Tuesday, November 10, 2015

Arianespace Successfully Launches ARABSAT-6B and GSAT-15 Satellites

Ariane 5 liftoff on flight VA227. Credit: Arianespace/ESA

Arianespace successfully sent a pair of satellites into orbit on Tuesday, using the company's flagship Ariane 5 launcher. The rocket, carrying ARABSAT-6B and GSAT-15 spacecraft lifted off at 4:34 p.m. EDT (21:34 GMT) from the Ariane Launch Complex No. 3 (ELA 3) at Europe's spaceport, located in Kourou, French Guiana. The mission, designated VA 227, lasted for one hour and eight minutes. Ariane 5, carrying a total payload of nearly 10 tons, put the two telecommunications satellites into geostationary transfer orbit (GTO).

The mission’s campaign started in late September, when the rocket’s cryogenic main stage (EPC) was erected on the launch pad. Few days later GSAT-15 arrived in Kourou and ARABSAT‑6B was shipped to French Guiana on Oct. 2. After the arrival, the satellite duo started a busy month of tests, fit checks and fueling operations ending with their integration to the payload adapter and encapsulation in the payload fairing. 

The rocket passed its Launch Readiness Review on Friday, Nov. 6 and was rolled out from the Spaceport’s Final Assembly Building (BAF) to the launch pad on Monday, Nov. 9.

The launch countdown started 11 hours and 30 minutes before the planned liftoff. Electrical systems were checked four hours later and after that Arianespace started the filling of main cryogenic stage with liquid oxygen and hydrogen. Connections between launcher and telemetry, tracking and command systems were checked for the last time approximately one hour before the liftoff. At T-7 minutes, a synchronized sequence started allowing tanks pressurization and switching to onboard power mode. The computers command the final electrical operations like the startup of the flight program, switching from ground power supply to onboard batteries and associated checks.

The liftoff started as planned with the ignition of the rocket’s solid boosters. The launch vehicle climbed vertically for about six seconds when a pitch motion started. The boosters were jettisoned at an altitude of about 230 feet (70 km), two minutes and 23 seconds into the flight. The fairing separated one minute later. It was followed by the separation of the EPC first stage at T+9 minutes.

ARABSAT-6B was released first, 27 minutes and 21 second after the launch. GSAT-15 was deployed 16 minutes later.

Shortly after the announcement that the two satellites had been injected into orbit, Arianespace Chairman and CEO Stéphane Israël said: "Arianespace is very proud this evening to have carried out another successful mission for our two faithful customers, who implement a wide range of practical applications based on satellite telecommunications. One of these customers, Arabsat, the inter-governmental organization leader of satellite operators in the Arab world; and ISRO, the Indian space agency that promotes a particularly ambitious space program. I would like to thank Arabsat and ISRO for their renewed trust. Launch after launch for more than 30 years, this expression of confidence honors us and also encourages us to keep meeting and exceeding their expectations.”

ARABSAT-6B, also known as BADR-7, was built by Airbus Defence and Space that provided the Eurostar E3000 platform and Thales Alenia Space (TAS) - responsible for the payload delivery. With a spacecraft power of 11.5 kW and a design life of more than 15 years, ARABSAT-6B is the first sixth-generation satellite in the Arabsat company’s fleet.

ARABSAT-6B has a liftoff mass 5.8 tons metric and reaches a total of 28 feet (8.5 meters) in length when fully deployed in orbit. It will provide broadcast, broadband, and telecommunications services over the Middle East, Africa, and Central Asia. The satellite features 27 active transponders in Ku-band and 24 spot beams in Ka-band, in addition to Ka-band transponders for additional services.

The spacecraft will be joining the Saudi Arabian Arabsat’s BADR-network at the 26 degrees East hotspot. To date, 17 Arabsat satellites have been launched into space.

“BADR-7 will be joining our Badr-network at Arabsat 26 degrees East hotspot, expanding our coverage over the Middle East and Africa (MEA) region. It will carry a dedicated Ka-band payload for broadband and interactive triple play services. BADR-7 will also enable Arabsat to access new markets in Ku-band for telecom and DTH over Africa,” said Khalid Balkheyour, President and CEO of Arabsat.

Founded in 1976, Arabsat is one of the world’s top satellite operators and is by far the leading satellite services provider in the Arab world.

GSAT-15 is India’s latest communication satellite. It will provide telecommunications services, as well as a dedicated navigation aid and emergency services for India. Weighing 3.1 metric tons at liftoff, GSAT-15 carries a total of 24 communication transponders in Ku-band as well as a GPS Aided GEO Augmented Navigation (GAGAN) payload operating in L1 and L5 bands.

GSAT-15, built by the Indian Space Research Organisation (ISRO), is based on the I-3K (I-3000) bus. It is a standard bus for 3-ton class satellites; the ‘I’ in I-3K stands for INSAT, a group of communication satellites developed and launched by ISRO. The I-3K bus can supply DC power up to 6,500 watts, and is suitable for satellites with a lift-off mass in the range of 3–3.4 metric tons.

The satellite measures nearly 10 feet (3 meters) in length when its two solar arrays are deployed. The spacecraft is expected to be operational for 12 years. It will be located at 93.5 degrees East longitude.

GSAT-15 is the 19th payload launched by Arianespace for ISRO. The GSAT satellites are developed by ISRO with an objective to make India self-reliant in broadcasting services.

ARABSAT-6B and GSAT-15 are the 519th and 520th satellites to be launched by Arianespace.

The Ariane 5 in the ECA configuration that was used in this launch is the heavy-lift rocket for missions to GTO and usually carries two telecommunications satellite payloads. It is powered during the initial flight phase by a cryogenic core stage and two solid rocket boosters, followed by the use of a cryogenic upper stage for orbital injection of the payload.

The 180 feet (54.8 meters) tall ECA is an improved version of the Ariane 5 launcher, designed to deliver payloads, mainly communications satellites, weighing up to 10 metric tons. Although it has the same general architecture, some significant changes were made to the basic structure of the generic version to increase thrust and enable it to carry heavier payloads.

Tuesday’s mission is the 227th liftoff of an Ariane vehicle from the Kourou Spaceport. It is the sixth Ariane 5 launch of 2015 (the 83rd Ariane 5 launch overall), and the 10th of 12 flights planned this year by Arianespace utilizing its family of the heavy-lift Ariane 5, the medium-lift Soyuz, and the lightweight Vega rockets.

Next Arianespace’s launch is currently scheduled for Dec. 2, when a Vega booster will blastoff with the LISA Pathfinder probe for the European Space Agency. It will be the sixth Vega launch in history.

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