In recent years, quantum physicists have successfully teleported entangled photons over a free-space distance of 143 kilometers (89 miles) using lasers, and 250 kilometers (155 miles) over optical fiber in the lab. In the past year we have also seen the first ground-to-air network, between a base station and an airplane flying 20 kilometers (12 miles) above. These were impressive feats, but to prove the possibility of a worldwide, satellite-based quantum network, larger distances are needed — something like the 400 kilometers (248 miles) to the ISS.

via European scientists propose world’s largest quantum network, between Earth and the ISS | ExtremeTech.