Today in the history of astronomy, the first interplanetary mission reveals our inaccessible companion planet.
Although its twin probe, Mariner 1, was destroyed shortly after launch, Mariner 2 (seen in this artist’s illustration) successfully reached Venus. Credit: NASA/JPL
- Mariner 1 and 2, twin spacecraft developed from the Ranger lunar probe and equipped with seven instruments, were designed for a joint mission to Venus; However, on July 22, 1962, Mariner 1 failed due to rocket failure just minutes after launch.
- Mariner 2 was successfully launched on August 27, 1962, and during its 110-day, 293 million kilometer journey to Venus, it confirmed the existence of the solar wind.
- On December 14, 1962, Mariner 2 conducted the first successful interplanetary mission, making a 42-minute flyby of Venus at a distance of approximately 34,000 kilometers.
- Scientific data from Mariner 2 indicate that Venus has a cold atmosphere, a dense and highly pressurized atmosphere, and an extremely hot surface with an absence of a magnetic field, which collectively characterize an inhospitable atmosphere.
Developed together, the twin Mariner 1 and 2 spacecraft were based on the Ranger lunar probes and were planned for a joint mission to our nearest neighbor planet. The probe consisted of seven instruments to study Venus’s atmosphere, temperature, and magnetic field. Mariner 1 launched on July 22, 1962, but the spacecraft was destroyed minutes after its first flight when its rocket veered off course. However, the launch of Mariner 2 on August 27 was successful and it headed for Venus. (Along the way, it confirmed the existence of the solar wind, proposed by Eugene Parker in 1958.)
Ultimately, after a journey of 110 days and 182 million miles (293 million kilometers), the spacecraft reached Venus. On December 14, 1962, it carried out the first successful interplanetary mission, flying approximately 21,000 miles (34,000 km) and scanning the planet for 42 minutes. Among other data, Mariner 2 showed that Venus was extremely hot, with heat coming from its surface, although its atmosphere remained cool. Mariner 2 also revealed that Venus’s atmosphere was much denser and more pressurized than Earth’s. These conditions, as well as the lack of a magnetic field, showed that Venus was inaccessible.
