The 3MV planetary probe (short for 3rd generation Mars-Venus) is a designation for a common design used by early Soviet unmanned probes to

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

and

Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...

. It was an incremental improvement of earlier

2MV The 2MV planetary probe (short for 2nd generation Mars-Venus) is a designation for a common design used by early Soviet uncrewed probes to Mars and Venus. It was an incremental improvement of earlier 1MV probes and was used for the Venera 5 an ...

probes and was used for

Zond 1 Zond 1 was a spacecraft of the Soviet Zond program. It was the second Soviet research spacecraft to reach Venus, although communications had failed by that time. It carried a spherical landing capsule, containing experiments for chemical analy ...

Zond 2 Zond 2 was a Soviet space probe, a member of the Zond program, and was the sixth Soviet spacecraft to attempt a flyby of Mars. (See Exploration of Mars) It was launched on November 30, 1964 at 13:12 UTC onboard Molniya 8K78 launch vehicle fro ...

and

Zond 3 Zond 3 was a 1965 space probe which performed a flyby of the Moon far side, taking 28 quality photographs. It was a member of the Soviet Zond program while also being part of the Mars 3MV project. It was unrelated to Zond spacecraft designed f ...

missions to Mars as well as several

Venera The Venera (, 'Venus') program was a series of space probes developed by the Soviet Union between 1961 and 1984 to gather information about the planet Venus. Thirteen probes successfully entered the Venusian atmosphere, including the two ...

probes. It was standard practice of the Soviet space program to use standardized components as much as possible. All probes shared the same typical characteristics and differed usually in equipment necessary for specific missions. Each probe also incorporated improvements based on experience with earlier missions.

Original design (1963-1965)

The probe consisted of three primary parts.

Orbital Compartment

The core of the stack was a pressurized compartment called the Orbital Compartment. This part housed the spacecraft's control electronics, radio transmitters and receivers, batteries, astro-orientation equipment, and so on. The compartment was pressurized to around 100

kPa The pascal (symbol: Pa) is the unit of pressure in the International System of Units (SI). It is also used to quantify internal pressure, stress, Young's modulus, and ultimate tensile strength. The unit, named after Blaise Pascal, is an SI ...

and thermally controlled to simulate earth-like conditions, which removed the need for special electronic components that could reliably operate in extreme conditions (on

the module depressurized in flight, severely damaging the probe's systems). Mounted on the outside of the Orbital Compartment were two

solar panels A solar panel is a device that converts sunlight into electricity by using photovoltaic (PV) cells. PV cells are made of materials that produce excited electrons when exposed to light. These electrons flow through a circuit and produce direct ...

which supplied power to the spacecraft. They were folded against the body of the probe during launch and were only deployed when the craft was already on its interplanetary trajectory. On the ends of each solar panel was a hemispherical

radiator A radiator is a heat exchanger used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in cars, buildings, and electronics. A radiator is always a ...

which radiated excess heat from the orbital compartment into space through a coolant loop. Also mounted on the Orbital Compartment was a 2 m parabolic high-gain antenna, used for long-range communications. Depending on the mission, the probe also used other antennas (for example, for communication with probes on the planet's surface).

Planetary Compartment

Below the Orbital Compartment was a second pressurized compartment called the Planetary Compartment. Depending on the mission the Planetary Compartment either housed scientific equipment for orbital observation of the planet or was designed to detach and land on the planet's surface.

