Lift-Off For Europe’s Space Laser Network

Europe has begun to roll out a data superhighway in orbit above the Earth. The first node in the network is a telecommunications satellite that has just launched from Kazakhstan.

It will use a laser to gather pictures of the planet taken by other spacecraft and then relay them to the ground.

One benefit will be to put information on natural disasters, such as flooding and earthquakes, into the hands of emergency responders far faster than has previously been possible.

Currently, it can take hours to get the pictures taken by Earth observation satellites down on the ground.

Part of the reason is that spacecraft can only transmit their images when they pass over a receiving dish, and they will have visibility of this antenna for just 10 minutes in most cases during every 90-minute tour around the globe.

The European Space Agency’s (Esa) answer is to fire the pictures upwardsinstead, via laser, to another satellite much higher in the sky that has a constant view of the ground station.

In the past couple of years, the agency has put up two Earth observers that are equipped with optical transmission equipment. These will now be able to offload their data through the new relay satellite, which will be positioned 36,000km above the equator at 9 degrees East.

Testing by Esa’s industrial partner, Airbus Defence and Space, shows it should be possible for the system to put pictures on the desks of the people who need them within 20 minutes of those images being acquired.

For some applications – such as the monitoring of pollution incidents, or illegal fishing or ocean piracy – the time saved could be critical to achieving an effective response.

The European Data Relay System, or EDRS for short, has been more than 10 years in development. Getting satellites to talk to each other via a narrow laser beam is no easy task, says Esa project manager Michael Witting.

“The difficulty is basically that you have to hit another satellite with your laser beam over a distance of over 40,000km, which is akin to hitting a two-euro coin over the distance of the Atlantic,” he told Amira News.

With a successful connection, data will move at a rate of up to 1.8Gbps.

EDRS will debut with the European Commission as its anchor customer. Brussels has a series of satellites called Sentinels that are systematically mapping the Earth, to help inform and enforce EU policies.

Prodigious volumes of data are expected from these satellites in the coming years and the traditional downlink solutions are no longer regarded as adequate to the task.

Esa officials will only declare Friday’s launch a success when they get confirmation that the relay satellite survived its ride to orbit.

The spacecraft, which is owned by the Paris-based commercial operator Eutelsat, left the Kazakh Baikonur cosmodrome atop a Proton rocket at 22.20 GMT on Friday (04:20 local time Saturday).

The drop-off high above the Earth was not expected to occur until nine hours and 12 minutes after lift-off, meaning it would be 07:32 GMT on Saturday, at the earliest, before ground controllers could assess the status of the mission.

Many weeks of testing lie ahead. EDRS should go into full service in the summer.

A second relay satellite will go up in 2017. Further platforms will be required to provide fully global, round-the-clock laser connections.

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