Despite slightly overcast skies, Ariane 5’s 96-percent success record continues to stay strong following tonight’s rousing launch of the Astra 5B and Amazonas 4A communications satellites by Mission VA-216 from the Guiana Space Centre in Kourou, French Guiana. Liftoff of the two-stage rocket occurred on time at 7:04 p.m. GFT (10:04 p.m. GMT) Saturday, at the opening of a 58-minute “window,” having succumbed to a 24-hour postponement from its original Friday target. At the time of writing, VA-216’s twin satellite cargoes had been successfully deployed from the two-tier Système de Lancement Double Ariane (SYLDA) payload dispenser into geostationary transfer orbit.As noted in AmericaSpace’s VA-216 preview article, this mission has been waiting in the wings for several months, having been originally scheduled for launch in mid-December 2013. Assembly operations of the Ariane 5’s 100-foot-tall (30-meter) “cryotechnic main stage” got underway at the Guiana Space Centre last October, and by November it had been installed onto its operational launch table in the Launcher Integration Building (BIL). The next phase of preparation was the attachment of Ariane 5’s twin solid-fueled boosters, followed by the cryogenic upper stage and the Vehicle Equipment Bay (VEB), containing the rocket’s computerized “brain.”
However, on 19 December, Arianespace announced that VA-217 would fly ahead of VA-216. In making this announcement, Chairman and CEO Stéphane Israël thanked the clients of both missions “for their trust” and praised the “excellent collaboration between our teams,” as well as highlighting Arianespace’s own “commitment and flexibility.” It was reported that VA-217 would fly on 23 January, with VA-216 following on 19 February. During this period, however, the nozzle of the second-stage cryogenic engine for VA-217 was inadvertently bumped and managers opted to replace it. This created a two-week delay until early February, which, in turn, pushed the VA-216 launch into early March. Postponed again by the need for additional “payload checks,” Arianespace finally announced Friday, 21 March, as the next available launch opportunity.
With liftoff targeted at the start of a 57-minute “window,” all appeared to be proceeding according to schedule, with flight readiness reviews completed Wednesday. Then, early on Thursday, shortly before the planned rollout of the Ariane 5 stack to the ELA-3 (Ensemble de Lancement Ariane) launch complex, Arianespace called a 24-hour postponement. Citing “high winds at ground level,” Arianespace opted to delay VA-216 until Saturday, 22 March, and noted that the situation prevented the rollout from the Final Assembly Building (BAF) to the launch complex. Conditions for rollout improved sufficiently by sunrise Friday, and the vehicle was transferred safely to ELA-3. Following rollout, Arianespace engineers set to work establishing electrical, fluid, and other connections between the booster and the launch complex facilities.
The loading of 260,000 pounds (118,000 kg) of liquid oxygen and 50,000 pounds (22,700 kg) of liquid hydrogen for the Vulcain-2 engine of the first stage got underway at T-4 hours and 50 minutes. The propellant tanks were pressurized for flight at T-4 minutes, and the 171-foot-tall (52-meter) vehicle transitioned to internal power. In the final seconds, systems aboard the rocket assumed primary command of all critical functions and the guidance system was unlocked to Flight Mode. The French-built Vulcain-2 roared to life at T-0, producing 300,000 pounds (136,000 kg) of thrust, although liftoff did not occur for another 7.5 seconds, as a series of computer-controlled health checks were undertaken. When all was verified to be well, the twin side-mounted solid-fueled boosters—each punching out 1.4 million pounds (635,000 kg) of propulsive yield and together generating 92 percent of the thrust to get Ariane 5 off the pad—ignited and at 7:04 p.m. GFT (10:04 p.m. GMT) Mission VA-216 was committed to flight.
The stack rose vertically for about five seconds, after which the two computers inside the VEB initiated a combined pitch and roll program maneuver, actively rotating the vehicle onto the correct flight azimuth to insert the Astra 5B and Amazonas 4A primary payloads into orbit. One minute into the ascent, the vehicle went supersonic and passed through “Max Q,” the period of maximum aerodynamic stress on the airframe. The two boosters were jettisoned at T+142 seconds, parachuting into the Atlantic Ocean about 300 miles (480 km) east of the launch site. Meanwhile, Ariane 5 had now reached a velocity of over 1,200 mph (1,900 km/h) and continued to climb under the impulse of its Vulcain-2 engine.
Three and a half minutes into the flight, the bullet-like payload shroud was detached, essentially splitting in half and exposing the twin satellites to the space environment for the first time. Shutdown of the Vulcain-2 occurred at about 8 minutes and 53 seconds after launch and the cryotechnic main stage descended 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 (2,770-kg) Aestus engine—ignited to pick up the baton for the final push into orbit. By now, the rocket was over 105 miles (170 km) high and traveling at more than 4,300 mph (6,900 km/h). Twenty-five minutes into the mission, at 7:29 p.m. GFT (10:29 p.m. GMT), Geostationary Transfer Orbit (GTO) was successfully attained.
In a similar fashion to previous Ariane 5 missions with dual satellites, Astra 5B and Amazonas 4A will ride aboard the upper and lower decks of the SYLDA payload dispenser. The former will occupy the upper portion of the SYLDA, with the latter sitting “beneath” it. Astra 5B was deployed first, at T+27 minutes and 3 seconds, by which time the vehicle was traveling at 20,490 mph (32,976 km/h) and had covered a distance of 6,245 miles (10,050 km) from the Guiana Space Centre. With its uppermost passenger now gone, the SYLDA separated from the vehicle at 7:37 p.m. GFT (10:37 p.m. GMT), exposing Amazonas 4A to the space environment, ahead of its own deployment. To a roar of applause from mission controllers, Amazonas 4A was released into space at 7:39 p.m. GFT (10:39 p.m. GMT) at a Mission Elapsed Time of 34 minutes and 37 seconds. Following the successful deployment of both satellites, Arianespace Chairman and CEO Stéphane Israël noted that VA-216 was the 59th successful Ariane 5 mission in a row. He joked that Amazonas 4A would soon be broadcasting the 2014 Brazil World Cup “if France does not win!”
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 September 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 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.”
Tonight’s flight was the 73rd flight by an Ariane 5, which first flew in June 1996, and the 217th overall flight by a member of Arianespace’s rocket family, since the maiden voyage of an Ariane 1, way back in December 1979. With the completion of VA-216, the remainder of 2014 promises to be busy for Arianespace, with further Ariane 5 missions planned in May and July. The first of these flights will deliver the Measat 3B and Optus 10 communications satellites into orbit, whilst the second will loft the final Automated Transfer Vehicle (ATV)-5 toward the International Space Station (ISS) on behalf of the European Space Agency (ESA). Meanwhile, the Ariane 5 cryotechnic main stage for the ATV-5 mission—named in honor of Belgian astronomer Georges Lemaître—arrived at the Guiana Space Centre on Thursday, 20 March aboard the MN Toucan cargo ship for processing operations.