The new satellite will measure the amount of carbon stored in forests

The satellite is the first to use a type of radar technology called P-band radar - which scientists hope will allow them to more easily differentiate between trees and wood.The mission is one of the biggest in the history of science. It stands several metres high and weighs more than a tonne.

At the end of next year, it will unfurl a 12-meter radar dish that will fold up like an umbrella along its side for launch.'Airbus Defence and Space engineer Vicki Lonnon sees it as quite the sight to behold.

'It's difficult to simulate space fully from the ground, so it's essentially modelling right now. So it will be quite exciting to see that happen.'Its collapsible antenna is crucial to the dish's mission: to observe Earth's forests, from the cold emptiness of space, in a very different way. The engineering team is testing the release and unfolding mechanism many times.

The BIOMASS satellite is the first to launch a technology called P-band radar into space. The radar has a long wavelength of 70cm, so despite the big, bulky antenna, it works well It will reveal something never before seen from space: trees' wood.

'If you saw a forest at this wavelength, you wouldn't be able to distinguish the leaves and branches,' says University of Sheffield researcher Professor Shaun Quegan.

'The biomass is in the framework of the tree. That's where the biomass is.'As we face a climate crisis, scientists are becoming increasingly reliant on measuring biomass.

The forest plays a vital role in reducing global warming. The plants absorb and store about a third of the carbon we pump into the atmosphere through photosynthesis. The thickest branches and trunks of trees contain most of the biomass.

In fact, these are the very same bits of trees that have proven very difficult to measure from space so far. The amount of carbon that is contained in forests around the globe is largely based on guesswork, extrapolated from a few detailed studies of small patches.

It is only possible to measure so many trees by hand in the tropics, the Amazon, and the Congo basin, says Professor Simon Lewis of University College London. The satellite, however, can provide us with information on large areas.

It's crucial to know the amount of carbon in forests, as we keep chopping and burning them.It might be possible to calculate the impacts of deforestation on climate change much more accurately if scientists were able to measure it from space.

The BIOMASS satellite could also provide an impartial assessment of how much carbon differing countries' forests store, which is crucial to the international negotiations on climate change.

The inventory plays a crucial role in assisting countries to protect their forests, and holding them responsible for pledges to prevent the logging or burning of these valuable carbon stores.