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| Space on May 18, 2010

What is the most distant human object from Earth?

The most distant human object from Earth is a spacecraft named Voyager 1, now over 16 billion kilometers – 10 billion miles – away from home.

The most distant man-made object from Earth is the spacecraft Voyager 1, which in 2010 is over 16 billion kilometers – 10 billion miles – away from Earth. This spacecraft was launched in 1977, and continues to travel away from both the Earth and sun.

Voyager 1 has passed Jupiter, Saturn, Uranus and Neptune – and their moons – and revealed details about these worlds that no one had imagined. In 1989, the Voyager left the planets behind. Another spacecraft named Voyager 2 followed close behind.

Here is a wonderful collection from images taken by the Voyager 1 spacecraft as it journeyed outward in our solar system. These six narrow-angle color images were made from the first ever ‘portrait’ of the solar system taken by Voyager 1, when it was more than 4 billion miles from Earth. These blown-up images, left to right and top to bottom are Venus, Earth, Jupiter, and Saturn, Uranus, Neptune. Mercury is too close to the sun to be seen. Mars was not detectable by the Voyager cameras due to scattered sunlight in the optics, and Pluto was not included in the mosaic because of its small size and distance from the sun. Earth appears to be in a band of light because it coincidentally lies right in the center of the scattered light rays resulting from taking the image so close to the sun.

EarthSky spoke to Ed Stone of NASA about the Voyager spacecraft. He is Project Scientist for the Voyager mission.

Stone said both Voyager spacecraft were designed back in the early 1970s. At that time, no spacecraft had gone as far as Saturn, which was a four-year journey – already a major leap. Saturn is ten times as far from the sun as Earth is. Stone said, “We built spacecraft with enough redundancy – that is backup systems – so that they could keep going.”

And keep going they did! The Voyagers have now been traveling for 33 years. Space scientists have slowly but surely been switching to Voyager’s backup systems.

Stone added that, eventually, the two Voyagers won’t have enough power to keep all of their instruments going. “We will have to shut them off probably,” he continued, “but what we will do is not shut them off permanently, but cycle between the instruments, so that we will continue to sample the full range of what’s measured out there.”

Today, Voyager 1 and Voyager 2 continue to explore the environment of space. Both are currently traveling through the heliosheath, a region of space where solar wind is slowed by interstellar gas.

The heliosheath is at the outer limits of what’s known as the heliosphere. The word “helios” is an ancient Greek word for “sun.” The heliosphere is the outermost region of the sun’s influence. It’s like a “bubble” blown in space by charged particles being thrown off by our sun. (These particles are better known as solar wind.) Our sun and planets are inside this bubble, and outside is interstellar space, or the space between the stars.

Our heliosphere, and the sun and planets inside it, travel through interstellar space at about 26 kilometers – about 16 miles – per second.

No human – or human-made object – has ever visited the edge of the heliosphere. But two spacecraft – the Voyagers 1 and 2 – are expected to pass through this “bubble” soon.

Afterwards, the spacecraft will reach interstellar space – the space between stars. According to NASA, both Voyagers have enough fuel and electricity to run through the year 2020.

In April of 2010, however, NASA announced that Voyager 2 was having some difficulty reporting its science data. Ed Stone believes this problem might be the result of a flipped bit switch, which prevents certain data from being properly formatted and/or stored.

Experts say it may be difficult to repair the craft – even with radio signals – because of its current distance from Earth. Time will tell, but these two spacecraft – Voyagers 1 and 2 – already have their place in history as true pioneers in our solar system.