WASHINGTON — A Vega C rocket successfully launched an Earth science satellite for the European Space Agency, a mission officials said was also a demonstration of European space sovereignty.
The Vega C rocket lifted off April 29 at 5:15 a.m. Eastern from the European spaceport in French Guiana. The payload, ESA’s Biomass satellite, separated from the rocket’s Avum upper stage nearly an hour after liftoff after being placed into its planned sun-synchronous orbit at an altitude of 666 kilometers.
The 1,250-kilogram satellite was built by Airbus Defence and Space as part of ESA’s Earth Explorer program of Earth science missions. The spacecraft’s primary instrument is a P-band synthetic aperture radar (SAR) that will, in effect, weigh the Earth’s forests to determine how much carbon is stored in them and how that changes over time.
“It has the capability to do sort of a scan, like when you do a medical scan, of the forest,” said Simonetta Cheli, ESA’s director of Earth observation programs, at a prelaunch briefing.
Biomass has a planned 5.5-year mission, with the first 18 months devoted to a “tomographic phase” where the spacecraft’s radar will map the inner structure of forests. The next four years will be used for a series of interferometric observations of those forests to measure changes in forest height and biomass.
The spacecraft will also be used for observations of other terrain, such as glaciers and deserts, taking advantage of the radar’s ability to penetrate ice and sand. ESA said it will collaborate with NASA, exchanging data with the NISAR spacecraft set to launch in the coming months with its own SAR instrument operating at higher frequencies.
P-band operates at lower frequencies than other SAR instruments, said Justin Byrne, head of science and Mars programs at Airbus, at the prelaunch briefing. “That required us to develop brand new technology in the [radio-frequency] chain,” he said, such as amplifiers and electronics.
The radar uses a 12-meter deployable antenna, provided by L3Harris. The deployment of the radar will start a couple days after launch and take four days, he said at a post-launch press conference.
The launch was the first for the Vega C since its return to flight in December 2024, nearly two years after a launch failure on a mission designated VV22. “We are still in the aftermath of the VV22 failure and be assured that everything has been done to ensure a safe launch of Biomass,” said Toni Tolker-Nielsen, ESA’s director of space transportation, at the prelaunch briefing.
Asked to elaborate, he said ESA was giving the vehicle extra attention. “We are scrutinizing, very closely, all of the launcher for any anomalies or weak points,” he said. Those reviews would last for five launches of the rocket, starting with last December’s return to flight.
After the launch, officials emphasized the importance of having both Vega C and the larger Ariane 6 in operation. “In the current context, full of uncertainty and with some geopolitical evolution,” said David Cavaillolès, chief executive of Arianespace, “the fact that we are able to cover any mission with our two launchers is something that is of utmost importance.”
“In the recent past, we all discovered what sovereignty and sovereign access to space meant,” he said, a reference to Europe’s recent “launcher crisis” that required it to purchase launches from SpaceX. “Now we are back and, of course, our big challenge now is to ramp up and do more and more launches.”
Arianespace has conducted two launches this year, one each of the Ariane 6 and Vega C. He said there are four more Ariane 6 and two more Vega C launches planned for this year, with the next being another Vega C launch in July.
Arianespace is in the process of transitioning launch services of Vega C to Avio, the prime contractor of the rocket, with Arianespace responsible for the next three Vega C launches before Avio takes over. At the prelaunch briefing, officials from Arianespace and Avio said that transition of responsibility was going well.
