NASA's 10 Greatest Achievements

The Juno Spacecraft, a Trip to Jupiter
This model of the Juno spacecraft was shown at a news briefing at California's Jet Propulsion Laboratory before Juno entered orbit around Jupiter on June 30, 2016. NASA

In 1972, NASA's Pioneer 10 probe became the first manmade object to pass through the asteroid belt. Upon making it across, the spacecraft again broke new ground when it took the unprecedented step of observing a so-called outer planet — in this case, Jupiter [source: Laboratory for Atmospheric and Space Physics].

Now another probe is checking out the gas giant. Launched from the Cape Canaveral Air Force Station on Aug. 5, 2011, Juno's mission is to study various aspects of Jupiter, including the planet's gravitational fields and tempestuous atmosphere. The probe finally reached the colossal planet on July, 4, 2016. En route, Juno set a new spacefaring record. A trio of 30-foot (9 meter) solar arrays power this magnificent craft. On Jan. 13, 2016, Juno found itself 493 million miles (793 million kilometers) away from the sun. No other solar-powered spacecraft has ever traveled such a great distance [source: Jet Propulsion Laboratory].

The probe is currently orbiting the gas giant in an elliptical fashion, taking a route that brings it within about 2,600 miles (4,200 kilometers) of the tops of Jupiter's clouds. Juno has made some mind-boggling discoveries so far. For example, thanks to data it's collected, we now know that Jupiter's iconic bands aren't just surface-level decorations; the jet streams that drive them can run at least 1,864 miles (3,000 kilometers) deep [source: Georgiou].

Another spacecraft, launched two years before Pioneer 10, did something even more compelling. Instead of navigating the asteroid belt or interrogating Jupiter, it saved a human crew that could've been forever lost in space.

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