Today the Space Race is widely viewed poignantly and fondly as a race to the Moon that culminated with Apollo 11 “winning” the Race for the United States. In fact, it encompassed a much broader range of competition between the Soviet Union and the United States that affected everything from military technology to successfully launching satellites that could land on Mars or orbit other planets in the Solar System.

In fact, the Soviet Union had spent much of the 1950s leaving the United States in its dust (and rocket fuel). President Eisenhower and other Americans who could view Soviet rockets in the sky were justifiably worried that Soviet satellites in orbit could soon be spying on them, or, even worse, dropping nuclear bombs on them. And in 1960, when Eisenhower’s administration began planning and funding for the famous Apollo program that would land the first men on the Moon in 1969, the Soviet Union was already thinking further ahead, literally. In one of the worst kept secrets of the Space Race, the Soviet Union launched two probes, Korabl 4 and Korabl 5, toward Mars in October 1960.

Even had the Soviet Union managed to keep the probes a secret, it wouldn’t have mattered because both probes fell out of the sky before reaching Earth’s orbit. The Soviets’ rocket systems had failed, which would be a recurring problem for them throughout the 1960s.

Several years before Mariner 9’s successful orbiting mission, NASA had begun designing missions for unmanned landings on Mars that would use a spacecraft consisting of an orbiter module and a landing module. The design of the modular spacecraft came from NASA’s successful use of a similar spacecraft delivery system for the Apollo program’s manned missions to the Moon.

Both Viking landers were huge successes just for landing on Mars and transmitting data, but they would end up exceeding NASA’s wildest expectations. NASA hoped the Viking missions would provide better images of Mars’ surface and the ability to determine the chemistry and biology of the soil, which might indicate signs of life. The Viking missions ended up providing an extremely comprehensive overview of the Martian surface and atmosphere.

The Viking orbiters successfully orbited around Mars thousands of times, taking thousands of pictures, looking for signs of water in the atmosphere, and thermally mapping the heat on Mars’ surface. Most importantly, the orbiters’ pictures indicated wide, deep valleys on the surface, which was strong evidence of water. Both orbiters continued to transmit their data and the landers’ data for a few years before running out of fuel. The Viking landers were even more successful. Both Viking landers functioned on Mars’ surface for several years, successfully analyzing Martian soil, analyzing Mars’ weather and atmosphere, searching for life, and taking pictures from the surface.