It has been a busy year for Arianespace—the French-led launch services organization, which operates the Vega, Soyuz, and Ariane 5 vehicles from the Guiana Space Centre in Kourou, French Guiana—and the 2013 flight schedule shows no sign of slowing down, with a planned mission in mid-December to loft a pair of communications satellites into geostationary transfer orbit. Ariane Flight VA-216 will see the monster Ariane 5 fly from the ELA-3 (Ensemble de Lancement Ariane) launch complex on about 13 December, carrying Amazonas 4A for Spain’s Hispasat company to expand Ku-band television services over Latin America and Astra 5B to support Ku- and Ka-band broadcasting for Luxembourg-based SES.
Assembly of the Ariane 5 got underway last week with the emplacement of the 100-foot-tall “cryotechnic main stage” on its operational launch table in the Launcher Integration Building (BIL) at the Guiana Space Centre. This stage will eventually be loaded with 260,000 pounds of liquid oxygen and 50,000 pounds of liquid hydrogen to feed its French-built Vulcain-2 engine, which generates 300,000 pounds of thrust at liftoff. Described by Arianespace as “a well-established integration flow,” the next steps will involve the mating of two solid-fueled boosters, after which the cryogenic upper stage and Vehicle Equipment Bay (VEB)—containing the computerized “brains” of Ariane 5—will be installed as a single unit.
When the entire vehicle stack is integrated, it will be transferred from the BIL to the Final Assembly Building (BAF) to be joined by its twin satellite passengers for Flight VA-216. This will most likely take place in mid-November. As its numerical designation implies, this will be the 216th flight by Arianespace’s rocket family since the maiden voyage of Ariane 1 in December 1979. It will also be the 72nd mission by the Ariane 5 variant, which made its first flight back in June 1996.
In a similar manner to previous Ariane 5 missions with dual satellite passengers, Astra 5B and Amazonas 4A will ride aboard the upper and lower decks of the SYLDA (Système de Lancement Double Ariane) payload dispenser. Astra 5B will occupy the upper portion of the SYLDA, with Amazonas 4A sitting “beneath” it. Judging from timelines of previous missions, the two satellites should be thus integrated with the SYLDA in late November. Final flight readiness reviews will occur two days before launch and, pending a unanimous “Go” from mission managers, the VA-216 vehicle will be rolled out from the BAF to the ELA-3 launch zone about 24 hours ahead of liftoff. Rollout will require about 40 minutes, after which engineers will set about establishing electrical, fluid, and other connections. The exact launch time on 13 December has yet to be formally announced.
This year, 2013, has been an exciting and dramatic one for the Ariane 5, with four launches accomplished. In February, Flight VA-212 lofted the Amazonas-3 and Azerspace-1/Africasat-1A payloads, followed by the Automated Transfer Vehicle (ATV)-4 “Albert Einstein” to the International Space Station aboard VA-213 in June, the Alphasat and Insat-3D satellites aboard VA-214 in July, and, most recently, the Eutelsat 25B/Es’hail-1 and GSAT-7 satellites aboard VA-215 in August. Additionally, Arianespace flew its Vega lightweight booster on Flight VV-02 in May to deliver the Proba-V, VNRedSat-1A, and ESTCube-1 satellites into orbit.
Ariane 5 launches follow a well-trodden path. Four minutes ahead of liftoff, the propellant tanks will be pressurized for flight and the 171-foot-tall vehicle will transition to its internal power supplies. In the final seconds, systems aboard the rocket assume primary control of all vehicle critical functions and the guidance system is unlocked to Flight Mode. The Vulcain-2 engine will roar to life at T-0, although liftoff itself does not occur for another 7.5 seconds, as a series of computer-commanded health checks are conducted. When all is verified to be well, the twin side-mounted solid-fueled boosters—each with a propulsive yield of around 1.4 million pounds—will ignite and VA-216 will be committed to flight.
The stack will rise vertically for about 5 seconds, after which the two computers inside the VEB will initiate a combined pitch and roll program maneuver, actively rotating Ariane 5 onto the correct flight azimuth to inject Amazonas-4A and Astra-5B into orbit. A minute into the ascent, the vehicle will go supersonic and then pass through “Max Q,” the period of maximum aerodynamic stress on the airframe. The two solid-fueled boosters will be jettisoned at T+142 seconds, parachuting into the Atlantic Ocean about 300 miles east the launch site. Meanwhile, Ariane 5 will by now have reached a velocity of over 1,200 mph and will continue to climb under the impulse of its Vulcain-2 engine. Three and a half minutes into the flight, the bullet-like payload shroud will be detached, exposing the twin satellite cargoes to the space environment for the first time.
Shutdown of the Vulcain-2 is expected about 8 minutes and 53 seconds after launch, and the cryotechnic main stage will descend to a splashdown off the coast of Africa, in the Gulf of Guinea. Meanwhile, the second stage—powered by a restartable, 6,100-pound-thrust Aestus engine—will ignite to pick up the baton for the final push into orbit. By now, the rocket will be over 105 miles high and traveling at more than 4,300 mph. Sixteen minutes later, having reached a velocity of 5,700 mph, Geostationary Transfer Orbit (GTO) will be attained. Astra 5B will depart the SYLDA shortly thereafter, followed by Amazonas 4A a few minutes later.
Astra 5B has been built by EADS Astrium, following a November 2009 contract awarded by Luxembourg-based satellite provider SES. This contract also encompassed the construction of the Astra 2E satellite, which was launched last week aboard the Proton-M “Return to Flight” mission from Baikonur Cosmodrome in Kazakhstan. The contract envisaged the launch of four new satellites—Astra 2E, Astra 2F, Astra 2G, and Astra 5B—between 2012-2014. Two of the three Astra 2 satellites have already been launched, with 2G currently scheduled to fly in the first quarter of 2014. The arrival of Astra 5B in its orbital position at 31.5 degrees East longitude is expected to extend SES’s transponder capacity and geographical reach “over Eastern European and neighboring markets for Direct-to-Home, Direct-to-Cable and contribution feeds to Digital Terrestrial Television networks.”
With Astra 5B deployed first from the SYLDA, the turn will then come for Amazonas 4A, which has been built by Orbital Sciences Corp., under contract to the Hispasat organization, headquartered in Madrid, Spain. The satellite will be situated at 61 degrees West longitude to cover the entire landmass of South America, from Venezuela and Colombia in the north to Argentina and Chile in the south. With the higher-powered Amazonas 4B scheduled for launch in 2015, the two satellites were described by Orbital as “examples of Hispasat’s strong commitment to the Latin American market.”
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