Artist's concept of Mariner 2.
Mariner 2 was the first spacecraft to fly by another planet. The spacecraft passed within 34,762 kilometers (about 21,600 miles) of Venus, discovering the planet's slow retrograde rotation (turning the opposite direction of its orbit around our Sun).
JPL scientists display Venus data from Mariner 2
During a 42-minute scan, Mariner 2 also found the surface of Venus was obscured by perpetual cloud cover up to an altitude of 60 km (37 miles). But, using an infrared radiometer, the spacecraft detected a surface atmosphere that was hot, high pressure and comprised mostly of carbon dioxide. Interestingly, Mariner 2 found no magnetic field.
Mariner 2 also made the first direct observation of the solar wind, which at that point had been predicted but not proven to exist. The spacecraft was last heard from on Jan. 3, 1963. It is presumably still in orbit around the Sun. |