Laser satellite communication is very promising

The satellites are now using radio waves to exchange data. Now data rates can be increased by a hundred times by using lasers instead of radio signals. Two satellites are being tested, each with a diode laser pump module deployed with the help of Fraunhofer researchers, Germany.

(Photo: ESA-J.Huart)

The data was transmitted and back at the speed of light between the two TerraSAR-X satellites of Germany and the US NFIRE, over a long distance of more than 5000 kilometers in space without any Any mistake. What is special about this cosmic experiment conducted by Tesat-Spacecom is the laser-transmitted data. The bandwidth achieved in the test is a hundred times greater than conventional data transmissions with radio waves, allowing the transmission of a data rate equivalent to 400 DVDs per hour.

This new technology opens up the possibility of transmitting large data packets between multiple satellites in the future , for example, can send image data from Earth observation satellites to a ground station. This has not been done so far, because the width of radio waves is not wide enough. Another advantage of this new form of communication is that lasers are easier to focus than radio waves, which means that data transmission can be directed more accurately.

Satellite communication on satellites can be started with pump modules developed by ILT Fraunhofer Laser Institute researchers in Aachen, in the name of Tesat GmbH & Co. This is part of a program sponsored by the German Aeronautics Center (DLR). 'Modules need to withstand vibrations and accelerations on the satellite chamber during launch and then have to withstand harsh conditions in the universe, such as extremely high radiation levels and strong temperature differences. ', Martin Traub, Development Manager at ILT, said.

'That's why we tested before pumping modules under extremely harsh conditions, with temperatures ranging from –35 ^o C to 60 ^o C, 1300 times more powerful than left. soil, and gamma rays'.

Modules should not be too big or too heavy to use in the universe: they are 5 x 5 x 2 cm in size, only slightly larger than a matchbox and weigh a little heavier than chocolate bars of 130 grams. 'We have achieved this minimum weight by choosing suitable materials and a sophisticated shell: Any material that is not absolutely basic is crushed', Traub said. know.

The major challenge still exists is that although the weight has been reduced, the amount of heat generated by the laser's few watts of power still needs to be overcome.