Editing Mars program (section)

===Mars 3MP===
[[Image:Mars 6.jpg|thumb|right|[[Mars 6]] and [[Mars 7]]]]
In 1973 the speed required to place a spacecraft in an interplanetary trajectory had to be increased.  Thus the Proton could not deliver spacecraft with an orbiter and an attached lander to the necessary trajectory to reach Mars, as had been possible in 1971. To resolve this problem, four spacecraft were launched. The Mars 4 and 5 orbiters, which had been launched separately, were used to relay communications, and to complete mission objectives which would have been completed by landers. Two landers were launched with orbiter type buses (Mars 6 and 7), but without fuel to enter orbit of the Mars satellite.

{| class="wikitable sortable"
! Public name
! Internal name
! Mission
! Launch date
! Carrier rocket
! Outcome
! Remarks
|-
| [[Mars 6]] || 3MP No.50P || Flyby/<br>Lander || 5 August 1973 || [[Proton-K]]/[[Blok D|D]] || {{Partial failure}} || Lander transmitted 224 seconds of (corrupted) atmospheric data before crash-landing on 12 March 1974. Landing coordinates were {{Coord|23.90|S|19.42|W|globe:Mars}} within [[Margaritifer Terra]]<ref name=nssdc-m6/>
|-
| [[Mars 7]] || 3MP No.51P || Flyby/<br>Lander || 9 August 1973 || [[Proton-K]]/[[Blok D|D]] || {{Failure}} || Missed Mars by 1,300 km on 9 March 1974 due to premature spacecraft separation. Intended landing coordinates were {{Coord|50|S|28|W|globe:Mars}}. Last contact with flyby bus on 25 March 1974<ref name=nssdc-m7/>
|}