ESA completes the swan song of its Vega rocket with the launch of Sentinel-2C

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Sentinel-2 in the Vega launch tower. Image: ESA-CNES-ARIANESPACE/CSG-T video optics. Leduc

Update 10:52 pm EDT: Arianespace has confirmed the successful deployment of the Sentinel-2C spacecraft.

The European Space Agency (ESA) has completed its transition to its Vega-C mission with the final launch of its first generation Vega. The mission, called VV24, brought an Earth imaging satellite into a sun-synchronous orbit.

The liftoff of the 22nd and final Vega rocket took place on Wednesday, September 4 at 10:50 pm GFT (9:50 pm EDT, 0150 UTC) from the Europa Spaceport in Kourou, French Guiana. During the last hours before the mission was to be launched, Arianespace posted on social media that the mission had been cleared for its first launch attempt on Tuesday.

“Due to electrical problems on the ground links #VV24 the launch timeline has been interrupted,” Arianespace wrote on X, first Twitter. “Checks are being made to confirm a new launch attempt tomorrow, September 4, at 10:50 pm local time in Kourou. The launcher and its passenger, Sentinel-2C, are in stable and safe conditions.

The mission was initially cleared to proceed through a launch readiness review that concluded on September 2.

The Copernicus Sentinel-2C satellite was deployed from the launcher approximately 57 minutes and 20 seconds after liftoff. Officials expect to receive a signal from the spacecraft within 12 minutes of separation.

“We are really happy to start the Vega year with the flagship program of the European Union, Copernicus, to enhance life on Earth,” said Stéphane Israël, CEO of Arianespace, the company that manages the Vega rocket. “This mission really highlights Arianespace’s commitment to space for a better life on Earth.”

Israël said the launch campaign, which formally began on July 12, went “perfectly well”. He said the spacecraft began fueling on August 16 and was integrated with the upper stage on August 27.

Beginning of the end

The Vega rocket began its service in 2012 and has launched 21 times since then. The goal was to have a smooth and seamless transition from Vega to the Vega-C rocket, but an upper stage problem during Vega-C’s second flight put a wrench in that plan.

On December 20, 2022, about 151 seconds into the flight, that rocket encountered “a progressive decrease in chamber pressure” on the second stage of the rocket (Zeifro40). An Independent Commission of Inquiry (IEC) inquiry and subsequent tests followed.

Back in October 2023, an Arianespace spokesperson told Spaceflight Now that Vega’s final launch was targeted for the first quarter of 2024, following a return to the Vega-C flight mission in late 2023. However, those plans have also changed as work. continued to better understand the anomaly.

“I can assure you that there is nothing in common between that failure and Vega. Even the Zeifro40 engine is not used in that vehicle,” said Toni Tolker-Neilsen, ESA’s Space Transport Director, during a prelaunch press conference . “We have completely redesigned the Zeifro40 nozzle to make it much more robust and we have done a very successful test of this engine with the new nozzle design.”

That test took place in July and a second test is scheduled for October. Tolker-Neilsen said there is “very good confidence” in the results of the July test and said they believe next month’s test will also go well, setting a return to flight in November.

“This schedule has been stable [for] many, many months. More than a year, we have had a very stable situation and we have followed a plan that was established in the middle of last year, actually, and I am very confident that we will be able to do it”, Tolker. – Neilsen said.

“It would be a launch of Sentinel-1C, which is waiting for its launch.”

Once the transition occurs, Arianespace will be responsible for all launches up to VV29, which represents a total of six missions, including the VV24 flight of Vega. After that point, Avio becomes Vega’s “sole launch provider and operator,” according to Israël.

He said they have missions booked through VV39 with a range of clients, starting with the European Commission. Starting this month, the member states of ESA have decided that Avio will begin to commercialize Vega-C and seek non-governmental customers in addition to those of the various governmental bodies.

Tolker-Neilsen said there are four Vega-C launches planned in 2025 and five in 2026. Israël asserted that customers are there to fill this manifest, adding that “it will be Avio’s responsibility, of course, five Vega- C for every year from 2026 onwards”. He said they would like to see an annual cadence of nine to 11 Ariane 6 launches with five Vega-C missions.

Copernicus’ quarter century

The spacecraft aboard the Vega rocket that will be launched Tuesday night is part of a program that marks its 26th anniversary this year. There are seven first generation satellites that are in operation and there are 13 more satellites planned.

Currently, Sentinel-2A and Sentinel-2B operate in the same orbit, but 180 degrees apart. At an altitude of 786 km (488.4 mi.), they will image all of Earth’s coastal and terrestrial waterways every five days using 13 spectral bands.

The first two Sentinel-2 satellites orbit at an inclination of 98.62 degrees.

Once commissioned, Sentinel-2C, the third in the Sentinel-2 series, will replace Sentinel-2A, which was launched on June 23, 2015. Similarly, once Sentinel-2D has launched, it will replace Sentinel-2B, which launched in March. 7, 2017.

“There are already two satellites flying, but they are actually getting old. It is very important to launch a new satellite before the others get too old,” said Mauro Facchini, Head of the European Commission’s Earth Observation Unit.

The Sentinel-2C spacecraft is fed with 133 kg of hydrazine and then pressurizes the tank with helium up to 21 bars. The process was carried out in shifts by the propulsion team from AGG Lampoldshausen on August 16, 2024. Image: ESA-CNES-ARIANESPACE/Optique vidéo du CSG–S. Martin

ESA said the two-satellite constellation is similar in mission scope to NASA’s Landsat program and France’s Satellite pour l’Observation de la Terre (SPOT) satellite series, which are in operation from 1972 and 1986 respectively.

The Sentinel-2 satellites have a lifetime of approximately 7.25 years, which includes a three-month in-orbit commissioning phase. The batteries have an operational life of 12 years, to count the end of life, deorbiting maneuvers.

They have a MultiSpectral Instrument (MSI), which ESA said uses a so-called “push-broom concept”.

“A push-broom sensor works by collecting image data files across the orbital band and uses the forward motion of the spacecraft along the orbit path to provide new files for acquisition,” wrote l ESA. “The average observation period over land and coastal areas is about 17 minutes and the maximum observation period is 32 minutes.”

These satellites have been used to help improve agriculture, as well as monitor the health of forests and monitor methane.

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