Engines: The 4MV planetary probe (short for 4th-generation Mars-Venus probe) is a designation for a common design used for Soviet unmanned probes to Mars and Venus.

[1][2] The same base design was also used for earth-orbiting space observatories.

The spacecraft bus has a height of 2.8 meters (9 ft 2 in) and a solar panel span of 6.7 meters (22 ft).

The central section of the bus has a diameter of about one meter (3 ft 3 in) and contained propellant.

The main engine (KTDU-425) is encircled by a conical instrument compartment with the diameter of 2.35 meters (7 ft 9 in) at the base.