3MV

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 and Venus. It was an incremental improvement of earlier 2MV probes and was used for Zond 1, Zond 2 and Zond 3 missions to Mars as well as several Venera probes. It was standard practice of the Soviet space program to use standardized components as much as possible. All probes shared the same general characteristics and differed only in equipment necessary for specific missions. Each probe also incorporated improvements based on experience with earlier missions.

Design

The probe consisted of three primary parts: 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 and thermally controlled to simulate earth-like conditions, which removed the need for special electronic components that could reliably operate in extreme conditions (on Zond 1 the module depressurized in flight, severely damaging the probe's systems).