Editing Mars 2

{{Short description|Soviet orbiter and lander mission to Mars (1971–1972)}}
{{Use dmy dates|date=May 2020}}
{{other uses|Mars II (disambiguation)}}
{{more citations needed|date=May 2014}}
{{Infobox spaceflight
| name                  = Mars 2

<!--image of the spacecraft/mission-->
| image                 = Mars3 iki.jpg
| image_size            = 300px

<!--Basic details-->
| mission_type          = [[Mars]] orbiter/lander
| operator              = Soviet space program
| COSPAR_ID             = {{COSPAR|1971-045A}}<br>{{COSPAR|1971-045D}}
| SATCAT                = 5234<br>5739
| mission_duration      = {{time interval|19 May 1971|22 Aug 1972}}

<!--Spacecraft properties-->
| spacecraft_type       = [[4MV|4M]] No. 171
| manufacturer          = [[OKB-1]]
| launch_mass           = <small>Total:</small><br>{{cvt|4650|kg|lb|abbr=on}}<br><small>Orbiter:</small><br>{{cvt|3440|kg|lb}}<br><small>Lander:</small><br>{{cvt|1210|kg|lb}}<ref>{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1971-045A|title = NASA - NSSDCA - Spacecraft - Details}}</ref>
| landing_mass          = {{cvt|358|kg|lb}}
| dry_mass              = {{cvt|2265|kg|lb}}
| dimensions            = {{cvt|4.1|xx|2.0|xx|5.9|m|ft}}

<!--Launch details-->
| launch_date           = {{start-date|19 May 1971, 16:22:44|timezone=yes}}&nbsp;UTC
| 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]]

<!--end of mission-->
| disposal_type         = Decommissioned
| declared              = {{end date|1972|08|22}}
| last_contact          = July 1972<ref>See Mars 3 article in https://solarsystem.nasa.gov/resources/1060/beyond-earth-a-chronicle-of-deep-space-exploration/</ref>

<!--orbit parameters-->
<!--as science-related articles, SI units should be the principal units of measurement, however we usually use {{convert}} to display imperial units in parentheses after the initial values-->
| orbit_reference       = [[Areocentric orbit|Areocentric]]<ref name="EA">{{cite web |url=http://www.astronautix.com/m/marsm-71.html|title=Mars M-71|author1=Mark Wade|publisher=Encyclopedia Astronautica|access-date=27 May 2024}}</ref>
| orbit_periapsis       = {{cvt|1380|km|mi}}
| orbit_apoapsis        = {{cvt|24940|km|mi}} 
| orbit_inclination     = 48.9°
| orbit_period          = 18 hours
| apsis                 = areion

|interplanetary         = <!--Infobox spaceflight/IP can be called multiple times for missions with multiple targets or combined orbiter/lander missions, etc-->
 {{Infobox spaceflight/IP
   |type                = orbiter
   |object              = [[Mars]]
   |orbits              = 362
   |arrival_date        = 27 November 1971
 }}

 {{Infobox spaceflight/IP
   |type                = lander_impact
   |object              = [[Mars]]
   |arrival_date        = 27 November 1971
   |location            = {{Coord|45|S|47|E|globe:Mars|name=Mars 2 Lander impact}}
 }}

<!--Only use where a spacecraft/mission is part of a clear programme of sequential missions. 
If in doubt, leave it out-->
| programme             = '''[[Mars program]]'''
| previous_mission      = [[Kosmos 419]]
| next_mission          = [[Mars 3]]

<!--mission insignia or patch-->
| insignia              = 1972 CPA 4113.jpg
| insignia_caption      = Mars 2 stamp
}}

The '''Mars 2''' was an uncrewed [[space probe]] of the [[Mars program]], a series of uncrewed Mars [[Lander (spacecraft)|landers]] and [[orbiter]]s launched by the [[Soviet Union]] beginning 19 May 1971.

The Mars 2 and [[Mars 3]] missions consisted of identical spacecraft, each with an orbiter and an attached lander. The orbiter is identical to the [[Venera 9]] bus. The type of bus/orbiter is the [[4MV]]. They were launched by a [[Proton-K]] heavy launch vehicle with a [[Blok D]] upper stage. The lander of Mars 2 became the first human-made object to reach the surface of Mars, although the landing system failed and the lander was lost.

