Zond 1 was launched from an earth orbiting platform Tyazheliy Sputnik (64-016A) towards Venus. It flew by Venus on July 19, 1964, at a distance of 100,000 km and entered a heliocentric orbit. The announced mission objectives were space research and testing of onboard systems and units. Communications from the spacecraft had failed on May 24, 1964.
Spacecraft and Subsystems
Zond 1 was part of the Soviet 3MV-1 series of satellites, and consisted of a main spacecraft bus and a lander. The total mass was 948 kg, of which 290 kg was the lander. The spacecraft was 3.6 m tall and 1.1 m in diameter. The main spacecraft carried a radiation detector, cosmic ray detector, magnetometer, ion detector, atomic hydrogen detector, charged particle detector, and micrometeorite detector. The lander had its own suite of instruments: temperature, density, and pressure sensors; barometer, thermometer, radiation detector; micro-organism detector; atmospheric composition experiment; acidity measurement instrument; electrical activity detector; luminosity detector; and photometer. Propulsion for mid-course corrections was provided by a KDU-414 rocket burning UDMH and nitric acid with 200 kg thrust. Attitude control was via a set of pressurized nitrogen thrusters. Gyroscopes and star, Sun, and Earth trackers were used for orientation. The spacecraft also had a bank of electric ion thrusters. Power was provided by 4 meter span solar panels charging a 14 volt, 112 amp/hr system. Communications were via a 2 meter diameter high-gain antenna with transmissions at 922.76 MHz. There was also a 1-meter band receiver.
Although originally described as a "deep-space engineering test", Zond 1 was clearly intended as a Venus flyby and lander. After insertion into Earth parking orbit on 2 April 1964, the spacecraft was launched from a Tyazheliy Sputnik platform towards Venus. It made a trajectory correction on 3 April when it was only 560,000 km from Earth. The early correction probably indicated an error in its initial exit from Earth orbit. Within a week it was discovered that the pressurized inner compartment was leaking, probably through a crack in a welded seam or a glass covering of one of the sensors. The internal pressure had dropped to 1 mb, resulting in short-circuits in some of the electronics including the radio transmitter. The ion engines were turned on, but did not fire evenly and were turned off. Communications were failing, but ground control worked out a way to communicate through the lander and control the spacecraft. A second trajectory correction of 50 m/s was made on 14 May at a distance of 14 million km, which put Zond 1 on a course to pass within about 100,000 km of Venus on 19 July, but communication was lost on 24 May. The silent spacecraft passed Venus and went into heliocentric orbit.
Spacecraft image for illustrative purposes - not necessarily in the public domain.