Engine

Course correction capabilities were provided by a

KDU-414 The KDU-414 (''Russian Корректирующая Двигательная Установка'', Corrective Propulsion Unit), is a pressure-fed liquid rocket Propulsion Unit developed and produced by the Isayev Design Bureau (today known as ...

engine attached to the top of the Orbital Compartment. It provided a maximum thrust of around 2 kN and used

UDMH Unsymmetrical dimethylhydrazine (abbreviated as UDMH; also known as 1,1-dimethylhydrazine, heptyl or Geptil) is a chemical compound with the formula H2NN(CH3)2 that is primarily used as a rocket propellant. At room temperature, UDMH is a colorle ...

and

nitric acid Nitric acid is an inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but samples tend to acquire a yellow cast over time due to decomposition into nitrogen oxide, oxides of nitrogen. Most com ...

as propellants. Attitude control was achieved by several small

cold gas thruster A cold gas thruster (or a cold gas propulsion system) is a type of rocket engine which uses the expansion of a (typically inert) pressurized gas to generate thrust. As opposed to traditional rocket engines, a cold gas thruster does not house any co ...

s. The whole stack was 3.6 m high and weighted around 1000 kg.

NPO Lavochkin version (1967-1972)

In 1965, a few months before his death, OKB-1 Chief Designer

Sergei Korolev Sergei Pavlovich Korolev (14 January 1966) was the lead Soviet Aerospace engineering, rocket engineer and spacecraft designer during the Space Race between the United States and the Soviet Union in the 1950s and 1960s. He invented the R-7 Sem ...

switched over the role of Space Probe design and construction to aviation manufacturer NPO Lavochkin. Many changes were made to the 3MV, which began receiving the new designation system used by Lavochkin, the first one being V-67 (Venus 1967). This included the removal of the Radiator spheres on the ends of the solar panels, replaced by the use of antennas as a radiator, increasing the size of the panels. The probe was also heavier than the previous

Venera 3 Venera 3 ( meaning ''Venus 3'') was a Venera program space probe that was built and launched by the Soviet Union to explore the surface of Venus. It was launched on 16 November 1965 at 04:19 UTC from Baikonur, Kazakhstan, USSR. The probe comp ...

. This was due to the change in Soviet thinking of the possible temperature of Venus, with this leading to the V-67 lander being strengthened (although still not strong enough) for the expected harsher environment. It was also equipped with an

ablative heat shield Atmospheric entry (sometimes listed as Vimpact or Ventry) is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. Atmospheric entry may be ''uncontrolled entr ...

.* After Venera 4's failure to reach the surface of Venus intact, the next 3MV probes (

Venera 5 Venera 5 ( meaning ''Venus 5'') was a space probe in the Soviet space program ''Venera'' for the exploration of Venus. Venera 5 was launched towards Venus to obtain atmospheric data. The spacecraft was very similar to Venera 4 although it was ...

and 6) were strengthened again, this time to withstand a 450-g (compared to the 300-g entry of Venera 4) re-entry due to the 1969 launch window's higher velocity. The V-70 design took this further, with the capsule being slightly more egg-shaped. It was designed to survive 150 atmospheres and 540°C (1004°F). The Parachute was also changed to the heavier weight and the lander was set to -8°C before detaching from the 3MV bus. Due to these changes, Venera-7 became the first spacecraft to land on Venus, and another planet successfully. The final version of the 3MV bus, the V-72 probes, were launched in early 1972, with one failing to reach Venus (

Kosmos 482 Kosmos 482 ( meaning ''Cosmos 482'') was an attempted Soviet Venus probe. Launched 31 March 1972, at 04:02:33 UTC, it failed to escape low Earth orbit. Because of this, its name was retrospectively changed to " Kosmos" which was used for Ear ...

which was still orbiting Earth as of 2011). The 3MV was superseded by the newer 4V-1 probes beginning in 1975 with

Venera 9 Venera 9 (), manufacturer's designation: 4V-1 No. 660, was a Soviet uncrewed space mission to Venus. It consisted of an orbiter and a lander. It was launched on June 8, 1975, at 02:38:00 UTC and had a mass of . The orbiter was the first sp ...

and 10, based on the M-71/73 probes (Mars-2-7).

Variants

* Venera 3MV-1A:

Kosmos 21 Kosmos 21 ( meaning ''Cosmos 21'') was a Soviet spacecraft. This mission has been tentatively identified by NASA as a technology test of the Venera series space probes. It may have been an attempted Venus impact, presumably similar to the later ...

