Europe’s first mission to Mercury, a quartet of Galileo navigation spacecraft, a global winds observatory, and a new European weather satellite have arrived at an equatorial launch base in French Guiana in preparation for launches in the coming months.
The set of European missions are set to ride into space aboard four rockets, amid several more commercial flights carrying communications satellites to orbit, in what is shaping up to be a busy second half of the year for Arianespace, the French company which oversees Ariane 5, Soyuz and Vega launch operations at the European-run spaceport in Kourou, French Guiana.
The rapid-fire launch campaigns are already underway at the space center on the northeastern coast of South America, where technicians are preparing rocket and satellite hardware for liftoff.
Galileo navigation network ready to receive reinforcements
Arianespace will kick off its second-half launch schedule July 25 with an Ariane 5 rocket flight carrying four Galileo navigation satellites into an orbit more than 14,000 miles (around 23,000 kilometers) above Earth.
Liftoff is set for for an instantaneous opportunity at 1125:01 GMT (7:25:01 a.m. EDT; 8:25:01 a.m. French Guiana time) on July 25.
The four new Galileo spacecraft, built by OHB in Germany with navigation payloads provided by SSTL in the United Kingdom, will add to Europe’s home-grown navigation network, an analog to the U.S. Air Force-run Global Positioning System. With the July 25 launch, Europe will have launched 26 satellites into the operational Galileo fleet, which needs 24 active spacecraft, plus six spares, to provide independent global positioning and timing services.
But two of the Galileo satellites were launched into the wrong orbit in 2014, and another is afflicted with an antenna program, limiting its utility.
Managed by the European Commission — the European Union’s executive arm — and supported by the European Space Agency, the Galileo program has 12 more satellites in development for additional launches beginning in late 2020.
The four Galileo satellites set for launch later this month arrived at the Guiana Space Center on two trans-Atlantic airplane shipments in May and June, and the core components of the Ariane 5 launcher for the July 25 flight arrived in French Guiana from Europe aboard Ariane Group’s rocket transport vessel on May 30.
Workers at the French Guiana launch base have fueled the four Galileo satellites with maneuvering propellants for their 12-year navigation missions, and ground crews have assembled the Ariane 5 rocket with its cryogenic core stage, twin solid rocket boosters, vehicle equipment bay, and storable propellant upper stage.
Mounted on its vertical launch table, the Ariane 5 will be transferred to from the spaceport’s launcher integration building to the nearby final assembly building for attachment of the mission’s four satellite passengers and payload shroud.
The upcoming Ariane 5 mission, numbered VA244 in Arianespace’s flight sequence, will be the 33rd and last to fly with an Aestus engine, a powerplant fueled by toxic hydrazine and nitrogen tetroxide, which can be stored for long durations. Unlike the hydrogen-fueled HM7B engine used on most Ariane 5 flights, the Aestus engine can be reignited multiple times in space, allowing it to place payloads such as the Galileo navigation satellites directly into high-altitude orbits.
Ariane Group is developing a restartable cryogenic engine named Vinci to replace the HM7B on Europe’s new Ariane 6 rocket set for a maiden flight in mid-2020.
ESA’s Aeolus winds mission arrives in French Guiana
Arianespace’s next mission, set for Aug. 21 at 2120 GMT (5:20 p.m. EDT; 6:20 p.m. French Guiana time), will use a light-class solid-fueled Vega launcher to place ESA’s Aeolus Earth science satellite into orbit.
ESA says Aeolus will be the first mission to measure wind profiles on a global scale, employing an ultraviolet laser instrument to probe the lowest 18 miles (30 kilometers) of Earth’s atmosphere, collecting data on winds, aerosols and clouds at different altitudes.
The wind measurements will help scientists understand how the atmosphere works, and also support improved climate change predictions, and better forecasts of hurricanes.
Aeolus arrived in Cayenne, French Guiana, on June 27 on ship that carried it on a nearly two-week journey from France, and the satellite was trucked to the nearby space center to begin launch preparations.
While workers stack the four-stage Vega rocket on its launch pad, technicians inside a clean room at the Guiana Space Center will ensure Aeolus survived the trip to the launch base unscathed, then load propellant into the spacecraft.
The Aug. 21 liftoff will mark the 12th launch of a Vega rocket, developed by a European consortium led by Italian industry, and the first Vega flight of 2018. The Vega rocket will place the Aeolus spacecraft into a relatively low orbit around 200 miles (320 kilometers) above Earth.
Officials from ESA and Airbus Defense and Space, which built the Aeolus spacecraft, decided to transport the satellite across the Atlantic Ocean on a ship rather than on an aircraft. Engineers were worried the Aeolus mission’s sophisticated laser instrument could be damaged by a sudden pressure change inside a transport plane’s cargo bay.
The roughly 3,000-pound (1,360-kilogram) satellite is designed to handle the pressure change it will encounter during launch, but not the quick rise in pressure it would have seen during a sudden descent.
Aeolus will be ESA’s fifth Earth Explorer mission to launch, the next in a series of Earth science projects that have studied Earth’s ice sheets, oceans, water cycle, and magnetic and gravity fields.
The mission took twice as long to develop as originally planned after ESA started working on Aeolus in 2002.
“It’s the first time we’ve done this kind of instrument, in ultraviolet, ever in the world,” said Anders Elfving, ESA’s Aeolus project manager. “So it’s really a breakthrough technology. It’s learning how to master these technologies. There is no reference, and we could not fall back on another mission, so we had to find out al the troubles and solutions by ourselves the first time.”
100th Ariane 5 launch scheduled for September
Another Ariane 5 launch is targeted for Sept. 5 around 2120 GMT (5:20 p.m. EDT; 6:20 p.m. French Guiana time) with the U.S.-built Horizons 3e and Azerspace 2/Intelsat 38 commercial communications satellites.
The milestone mission, designated VA243, will be the 100th launch of an Ariane 5 rocket since Europe’s workhorse launch vehicle debuted in 1996.
That distinction was supposed to go the July 25 launch with four Galileo satellites, but Arianespace shuffled its launch manifest earlier this year after an Indian telecom craft that was slated to fly on the VA243 mission in May had to be returned to its factory for inspections.
Officials ordered the GSAT 11 satellite back to India as a precaution after losing contact with another Indian communications satellite, named GSAT 6A, a few days after its launch on an Indian rocket.
The decision by Indian officials left Arianespace looking for another geostationary payload to launch in tandem with the Azerspace/Intelsat 38 telecom satellite, GSAT 11’s original co-passenger.
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