Sentinel-2A ready for space


After six months of intensive testing, the first Sentinel-2 satellite developed and built by Airbus Defence and Space for the European Space Agency (ESA) is getting ready for its mission in space.

Sentinel-2A will be the second satellite of the Copernicus program to be launched. Copernicus is an operational project led by the European Commission (EC) in partnership with the European Space Agency (ESA). The Copernicus Sentinels supply remote sensing data of the Earth to deliver key operational services related to environment and security.

1501xx Sentinel 2A fit2Sentinel-2 is the next important milestone to deploy Europe´s Copernicus program for which Airbus Defence and Space is a key contributor. Airbus Defence and Space is prime contractor for five of the seven Sentinel missions, and has built state-of-the-art instruments and components for the others. Sentinel-2A is equipped with a laser terminal made by Tesat-Spacecom to transmit data to satellites in geostationary orbit carrying the European Data Relay System, EDRS. These satellites then transmit the Sentinel-2 data to the ground. This principle was first demonstrated in November 2014 when Sentinel-1A, which carries a similar laser terminal, linked up with Alphasat to deliver data.

In IABG’s facilities in Ottobrunn (near Munich, Germany) Airbus Defence and Space engineers put Sentinel-2A through a rigorous test campaign that included acoustic testing to simulate the huge noise generated at launch, vibration and separation shock testing to simulate mechanical launch loads, and thermal vacuum testing to simulate the environment in space. Marking a significant milestone in preparations for launch, Sentinel-2A’s laser terminal, or ‘optical communication payload’, has recently come through a set of rigorous tests. The tests included a ‘trajectory test’ where the unit’s pointing assembly was swivelled, as it would in orbit to align itself with the geostationary EDRS satellite.

Janice Patterson from ESA said, “The optical communications payload is very complex and the success of this recent test is a testament to our collaboration with Tesat-Spacecom GmbH, who developed the laser communication terminal and the downlink system, the DLR German Aerospace Center, who contributed to the funding, and Airbus Defence and Space, the Sentinel-2 prime contractor.”

The 1.1 ton satellite is now scheduled to be shipped to the European spaceport in Kourou, French Guiana, in April. The S2A launch by VEGA is scheduled in June. Sentinel-2A will deliver optical images from the visible to short-wave infrared range of the electromagnetic spectrum from an altitude of 786 kilometres using 13 spectral bands with a resolution of 10, 20 or 60 meters and a swath width of 290 km. This combination is unprecedented in the category optical imagers. The data will be used for studying land use, soil sealing, land management, agriculture, forestry, natural disasters (floods, forest fires, landslides, erosion) and to assist humanitarian aid missions. Environmental observation in coastal areas likewise forms part of these activities, as does glacier, ice and snow monitoring.

Sentinel-2B, which is identical in design, is planned for launch mid-2016. These two satellites orbiting the earth every 100 minutes will be able to capture images of our planet’s entire land surface in less than five days.

IMAGE SOURCE: ESA (C.Wildner), ESA/ATG medialab
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