1959: The space probe Luna 3 takes the first photographs of the far side of the moon.

The radio-controlled Luna 3 was part of the Soviet Union’s highly successful lunar program, which completed 20 missions to the moon between January 1959 and October 1970.

Although the United States won the race to land a human on the moon, the Russians achieved a number of their own lunar milestones, including the first flyby (Luna 1), first surface impact (Luna 2), first soft landing (Luna 9) and first lunar orbiter (Luna 10).

Luna 3’s mission objective was to provide the first photographs from the moon’s far side. To achieve this, the probe was equipped with a dual-lens 35mm camera, one a 200mm, f/5.6 aperture, the other a 500mm, f/9.5. The photo sequencing was automatically triggered when Luna 3’s photocell detected the sunlit far side, which occurred when the craft was passing about 40,000 miles above the lunar surface.

Luna 3’s camera took 29 photographs over a 40-minute period, covering roughly 70 percent of the moon’s far side. The photographs were developed, fixed and dried by the probe’s onboard film processing unit. Seventeen images were successfully scanned and returned to Earth on Oct. 18, when Luna 3 was in position to begin transmitting.

Although the low-resolution images had to be boosted by computer enhancement on Earth, in the end they were good enough to produce a tentative map of the far side, no longer dark to human knowledge. Among the identifiable features were two seas, named Mare Moscovrae (Sea of Moscow) and Mare Desiderii (Sea of Dreams), and mountain ranges that differed starkly from those on the side of the moon facing Earth.

Contact with Luna 3 was lost Oct. 22, and its ultimate fate remains unknown. It may have burned up in Earth’s atmosphere in March or April 1960, or it may have survived in orbit as late as 1962.

Source: NASA

Photo: Though taken Oct. 7, 1959, the first image of the far side of the moon was not transmitted back to Earth until 11 days later. (Courtesy NASA)

This article first appeared on Wired.com Oct. 7, 2008.