==Overview==
* Launch Date/Time:
** Mars 2: 19 May 1971 at 16:22:44 UTC
* Launch mass (including fuel):
** Combined: {{convert|4650|kg|lb|abbr=on}}
** Orbiter: {{convert|3440|kg|lb|abbr=on}}
** Lander: {{convert|1210|kg|lb|abbr=on}}
* On-orbit dry mass: {{convert|2265|kg|lb|abbr=on}}
* Dimensions: {{convert|4.1|m|ft|1|abbr=on}} tall, {{convert|2|m|ft|1|abbr=on}} across ({{convert|5.9|m|ft|1|abbr=on}} across with solar panels deployed)

==Launch==
On 19 May 1971, the [[Proton-K]] heavy launch vehicle launched the probe from [[Baikonur Cosmodrome]]. After the first stage separated the second stage was ignited. The third stage engine blasted Mars 2 into parking orbit, then the Blok D upper stage sent Mars 2 on the trans-Mars trajectory.

==Orbiter==
The Orbiter type was the 4MV, used also for Mars-3 and later Mars and Venera Probes. The orbiter engine performed a burn to put the spacecraft into a {{nowrap|{{convert|1380|x|24,94| km|adj=on}}}}, 18-hour orbit about Mars with an inclination of 48.9 degrees. Scientific instruments were generally turned on for about 30 minutes near periapsis.

The orbiter's primary scientific objectives were to image the Martian surface and clouds, determine the temperature on Mars, study the topography, composition and physical properties of the surface, measure properties of the atmosphere, monitor the [[solar wind]] and the interplanetary and Martian [[magnetic field]]s, and act as a communications relay to send signals from the landers to the Earth.

By coincidence, a particularly large [[Storm#Extraterrestrial storms|dust storm]] on Mars adversely affected the mission.  When [[Mariner 9]] arrived and successfully orbited Mars on 14 November 1971, just two weeks prior to Mars 2 and Mars 3, [[Planetary science|planetary scientists]] were surprised to find the [[celestial body's atmosphere|atmosphere]] was thick with "a planet-wide robe of [[dust]], the largest storm ever observed."  The surface was totally obscured.  Unable to reprogram the mission computers, both Mars 2 and Mars 3 dispatched their landers immediately, and the orbiters used up a significant portion of their available data resources in snapping images of the featureless dust clouds below, rather than the surface mapping intended.<ref name=Pyle2012-M9>
{{cite book |last=Pyle|first=Rod |title=Destination Mars |year=2012 |publisher=[[Prometheus Books]] |isbn=978-1-61614-589-7 |pages=73–78 |quote=...Mars 2 and Mars 3.  Both reached Mars shortly after Mariner 9.  Unfortunately, these Soviet ships were not reprogrammable, as was the case with Mariner 9, and rather than wait out the huge, planet-wide dust storm, they proceeded to follow their programming right on schedule.  Landers were dispatched from each, the first crashing and the second apparently reaching the surface intact but losing radio contact immediately.  The orbiters fared little better; following their simple logic, both used up their available resources snapping images of the featureless dust clouds below.}}</ref>

The Mars 2 orbiter sent back data covering the period from December 1971 to March 1972, although transmissions continued through August. It was announced that Mars 2 and Mars 3 had completed their missions by 22 August 1972, after 362 orbits. The probe, combined with Mars 3, sent back a total of 60 pictures. The images and data revealed mountains as high as {{convert|22|km}}, atomic hydrogen and oxygen in the upper atmosphere, surface temperatures ranging from {{convert|−110|to|13|C}}, surface pressures of 5.5 to 6 mbar (0.55 to 0.6 [[kilopascal|kPa]]), water vapor concentrations 5,000 times less than in the Earth's atmosphere, the base of the ionosphere starting at {{convert|80|to|110|km}} altitude, and grains from dust storms as high as {{convert|7|km}} in the atmosphere. The images and data enabled the creation of surface [[Raised-relief map|relief map]]s,<ref name=Perminov1>{{cite book|last=Perminov|first=V.G.|title=The Difficult Road to Mars - A Brief History of Mars Exploration in the Soviet Union|date=July 1999|publisher=NASA Headquarters History Division|isbn=0-16-058859-6|pages=[https://archive.org/details/difficultroadtom00perm/page/34 34–60]|url=https://archive.org/details/difficultroadtom00perm/page/34}}</ref> and gave information on Martian [[gravity]] and magnetic fields. The orbiter remains in Martian orbit.

==Lander==
[[File:Mars map Viking 1 Mars 2 Mars Pathfinder Opportunity.png|thumb|Map of Mars, showing the location of Mars 2 center left, in relation to ''[[Viking 1]]'', ''[[Mars Pathfinder]]'' and ''[[Opportunity rover|Opportunity]]'']]

===Lander spacecraft system===
[[File:FP2A3620 (23497688248) (cropped).jpg|thumb|Mars 3 Lander model at the [[Memorial Museum of Cosmonautics]] in Moscow]]
The Mars 2 descent module was mounted on the bus/orbiter opposite the propulsion system. It consisted of a spherical {{convert|1.2|m}} diameter landing capsule, a {{convert|2.9|m}} diameter conical aerodynamic braking shield, a parachute system and retro-rockets.

