It looks for all the world like a giant brolly, but there's no rain where it's going.
This immense reflector-antenna is heading into space, to "weigh" Earth's forests.
It's a key component on the European Space Agency's Biomass mission, now under construction in the UK at aerospace manufacturer Airbus.
When unfurled, the space brolly's 12m by 15m wire-mesh membrane will be part of a very special P-band radar system.
It's special because of its long wavelength.
At 70cm, it can look past the leaf canopy of forests to map the woody parts below - all those trunks and branches.
Using an approach akin to tomography, like that used in a CT scan, the 1.2-tonne satellite will analyse slices through the trees on repeat passes to build up a picture of how much woody material is present.
Global maps should be produced every six months.
The plan is for Biomass to gather at least five years' worth of data, to be able to spot trends.
Trees are a two-way valve in the climate system. They absorb copious amounts of the greenhouse gas carbon dioxide (CO2), but they also release it when they die or are burnt.
Precise numbers for the flows in either direction through this valve are elusive, however.
"This mission is about getting a much better handle on the role of forests, in either emitting carbon dioxide through destruction, or taking up carbon dioxide through growth," said Prof Shaun Quegan, the mission's principal scientist from the University of Sheffield.
"At the moment, the amount that's being emitted from forests - the uncertainty on that number is 50% or a bit bigger, and I actually think 50% might be optimistic," the National Centre for Earth Observation (NCEO) researcher told BBC News.