Biomass satellite prepped for launch fuel load

Biomass satellite prepped for launch fuel load
by Erica Marchand
Paris, France (SPX) Apr 02, 2025

With its scheduled launch date of 29 April fast approaching, ESA's Biomass satellite has reached a critical stage in final preparations at Europe's Spaceport in French Guiana. After three weeks of detailed pre-launch activities, the satellite's propulsion subsystem has been fully checked and deemed ready for fuelling.

Led by the OHB-Sweden team, engineers completed the checkout of the propulsion system a full day ahead of schedule, marking a significant achievement in the countdown to liftoff.

The propulsion system features a network of tubing that channels hydrazine propellant from a 177-liter storage tank to eight thrusters. Arranged in pairs at each of the satellite's four corners, the thrusters are responsible for maneuvering the spacecraft once in orbit.

To ensure precise and secure propellant management, the setup includes a combination of flow control valves, latching valves, and service valves. Each thruster is protected by two flow control valves placed in series, both of which must be opened for the thruster to operate. These valves default to a closed state and require electrical power to activate, with internal magnets maintaining closure in the absence of power.

The system is organized into two branches, each housing four thrusters. Latching valves isolate each branch from the main tank, providing a reliable means to control and isolate propellant flow during operations. These bistable valves remain either open or closed until an electrical signal changes their state.

A critical part of the validation involved comprehensive leak testing. Engineers pressurized one side of each closed valve with helium while applying a vacuum on the other, then used helium detectors to identify any potential leaks. This painstaking process, requiring time and precision, ensured the system is fully sealed and ready to contain the hydrazine safely once fuelling begins.

With all valves verified and the system cleared, the satellite is now secure against unintended propellant loss. This milestone is a vital step ahead of the satellite's launch aboard a Vega-C rocket.

Beyond launch readiness, Biomass will soon deliver groundbreaking forest data. Once operational, the satellite will use its pioneering fully polarimetric P-band synthetic aperture radar to penetrate dense forest canopies and measure biomass levels, including trunks, stems, and branches where carbon is stored. The P-band radar's 70 cm wavelength enables it to image beneath the forest cover, making Biomass the first mission capable of acquiring such detailed forest structure data on a global scale.

This capability will significantly enhance our understanding of forest health, monitor deforestation, and improve carbon cycle modeling as part of ESA's broader Earth Explorer program.