The entire descent module had a fueled mass of {{convert|1,210|kg}}, the spherical landing capsule accounting for {{convert|358|kg}} of this. An automatic control system consisting of gas micro-engines and pressurised nitrogen containers provided attitude control. Four "gunpowder" engines were mounted to the outer edge of the cone to control pitch and yaw.

The main and auxiliary parachutes, the engine to initiate the landing, and the radar [[altimeter]] were mounted on the top section of the lander. Foam was used to absorb shock within the descent module. The landing capsule had four triangular petals which would open after landing, righting the spacecraft and exposing the instrumentation.

The lander was equipped with two television cameras with a 360 degree view of the surface as well as a [[mass spectrometer]] to study atmospheric composition; temperature, pressure, and wind sensors; and devices to measure mechanical and chemical properties of the surface, including a mechanical scoop to search for organic materials and signs of life. It also contained a pennant with the [[State Emblem of the Soviet Union]].

Four aerials protruded from the top of the sphere to provide communications with the orbiter via an onboard radio system. The equipment was powered by batteries which were charged by the orbiter prior to separation. Temperature control was maintained through thermal insulation and a system of radiators. The landing capsule was sterilised before launch to prevent contamination of the Martian environment.

====PrOP-M rover====
{{Main|PrOP-M}}
[[File:PrOP-M.jpg|thumb|Rendering of the PrOP-M]]
Mars 2 lander had a small {{convert|4.5|kg}} [[Mars rover]] on board, which would move across the surface on skis while connected to the lander with a {{convert|15|m|adj=on}} umbilical. Two small metal rods were used for autonomous obstacle avoidance, as radio signals from Earth would take too long to drive the rovers using remote control. The rover carried a dynamic penetrometer and a radiation densitometer.<ref name=Perminov1/>

The main PrOP-M frame was a square box with a small protrusion at the center. The frame was supported on two wide flat skis, one extending down from each side elevating the frame slightly above the surface.

The rover was planned to be placed on the surface after landing by a manipulator arm and to move in the field of view of the television cameras and stop to make measurements every {{convert|1.5|m}}. The traces of movement in the Martian soil would also be recorded to determine material properties.

Because of the demise of the lander, the rover was not deployed.

===Entry, descent, and crash landing===
The descent module separated from the orbiter on 27 November 1971 about 4.5 hours before reaching Mars. After entering the atmosphere at approximately 6&nbsp;km/s, the descent system on the module malfunctioned, possibly because the angle of entry was too steep. The descent sequence did not operate as planned and the parachute did not deploy.<ref name=Perminov1/>
The descent module became the first man-made object to impact the surface of Mars. The exact crash site is unknown, but it is estimated to be at {{Coord|45|S|313|W|display=inline,title|globe:Mars}}.<ref name=Pyle2012-M9/><ref name="coord">{{cite web|url=http://www.planetary.org/explore/space-topics/space-missions/missions-to-mars.html#mars2 |title=Missions to Mars |publisher=[[The Planetary Society]]}}</ref> Attempts to contact the probe after the crash were unsuccessful.

==See also==
{{portal|Spaceflight}}
* [[List of Mars orbiters]]
* [[List of missions to Mars]]
* [[Mars 1M]]
* [[Mars program]] 
* [[Space exploration]]
* [[Timeline of artificial satellites and space probes]]
* [[Robotic spacecraft]]

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

==External links==
{{commons|Mars probe program}}
* [http://www.mentallandscape.com/C_CatalogMars.htm Catalog of Soviet Mars images]
* [http://nssdc.gsfc.nasa.gov/planetary/planets/marspage.html NASA's mars probe website]
* [https://web.archive.org/web/20071005010633/http://www.strykfoto.org/mars3.htm Ted Stryk's page on enhancing the partial photo]  
* [[s:ru:Сообщение ТАСС о посадке автоматической станции Марс-3|TASS notice on the Mars-3 landing (in Russian)]] ([[Wikisource]])
* [https://ui.adsabs.harvard.edu/abs/1990SpFl...32..273K/abstract "The Rocky Soviet Road to Mars" by Larry Klaes – EJASA October 1989]

{{Mars programme}}
{{Features and artificial objects on Mars}}
{{Orbital launches in 1971}}
{{Mars spacecraft}}

[[Category:Space program of the Soviet Union]]
[[Category:1971 in the Soviet Union]]
[[Category:Spacecraft launched in 1971]]
[[Category:Mars program]]
[[Category:Lunae Palus quadrangle]]
[[Category:Derelict satellites orbiting Mars]]
[[Category:Mars rovers]]
[[Category:Geography of Mars]]
[[Category:Non Earth orbiting satellites of the Soviet Union]]
[[Category:1971 on Mars]]