This is a list of space probes that have left Earth orbit (or were launched with that intention but failed), organized by their planned destination. It includes planetary probes, solar probes, and probes to asteroids and comets, but excludes lunar missions, which are listed separately at List of lunar probes and List of Apollo missions. Flybys (such as gravity assists) that were incidental to the main purpose of the mission are also included. Flybys of Earth are listed separately at List of Earth flybys. Confirmed future probes are included, but missions that are still at the concept stage, or which never progressed beyond the concept stage, are not. Key Colour key: † means "tentatively identified", as classified by NASA. These are Cold War-era Soviet missions, mostly failures, about which few or no details have been officially released. The information given may be speculative. Date is the date of: closest encounter (flybys) impact (impactors) orbital insertion to end of mission, whether planned or premature (orbiters) landing to end of mission, whether planned or premature (landers) launch (missions that never got underway due to failure at or soon after launch) In cases which do not fit any of the above, the event to which the date refers is stated. Note that as a result of this scheme missions are not always listed in order of launch. Some of the terms used under Type: Flyby: The probe flies by an astronomical body, but does not orbit it Orbiter: Part of a probe that orbits an astronomical body Lander: Part of a probe that descend to the surface of an astronomical body Rover: Part of a probe that acts as a vehicle to move on the solid-surface of an astronomical body Penetrator: Part of a probe that impacts an astronomical body Atmospheric probe or weather balloon: Part of a probe that descend through or floats in the atmosphere of an astronomical body Sample return: Parts of the probe return to Earth with physical samples Under Status, in the case of flybys (such as gravity assists) that are incidental to the main mission, "success" indicates the successful completion of the flyby, not necessarily that of the main mission. Solar probes While the Sun is not physically explorable with current technology, the following solar observation probes have been designed and launched to operate in heliocentric orbit or at one of the Earth–Sun Lagrangian points – additional