Space telescope to maintain. The Hubble Space Telescope was serviced by the Space Shuttle while many other space telescopes cannot be serviced at all. Space observatories can generally be divided into two classes: missions which map the entire sky (surveys), and observatories which focus on selected astronomical objects or parts of the sky. Satellites have been launched and operated by NASA, ISRO, ESA, Japanese Space Agency and the Soviet space program later succeeded by Roskosmos of Russia. As of 2018, many space observatories have already completed their missions, while others continue operating on extended time. However, the availability of space telescopes and
Rendezvous: A Space Shuttle Simulation Rendezvous: A Space Shuttle Simulation Rendezvous: A Space Shuttle Simulation, is a space simulator published 1982 by Edu-Ware, and developed by Titan Computer Products and NASA scientist Wesley Huntress. Accompanied by a thick "Spacecraft Operations" manual with a chapter on use in the classroom, this flight simulator was marketed as being as educational as it was fun to play. The simulation is centered on a typical Space Shuttle mission to service a space station. Mission phases include "Earth Lift-Off", "Orbital Rendezvous", "Approach" and "Alignment and Docking". It was released for the Apple II in 1982 with positive feedback from reviewers.