(3MV-1 No.1), 3MV-1A (failure) * Venera 3MV-1:

Zond 3MV-1 No.2 Zond 3MV-1 No.2 (or No. 4A ), also known as Venera 1964A in the West, was a Soviet spacecraft, which was launched in 1964 as part of the Zond program. Due to a problem with its carrier rocket third stage, it failed to reach low Earth orbit. La ...

(failure),

Kosmos 27 Kosmos 27 ( meaning ''Cosmos 27''), also known as Zond 3MV-1 No.3 was a space mission intended as a Venus impact probe. The spacecraft was launched by a Molniya 8K78 carrier rocket from Baikonur. The Blok L stage and probe reached Earth orbit ...

(3MV-1 No.3),

(3MV-1 No.4)) * Mars 3MV-4A:

(3MV-4A No.2),

(3MV-4A No.3) * Venera 3MV-4:

Venera 2 Venera 2 ( meaning ''Venus 2''), also known as 3MV-4 No.4 was a Soviet spacecraft intended to explore Venus. A 3MV-4 spacecraft launched as part of the Venera programme, it failed to return data after flying past Venus. Venera 2 was launched ...

(3MV-4 No.4),

Kosmos 96 Kosmos 96 ( meaning ''Cosmos 96''), or 3MV-4 No.6, was a Soviet spacecraft intended to explore Venus. A 3MV-4 spacecraft launched as part of the Venera programme, Kosmos 96 was to have made a flyby of Venus. However, due to a launch failure, it ...

(3MV-4 No.6) * Venera 3MV-3:

(3MV-3 No.1), Venera 3MV-3 * Venera 3V (V-67):

Venera 4 Venera 4 (), also designated 4V-1 No.310, was a probe in the Soviet Venera program for the exploration of Venus. The probe comprised a lander, designed to enter the Venusian atmosphere and parachute to the surface, and a carrier/ flyby space ...

(V-67 No. 310),

Kosmos 159 Kosmos 159 (, meaning ''Cosmos 159''), E-6LS No.111, was one of many satellites designed during the Soviet space program given the designation Kosmos. This satellite was specifically designed to be a high orbit satellite used to gain informatio ...

(V-67 No.311) * Venera 3V (V-69)

(V-69 No. 330),

Venera 6 Venera 6 (' meaning ''Venus 6''), or 2V (V-69) No.331, was a Soviet spacecraft, launched towards Venus to obtain atmospheric data. It had an on-orbit dry mass of . The spacecraft was very similar to Venera 4 although it was of a stronger desi ...

(V-69 No. 331) * Venera 3V (V-70):

Venera 7 Venera 7 () was a Soviet spacecraft, part of the Venera series of probes to Venus. When it landed on the Venusian surface on 15 December 1970, it became the first spacecraft to soft land on another planet and the first to transmit data from the ...

(V-70 No.630),

Kosmos 359 Kosmos 359 was an unmanned Soviet probe launched on 22 August 1970. The probe's intended purpose was to explore Venus, but an error caused the final-stage rocket to malfunction. This left the craft trapped in an elliptical orbit around Earth for ...

(V-70 No.631) * Venera 3V (V-72):

Venera 8 Venera 8 ( meaning ''Venus 8'') was a probe in the Soviet Venera program for the exploration of Venus and was the second robotic space probe to conduct a successful landing on the surface of Venus. Venera 8 was a Venus atmospheric probe and la ...

(V-72 No.670),

(V-72 No.671)

References

"The Mystery of Zond 2"
by Andrew Lepage, EJASA, April 1991, retrieved on January 21, 2012

by Anatoly Zak, July 2007, retrieved on December 2, 2007

by Anatoly Zak, August 2007, retrieved on December 2, 2007 Soviet Mars missions Soviet Venus missions Soviet space probes {{USSR space probes