solar observatories were placed in Earth orbit and are not included in this list: 1960–1969 1974–1997 2000–present Proposed Mercury probes Venus probes Early programs encompassing multiple spacecraft include: Venera program — USSR Venus orbiter and lander (1961–1984) Pioneer Venus project — US Venus orbiter and entry probes (1978) Vega program — USSR mission to Venus and Comet Halley (1984) 1961–1969 1970–1978 1982–1999 2006–present Proposed Earth flybys See List of Earth flybys In addition, several planetary probes have sent back observations of the Earth-Moon system shortly after launch, most notably Mariner 10, Pioneers 10 and 11 and both Voyager probes (Voyager 1 and Voyager 2). Lunar probes See List of lunar probes Mars probes Major early programs encompassing multiple probes include: Zond program — failed USSR flyby probe Mars probe program — USSR orbiters and landers Viking program — two NASA orbiters and landers (1974) Phobos program — failed USSR orbiters and Phobos landers 1960–1969 1971–1976 1988–1999 2001–2009 2011–2018 2020–Present Proposed Phobos probes Ceres probes Asteroid probes Jupiter probes Saturn probes Titan probes Uranus probes Neptune probes Pluto probes Comet probes Kuiper Belt probes Probes leaving the Solar System Other probes to leave Earth orbit For completeness, this section lists probes that have left (or will leave) Earth orbit, but are not primarily targeted at any of the above bodies. Cancelled probes and missions See also Lists of spacecraft List of uncrewed spacecraft by program Discovery and exploration of the Solar System Robotic spacecraft Satellites Sample return mission Timeline of Solar System exploration References External links Planetary Society: Cassini's Tour of the Saturn System Lists of spacecraft Spaceflight timelines Lists of space missions Probes Lists of Solar System objects