Zond 1
Soviet Venus probe that lost contact before flyby.
Zond 1 was a Soviet spacecraft of the Zond program and the second Soviet research spacecraft to reach Venus, though communications had failed by that time. It carried a 90 cm spherical landing capsule with experiments for atmospheric chemical analysis, gamma-ray measurements of surface rocks, a photometer, temperature and pressure gauges, and a motion/rocking sensor for water landings. An experimental ion thruster was also carried for evaluation.
Quick Facts
- Names list
- Zond 3MV-1 No. 4
- Operator
- OKB-1
- Satcat
- 00785
- Mission duration
- April 2, 1964 02:40, May 24, 1964
- Spacecraft bus
- 3MV-1
- Launch mass
- 948 kg / 2,090 lb
- Dry mass
- 290 kg / 639 lb
- Dimensions
- 3.6 m / 11 ft 10 in tall / 1.1 m / 3 ft 7 in diameter
Facts from the source article.
Spacecraft design
Zond 1 was a 3MV design, the second generation interplanetary Soviet bus, improving on the 2MV design used for earlier Mars and Venus missions. The launch vehicle was the new 8K78M Molniya, an improved version of the 8K78 Molniya whose Block-L upper stage had caused failures in previous interplanetary missions. Two solar panels provided about 4 square meters of surface area, with hemispherical radiators at their ends for thermal control. A 2-meter high-gain directional antenna was placed on the anti-sun side, and various low-gain antennas provided omnidirectional communications.
Mission
The spacecraft was launched on April 2, 1964, from Tyuratam, and the launch vehicle performed flawlessly. During the first communications session, ground controllers detected a leak letting air escape from the pressurized orbital compartment, which housed electronics requiring pressurization to function; Soviet electronics used vacuum tubes that would overheat without cooling air. The leak was traced to a bad weld near the quartz window for the star and Sun sensors, and the compartment would depressurize completely in one week. A mid-course correction on April 3 succeeded. By April 9, pressure was undetectable, so ground controllers routed signals through redundant transmitters on the lander. On May 14, a second mid-course correction cut off prematurely, achieving only 30 m/s of the designed 50 m/s, causing the spacecraft to miss Venus by 100,000 km. An ill-timed command turned on the radio system while rarefied atmosphere remained, causing electronics to short out by corona discharge. By mid-April, main spacecraft electronics had failed, but communication via the lander continued, and space radiation and atomic-hydrogen spectrometer measurements were received. The experimental ion thruster attitude control system operated erratically, possibly due to pressure loss. One star tracker's glass cover cracked, forcing spin-stabilization. Communication was maintained until mid-June, a month before the Venus flyby, but all communications had failed by May 24. Zond 1 passed 100,000 km from Venus on July 14, 1964.
More in Space Probes of ESA, Japan, China, India and the USSR
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