Why the ESA's world-first Biomass satellite is 'very timely' for understanding Earth's climate

Without forests, a large portion of this carbon would remain in the atmosphere as carbon dioxide (CO2) - the principal greenhouse gas responsible for global heating. Still, the Earth's forests are dwindling on an unimaginable scale- since 2010, 11 million hectares per year have been lost. That's the equivalent of roughly 30 football fields per minute. Therefore, it makes sense to implement a careful forest management strategy.

This is where the UK-built satellite Biomass comes in - it is a key component of the European Space Agency's (ESA) Biomass mission. It will measure Earth's biomass to better estimate the amount of carbon that Earth's forests store and aid in their protection.

Having recently departed for final testing before its scheduled launch in Q2 2024, Interesting Engineering (IE) spoke with Michael Fehringer, ESA Project Manager for the Biomass mission, to explore further.

Biomass will be the seventh satellite in orbit within ESA's Earth Explorer program

The ESA's Earth Explorer program consists of several research missions focused on different facets of our planet's ecosystem. This includes Biomass, which will be the program's seventh satellite in orbit. ESA's Earth Explorer program covers the entire Earth, from our planet's surface and interior to its atmosphere, biosphere, hydrosphere, and cryosphere. Biomass will measure the amount of carbon in the world's forests.

"It takes about seven months to generate one global map. The mission will last at least five years so that the evolution can be monitored. This is important because one wants to see where the carbon goes that is emitted through human activities," Micheal Fehringer explained to IE.

Fehringer explained that about one-third of the emitted CO2 goes into plants, but the uncertainties are high. Furthermore, trees act as a two-way climate valve. In other words, while they absorb a significant amount of CO2, they release it when they are burned or die and decompose.

Biomass will thus critically contribute to a better understanding of the carbon cycle, an essential input to all climate modeling, and critical in achieving net zero targets.

A world first: 'The novelty is its wavelength of about 70cm. Such a radar has never been flown on a civil satellite'

Equipped with a completely polarimetric P-band radar, Biomass will be the first satellite to carry one into space.

"The novelty is its wavelength of about 70 centimeters (cm). Such a radar has never been flown on a civil satellite. The long wavelength can penetrate the leaves of the trees and see down to the ground and thus measure the volume in the trees," revealed Fehringer.

According to the ESA project manager, an optical instrument would only see the top leaves of the trees, which is useless for the team's application.

'The instrument is incredibly sensitive; we can receive signals down to a number in Watts with 13 zeros behind the comma'

We are told that Biomass works by sending 30-microsecond pulses to the ground and picking up the reflection via a giant 12-meter diameter antenna. "The instrument is incredibly sensitive; we can receive signals down to a number in Watts with 13 zeros behind the comma," Fehringer described.

As a result, the satellite will pick up a signal that varies depending on the different forest components and contains data that can be used to calculate measurements like biomass and height. Biomass works by amplifying the signals from an orbit at 600 km height to reach the Earth and back to space, claims Airbus, the UK-based aeronautics and space firm that built the instrument.

And the end product? The delivery of exceptionally precise biomass maps for tropical, temperate, and boreal forests that are impossible to get on the ground. Better yet, it will be the first satellite in the world equipped to examine the forests of Earth in three dimensions.

Biomass departs for final testing in Toulouse, France- thanks to Airbus

ESA's Biomass satellite is no longer housed at Airbus's UK facility. It's off for final testing in Toulouse, led by twenty engineers from the UK-based team, with assistance from on-site colleagues and Airbus in Friedrichshafen, Germany.

In order to simulate launch conditions and the harsh environment in orbit, the spacecraft will undergo a thorough environmental test program. This will include thermal vacuum tests, mechanical vibration tests, and acoustic and electromagnetic compatibility tests.

Airbus 🇬🇧 waves its last goodbyes 👋 to #Biomass as it heads to Airbus 🇫🇷 for its final pre-launch testing.@ESA’s flagship Earth Explorer will deliver exceptionally accurate maps of Earth’s forests and transform the way we monitor our planet's biomass🌍
🔗https://t.co/pdcajfkFy8 pic.twitter.com/cJDCaUXaHB

— Airbus Space (@AirbusSpace) November 2, 2022

The UK team will prepare for the in-orbit commissioning and operating phases in addition to testing, with a second team handling the delivery of the ground calibration transponder currently located in New Norcia, Australia. 

'This latest milestone builds on the successes of the previous ESA missions Sentinel-5P and Aeolus'

This all comes after the Stevenage team successfully finishes Biomass' mechanical and electrical assembly. Additionally, testing of the spacecraft's propulsion system, harness, and all avionics equipment, despite the production and manufacturing hurdles brought on by the pandemic, has also been finalized.

Furthermore, the crew has also attached and finished experimenting with the giant deployable reflector's deployment as well as incorporating the radar equipment into the satellite, completing the spacecraft's mechanical construction.

"This latest milestone builds on the successes of the previous ESA missions Sentinel-5P and Aeolus, confirming Airbus as a leader in Earth observation and environmental monitoring satellite manufacturing, "said Richard Franklin, Managing Director of Airbus Defence and Space UK in a press release.

Beyond measuring biomass: A look into the evolution of Earth's surface and a large scale treasure hunt

The Biomass mission will have various other 'secondary' goals in addition to delivering data on all forests on Earth.

"We will also contribute to deforestation monitoring and various UN initiatives to monitor regrowth. We will measure this in tons of carbon per hectare forest and its evolution over time," said Fehringer.

In other words, the Biomass satellite will enable researchers to revisit earlier measurements and observe whether forests are being degraded or destroyed. In doing so, they will be in a better position to model the impact and take early action to correct that.

The novel technology also makes possible the examination of the forest's topography (i.e., the forms and features of its surface). Researchers may then be able to determine locations where water originally flowed beneath the Earth's surface.

Another use for Biomass could be locating sites of archaeological significance.

Science Vs. Military: 'The same band is usually reserved for observing approaching missiles'

Nevertheless, it has taken Biomass a while to get to this point.

The science dates back to the late 1980s, when a forest in Eastern England was flown over by an experimental P-band radar to demonstrate its viability. However, at that time, such a system seemed unlikely to ever reach space, because the specific radar frequencies were set aside for military purposes. In fact, the US military exploits the same band to watch for missiles approaching North America and Northern Europe.

Even now, "[Biomass] cannot operate above Europe, Canada, and the US [North America] because military applications operate there," said Fahringer to IE.

According to BBC News, a request for a small window in this sensitive area of the electromagnetic spectrum to allow the scientific application had to be made to the International Telecommunications Union.

The mission's lead scientist, Prof. Shaun Quegan, from the University of Sheffield, indicated in the same article that the team is not very concerned about this constraint. He said that such places in the world already have quite reliable forest statistics.

Quegan clarified that the main areas of uncertainty are found in Asia and the tropics, where Biomass can freely use its instrument.

'[Biomass' Q2 2024 launch date] is very timely for climate modeling support'

Biomass is scheduled to be carried into space from Kourou, French Guiana, on a Vega rocket in Q2 2024, when it will begin its five-year mission.

And as a closing remark, Michael Fahringer highlighted to IE," [This] is very timely for climate modeling support."

The phrase, "Earth is a fine place and worth fighting for," by the famous late author Ernest Hemingway comes to mind. On that note, IE looks forward to keeping you posted on how Biomass progresses into orbit to monitor, aid in learning, and in this case, "fight" for our planet.