Eight years in space

Satellite mission MOS successfully completed

A photograph of the German Bight - it impressively demonstrates how the individual components that overlap in the color image (left) can be separated with the special evaluation methods. This becomes clear from the completely different distribution patterns. © DLR
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For eight years, the environmental sensor MOS sent data about the state of the oceans from space. "Now he has run out of fuel and he is slowly drifting towards the earth, but the mission is a complete success, " Dr. Andreas Neumann, from the German Aerospace Center (DLR). "Through his more than 350, 000 high-resolution images, we have learned a lot about the ecological state of coastal waters." The only 54-pound device in 1996 was the first of its kind in space. The experience gathered with him, among other things, the 2001 sent into space environmental satellite ENVISAT good.

Decomposed light

Aftershocks and position of plate boundary in Himalya © USGS

MOS stands for Modular Optoelectronic Scanner. Such a device is also referred to as imaging spectrometer and was used for the first time on this mission. Also on board the European environmental satellite ENVISAT this technology forms the heart. Such a spectrometer breaks up the incoming light into different wavelengths and generates several different images. Each image contains the information that is transported at the respective wavelength. With this information from space, scientists have been able to show for the first time that with a combination of different images and thus wavelengths, where certain algae occur in mass, how much mud a river transports to the sea, where a tanker loses oil. How these wavelengths in the computer must be combined to make the desired information visible, was one of the basic questions that were answered with the environmental sensor MOS. Especially in coastal waters, it is very difficult to recognize from space which substances are contained in the water and how the quality of the water is, as their color varies greatly from season to region.

Big Brother for the oceans

With the help of MOS data and simultaneous water samples from the respective area, DLR researchers and colleagues developed and tested appropriate evaluation methods worldwide. These were thus already available at the beginning of the great ENVISAT mission. Thanks to these methods, scientists are now able to monitor the water quality from space and, if necessary, z. B. warn of poisonous algal blooms.

A lot of work for everyone

Back side of the largest fragment of the Atikythera mechanism Marsyas / CC-by-sa 3.0

MOS was also particularly interesting because its record eight-year mission duration overlapped with several other satellites gathering information about the World Ocean. Therefore, his data, which are considered to be highly reliable, serve as a benchmark for various European and American satellite missions. The DLR cooperated closely with the Indian space organization ISRO on this mission, which provided the satellite and another remote sensing instrument. Not all information from MOS will be evaluated for a long time yet and the team of international scientists will need it for a while longer. But this is also understandable at 350, 000 recording after more than 40, 000 earth orbits.

(DLR / GeoUnion, 11.06.2004 - Kirsten Achenbach / Forschungszentrum Ozeanr nder) Display