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. • 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. ==Lunar probes by date==