China-France satellite launched to monitor most powerful explosions in space

The Space-based multi-band astronomical Variable Objects Monitor (SVOM) has blasted off to record intense gamma-ray bursts

Science

Ling Xinin Ohio

Published: 3:22pm, 22 Jun 2024

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An observatory built by Chinese and French researchers will hunt for the universe’s most powerful explosions after being launched into a low-Earth orbit in another landmark space mission between the two countries.

The Space-based multi-band astronomical Variable Objects Monitor, or SVOM, blasted off on top of a Long March 2C rocket from western China’s Xichang Satellite Launch Centre at 3pm Chinese time on Saturday, state news agency Xinhua reported.

The 930kg (2,050-pound) probe, which took hundreds of scientists and engineers nearly two decades to develop, will orbit Earth at 625km (450 miles) above the ground to accurately measure the location and energy of distant, violent explosions known as gamma-ray bursts.

The project, led by the China National Space Administration (CNSA) and the French space agency CNES, began in 2006.

“The launch of SVOM closed a loop which started 18 years ago,” François Gonzalez, SVOM’s French project manager at CNES, said.

Over the years, members of the scientific and technical teams learned how to “adapt their own ways” to work together and push the mission forward, he said.

“We’ve been through ups and downs, but the strength of this cooperation is the team spirit between the Chinese and French people,” Gonzalez said.

Gamma-ray bursts are produced during extremely energetic events in the distant universe, such as the merging of two black holes or the collapse of a massive, dying star.

While such flashes of light give unique insights into major cosmic phenomena, they are notoriously hard to catch as they can appear anywhere in the sky and last for just a few seconds.

On top of that, gamma rays are readily absorbed by the Earth’s atmosphere, so the only way to record them is to place probes in space.

SVOM would be able to observe in different wavelengths and obtain “the most complete set of data” showing how the explosions occur and evolve over time, Gonzalez said.

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SVOM is equipped with four state-of-the-art instruments – two built in France and two in China. For instance, the French-built ECLAIRs telescope will play a critical role, autonomously spotting bursts in near-real time in the gamma as well as x-radiation energy range.

Meanwhile, the Chinese-made visible telescope will track light emitted in the visible range after the gamma-ray burst, as part of the explosion process.

Bertrand Cordier, the mission’s French principal investigator from the Saclay Nuclear Research Centre near Paris, noted that coordinated observations between the SVOM and large, ground-based telescopes were key to understanding the explosions.

“The major challenge of the mission is to determine the origin of gamma-ray bursts,” Cordier said. “What environment do they come from? At what period are they created? Only detailed analyses of their light carried out by terrestrial telescopes can answer these questions.”

SVOM is expected to detect 70 to 80 gamma-ray bursts each year.

“Examined in all possible ways, gamma-ray bursts will hopefully no longer be seen as mysterious objects, but rather as great tools for exploring the unknown,” he said.

Space has been a top priority for scientific collaboration between the two countries. The partnership between the two national space agencies started in 1997, when Beijing and Paris signed an agreement on the peaceful use of outer space.

This mission will study gamma-ray bursts and other high energy phenomena. Photo: SVOM collaboration

The China-France Oceanography Satellite, launched in 2018, has allowed scientists from around the world to make more accurate ocean forecasts and deliver earlier warnings of severe weather events.

This year, a French instrument called Detection of Outgassing RadoN, or Dorn, took a ride with China’s Chang’e-6 mission to land on the far side of the moon. Dorn is the first French scientific instrument to have touched down on the lunar surface.

The two countries are considering the feasibility of carrying an instrument similar to Dorn for moon surface measurements on board China’s coming Chang’e-8 mission, which is expected to launch in 2028, according to space observers.