 ULTRASAT will observe a large patch of sky, more than 200 square degrees, alternating every six months between the southern and northern hemisphere.The satellite will orbit the Earth from an altitude of about 300 km above the geosynchronous orbit, getting a ‘ride’ as a secondary payload in the fairing of the rocket carrying a communications satellite.A joint American-Israeli proposal for this project was submitted to NASA by a team from Caltech/JPL (Jet Propulsion Laboratory), the Weizmann Institute of Science and Israel Aerospace Industries (IAI).