MV and MV entry probes

The second and third generations of OKB-1 probes saw continued development of the engineering subsystems needed to fly a spacecraft in interplanetary space reliably. The Venus and Mars probes were both based on the same generic design. A cruise/flyby spacecraft carried instrumentation for cruise science and either an entry probe ('descent apparatus') for in situ atmospheric measurements, or a remote sensing payload ('special compartment') for flyby observations.

Failures during launch, Earth escape or cruise meant that none of these probes returned data from another world, however, they were the first that are known to have carried scientific experiments destined for the atmospheres of Venus and Mars. Spherical in shape, they were attached to the flyby spacecraft by metal straps. These were to release the entry probe shortly before arrival. The probes

Figure 16.1 Venera IVA.

were designed to deploy a parachute system and transmit one-way data direct to Earth. Their design subsequently evolved into that of the successful Venera 4-8 probes.

Six 2MV probes were launched between August and November 1962; however, only Mars 1, carrying a remote sensing payload, left Earth orbit. Those carrying entry probes to Venus were type 2MV-1, while those carrying entry probes for Mars were type 2MV-3. The 2MV-2 and 2MV-4 craft were for Venus and Mars flybys, respectively. Interestingly, the design of the 2MV-3 entry probes assumed that the Martian atmosphere was much denser than the thin atmosphere later confirmed by the Mariner 4 flyby. It thus had a ballistic coefficient much too high

Target Objectives

Prime contractor Launch site, vehicle

Venus Venus Mars

In situ measurements of the atmospheres and surfaces of

Venus and Mars OKB-1

Baikonour, Molniya 8K78

Launch date Arrival date

Landing site co-ordinates End(s) of mission(s) Entry mass (kg) Payload experiments

Delivery architecture Thermal aspects Power aspects Communications architecture EDL architecture

Landing speed(s) Active operations

(deployments, etc.) Key references

Sputnik 19 (2MV-1) 25/08/1962

Sputnik 20 (2MV-1) 01/09/1962

Sputnik 24 (2MV-3) 04/11/1962

Failed to leave Earth orbit - 350

• Chemical gas analysers (Florenskii, Andreichikov)

• Anti-coincidence gamma-ray counter using gas-discharge tubes (Lebedinskii, Krasnopolskii)

• Mercury-switch movement counter (Lebedinskii, Krasnopolskii)

Delivery by flyby spacecraft Unknown Primary battery One-way DTE

0.9 m diameter, spherical ablative aeroshell and 3-stage parachute system Unknown Unknown

Perminov, 1999; Kurt, 1994; Maksimov, 1997; Johnson, 1979; Semenov, 1994; Varfolomeyev, 1998

to decelerate to a speed slow enough for safe parachute release, and would in fact have plummeted to the Martian surface at high speed.

Nine 3MV probes were launched between November 1963 and November 1965, to perform Mars and Venus (Venera) missions as well as interplanetary probe test (Zond) flights. Although one 3MV was lost in a launch failure, three failed to leave Earth orbit, and none returned data from Mars or Venus, the five remaining 3MV craft were partially successful in gaining valuable experience in the development and operation of spacecraft in interplanetary space. For example, Zond 3 returned images of the lunar far side, improving on those that had been returned by Luna 3 in 1959. Venera 3, and its flyby sibling Venera 2, were both lost shortly before arrival at Venus. Following the 3MV spacecraft, responsibility for the unmanned lunar and planetary probes was transferred to OKB-301, later the Babakin Space Centre of NPO Lavochkin.

Figure 16.2 shows a 2MV-1 or 2MV-3 craft (left) and a 3MV-3 (Venera 3) (right). The earlier 3MV-1 craft (e.g. Zond 1) were probably around 70 kg lighter, lacking modifications such as the large optical-baffle assembly seen on Venera 3.

Target Objectives

Prime contractor Launch site, vehicle

Launch date Arrival date

Landing site co-ordinates End(s) of mission(s)

Entry mass (kg) Payload experiments

Venus

In situ measurements of the atmosphere and surface of Venus OKB-1

Baikonour, Molniya 8K78M

Cosmos 27 (3MV-1) 27/03/1964

Failed to leave Earth orbit

Zond 1

Lost during cruise

Venera 3 (3MV-3) 16/11/1965 01/03/1966 unknown

Lost during cruise (only 17 days before arrival) 337

T, P, density sensors (Mikhnevich) G8-I & G8-II chemical gas analysers (Florenskii, Andreichikov (Surkov??)) Anti-coincidence gamma-ray counter using STS-5 gas-discharge tubes (Lebedinskii or Avdiushin?) Airglow photometer (Lebedinskii, Krasnopolskii) Micro-organism detection experiment? (unflown proposal?)

Delivery architecture Thermal aspects Power aspects Communications architecture EDL architecture

Landing speed(s) Active operations

(deployments, etc.) Key references

Delivery by flyby spacecraft Unknown Primary battery One-way DTE

0.9 m diameter, spherical ablative aeroshell and parachute system Unknown Unknown

Marov and Grinspoon, 1998; Hunten et al., 1983; Perminov, 1999; Kurt, 1994; Maksimov, 1997; Johnson, 1979; Semenov, 1994

Figure 16.2 2MV (left) and 3MV (right) craft with entry probes.
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