Laser beams message between satellites
Two satellites have become the first to exchange information from different orbits using a laser . The feat may lead to super-fast data-relay systems between spacecraft.
The laser link took place on Friday between two satellites designed to test communications technologies.
One, a Japanese mission called Kirari (Optical Inter-orbit Communications Engineering Test Satellite), flies at an altitude of 610 kilometres, in low-Earth orbit. The other, a European satellite called ARTEMIS (Advanced Relay and Technology Mission), soars 36,000 kilometres above Earth in geostationary orbit.
Pointing and maintaining a laser connection between the two satellites is difficult because they can be as much as 45,000 kilometres apart and are moving at a relative speed of several kilometres per second.
