Ariane 5 Primed for Thursday Mission With Athena-Fidus and ABS-2 Satellites

Arianespace Ariane 5 French Guiana ESA Ariane 5 rocket GSAT 1 image credit Arianespace posted on AmericaSpace

Mission VA-217 will be powered uphill by the Vulcain-2 engine of the cryotechnic main stage and twin side-mounted solid-fueled rocket boosters. Photo Credit: ESA – CNES Arianespace Optique video du CSG JM Guillon

More than five months since the roar of an Ariane 5 last rocked the Guiana Space Centre in Kourou, French Guiana, another of these giant rockets stands ready for liftoff from the ELA-3 (Ensemble de Lancement Ariane) complex at 5:30 p.m. GFT (3:30 p.m. EST) Thursday, 6 February. Launch is timed to occur at the opening of a 125-minute “window,” and the 32-minute flight will deploy two payloads from Ariane 5’s two-tiered SYLDA (Système de Lancement Double Ariane) satellite dispenser. Mission VA-217 will deliver the joint French/Italian Athena-Fidus military communications satellite and Asia Broadcast Satellite’s ABS-2 commercial communications satellite into geostationary transfer orbit. Operated by the Paris-headquartered Arianespace launch services organization, VA-217 will mark the 72nd flight by an Ariane 5, which first flew in June 1996, and the 216th overall flight since the maiden voyage of the Ariane 1, way back in December 1979.

Originally, Mission VA-216—carrying the Amazonas-4A communications satellite for Spain’s Hispasat company to expand Ku-band television services across Latin America and the Astra-5B communications satellite to support Ku-band and Ka-band broadcasting for Luxembourg-based SES—was scheduled to fly ahead of VA-217, with launch planned for mid-December 2013. Assembly of the Ariane 5’s 100-foot-tall (30-meter) “cryotechnic main stage” got underway at the South American launch site in early October, and by November it had been installed onto its operational launch table in the Launcher Integration Building (BIL). The next step was the attachment of the twin solid-fueled boosters, followed by the cryogenic upper stage and the Vehicle Equipment Bay (VEB), the latter of which contains Ariane 5’s computerized “brain.”

On 19 December, Arianespace announced that VA-217 would fly before VA-216. In making the 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 launch on 23 January, with VA-216 expected to follow 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. The stack was transferred to the Final Assembly Building (BAF) on 26 December, and the nozzle replacement was conducted shortly afterward, with the targeted launch date for VA-217 slipping by two weeks until no earlier than 6 February.

In the meantime, processing of the Athena-Fidus and ABS-2 payloads was proceeding with exceptional smoothness. Both satellites arrived separately at Félix Éboué Airport, near French Guiana’s capital, Cayenne, in early December, aboard chartered An-124 transport aircraft. They were then transferred by truck to the Guiana Space Centre. Following unpacking and intial checks, they were moved to the S5 payload preparation center and loaded with propellants and high-pressure gases. Last week, they were lowered into their respective positions within the SYLDA inside the BAF. The ABS-2 satellite occupies the uppermost deck of the SYLDA and will be deployed first on Thursday’s mission, whilst Athena-Fidus is located beneath it in the lower deck.

The Athena-Fidus satellite is loaded into the lower portion of the SYLDA payload dispenser. Photo Credit: Arianespace

The Athena-Fidus satellite is loaded into the lower portion of the SYLDA payload dispenser. Photo Credit: Arianespace

Mission VA-217 will deliver a payload-lift performance of more than 22,500 pounds (10,200 kg), which includes the combined total of over 20,700 pounds (9,400 kg) for the two satellites, the SYLDA, and the integration hardware. A final launch readiness review was conducted yesterday (Tuesday), and rollout of the VA-217 stack from the BAF to the ELA-3 launch complex is expected to occur today (Wednesday).

