The UK is going to lead a space mission to get an absolute measurement of the light reflected off Earth’s surface.
The information will be used to calibrate the observations of other satellites, allowing their data to be compared more easily.
Called Truths, the new spacecraft was approved for development by European Space Agency member states in November.
Proponents of the mission expect its data to help reduce the uncertainty in projections of future climate change.
Scientists and engineers met on Tuesday to begin planning the project. Industry representatives from Britain, Switzerland, Greece, the Czech Republic and Romania gathered at Esa’s technical centre in Harwell, Oxfordshire.
The agency has allocated €32.4m (£27.7m) for the initial design phase, with the scientific lead on the mission to be taken by Britain’s National Physical Laboratory.