List of Solar System Probes - Key

Key

Colour key:

– Mission or flyby completed successfully (or partially successfully)		– Failed or cancelled mission
– Mission en route or in progress (including mission extensions)		– Planned mission

• † 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 a 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 ballon: Part of a probe that descend through or floats in the atmosphere of an astronomical body
• Sample return: Parts of the probe return back 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.