Mission Type: Impact
Launch Vehicle: 8K78 (no. L1-7)
Launch Site: Tyuratam (Baikonur Cosmodrome), NIIP-5 / launch site 1, USSR
Spacecraft Mass: c. 645 kg
Spacecraft Instruments: 1) three-component magnetometer; 2) variometer and 3) charged-particle traps
References:
Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, Monographs in Aerospace History No. 24, by Asif A. Siddiqi
National Space Science Data Center, http://nssdc.gsfc.nasa.gov/

This mission was the first attempt to send a spacecraft to Venus. Original intentions had been to send the 1V spacecraft to take pictures of the Venusian surface, but this proved to be far too ambitious a goal. Engineers instead downgraded the mission and used the 1VA spacecraft for a simple Venus atmospheric entry. The 1VA was essentially a modified 1M spacecraft used for Martian exploration.

The spacecraft contained a small globe containing various souvenirs and medals commemorating the mission. This flight was also the first occasion on which the Soviets used an intermediate Earth orbit to launch a spacecraft into interplanetary space.

Although the booster successfully placed the probe into Earth orbit, the fourth stage (the Blok L) never fired to send the spacecraft to Venus. A subsequent investigation showed that there had been a failure in the PT-200 DC transformer that ensured power supply to the Blok L guidance system. The system had evidently not been designed to work in a vacuum. The spacecraft + upper-stage stack reentered Earth's atmosphere on 26 February 1961. The Soviets announced the total weight of the combination as 6,483 kilograms.