PARIS– Airbus Defence and Space UK will build the European Space Agency’s Biomass forest-carbon-monitoring satellite under a contract valued at 229 million euros ($260 million), the two parties announced May 3.

Stevenage, England-based Airbus UK will be prime contractor for the 1,250-kilogram spacecraft, which is expected to launch in 2021, they said.

Biomass’s showcase instrument will be its P-band synthetic-aperture radar antenna, whose main instrument will be built by Airbus’s Friedrichshafen, Germany, facility, with the 12-meter-diameter deployable antenna built by Harris Corp. of Melbourne, Florida.

The 22-nation ESA has budgeted the entire Biomass mission at 420 million euros, a figure that includes the satellite’s construction, launch aboard a European Vega rocket and five years of operations in low Earth orbit.

The mission is designed to observe annual changes in biomass in most of the world’s forests over multiple growth cycles.

Unlike the Sentinel series of Earth observation satellites, Biomass is not part of the European Commission’s multibillion-dollar Copernicus Earth observation program, although Biomass will contribute data to it.

Biomass is all-ESA, and it one of several satellites that ultimately could be used to provide data to global governments committing to the COP21 goals with respect to carbon emissions.

Biomass will be the first space-borne P-band antenna. One of its drawbacks is that P-band, at between 420 and 450 megahertz, is also in use by the U.S. Department of Defense and several of its allies for ground-based missile warning and space surveillance – a system known as the Space Object Tracking Radar network.

Signal overlap between Biomass and these military transmissions will mean Biomass’s coverage will not include North America, Britain, Greenland and Turkey.

ESA had been worried that other regions might deploy radars using in P-band, but that apparently has not happened, and Biomass’s overall value was judged so great as to overcome the fact that it will be blind in these areas.

Alternative radars in X- and C-band, which have been used for many satellite Earth observation missions, do not provide the vertical detail of P-band, ESA concluded. Airbus said the radar, able to peer beneath forest cover, will improve digital elevation maps in forested regions.

Airbus also operates, on a commercial basis, the German TerraSAR-X and TanDEM-X X-band radar Earth observation satellites, financed by the German government with Airbus contributions.

The early competition for the Biomass contract was between Airbus and Thales Alenia Space Italy. The Italian government’s decision to reduce its contributions to ESA’s Earth observation program all but took Thales Alenia Space Italy out of the competition. OHB SE of Germany stepped in to compete with Airbus.

Biomass will use Airbus’s AstroBus-Medium satellite frame and the overall program will be with Airbus’s British division. Jo Johnson, Britain’s minister for universities and science, attended the signing ceremony on April 29 in Stevenage, as did Katherine Courtney, the new chief executive of the UK Space Agency.

Signing the contract were Volker Liebig, ESA’s director of Earth observation, and Andrew Sroomer, Airbus’s UK director for Earth observation, navigation and science.

“It is our membership of ESA and our reputation for science and innovation that enables UK industry to win major satellite manufacturing contracts like this one, creating jobs around the country,” Johnson said.

Colin Paynter, managing director for Airbus Defence and Space Ltd., said the contract “is fantastic news for the UK space industry, building on the experience and capabilities of missions such as Sentinel-5 Precursor, Solar Orbiter and Lisa Pathfinder.”

The AstroBus platform has also been used on the Spot 6, Spot 7 and Ingenio optical Earth observation satellites.

Peter B. de Selding was the Paris bureau chief for SpaceNews.