Two U.S.-built Intelsat communications satellites have hitched on to an Ariane 5 rocket for launch from French Guiana next week, the first time the storied company has put two of its spacecraft on the same booster.
The spacecraft, both owned by Intelsat but intended for different missions, will blast off on top of the Ariane 5 launcher Aug. 24 at 2155 GMT (5:55 p.m. EDT), the opening of the day’s 45-minute launch window.
Ground crews topped off the 180-foot-tall (55-meter) Ariane 5 rocket inside the final assembly building at the Guiana Space Center last weekend.
The Intelsat 33e and Intelsat 36 satellites were transported one-by-one from separate processing clean rooms at the space center to the Ariane 5’s final assembly building.
The Boeing-built Intelsat 33e satellite, the second in a series of modernized “Intelsat Epic” communications craft, arrived at the rocket assembly structure first. Workers mated the 14,550-pound (6.6-metric ton) spacecraft on top of the Ariane 5’s Sylda adapter Aug. 9, then enclosed Intelsat 33e inside the rocket’s nose cone.
The Intelsat 36 spacecraft, made by Space Systems/Loral, arrived at the final assembly building Aug. 11 and was lifted on top of the Ariane 5’s second stage a day later. The 7,171-pound (3,253-kilogram) satellite will offer direct-to-home television services to South Africa and other communications services across Africa and the Indian Ocean region.
On Aug. 13, ground crews completed the payload integration procedures by lowering the tip of the Ariane 5 rocket — containing Intelsat 33e, the Sylda dual-payload attach fitting, and the fairing — over the top of Intelsat 36 and the second stage.
The payloads were added to the rocket nearly a month after technicians completed stacking of the Ariane 5 inside the nearby launcher integration building. The Ariane’5 hydrogen-fueled core stage was erected first July 9, followed by the addition of the rocket’s two strap-on boosters July 11. The rocket’s second stage was hoisted on top of the Ariane 5 on July 15.
The rocket was transferred from the launcher integration building to the nearby final assembly building Aug. 3.
The launch team conducted a countdown rehearsal Thursday, and plans called for engineers to arm the Ariane 5 booster Friday. A launch readiness review is on tap Monday, followed by rollout of the Ariane 5 on rails for the 1.7-mile (2.7-kilometer) trip the ELA-3 launch zone Tuesday.
The Ariane 5 will be fueled with super-cold liquid hydrogen and liquid oxygen propellants Wednesday afternoon, leading to liftoff a few minutes after sunset in French Guiana.
After taking off and turning east over the Atlantic Ocean, the two-stage rocket will first deploy the Intelsat 33e satellite at T+plus 28 minutes, 47 seconds, a few minutes after it reaches a targeted geosynchronous transfer orbit. Once Intelsat 33e separates, the rocket will jettison the barrel-shaped Sylda adapter to reveal Intelsat 36 for release at T+plus 41 minutes, 50 seconds.
Wednesday’s launch will mark the fourth Ariane 5 flight of 2016, and the sixth Arianespace mission overall this year, including two Soyuz launches from the spaceport on the northeastern cost of South America.
It will be the 87th Ariane 5 launch overall since 1996, and the 57th flight by the Ariane 5 ECA configuration with a cryogenic upper stage. The flight is codenamed VA232, short for Vol Ariane 232, and is the 231st launch by a member of the Ariane rocket family since 1979.
The Ariane launch manifest is currently out of order due to delays in satellite availability. The next Ariane 5 flight set for Oct. 4 takes the VA231 number.
More photos of the Ariane 5 rocket receiving the Intelsat 33e and Intelsat 36 satellites are posted below.
Email the author.
Follow Stephen Clark on Twitter: @StephenClark1.