Mars 4 (), also known as 3MS No.52S was a

Soviet The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

spacecraft intended to explore Mars. A 3MS spacecraft launched as part of the

Mars program The Mars program was a series of uncrewed spacecraft launched by the Soviet Union between 1960 and 1973. The spacecraft were intended to exploration of Mars, explore Mars, and included planetary flyby, flyby probes, Lander (spacecraft), landers an ...

me, it was intended to enter orbit around Mars in 1974. However, computer problems prevented orbital insertion from occurring.

Spacecraft

The Mars 4 spacecraft carried an array of instruments to study Mars. In addition to cameras, it was equipped with a radio telescope, an IR

radiometer A radiometer or roentgenometer is a device for measuring the radiant flux (power) of electromagnetic radiation. Generally, a radiometer is an infrared radiation detector or an ultraviolet detector. Microwave radiometers operate in the micro ...

, multiple

photometer A photometer is an instrument that measures the strength of electromagnetic radiation in the range from ultraviolet to infrared and including the visible spectrum. Most photometers convert light into an electric current using a photoresistor, ...

polarimeter A polarimeter is a scientific instrument used to measure optical rotation: the angle of rotation caused by passing linearly polarized light through an Optical activity, optically active substance. Some chemical substances are optically active, ...

s, a

magnetometer A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, ...

, plasma traps, an electrostatic analyzer, a

gamma-ray spectrometer A gamma-ray spectrometer (GRS) is an instrument for measuring the distribution (or spectrum—see Gamma spectroscopy#Scintillation detectors, figure) of the intensity of gamma radiation versus the energy of each photon. The study and analysis of ...

, and a radio probe. Built by Lavochkin, Mars 4 was the first of two 3MS spacecraft launched to Mars in 1973, being followed by

Mars 5 Mars 5 (), also known as 3MS No.53S was a Soviet spacecraft launched to explore Mars. A 3MS spacecraft launched as part of the Mars programme, it successfully entered orbit around Mars in 1974. However, it failed a few weeks later. Spacecraft ...

. 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 Mars 6 (), also known as 3MP No.50P was a Soviet Union, Soviet spacecraft launched to explore Mars. A 3MP bus spacecraft launched as part of the Mars program, it consisted of a lander, and a coast stage with instruments to study Mars as it flew p ...

and

Mars 7 Mars 7 (), also known as 3MP No.51P was a Soviet spacecraft launched in 1973 to explore Mars. A 3MP bus spacecraft which comprised the final mission of the Mars programme, it consisted of a lander and a coast stage with instruments to study Mars ...

, were launched during the 1973 window.

Launch

Mars 4 was launched by a Proton-K carrier rocket, a Blok D upper stage, flying from Baikonur Cosmodrome Site 81/23. The launch occurred at 19:30:59 UTC on 21 July 1973, with the first three stages placing the spacecraft and upper stage into a low Earth

parking orbit A parking orbit is a temporary orbit used during the launch of a spacecraft. A launch vehicle follows a trajectory to the parking orbit, then coasts for a while, then engines fire again to enter the final desired trajectory. An alternative trajec ...

before the Blok D fired to propel Mars 4 into heliocentric orbit bound for Mars. Shortly after performing a course correction on 30 July 1973, two onboard computers failed, leaving Mars 4 unable to perform maneuvers. As a result of this, it was unable to enter orbit around Mars. Twelve photographs were taken on 10 February 1974 from 15:32 UTC to 15:38 UTC as the probe flew past Mars with a closest approach of at 15:34 UTC.Siddiqi, Asif A. (2016). Beyond Earth: A Chronicle of Deep Space Exploration 1958-2016, NASA History Program Office, http://www.nasa.gov/ebooks.

Scientific Instruments

Mars 4 orbiter carried 15 scientific instruments on board to study Mars from orbital trajectory * Atmospheric Radio-probing Instrument *

Radio Telescope A radio telescope is a specialized antenna (radio), antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky. Radio telescopes are the main observing instrument used in radio astronomy, which studies the r ...

Infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...

Radiometer * Spectrophotometer * Narrow-band

Photometer A photometer is an instrument that measures the strength of electromagnetic radiation in the range from ultraviolet to infrared and including the visible spectrum. Most photometers convert light into an electric current using a photoresistor, ...

* Narrow-band Interference- Polarization Photometer * Imaging System *

s * Two

Polarimeter A polarimeter is a scientific instrument used to measure optical rotation: the angle of rotation caused by passing linearly polarized light through an Optical activity, optically active substance. Some chemical substances are optically active, ...

s * Ultraviolet Photometer * Scattered

Solar Radiation Sunlight is the portion of the electromagnetic radiation which is emitted by the Sun (i.e. solar radiation) and received by the Earth, in particular the visible light perceptible to the human eye as well as invisible infrared (typically p ...

Photometer * Gamma Spectrometer *

Magnetometer A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, ...

* Plasma Traps * Multichannel Electrostatic Analyzer

References

{{Use dmy dates, date=May 2020 1973 in the Soviet Union Spacecraft launched in 1973 1973 in spaceflight Mars program Derelict satellites in heliocentric orbit 4MV Non Earth orbiting satellites of the Soviet Union

Spacecraft

Launch

Scientific Instruments

See also

References