Forest satellite’s big antenna opens up

Following liftoff, orbital injection acquisition of its first signal and satellite in-orbit checks, the successful deployment of Biomass’ mesh antenna reflector marks the final key step in the launch and early operations phase.

Before the 12-metre-diameter reflector could be unfolded, its 7.5-metre-long supporting boom needed to be deployed.

ESA’s Stefan Kiryenko, who has been responsible for development of the antenna reflector, explained, “The boom deployment was carried out in three carefully planned stages, each lasting about five minutes. However, only one stage was executed per day, timed to coincide with specific satellite passes that provided optimal coverage from ground stations.

“Once the boom was fully extended, we proceeded to deploy the mesh antenna reflector, which essentially unfolds like an umbrella above the satellite.”

The photographs in the animated sequence below come from a camera installed on the Biomass satellite and offer a rare glimpse into the action in space. The camera was provided by the Swiss company MCSE.

ESA’s Biomass Project Manager, Michael Fehringer, added, “First, we had to disable the satellite’s attitude and orbit control system so it could ‘float’ freely, avoiding any unwanted torque during the antenna’s deployment. Then, we fired two pyrotechnic devices to release the belt securing the folded antenna.

“We had just a 24-minute window of visibility during the antenna deployment, during which ground stations in Inuvik (Canada), Svalbard (Norway), and Kiruna (Sweden) handed over coverage seamlessly. However, the procedure takes slightly longer so we had to wait for another pass to confirm it had opened correctly – and indeed, it was successful.

“I’d like to thank L3H – the supplier of the antenna reflector, Airbus – the prime contractor for Biomass, and the ESA teams who have all worked to make this wonderful moment and key milestone happen.”

The animation below, an artist’s impression, shows the deployment of the boom and the antenna.

Carrying the first P-band synthetic aperture radar in space, the Biomass mission is designed to deliver crucial information about the state of our forests and how they are changing, and, importantly, to further our knowledge of the role forests play in the carbon cycle.

The antenna reflector transmits the radar’s footprint onto Earth’s surface and receives the returned signal, which carries information about the carbon content of forests.

ESA’s Director of Earth Observation Programmes, Simonetta Cheli, noted, “I’m delighted to see Biomass successfully deploy its remarkable antenna – a major milestone for one of our most pioneering Earth Explorer missions.

“These missions, developed through our FutureEO research and development programme, are designed to demonstrate cutting-edge space technologies and deliver exceptional insights about our planet.

“With this achievement, we’re another significant step closer to unlocking unprecedented knowledge about the world’s forests, including crucial data on carbon stocks and fluxes – fundamental to understanding and managing Earth’s carbon cycle. It’s a proud moment for European science and technology.”

With Biomass’ antenna open, satellite operators at ESA’s mission control centre expect to complete the launch and early orbit phase by the end of the week.

After this, the mission will enter its commissioning phase, which will last around six months.