Missions

Launch Date	Feb. 12, 1961 | 00:34:37 UT
Launch Site	Baikonur Cosmodrome, Kazakhstan, Russia | Launch Site 1
Destination	Venus
Type	Impact
Status	Unsuccessful
Nation	Soviet Union
Alternate Names	Unnamed Venera

Goals

The Soviet Union’s second attempt to make the first scientific survey of Venus.

Accomplishments

None. Mission controllers lost contact with with the spacecraft about 20 days into the voyage. The inert spacecraft eventually passed at a distance of about 62,000 miles (100,000 kilometers) and entered heliocen­tric orbit.

In Depth

This was the second of two Venus impact probes that the Soviets launched in 1961.

This time, the probe successfully exited Earth orbit and headed toward Venus. Despite some initial problems with the solar orientation system, the spacecraft responded properly during a communica­tions session on Feb. 17, 1961 at a dis­tance of 1.2 millions mile (1.9 million kilometers).

Unfortunately, controllers were unable to regain contact during a subsequent communications attempt on February 22. A later investiga­tion indicated that the spacecraft had lost its permanent solar orientation due to a faulty optical sensor that malfunctioned because of excess heat after the spacecraft’s thermal control system failed.

The inert spacecraft eventually passed by Venus on May 19-20, 1961 at a distance of about 62,000 miles (100,000 kilometers) and entered heliocen­tric orbit.

Spacecraft

Spacecraft Instruments:

1. Electrostatic analyzer for solar plasma

2. Photoconductive particle detectors

3. Rubidium vapor magnetometer

4. Triple-coincidence cosmic-ray telescope

5. Cosmic-ray integrating ionization chamber

6. X-ray scintillation detectors

7. Micrometeoroid dust particle detectors

8. Lyman alpha scanning telescope

Selected References

Siddiqi, Asif A. Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, NASA, 2002.