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Mars 4 (Russian: Марс-4), also known as 3MS No.52S was a Soviet spacecraft intended to explore Mars. A 3MS spacecraft launched as part of the Mars programme, it was intended to enter orbit around Mars in 1974. However, computer problems prevented orbital insertion from occurring.[4]

Mars 4

A picture of Mars 4.
Mission type	Mars orbiter[1]
Operator	Lavochkin
COSPAR ID	1973-047A
SATCAT no.	6742
Mission duration	9 days (launch day to day of last contact)
Spacecraft properties
Spacecraft	3MS No.52S
Manufacturer	Lavochkin
Launch mass	3,440 kg fully fueled[2]
Start of mission
Launch date	21 July 1973, 19:30:59 (1973-07-21UTC19:30:59Z) UTC[3]
Rocket	Proton-K/D
Launch site	Baikonur 81/23
End of mission
Last contact	10 February 1974, 15:38 UTC
Orbital parameters
Reference system	Heliocentric
Flyby of Mars (failed orbiter)
Closest approach	10 February 1974, 15:34 UTC
Distance	1,844 km (1,146 mi)

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, multiple photometers, polarimeters, a magnetometer, plasma traps, an electrostatic analyzer, a gamma-ray spectrometer, and a radio probe.[5]

Built by Lavochkin, Mars 4 was the first of two 3MS spacecraft launched to Mars in 1973, being followed by Mars 5. 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 4 was launched by a Proton-K carrier rocket, a Blok D upper stage, flying from Baikonur Cosmodrome Site 81/23.[3] 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 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 1,844 kilometres (1,146 mi) at 15:34 UTC.[6]

Scientific Instruments

Mars 4 orbiter carried 15 scientific instruments on board to study Mars from orbital trajectory[5]

• Atmospheric Radio-probing Instrument
• Radio Telescope
• Infrared Radiometer
• Spectrophotometer
• Narrow-band Photometer
• Narrow-band Interference-Polarization Photometer
• Imaging System
• Photometers
• Two Polarimeters
• Ultraviolet Photometer
• Scattered Solar Radiation Photometer
• Gamma Spectrometer
• Magnetometer
• Plasma Traps
• Multichannel Electrostatic Analyzer

See also

• List of missions to Mars
• Timeline of artificial satellites and space probes

References

На других языках

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- [en] Mars 4

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[ru] Марс-4

«Марс-4» — советская автоматическая межпланетная станция серии М-73, запущенная 21 июля 1973 года в 19:30:59 UTC по программе «Марс». Серия М-73 состояла из четырёх АМС четвёртого поколения, предназначенных для изучения планеты Марс. Космические аппараты «Марс-4» и «Марс-5» (модификация М-73С), должны были выйти на орбиту вокруг планеты и обеспечивать связь с предназначенными для работы на поверхности автоматическими марсианскими станциями. Спускаемые аппараты с автоматическими марсианскими станциями доставляли космические аппараты «Марс-6» и «Марс-7» (модификация М-73П).

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