Editing Mars 5

{{Short description|Soviet orbiter mission to Mars (1973–1974)}}
{{Infobox spaceflight
| name                  = Mars 5
| image                 = Mars 4-5.jpg
| image_size            = 300px

| mission_type          = [[Mars]] orbiter<ref>{{cite web|url=http://space.skyrocket.de/doc_sat/ip_probe.htm|title=Interplanetary Probes|work=Gunter's Space Page|first=Gunter|last=Krebs|access-date=12 April 2013}}</ref>
| operator              = Soviet space program
| COSPAR_ID             = 1973-049A
| SATCAT                = 6754
| mission_duration      = {{time interval|25 Jul 1973|28 Feb 1974|sep=,}}
| spacecraft            = [[3MS]] No.53S
| manufacturer          = [[NPO Lavochkin]]
| launch_mass           = {{cvt|3440|kg|lb}}<ref>{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1973-049A|title=Mars 5|access-date=6 December 2018}}</ref>

| launch_date           = {{start-date|25 July 1973, 18:55:48|timezone=yes}}&nbsp;UTC<ref name="LL">{{cite web|url=http://planet4589.org/space/log/launchlog.txt|title=Launch Log|first=Jonathan|last=McDowell|work=Jonathan's Space Page|access-date=12 April 2013}}</ref>
| launch_rocket         = [[Proton-K]]/[[Blok D|D]]  
| launch_site           = [[Baikonur Cosmodrome|Baikonur]] [[Baikonur Cosmodrome Site 81|81/24]]
| last_contact          = {{end-date|28 February 1974}}
| launch_contractor     = [[Khrunichev State Research and Production Space Center|Khrunichev]]

| orbit_epoch           = 12 February 1974
| orbit_reference       = [[Areocentric orbit|Areocentric]]<ref name="EA">{{cite web |url=http://www.astronautix.com/m/marsm-73.html|title=Mars M-73|author1=Mark Wade|publisher=Encyclopedia Astronautica|access-date=27 May 2024}}</ref>
| orbit_periapsis       = {{convert|1760|km}}
| orbit_apoapsis        = {{convert|32586|km}}
| orbit_inclination     = 35.3°
| orbit_period          = 24.88 hours
| apsis                 = areon

|interplanetary         = 
 {{Infobox spaceflight/IP
   |type                = orbiter
   |object              = [[Mars]]
   |orbits              = 
   |arrival_date        = 12 February 1974, 15:45&nbsp;UTC<ref name="NSSDC"/>
 }}

| programme             = '''[[Mars program]]'''
| previous_mission      = [[Mars 4]]
| next_mission          = [[Mars 6]]
}}

'''Mars 5''' ({{Langx|ru|Марс-5}}), also known as '''3MS No.53S''' was a [[Soviet Union|Soviet]] spacecraft launched to explore Mars. A 3MS spacecraft launched as part of the [[Mars program]]me, it successfully entered orbit around Mars in 1974. However, it failed a few weeks later.<ref name="NSSDC">{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1973-049A|title=Mars 5|publisher=US National Space Science Data Centre|access-date=12 April 2013}}</ref>

== Spacecraft ==
The Mars 5 spacecraft carried an array of instruments to study Mars. In addition to cameras, it was equipped with a radio telescope, an IR radiometer, multiple photometers, polarimeters, a [[magnetometer]], plasma traps, an electrostatic analyser, a [[gamma-ray spectrometer]], and a radio probe.<ref name="DSC73">{{cite book|url=https://history.nasa.gov/monograph24/1973.pdf |archive-url=https://web.archive.org/web/20040925103513/http://history.nasa.gov/monograph24/1973.pdf |archive-date=2004-09-25 |url-status=live|last=Siddiqi|first=Asif A.|title=Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000|series=Monographs in Aerospace History, No. 24|year=2002|publisher=NASA History Office|chapter=1973|pages=101–106}}</ref> The Three cameras were a 52mm Vega, a 350mm Zulfar and a panoramic camera.<ref name=Harvey154>{{cite book |last=Harvey |first=Brian |date=2007 |title=Russian Planetary Exploration History, Development, Legacy and Prospects  |publisher=Springer-Praxis |page=154 |isbn=9780387463438}}</ref>

Built by Lavochkin, Mars 5 was the second of two 3MS spacecraft launched to Mars in 1973, following [[Mars 4]]. A 3MS was also launched during the 1971 launch window as [[Kosmos 419]]. However, due to a launch failure, it failed to depart Earth orbit.
In addition to the orbiters, two 3MP lander missions, [[Mars 6]] and [[Mars 7]], were launched during the 1973 window.

== Launch ==
Mars 5 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 18:55:48 UTC on 25 July 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 5 into [[heliocentric orbit]] bound for Mars.

The spacecraft performed course correction manoeuvres on 3 August 1973 and 2 February 1974.<ref name="DSC73" />

==Mars orbit==

The probe reached Mars on 12 February 1974. At 14:44:25 the spacecraft's engines ignited to begin its orbit insertion burn, which successfully placed it into an Areocentric orbit with a [[apsis|periapsis]] of {{convert|1760|km}}, an [[apsis|apoapsis]] of {{convert|32586|km}}, and 35.3 degrees [[orbital inclination|inclination]].<ref name="NSSDC"/><ref name="DSC73"/>

The spacecraft's pressurised instrument compartment began to leak as soon as the spacecraft entered orbit around Mars, which controllers believed to be the result of a micrometeoroid impact during orbital insertion. It ceased operations on 28 February, having returned 180 photographic frames, 43 of which were of usable quality.<ref name="DSC73"/> The probe's original planned lifetime in Mars orbit had been three months.<ref name=Harvey161>{{cite book |last=Harvey |first=Brian |date=2007 |title=Russian Planetary Exploration History, Development, Legacy and Prospects  |publisher=Springer-Praxis |pages=161–165 |isbn=9780387463438}}</ref> The probe's gamma ray spectrometer measured the uranium, thorium and potassium content of the surface the probe passed over and found they were similar to [[igneous rock]]s on Earth.<ref name=Harvey161 /> The exact ratios of the elements varied with the age of the surface.<ref name=Harvey161 /> Mars 5's Infrared radiometer reported a daytime surface temperature of between {{convert|-44|and|-2|C}}.<ref name=Harvey154 /><ref name=Harvey161 />  Night time temperatures were measured at {{convert|-73|C}}.<ref name=Harvey161 /> 

The probe also made a number of observations of Mars's atmosphere.<ref name=Harvey161 /> It found an ozone layer at an altitude of {{convert|30|km}} and observed clouds.<ref name=Harvey161 />

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

== References ==
{{reflist|2}}

{{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:1973 in spaceflight]]
[[Category:1973 in the Soviet Union]]
[[Category:Derelict satellites orbiting Mars]]
[[Category:Mars program]]
[[Category:Spacecraft launched in 1973]]
[[Category:4MV]]
[[Category:Non Earth orbiting satellites of the Soviet Union]]