The first human-made object to fly past Saturn and also the first one to ever return the first pictures of the polar regions of Jupiter, Pioneer 11, was launched on April 6 in 1973.  Being a twin spacecraft to Pioneer 10 that was launched a year earlier,  Pioneer 11 has been one of NASA’s most ambitious missions. It has never failed to cater to us with picturesque revelations of the gas giants. Here’s a preview of what Pioneer 11 saw in its two decades of the voyage of our solar system!

An artist's concept of NASA's Pioneer 11 spacecraft. (Image: NASA)
An artist’s concept of NASA’s Pioneer 11 spacecraft. (Image: NASA)

The launch of Pioneer 11

On March 2, 1972, Pioneer 10 was launched. It became the first spacecraft to fly beyond Mars and the first to fly through the asteroid belt and zip by Jupiter. Pioneer 10’s success motivated the scientists and engineers to leap ahead, and on the same grounds, Pioneer 11 was launched. Pioneer 11 blasted off from Cape Canaveral on April 5, 1973, intending to fly three times closer to Jupiter than Pioneer 10 and also to whiz past Saturn for the first time.

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Jupiter’s voyage

Following a trajectory directed at Jupiter without any prior gravitational assists, Pioneer 11 crossed the asteroid belt in 1974 and eventually flew past Jupiter in November and December 1974. Pioneer had its closest approach with the gas giant on December 2, and it passed at 42,828 kilometers (26,612 mi) above the cloud tops at that point.

Jupiter as seen from above its north pole by Pioneer 11 in 1974. (Image: NASA)
Jupiter as seen from above its north pole by Pioneer 11 in 1974. (Image: NASA)

While passing over Jupiter,  Pioneer 11 obtained intrinsically detailed images of the giant’s Great Red Spot. The spacecraft became the pioneer in transmitting images of Jupiter’s immense polar regions. Not only this, Pioneer’s observation played a key role in determining the mass of Jupiter’s moon Callisto.

Cloud bands along the edge of Jupiter as observed by Pioneer 11
Cloud bands along the edge of Jupiter as observed by Pioneer 11

After exploring Jupiter, Pioneer 11 used the planet’s gravity as a helping hand to alter its trajectory and velocity, to eventually set itself on a five-year journey towards its most awaited target, Saturn.

The ultimate target: Saturn

After flinging through the solar system for five long years, Pioneer began its observations of the ringed beauty in late July 1979.

By now, Voyager 1 and Voyager 2 had already completed their flybys of Jupiter and were heading towards Saturn. Pioneer was expected to provide maximum support to the Voyager spacecraft by experiencing the risks that could damage them.

This image of Saturn and its largest moon Titan as taken from Pioneer 11 when it was 1,768,422 miles (2,846,000 km) from Saturn. (Image: NASA)
This image of Saturn and its largest moon Titan as taken from Pioneer 11 when it was 1,768,422 miles (2,846,000 km) from Saturn. (Image: NASA)

Going by the plan to detect the dangers, Pioneer 11 passed within 13,000 miles of Saturn’s cloud tops at a velocity of 71,000 miles per hour on September 1, 1979. Pioneer 11 took around  440 images during this encounter, thereby sending back data on Saturn’s rings and its satellites.

Pioneer’s data revealed that Saturn’s atmosphere consists mostly of liquid hydrogen. It also confirmed the fact that the planet had a magnetic field. Furthermore, Pioneer captured images of Saturn’s moon Titan that revealed the satellite as an orange cloud-shrouded globe having a global temperature of minus 315°F. Pioneer revealed that Titan was too cold to host life as we know it.

Pioneer 11 Completes 48 Years In Space: Here's What The Spacecraft Saw In Its Journey. 1
Saturn’s moon Titan

Pioneer 11 also discovered two new moons of Saturn and revealed a new ring, the F ring, orbiting Saturn outside the A ring. Moreover, Pioneer sent unique images of Titan’s rings where the rings appeared dark, and instead, the gaps in the rings appeared as bright rings.

Pioneer eventually completed its study of the ringed planet in October 1979 and went on to explore the wonders of interstellar space.

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The journey towards the center of the Milky Way

After leaving Saturn, Pioneer 11 headed itself out on a journey opposite to that of Pioneer 10. Flying through the solar system, it started traveling towards the center of the galaxy, in the direction of Sagittarius.

The spacecraft crossed Neptune’s orbit on Feb. 23, 1990, and became the fourth spacecraft to do so after Pioneer 10, Voyager 1, and 2. After exploring the solar system for about 22 years, NASA terminated its routine contact with the spacecraft on September 30, 1995. However, NASA continued to contact Pioneer for about 2 hours every once or twice a month but eventually lost final contact with the spacecraft on November 24, 1995.

Carrying a gold-anodized aluminum plaque featuring the nude figures of a human male and female along with several symbols designed to provide information about the origin of the spacecraft, Pioneer 11 is now heading in the direction of the constellation Scutum. It is expected to pass within 0.25pc of the K dwarf TYC 992-192-1 in 928,000 years.

Pioneer 11 will travel as a ghost ship in our galaxy.

– Fred Wirth, Pioneer Project Manager in 1995

Also Watch: Voyager 2 has found something strange in outer space

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