Cancelled space telescopes

proposed project by NASA to construct a system of space telescopes for detecting extrasolar terrestrial planets; postponed several times and finally cancelled in 2011

suggested ESA Cornerstone mission

cancelled NASA space telescope

XEUS (X-ray Evolving Universe Spectroscopy) was a space observatory plan developed by the European Space Agency (ESA) as a successor to the successful XMM-Newton X-ray satellite telescope. It was merged to the International X-ray Observatory (IXO) around 2008, but as that project ran into issues in 2011, the ESA component was forked off into Advanced Telescope for High Energy Astrophysics (Athena).

cancelled ESA mission to search for extrasolar planets

cancelled American-ESA-Japanese space telescope project

ASTRO-G (also known as VSOP-2, and very rarely called VSOP-B) was a planned radio telescope satellite by JAXA. It was expected to be launched into elliptic orbit around Earth (apogee height 25,000 km, perigee height 1,000 km).

NASA mission concept