and the launcher’s second mission this year.
The Brazilian-owned SGDC satellite, weighing around 12,643 pounds (5,735 kilograms) at launch, is the heavier of the two spacecraft aboard the Ariane 5 rocket. Koreasat 7 weighs 8,113 pounds (3,680 kilograms) with its propellant tanks full.
The rocket will target an orbit ranging from 155 miles (250 kilometers) to 22,323 miles (35,926 kilometers), with a tilt of 4 degrees to the equator.
The Ariane 5’s first stage Vulcain 2 main engine ignites as the countdown clock hits zero, throttling up to about 300,000 pounds of thrust and undergoing a computer health check before liftoff.
T+0:00:07: Solid rocket booster ignition and liftoff
The Ariane 5’s two solid rocket boosters ignite seven seconds later, each generating more than 1.3 million pounds of thrust, to push the vehicle into the sky from the ELA-3 launch pad.
T+0:00:50: Mach 1
The Ariane 5 rocket surpasses the speed of sound, heading east over the Atlantic Ocean.
T+0:02:21: Solid rocket boosters jettisoned
After each consuming 240 metric tons, or about 530,000 pounds, of pre-packed propellant, the solid rocket boosters are jettisoned.
T+0:03:22: Payload fairing jettisoned
The Ariane 5’s 17.7-foot-diameter (5.4-meter) payload fairing, made in Switzerland by Ruag Space, releases in a clamshell-like fashion once the rocket flies above the denser, lower layers of Earth’s atmosphere.
T+0:08:53: Vulcain 2 shutdown
The Ariane 5’s core stage Vulcain 2 main engine shuts down after consuming 175 metric tons (385,000 pounds) of cryogenic liquid hydrogen and liquid oxygen propellants.
T+0:08:59: Stage separation
The Ariane 5’s first and second stages separate. The 98-foot-long (30-meter) first stage will fall into the Atlantic Ocean near the Gulf of Guinea off the west coast of Africa.
T+0:09:03: HM7B ignition
The Ariane 5’s upper stage HM7B engine ignites for a 15-minute, 54-second burn to place the SGDC and Koreasat 7 satellites into geostationary transfer orbit. The HM7B engine burns liquid hydrogen and liquid oxygen, and generates more than 14,000 pounds of thrust.
T+0:24:57: HM7B shutdown
The HM7B engine shuts down after placing the SGDC and Koreasat 7 satellites into geostationary transfer orbit with a low point of 155 miles (250 kilometers), a high point of 22,323 miles (35,926 kilometers), and an inclination of 4 degrees to the equator.
T+0:28:11: SGDC separation
The SGDC satellite, riding in the upper position on the Ariane 5’s dual-payload stack, deploys to begin an 18-year mission supporting the Brazilian military and providing broadband services for Brazilian citizens.
T+0:29:52: Sylda 5 separation
The Sylda 5 dual-payload adapter structure jettisons from the Ariane 5 upper stage, revealing the Koreasat 7 spacecraft for deployment.
T+0:36:46: Koreasat 7 separation
The Koreasat 7 satellite separates from the Ariane 5’s upper stage to begin a 21-year mission for KTsat.
The pre-launch news conference for the Jason 3 ocean altimetry mission, scheduled for launch from Vandenberg Air Force Base, California, aboard a SpaceX Falcon 9 rocket. (Membership required.)
An Ariane 5 countdown in French Guiana was aborted Tuesday with the European-made rocket’s main engine already running, postponing the launch of two commercial communications satellites until engineers can resolve the problem.
The next flight of Europe’s heavy-lift Ariane 5 rocket, set for July 28 from French Guiana, will carry a record payload of three multi-ton satellites toward geostationary orbit, including a pair of U.S.-built commercial communications payloads and Northrop Grumman’s second robotic satellite servicing spacecraft.
