Franco-Chinese gamma-ray burst mission blasts off from Xichang!

A Long March 2C rocket lifted off from the Xichang Satellite Launch Center earlier today carrying the SVOM, or Space Variable Objects Monitor, spacecraft into a low Earth orbit. The launch is said to have occurred at 15:00 pm China Standard Time, or 07:00 am Universal Coordinated Time.

The launch of SVOM from Xichang is the culmination of twenty years of planning, and ten years of development. SVOM is a joint gamma-ray burst mission between France and China, with a full list of collaborators from each nation available here.

Wei Jianyan, SVOM's Chinese Principal Investigator, said the following about the mission after the launch:

"We are looking forward to some important discoveries, such as the earliest gamma-ray bursts that occurred when the universe was still in its childhood, which will help us study cosmic evolution"

Bertrand Cordier, SVOM's French Principal Investigator, also commented on the mission after the launch saying:

"By using the gamma-ray bursts as a tool to observe the early universe, we can observe maybe the first stars," – "This is very interesting because this is the only way to get information about the universe at this age."

The team behind SVOM consists of roughly one-hundred scientists, with approximately sixty percent from China and forty percent from France. Each team member has equal access to all of the scientific data, along with the rest of the scientific community, according to collaborators from both nations.

This was also the 525th launch of a Long March rocket.

What is SVOM?

SVOM, or Space Variable Objects Monitor, is a small 950-kilogram X-ray telescope spacecraft developed by France's Centre national d'études spatiales, the Chinese Academy of Sciences, and the China National Space Administration. Initially, the SVOM spacecraft will operate in low Earth orbit for three years.

The objectives of the SVOM mission are to: detect all known types of gamma-ray bursts, provide fast and reliable gamma-ray burst position information, measure the broadband spectral shape and temporal evolution of the early and late afterglow via visible X-rays, quickly identify afterglows of detected gamma-ray burst in X-ray and optical wavelengths, and measure the broadband spectral shape and temporal properties of emissions from gamma-ray bursts. In order to perform its observations, SVOM has some of its instruments on the spacecraft in space, and some on the ground in China, France, and other nations.

Spacecraft-based mission elements

The ECLAIRs telescope is a key part of SVOM and will autonomously detect and locate gamma-ray bursts via observing the sky in the X-ray and gamma-ray wavelengths. Teams expect ECLAIRs to detect approximately seventy gamma-ray bursts per year.

SVOM's gamma-ray monitor consists of three gamma-ray detectors operating in the 15 kilo-electronvolt 5 mega-electronvolt energy range with a field of view of 2.6 steradians. The gamma-ray monitor will be responsible for measuring the spectrum and the variation of gamma emissions during a burst.

The Microchannel X-ray Telescope will observe gamma-ray bursts in the X-ray range at an energy between 0.2 and 10 kilo-electronvolt. It will also locate sources of gamma-ray bursts at a higher accuracy than ECLAIRs. The telescope was also jointly developed by France's Centre national d'études spatiales and Institut de recherche sur les lois fondamentales de l'Univers, the University of Leicester in the United Kingdom, and the Max-Planck Institute für extraterrestische Physik in Germany.

The Visible Telescope is SVOM's dedicated optical tracking telescope that will observe the emissions of a gamma-ray burst in the visible light wavelength. Teams expect the Visible Telescope to detect approximately sixty gamma-ray bursts per year.

Ground-based mission elements

The Ground-based Wide Angle Camera for the SVOM mission is forty cameras on ten mounts, each carrying four cameras. The ground-based cameras will observe in the visible light wavelength from the Xinglong Observatory, north of Beijing, and the Muztagh Ata Observatory, in western China.

SVOM's Ground Follow-up Telescope is actually two telescopes located on different sides of the Pacific. The French Ground Follow-up Telescope is located at the National Astronomical Observatory (OAN) of San Pedro Mártir, in Mexico, and can make observations in the infrared and visible light wavelengths. The Chinese Ground Tracking Telescope is located at Ali Observatory, in western China, and will monitor gamma-ray bursts found by SVOM within fifteen minutes of its being detected.

SVOM also has an Alert Network of over forty very high frequency antennae located across the globe. The Alert Network allows the SVOM spacecraft to alert teams on the ground that it has detected a gamma-ray burst, while above almost any point on the planet, and relay that information to its mission control center in France. The antennas are located between thirty degrees north and south of the equator, a full list of the antennas can be found here. Signals from the spacecraft can also be sent through China's BeiDou Navigation Satellite System when available.

The French Science Center is where the Alert Network relays information from the SVOM spacecraft to. The science center will analyze the data shortly after receiving it and distribute needed information for follow-up observations using ground-based mission elements.

What is the Long March 2C?

The Long March 2C is a two-stage rocket manufactured by the China Academy of Launch Vehicle Technology and burns Dinitrogen Tetroxide and Unsymmetrical Dimethylhydrazine in its first and second stages.

The Long March 2C is claimed to be able to lift up to 3,850 kilograms to low Earth orbit, 1,900 kilograms to a sun-synchronous orbit, or 1,250 kilograms to geosynchronous transfer orbit.

The first stage is powered by four YF-21C engines which generates 302 tons of thrust from burning Dinitrogen Tetroxide and Unsymmetrical Dimethylhydrazine. The second stage is powered by a single YF-24E engine that produces 80 tons of thrust while also burning Dinitrogen Tetroxide and Unsymmetrical Dimethylhydrazine.

On the launchpad, the launch vehicle stands at 42 meters tall and weighs 233,000 kilograms when fully fuelled.