S-Cam: A technology demonstrator for the astronomy of the future

S-Cam is a cryogenic camera developed within the Astrophysics Division of E SA Space Science Department. The camera has been designed as a technology d emonstrator, aiming to prove the potential of a new generation of single-ph oton counting detectors based on Superconducting Tunnel Junctions (STJs), T his article provides an overview of the cryogenic detector development, a d escription of the S-Cam system and a summary of the results obtained both d uring testing at ESTEC and during actual observations at the William Hersch el Telescope in La Palma (Canary Islands, Spain). Initial observations were performed on the Crab pulsar, a neutron star about 10 km in diameter and a bout 6000 light years from Earth, with a weight equal to that of our Sun an d spinning with a period of 33 msec.