Ariane 5 launches Intelsat 37e & BSAT-4a at second attempt

by Chris Bergin

Arianespace conducted the fifth Ariane 5 launch of the year with the lofting of the Intelsat 37e & BSAT-4a satellites from Europe’s Spaceport in French Guiana on Friday. The attempt came after the rocket aborted on the pad due to an electrical issue with a booster post-main engine ignition. The abort stopped the boosters from igniting and allowed for safing to take place.

Ariane 5 launch:

The initial launch attempt was proceeding without issue as the countdown reached zero marking the point at which the Vulcain main engine ignites and ramps up during the seconds that follow. At that point the vehicle lights its two solid rocket boosters and lifts off from the pad.

However, this time, for the first time since 2011, the main engine ignition was followed by a shutdown.

No further details were immediately provided in the post-scrub comments, other than to say the new launch date would be decided in the coming days, after an investigation takes place. The delay lasted for two weeks in the end.

Arianespace noted the issue was with the electrical system in one of the boosters.

“Just after the ignition of Ariane 5’s main stage Vulcain engine, the on-board computer detected an anomaly affecting electrical equipment on one of the two solid-propellant boosters (EAP). This anomaly led to an interruption of the automated lift-off sequence,” said the company statement.

“This interruption is perfectly compliant with our procedures which authorize a launch only if 100% of launcher equipment is fully operational. This rule guarantees the reliability and robustness of our launch system. An analysis started immediately after the countdown interruption. It will continue to identify the anomaly’s cause and determine the measures to be taken in order to resume launch operations as soon as possible.”

The Ariane 5 was transferred to the Final Assembly Building (BAF) on Thursday, once the tanks had been purged. The two satellites, Intelsat 37e and BSAT-4a, were safe under the fairing atop the launcher.

“As soon as the analysis of the anomaly has been completed, Arianespace will announce a new launch date. The objective is to launch around the end of September 2017,” the company added. “This postponement does not affect the other launches scheduled for the end of 2017.”

The Ariane 5 ECA (Cryogenic Evolution type A) – the most powerful version in the Ariane 5 range of rockets – was employed once again for this flight, a vehicle that is an improved version of the generic Ariane 5 launcher.

Those improvements relate mainly to the structure of the Ariane 5, allowing for an increased thrust and ability to carry heavier payloads into orbit.

Designed to place payloads weighing up to 9.6 tonnes into GTO, this increased capacity allows the Ariane 5 ECA to handle dual launches of very large satellites.

This mission was designated Flight VA239 in Arianespace’s launcher family numbering system. The fifth mission of the year was also be the eighth launch of the year for Arianespace. This is because Arianespace now enjoys a full family of launch vehicles.

With the introduction of Soyuz at the Spaceport in 2011, Arianespace’s family was joined by the lightweight Vega vehicle, following her successful debut in 2012.

The future fleet of Ariane 6 and Vega C launch systems may also involve a level of reusability in the future.

The new launch pad for the Ariane 6 rocket is taking shape at the spaceport, as seen in new photos tweeted in recent days.

With its current fleet, Arianespace is targeting a total of 12 missions in 2017 utilizing its family of the heavy-lift Ariane 5, medium-lift Soyuz and lightweight lifter Vega.

Ariane 5 continues to be the company’s workhorse, usually launching two spacecraft at a time to Geostationary Transfer Orbit (GTO).

Ariane 5’s previous mission involved the lofting of Inmarsat S EAN/HellasSat 3 and GSAT-17, while the company’s most recent mission involved its Vega rocket with the launch of the VENµS and OPTSAT 3000 satellites.

Preparations for the next mission saw the arrival of the two passengers set to ride uphill on the Ariane 5 rocket, a launch vehicle that was already deep into integration processing.

The BSAT-4a satellite, designed and built for Broadcasting Satellite System Corporation (B-SAT), arrived at the European Spaceport in Kourou, French Guiana last month.

The satellite – which was designed and built by Space Systems Loral (SSL) – will be used for Direct-to-Home (DTH) television service in Japan.

“The completion and delivery of this high-performance satellite to launch base demonstrates the success of our streamlined operations,” said Paul Estey, executive vice president and chief operating officer of SSL.

“We are honored that B-SAT put its trust in SSL for this next-generation satellite, and look forward to our teams working together with Arianespace to prepare the satellite for launch.”

BSAT-4a sports 24 Ku-band transponders and will expand the availability of advanced television services such as high definition and 4K/8K ultra-high definition.

Based on the SSL 1300 platform, the satellite is designed to provide service for 15 years or longer, adding to B-SAT’s three other satellites, BSAT-3a, BSAT-3b and BSAT-3c, although they are currently providing a 2K broadcasting service.

B-SAT has started 4K/8K test broadcasting from the BSAT-3 series and will provide new service, 4K/8K regular broadcasting service by BSAT-4a starting in December 2018.

“BSAT-4a is the first satellite we have purchased from SSL and we have been pleased with the support that we received from their skilled and experienced team,” added Takashi Yabashi, president and chief executive officer of B-SAT.

“SSL has proven its reputation as an agile and reliable partner during the production of our satellite and we are happy with its on-time delivery to launch base. Now we look forward to providing the expanded Ultra HD programming and high-quality direct-to-home service that this satellite enables.”

The other passenger for this dual launch was Intelsat 37e. This satellite was spotted leaving George Bush Intercontenteial Airport in Houston. It was a confirmed arrival at Kourou when Arianespace CEO Stéphane Israël tweeted a welcome message to the satellite.

This satellite was built by Boeing (Hughes) and is based on the BSS-702MP platform. It will be powered by two solar wings, each with three panels of ultra triple-junction gallium arsenide solar cells.

With a service life of 15 years, the satellite will use C-band, Ku-band and a steerable Ka-band capacity that will allow it to replace the Intelsat 901 spacecraft currently operating in the 18 degrees E location that Intelsat 37e will set up shop.

The launch follows closely on the heels of the previous Intelsat launch, which involved the lofting of the Intelsat 35e by a SpaceX Falcon 9 rocket from Kennedy Space Center’s 39A.

The next satellites in this family will be launches in 2018, with Intelsat 39, followed by Intelsat 38 and Horizons 3e.

Total payload lift performance for the launch was approximately 10,838 kg., with the Intelsat 37e and BSAT-4a satellites deployed to geostationary transfer orbit during a flight that lasted 47 minutes.

The launch mass was the second highest for Ariane 5, just slightly behind the record breaking 10,865 kilograms from the VA237 mission.

(Images via Arianespace, SSL)

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