Arianespace launches Galileo navigation satellites as last mission before Webb – Spaceflight Now


A Soyuz ST-B launcher takes off on Saturday evening from the Guyanese Space Center with two Galileo navigation satellites. Credit: ESA / CNES / Arianespace – Photo Optical Video of CSG – S. Martin

Deployment of the independent European navigation network Galileo resumed on Saturday evening with the targeted launch of two satellites aboard a Soyuz rocket, the last Arianespace mission from French Guiana before the historic liftoff of the James Webb Space Telescope later this month- this.

Four days late due to bad weather and a problem with a telemetry station downstream, a Soyuz launcher triggered its kerosene engines and pulled away from the Guyana Space Center on the northeast coast of the South America at 7:19:20 p.m. EST Saturday (0019:20 GMT Sunday).

Liftoff took place at 9:19 p.m. local time from the launch base in French Guiana, marking the start of the 26th Soyuz mission from the tropical spaceport.

Two previous launch attempts were canceled due to bad weather and officials canceled another countdown due to the unavailability of an on-board tracking station in the Atlantic Ocean.

The Russian-made Soyuz ST-B rocket lifted off with nearly a million pounds of thrust and soared through scattered clouds, arching northeast over the Atlantic Ocean . The Soyuz dropped four first-stage boosters two minutes after the mission began, then released its shell-shaped nose cone after hovering over the thickest layers of the atmosphere.

The main stage stopped and released approximately five minutes after takeoff, and a third stage engine ignited to continue flight into space. The Soyuz third stage completed its work approximately nine minutes after the start of the flight, then deployed a Russian Fregat upper stage for the final maneuvers to orbit the Galileo satellites.

The Fregat engine first fired to reach an egg-shaped transfer orbit, then the rocket walked for over three hours before relighting to circularize its orbit at an altitude of over 14,600 miles (23,500 kilometers). ) and an inclination of 57.1 degrees from the equator.

The two 1,576-pound (715-kilogram) Galileo satellites, mounted side-by-side during launch, deployed from the Fregat upper stage at around 11:11 p.m. EST (0411 GMT).

A few minutes later, the rocket’s telemetry confirmed a successful separation of the spacecraft.

Ground crews from a Galileo control center in Oberpfaffenhofen, Germany, took command of the spacecraft. The satellites deployed their solar panels as they were projected, officials said.

The spacecraft will perform a series of post-launch tests before entering operational service in a few months.

“Tonight we have another fantastic success for the Galileo program,” said Paul Verhoef, director of navigation at the European Space Agency.

Designed for 12-year missions, the new spacecraft will join 26 Galileo satellites already in orbit providing worldwide navigation services for the EU’s multibillion-euro flagship space program. Ten Soyuz and Ariane 5 rocket launches from French Guiana from October 2011 to July 2018 deployed the operational Galileo satellites, which are distributed over three orbital planes approximately 23,200 kilometers above Earth.

The full constellation needs 30 satellites, including 24 active platforms and six spare.

“The aim of the upcoming Galileo launch is to complete the satellite and population deployments of the various orbital planes to ensure that the constellation is complete,” said Andrea Cotellessa, head of the Galileo space segment management office at the European Commission. Space agency. “Our constellation requires eight operational satellites and two spare air satellites, and this has yet to be achieved.”

The next two European Galileo navigation satellites are ready to be attached to their Russian-made Fregat upper stage at the Guyana Space Center. Credit: ESA / CNES / Arianespace – Photo Optical Video of CSG – P. Baudon

Galileo satellites are already transmitting navigation signals to users around the world. Over 2 billion smartphones have been sold with Galileo compatible chipsets, allowing users to locate themselves with navigation signals from Galileo satellites as well as data from the US Army’s Global Positioning System network.

When fully operational, the Galileo network will provide independent navigation patches to users without the need for GPS signals. With the two networks available, the combination of Galileo and GPS data can give users a more accurate position estimate.

The Saturday night launch was the last mission from the French Guiana spaceport before takeoff on December 22 of the James Webb Space Telescope, a $ 9.7 billion observatory developed by NASA, ESA and the Canadian Space Agency. .

Webb, the most expensive space science mission in history, will take off on top of an Ariane 5 rocket. Guiana Space Center officials need around two weeks to reconfigure the infrastructure on the ground between launches, which means the Soyuz flight is scheduled to take off around December 8 to ensure Webb’s launch stays on schedule.

The complete Galileo constellation will consist of 24 satellites spread over three orbital planes, plus two spare satellites per orbit. Credit: ESA-P. Carril

The two Galileo spacecraft launched on Saturday evening were built by OHB in Bremen, Germany. L-band navigation payloads on each satellite were provided by SSTL in the UK.

The satellites are the first two of 12 Galileo spacecraft ordered under a third ESA batch contract in 2017. The “batch 3” satellites, with the same capacities as the previous 26, will support the Galileo constellation until ‘that a new generation of spacecraft is ready. for the launch.

Over the next few years, three Soyuz launches and three flights of the new European Ariane 6 rocket will each carry two Galileo satellites into orbit.

Second-generation satellites are expected to start launching by the end of 2024, according to ESA, which manages spacecraft development for the Galileo system on behalf of the European Commission, the EU’s executive body.

“They will be more powerful,” Verhoef said ahead of this week’s launch. “They will therefore also be heavier, but they will have more capacity. In particular, they will be fully flexible, fully digital, so that we can reprogram them in orbit.

“At the moment, with the first generation, if we are to provide any important new services, we are going to have to put completely new satellites into orbit,” said Verhoef. “With the second generation, we decided to do things differently and allow this capability, de facto, to be on the satellites, so that we can change things as the markets demand it in a relatively quick fashion.”

Earlier this year, the European Commission and ESA awarded contracts to Airbus and Thales Alenia Space for 12 second-generation Galileo, or G2, satellites. Each company has won a contract for six spacecraft, which will carry navigation payloads built on the European continent, rather than by SSTL in the UK.

SSTL was excluded from the new generation of Galileo satellites after Brexit. EU officials have demanded that sensitive elements of the Galileo program come from EU member states.

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