Spaceflight Insider

Ariane 5 pulls double duty launching two comsats from Kourou

Ariane 5 / VA232 (2016-08-24)

Archive photo of the Ariane 5 / VA232 launch with the Intelsat-33e and Intelsat-36 satellites on August 24, 2016. Photo Credit: S. Martin / ESA / CNES / Arianespace

Shortly after sunset on September 29, 2017, in Kourou, French Guiana, an Arianespace Ariane 5 lofted 23,894 pounds (10,838 kilograms) of payload into space in the form of two communications satellites. The Intelsat 37e satellite will support Africa, Europe, Central Africa, and Latin America, while the BSAT-4a satellite will provide Direct-to-Home (DTH) television service in Japan.

Ariane-5 / VA239 on the launch pad

Ariane 5 / VA239 on the launch pad. Photo Credit: P. Piron / ESA / CNES / Arianespace

Preparation and launch

This flight, designated VA239, marks the fifth Ariane 5 launch and the ninth launch out of the Guiana Space Centre in 2017. So far, Arianespace has launched 131,514 pounds (59,654 kilograms) of payload into space.

Arianespace kept the preparation of flight VA239 moving in a businesslike fashion, completing its final checkout seven minutes before liftoff. Finding everything nominal, the Ariane 5 entered its automated launch sequence.

The rocket’s propellant tanks were pressurized four minutes before launch and the rocket switched over to internal power with one minute before the end of the countdown.

Fire and smoke – of the purposeful kind – began once the countdown reached zero with the ignition of the rocket’s Vulcain liquid hydrogen- / liquid oxygen-consuming main engine.

Seven seconds later, the launch took place at 18:56 local time (5:56 p.m. EDT / 21:56 GMT) as the Ariane 5’s twin EAP solid rocket boosters ignited and pushed the stack into the sky.

Several seconds later, the vehicle began pitching out over the Atlantic Ocean. Seventeen seconds into the flight, the vehicle began its roll maneuver.

The twin EAP boosters burned through their 524,700 pounds (238 metric tons) of propellant in two minutes, 22 seconds before falling away, as planned. With the bright orange flames of the boosters gone, the thrust from the Vulcain EPC cryogenic main stage engine was practically invisible.

Jettisoning next, at 3 minutes, 23 seconds into the flight, was the payload fairing.

The EPC burned for just under nine minutes, cutting off 8 minutes, 56 seconds into the flight, and separating from the stack six seconds later.

Seconds after that, the ESC-A cryogenic upper stage ignited and began its burn to send Intelsat 37e and BSAT-4a into a geostationary transfer orbit.

The upper stage burned for over 16 minutes, cutting off just over 25 minutes after leaving South America.

After the upper stage moved to the right attitude, Intelsat 37e was separated 29 minutes, 50 seconds after blazing away from French Guiana.

To accommodate dual payloads, Ariane 5 has a fairing within the fairing called Syldra. It ensures the lower of the two payloads is not damaged during the first payload’s separation.

Once Intelsat 37e was safely away, the Syldra inner fairing separated from Ariane, exposing BSAT-4a to space. It too separated from the Ariane upper stage 47 minutes, 15 seconds after liftoff.

After the launch, Intelsat 37e and BSAT-4a will make their way to geosynchronous orbits and circularize their orbits to station-keeping positions at 342 degrees and 110 degrees east longitude, respectively.

LEFT: Intelsat 37e undergoes its fit-check during pre-flight preparations at the Spaceport. Photo Credit: J Mougenot / ESA / CNES / Arianespace. RIGHT: BSAT-4a is positioned atop its Ariane 5 launcher on Flight VA239. Photo Credit: J.M. Guillon / ESA / CNES / Arianespace

Stephen Spengler, Intelsat’s CEO, said: “Intelsat 37e is a powerful addition to our award-winning Intelsat EpicNG network. It brings new technology and resilience as we continue to deploy the first, all-digital, high-throughput satellite system.

“Intelsat 37e features enhanced power sharing technology and steerable beams, which bring additional flexibility to meeting regional and application requirements over the life of the satellite. Intelsat 37e reflects our multi-band, open architecture philosophy.

“Our overarching goal is to offer satellite services that unlock high-demand applications such as mobility and wireless infrastructure, supporting the growth of our customers.”

Video courtesy of Arianespace



Bart Leahy is a freelance technical writer living in Orlando, Florida. Leahy's diverse career has included work for The Walt Disney Company, NASA, the Department of Defense, Nissan, a number of commercial space companies, small businesses, nonprofits, as well as the Science Cheerleaders.

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