Editing Mars 3 (section)

==Lander==
[[File:FP2A3620 (23497688248) (cropped).jpg|thumb|Mars 3 Lander model at the [[Memorial Museum of Cosmonautics]] in Moscow]]

===Lander spacecraft system===
The Mars 3 descent module was mounted on the bus/orbiter opposite the propulsion system. It consisted of a spherical 1.2 m diameter landing capsule, a 2.9 m diameter conical aerodynamic braking shield, a parachute system and [[retro-rocket]]s.

The entire descent module had a fueled mass of 1210&nbsp;kg, the spherical landing capsule accounted for 358&nbsp;kg of this. An automatic control system consisting of [[cold gas thruster|gas micro-engine]]s and pressurized nitrogen containers provided attitude control. Four solid-fuel motors 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 Soviet coat of arms.

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 sterilized 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 3 lander had a small 4.5&nbsp;kg [[Mars rover]] on board, which would move across the surface on skis while connected to the lander with a 15-meter 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 1.5 metres. The traces of movement in the Martian soil would also be recorded to determine material properties.

Due to communication loss it is unknown whether the rover was deployed.

===Entry, descent, landing, transmission, and failure===
[[File:Mars 3 surface transmission.jpg|thumb|The only result received from the camera on Mars 3 lander.]]
Mars 3's descent module was released at 09:14 UT on December 2, 1971, 4 hours 35 minutes before reaching Mars.<ref name=nssdc-2/> The descent module [[Mars atmospheric entry|entered the Martian atmosphere]] at roughly 5.7&nbsp;km/s. Through [[aerodynamic braking]], [[parachute]]s, and [[retrorocket]]s, the lander achieved a soft landing at {{Coord|45|S|202|E|display=inline,title|globe:Mars}}<ref name=NASA-20130411/> and began operations.

The lander began transmitting to the Mars 3 orbiter 90 seconds after landing.<ref name=nssdc-2/> After 20 seconds, transmission stopped for unknown reasons.<ref name=nssdc-2/> It is not known whether the fault originated with the lander or the communications relay on the orbiter. The cause of the failure may have been related to the extremely powerful dust storm taking place at the time which may have induced a [[coronal discharge]], damaging the communications system. The dust storm would also explain the poor image lighting.<ref name=Perminov1/>

A partial image (70 lines) was transmitted. According to V. G. Perminov, the lead designer for Mars and Venus spacecraft at the Lavochkin design bureau during the early days of Mars exploration, the image was "a gray background with no details".<ref name=Perminov1/>

=== Possible images of lander on Mars ===
On April 11, 2013, NASA announced that the [[Mars Reconnaissance Orbiter|''Mars Reconnaissance Orbiter'' (MRO)]] may have imaged the Mars 3 lander hardware on the surface of Mars.  The [[HiRISE]] camera on the MRO took images of what may be the parachute, retrorockets, [[heat shield]] and [[lander (spacecraft)|lander]].<ref name=NASA-20130411/> This discovery was made by amateur space enthusiasts looking through publicly available archived images.<ref name=mars3-1/><ref name=mars3-2/>
{{wide image |PIA16920-MarsSoviet3Lander1971-PossibleDebrisField.jpg|800px|align-cap=center|Candidate hardware for 1971 Soviet Mars 3 lander.  The predicted landing site was at latitude 45 degrees south, longitude 202 degrees east, in [[Ptolemaeus (Martian crater)|Ptolemaeus Crater]] (images: [[HiRISE]], [[Mars Reconnaissance Orbiter|MRO]] - November 2007/left & 10 March 2013/right).<ref name=NASA-20130411/>}}
{{clear}}