 | |
| Mission type | Mars orbiter[1] |
|---|---|
| Operator | Soviet space program |
| COSPAR ID | 1973-049A  |
| SATCAT no. | 6754 |
| Mission duration | 7 months and 3 days |
| Spacecraft properties | |
| Spacecraft | 3MS No.53S |
| Manufacturer | Lavochkin |
| Launch mass | 3,440 kilograms (7,580 lb)[2] |
| Start of mission | |
| Launch date | 25 July 1973, 18:55:48 (1973-07-25UTC18:55:48Z) UTC[3] |
| Rocket | Proton-K/D |
| Launch site | Baikonur 81/24 |
| End of mission | |
| Last contact | 28 February 1974 (1974-03-01) |
| Orbital parameters | |
| Reference system | Areocentric[4] |
| Periareon altitude | 1,760 kilometres (1,090 mi) |
| Apoareon altitude | 32,586 kilometres (20,248 mi) |
| Inclination | 35.3° |
| Period | 24.88 hours |
| Epoch | 12 February 1974 |
| Mars orbiter | |
| Orbital insertion | 12 February 1974, 15:45 UTC[5] |
|
← Mars 4
Mars 6 →
| |
Mars 5 (Russian: Марс-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.[5]
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.[6] The Three cameras were a 52mm Vega, a 350mm Zulfar and a panoramic camera.[7]
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.
Mars 5 was launched by a Proton-K carrier rocket with a Blok D upper stage, flying from Baikonur Cosmodrome Site 81/24.[3] 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 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.[6]
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 periapsis of 1,760 kilometres (1,090 mi), an apoapsis of 32,586 kilometres (20,248 mi), and 35.3 degrees inclination.[5][6]
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.[6] The probe's original planned lifetime in Mars orbit had been three months.[8] 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 rocks on Earth.[8] The exact ratios of the elements varied with the age of the surface.[8] Mars 5's Infrared radiometer reported a daytime surface temperature of between −44 and −2 °C (−47 and 28 °F).[7][8] Night time temperatures were measured at −73 °C (−99 °F).[8]
The probe also made a number of observations of Mars's atmosphere.[8] It found an ozone layer at an altitude of 30 kilometres (19 mi) and observed clouds.[8]
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