With the launch of this next mission, Arianespace will mark its first Ariane 5 mission of 2014, with two more flights planned for the vehicle: VA-216 on 7 March, carrying Amazonas-4A and Astra-5B, and the fifth and final Automated Transfer Vehicle (ATV-5), named in honor of the late Belgian astronomer Georges Lemaître, for the European Space Agency (ESA) on 17 June. This compares favorably with 2013’s completion of no fewer than four Ariane 5 missions. Last year, the booster delivered the Amazonas-3 and Azerspace-1/Africasat-1A satellites into orbit in February, followed by ATV-4 “Albert Einstein” toward the International Space Station (ISS) in June, the Alphasat and Insat-3D satellites in July, and, most recently, the Eutelsat-25B/Es’hail-1 and GSAT-7 satellites in August.

Assuming that final preparations for Thursday’s VA-217 launch go well, 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 will get underway at T-4 hours and 50 minutes. The propellant tanks will be pressurized for flight at T-4 minutes, and the 171-foot-tall (52-meter) vehicle will be transferred to internal power supplies. In the final seconds, systems aboard the  rocket will assume primary command of all critical functions and the guidance system will be unlocked to Flight Mode. The French-built Vulcain-2 first-stage engine will roar to life at T-0, producing 300,000 pounds (136,000 kg) of thrust, although liftoff does not occur for another 7.5 seconds, as a series of computer-controlled health checks are conducted. When all is verified to be well, the twin side-mounted solid-fueled boosters—each with a propulsive yield of 1.4 million pounds (635,000 kg) and together generating 92 percent of the total thrust to get the Ariane 5 off the pad—will ignite and VA-217 will be committed to flight.

The stack will rise vertically for about five seconds, after which the two computers inside the VEB will initiate a combined pitch and roll program maneuver, actively rotating the vehicle onto the correct flight azimuth to insert Athena-Fidus and ABS-2 into orbit. One minute into the ascent, the vehicle will go supersonic and 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 (480 km) east the launch site. Meanwhile, Ariane 5 will by now have reached a velocity of over 1,200 mph (1,900 km/h) 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.

Technicians position the ABS-2 satellite atop the SYLDA, preparatory to installing the payload shroud. Photo Credit: Arianespace

Technicians position the ABS-2 satellite atop the SYLDA, preparatory to installing the payload shroud. Photo Credit: Arianespace

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 (2,770-kg) engine—will ignite to pick up the baton for the final push into orbit. By now, the rocket will be over 105 miles (170 km) high and traveling at more than 4,300 mph (6,900 km/h). Sixteen minutes later, having reached a velocity of 5,700 mph (9,170 km/h), Geostationary Transfer Orbit (GTO) will be attained. The target orbit is 153 x 22,330 miles (246 x 35,937 km), inclined six degrees to the equator.

With ABS-2 sitting in the uppermost payload deck of the SYLDA, it will be the first satellite to be deployed, at about 27 minutes and 19 seconds after liftoff. During a 15-year operational lifespan, it is expected that the 13,960-pound (6,330-kg) satellite will provide direct-to-home and cable television, data networks, and telecommunications for 60 percent of the world’s population, covering Russia, North Africa, Asia, and the Middle East. With a payload output of more than 12 kW and up to 89 active C-band, Ku-band, and Ka-band transponders across 10 different beams, it is one of the most powerful commercial communications satellites ever positioned over the Eastern Hemisphere. ABS-2 was built by Space Systems/Loral (SS/L) and will be stationed at 75 degrees East longitude, the prime geostationary orbital location for Asia Broadcast Satellite.

Five minutes after the ABS-2 deployment, at T+32 minutes and 28 seconds, Athena-Fidus—the lower passenger in the SYLDA—will also be released, effectively completing the VA-217 mission. “Athena-Fidus” is an acronym for the “Access on THeatres for European Nations Allied Force-French/Italian Dual-Use Satellite” and has been built by Thales Alenia Space on behalf of France’s Centre National d’études Spatiales (CNES, the French National Centre for Space Studies), the Italian Space Agency (ASI), and the French and Italian defense ministries. The 6,600-pound (3,000-kg) satellite will utilize the latest telecommunications standards, DVB-RCS and DVB-S2, to ensure optimum transmission capacity and service availability. Equipped with Extremely High Frequency (EHF) and Ka-band transponders, it will support the defense requirements for France, Italy, and Belgium, whilst also providing assistance in civil and national security, law enforcement, and firefighting. Designed for an operational life span of 15 years, Athena-Fidus will be positioned at 25 degrees East longitude.

 

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