Satellites that communicate with each other using laser beams, it is the lens to project EDRS (European Data Relay System). It just passed a milestone with first transmission between the Earth observation satellite Sentinel – 1A communication Alphasat satellite belonging to Inmarsat 36,000 km away. Transmission lasercom, carried out at a rate of 1.8 Gbit/s, may be increased to 7.2 GB/s later. Two satellites will be launched by Esa to create a network space laser able to absorb 6 terabytes of data that the great Copernicus of the Esa programme observation satellites will generate every day.
A laser network to no longer depend on the ground stations
The problem of a satellite observation of the Earth such as the Sentinel – 1a is simple. In orbit 700 km from the Earth, the satellite can transmit its radar images of the Earth’s surface when it passes within the range of a ground station. So multiply the stations to minimize the areas where the satellite can no longer communicate.
By putting in place a space laser network, the Sentinel satellites can continuously transmit their images by pulling laser on 2 geostationary satellites 36,000 km from Earth which then transmit them to the ground. With a budget of EUR 450 million, the project will build on 2 relays which first will be placed on Eutelsat switch, satellite communication that which is to be launched in 2015, a second a year later.
Nasa is also working on an equivalent project, the SCaN for Space Communications and
Navigation. It is with the first elements of this networked laser that Nasa has managed to establish a laser link to 80 Mbit/s with the LADEE mission in orbit around the moon.
In addition to the satellite resources optimization, these laser networks are strategic for the Nasa and Esa. They will help to free itself from stations on the ground in foreign countries. It will also be able to be operated by drones, as already shown in the illustration provided by ESA on the occasion of the announcement of EDRS.
Translation : Bing Translator
“Europe’s space-based, laser-powered data highway passes early test”, Reuters, November 28, 2014
“Successful Demonstration of Alphasat-Sentinel-1A Laser Link”, ESA press release, November 28, 2014
“Laser Link Offers High-Speed Delivery”, ESA press release, November 28, 2014