Editing Mars 7

{{short description|Failed Soviet flyby/lander mission to Mars (1973–1974)}}
{{Infobox spaceflight
| name                  = Mars 7
| image                 = Mars 6.jpg
| image_size            = 300px

| mission_type          = [[Mars]] flyby/lander<ref name=skyrocket1/>
| operator              = Soviet space program
| COSPAR_ID             = {{COSPAR|1973-053A}}<br>{{COSPAR|1973-053E}}
| SATCAT                = 6776<ref name=nssdc1/><br>7224
| mission_duration      = {{time interval|9 Aug 1973|25 Mar 1974|sep=,}}

| spacecraft            = [[4MV|3MP]] No.51P
| manufacturer          = [[NPO Lavochkin]]
| launch_mass           = {{cvt|3260|kg|lb}}<ref name=nssdc1/>
| landing_mass          = {{cvt|635|kg|lb}}

| launch_date           = {{start-date|9 August 1973, 17:00:17|timezone=yes}}&nbsp;UTC<ref name=LL/>
| launch_rocket         = [[Proton-K]]/[[Blok D|D]]  
| launch_site           = [[Baikonur Cosmodrome|Baikonur]] [[Baikonur Cosmodrome Site 81|81/24]]
| launch_contractor     = [[Khrunichev State Research and Production Space Center|Khrunichev]]
| last_contact          = 25 March 1974<ref name=beyond/>

| orbit_reference       = [[Heliocentric orbit|Heliocentric]]
| apsis                 = helion

|interplanetary         = 
 {{Infobox spaceflight/IP
   |type                = flyby
   |object              = [[Mars]]
   |component           = Bus
   |arrival_date        = 9 March 1974
 }}
 {{Infobox spaceflight/IP
   |type                = lander_flyby
   |object              = [[Mars]]
   |component           = Lander
   |arrival_date        = 9 March 1974
   |distance            = {{cvt|1300|km|mi}}
 }}

| programme             = '''[[Mars program]]'''
| previous_mission      = [[Mars 6]]
}}

'''Mars 7''' ({{Langx|ru|Марс-7}}), also known as '''3MP No.51P''' was a [[Soviet Union|Soviet]] spacecraft launched in 1973 to explore [[Mars]]. A 3MP bus spacecraft which comprised the final mission of the [[Mars program]]me, it consisted of a [[Lander (spacecraft)|lander]] and a coast stage with instruments to study Mars as it [[Flyby (spaceflight)|flew past]]. Due to a malfunction, the lander failed to perform a maneuver necessary to enter the [[Martian atmosphere]], missing the planet and remaining in [[heliocentric orbit]] along with the coast stage.

== Spacecraft ==
Mars 7 spacecraft carried an array of instruments to study Mars. The lander was equipped with a thermometer and barometer to determine the surface conditions, an accelerometer and radio altimeter for descent, and instruments to analyse the surface material including a [[mass spectrometer]].<ref name=DSC73/> The coast stage, or bus, carried a [[magnetometer]], plasma traps, cosmic ray and micrometeoroid detectors, stereo antennae, and an instrument to study [[proton]] and [[electron]] [[flux]]es from the [[Sun]].<ref name=DSC73/>

Built by Lavochkin, Mars 7 was the second of two 3MP spacecraft launched to Mars in 1973, having been preceded by [[Mars 6]]. Two orbiters, [[Mars 4]] and [[Mars 5]], were launched earlier in the 1973 Mars launch window and were expected to relay data for the two landers. However, Mars 4 failed to enter orbit, and Mars 5 failed after a few days in orbit.

== Launch ==
Mars 7 was launched by a Proton-K carrier rocket with a Blok D upper stage, flying from Baikonur Cosmodrome Site 81/24.<ref name=LL/> The launch occurred at 17:00:17 UTC on 9 August 1973, with the first three stages placing the spacecraft and upper stage into a [[low Earth orbit|low Earth]] [[parking orbit]] before the Blok D fired to propel Mars 7 into heliocentric orbit bound for Mars. The spacecraft performed a course correction on 16 August 1973.<ref name=DSC73/>

Mars 7's lander separated from the flyby bus on 9 March 1974. Initially, it failed to separate. However, it was eventually released to begin its descent. Due to a retrorocket failure, the probe missed the atmosphere of Mars, and, instead of landing, flew past along with the coast stage, with a closest approach of {{convert|1300|km|mi|abbr=on}}.<ref name=DSC73/> Known faults with the spacecraft's [[transistor]]s were blamed for the failure, along with that of Mars 4.<ref name=DSC73/>

{{Clear}}

==See also==
* [[List of missions to Mars]]
* [[Timeline of artificial satellites and space probes]]

==References==
{{Reflist|refs=

<ref name="beyond">{{cite book
| url= https://www.nasa.gov/sites/default/files/atoms/files/beyond-earth-tagged.pdf
| title= Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016
| author1= Asif A. Siddiqi
| publisher= [[NASA]]
| edition= second
| year= 2018
| isbn= 978-1-626-83043-1 }}
</ref>

<ref name="DSC73">{{cite book
| url= https://science.nasa.gov/wp-content/uploads/2023/09/DSC_monograph24.pdf
| author1= Asif A. Siddiqi
| title= Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000
| year= 2002
| publisher= [[NASA]]
| pages= 101–106
| id= NASA-SP-2002-4524
| isbn= 978-1-780-39324-7 }}
</ref>

<ref name="LL">{{cite web
| url= https://planet4589.org/space/gcat/data/derived/launchlog.html
| title= Launch Log
| author1= Jonathan McDowell
| work= Jonathan's Space Page
| access-date= 12 April 2013 }}
</ref>

<ref name="nssdc1">{{cite web
| url= https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1973-053A
| title= Mars 7
| website= nssdc.gsfc.nasa.gov
| publisher= [[NASA]]
| access-date= 12 April 2013 }}
</ref>

<ref name="skyrocket1">{{cite web
| author1= Gunter D. Krebs
| url= https://space.skyrocket.de/doc_sdat/mars-73-lander.htm
| title= Mars 6, 7 (Mars M73 Lander #1, #2)
| work= Gunter's Space Page
| access-date= 13 April 2013 }}
</ref>

}}

{{Portal bar|Spaceflight|Solar System}}
{{Mars programme}}
{{Orbital launches in 1973}}
{{Mars spacecraft}}

{{Use British English|date=January 2014}}
{{Use dmy dates|date=January 2014}}

[[Category:Spacecraft launched in 1973]]
[[Category:1973 in spaceflight]]
[[Category:1973 in the Soviet Union]]
[[Category:Mars program]]
[[Category:Derelict satellites in heliocentric orbit]]
[[Category:4MV]]