Mars 7 (Russian: Марс-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 as it flew past. Due to a malfunction, the lander failed to perform a maneuver necessary to enter the Martian atmosphere, missing the planet and remaining in heliocentric orbit along with the coast stage.
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Mission type | Mars flyby/lander[1] |
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Operator | Lavochkin |
COSPAR ID | Bus: 1973-053A Lander: 1973-053D[2] |
SATCAT no. | Bus: 6776 Lander: 7224[2] |
Mission duration | 7 months (launch to nearest approach) |
Spacecraft properties | |
Spacecraft | 3MP No.51P |
Manufacturer | Lavochkin |
Launch mass | 3,260 kg (fueled lander and bus)[2] |
Start of mission | |
Launch date | 9 August 1973, 17:00:17 (1973-08-09UTC17:00:17Z) UTC[3] |
Rocket | Proton-K/D |
Launch site | Baikonur 81/24 |
End of mission | |
Last contact | 25 March 1974[4] |
Orbital parameters | |
Reference system | Heliocentric |
Flyby of Mars | |
Spacecraft component | Bus |
Closest approach | 9 March 1974 |
Mars flyby (failed landing) | |
Spacecraft component | Lander |
Closest approach | 9 March 1974 |
Distance | 1,300 km (810 mi) |
Mars 7 spacecraft carried an array of instruments to study Mars. The lander was equipped with a thermometer and barometer to determine the surface conditions, an accelerometer and radio altimeter for descent, and instruments to analyse the surface material including a mass spectrometer.[5] The coast stage, or bus, carried a magnetometer, plasma traps, cosmic ray and micrometeoroid detectors, stereo antennae, and an instrument to study proton and electron fluxes from the Sun.[5]
Built by Lavochkin, Mars 7 was the second of two 3MP spacecraft launched to Mars in 1973, having been preceded by Mars 6. Two orbiters, Mars 4 and Mars 5, were launched earlier in the 1973 Mars launch window and were expected to relay data for the two landers. However, Mars 4 failed to enter orbit, and Mars 5 failed after a few days in orbit.
Mars 7 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 17:00:17 UTC on 9 August 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 7 into heliocentric orbit bound for Mars. The spacecraft performed a course correction on 16 August 1973.[5]
Mars 7's lander separated from the flyby bus on 9 March 1974. Initially, it failed to separate. However, it was eventually released to begin its descent. Due to a retrorocket failure, the probe missed the atmosphere of Mars, and, instead of landing, flew past along with the coast stage, with a closest approach of 1,300 km (810 mi).[5] Known faults with the spacecraft's transistors were blamed for the failure, along with that of Mars 4.[5]
Mars programme | |
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Past | |
Cancelled |
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Italics indicate failures at launch. |
← 1972 · Orbital launches in 1973 · 1974 → | |
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Luna 21 (Lunokhod 2) | Kosmos 543 | Kosmos 544 | Kosmos 545 | Kosmos 546 | Kosmos 547 | Molniya-1 No.31 | Kosmos 548 | Prognoz 3 | Kosmos 549 | Kosmos 550 | Kosmos 551 | OPS 6063 | OPS 8410 | Meteor-M No.29 | Kosmos 552 · Nauka-16KS No.2L | Salyut 2 | Molniya-2-5 | Pioneer 11 | Kosmos 553 | Kosmos 554 | Interkosmos 9 | Anik A2 | Unnamed | Kosmos 555 · Nauka-14KS No.2 | Kosmos 556 | Kosmos 557 | Skylab | OPS 2093 | Kosmos 558 | Kosmos 559 | Unnamed | Kosmos 560 | Unnamed | Skylab 2 | Kosmos 561 · Nauka-9KS No.1 | Meteor-M No.27 | Kosmos 562 | Kosmos 563 | Kosmos 564 · Kosmos 565 · Kosmos 566 · Kosmos 567 · Kosmos 568 · Kosmos 569 · Kosmos 570 · Kosmos 571 | Kosmos 572 | Explorer 49 | OPS 6157 | Kosmos 573 | Kosmos 574 | Kosmos 575 | OPS 4018 | Kosmos 576 | Unnamed | Molniya-2-6 | OPS 8261 | ITOS-E | Mars 4 | Kosmos 577 | Mars 5 | Skylab 3 | Kosmos 578 | Mars 6 | Mars 7 | OPS 8364 | Kosmos 579 | OPS 7724 | Kosmos 580 | Intelsat IV F-7 | Kosmos 581 | Kosmos 582 | Molniya-1-24 | Kosmos 583 | Kosmos 584 | Kosmos 585 | Kosmos 586 | Unnamed | Kosmos 587 | Soyuz 12 | OPS 6275 | Kosmos 588 · Kosmos 589 · Kosmos 590 · Kosmos 591 · Kosmos 592 · Kosmos 593 · Kosmos 594 · Kosmos 595 | Kosmos 596 | Kosmos 597 | Kosmos 598 | Kosmos 599 | Kosmos 600 | Kosmos 601 | Molniya-2-7 | Kosmos 602 | Explorer 50 | Kosmos 603 | Kosmos 604 | Transit-O 20 | Interkosmos 10 | Kosmos 605 | Kosmos 606 | Mariner 10 | NOAA-3 | Kosmos 607 | OPS 6630 · OPS 6630/2 · OPS 7705 | Molniya-1 No.32 | Skylab 4 | Kosmos 608 | Kosmos 609 | Kosmos 610 | Kosmos 611 | Kosmos 612 | Kosmos 613 | Molniya-1-26 | Kosmos 614 | Kosmos 615 | OPS 9433 · OPS 9434 | Explorer 51 | Kosmos 616 | Soyuz 13 | Kosmos 617 · Kosmos 618 · Kosmos 619 · Kosmos 620 · Kosmos 621 · Kosmos 622 · Kosmos 623 · Kosmos 624 | Kosmos 625 | Molniya-2-8 | Oreol 2 | Kosmos 626 | Kosmos 627 | |
Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in underline. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in (brackets). |
Spacecraft missions to Mars | ||||||||||
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Past |
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Future |
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Exploration |
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Missions are ordered by launch date. Sign † indicates failure en route or before intended mission data returned. |