Express (PLUTOKE) – replaced by New Horizons Old proposals - Mars Scout program Aerial Regional-scale Environmental Survey (ARES) (2000-2010 concept) TAU (spacecraft)- probe to 1000 AU (1980s concept) See also NASA: Large strategic science missions, the NASA flagship missions Discovery Program, medium cost NASA missions New Frontiers program, medium-large NASA missions to outer planets When We Left Earth: The NASA Missions – 2008 documentary covering NASA's mission history. Space exploration Timeline of Solar System exploration List of European Space Agency programmes and missions References Bibliography External links NASA - Missions Lists of space missions Missions