Wide-eyed Proba-V will track global vegetation daily
(麻豆淫院Org.com) -- The small but powerful camera of ESA's Proba-V mission can fit on a single laboratory table for testing. But when it reaches orbit, this compact sensor will deliver a daily overview of virtually all vegetation growth across Earth.
Daily global monitoring is an ambitious enough goal for a full-sized mission, but Proba is ESA鈥檚 smallest satellite platform - smaller than a cubic metre.
The aim is to have a microsatellite doing an equivalent job to the wide-swath 鈥榁egetation鈥� camera on France鈥檚 full-sized Spot-5 satellite. But engineers needed to shrink it by a factor of ten, swapping glass lenses for lighter aluminium mirrors and combining three separate telescopes.
A test version of Proba-V鈥檚 wide-viewing imager has been subjected to a combination of hard vacuum and temperature extremes in ESTEC鈥檚 Mechanical Systems Laboratory, simulating conditions it will face in space.
鈥淲e are checking the instrument temperature stays within set limits,鈥� said Jorg Versluys of Belgium鈥檚 OIP, the company building the imager. 鈥淏ecause its three telescopes have overlapping views, any temperature-driven deformation could put them out of alignment.鈥�
Proba-V is a new departure for the Proba series, explained Karim Mellab, Proba-V Project Manager: 鈥淧roba-V鈥檚 Vegetation payload will need to be operational on top of its experimental nature.鈥�
For the past 12 years, the Vegetation camera on Spot-4 and Spot-5 has been recording global vegetation growth and land cover changes, using its extremely wide 2250 km multispectral viewing swath and the ability to revisit all locations on Earth on a daily basis.
But France鈥檚 planned Pleiades follow-on satellites have no room to carry further Vegetation cameras. Instead, ESA and the Belgian Federal Science Policy Office began investigating the feasibility of flying a cut-down version of the instrument to continue delivering data to its users.
鈥淥ne of our main objectives is to get the new sensor in orbit by mid-2012,鈥� explained Mr Mellab. 鈥淭his will give us overlap with Spot-5鈥檚 Vegetation sensor, allowing us to calibrate the new instrument.鈥�
Provided by European Space Agency
