The Voyager spacecraft is nearing the outer limits of the solar system and soon will be entering interstellar space. What could be cooler than that?
The spacecraft, which was launched in 1977, is now almost 11 billion miles from Earth. It is so far away from the Sun that it is no longer detecting that the solar wind is moving charged particles away from the Sun. Instead, Voyager has reached a far away region of space where the force of the solar wind has been countered by charged particles from other solar systems. The region is caused the heliopause, and it marks the end of the solar system.
Voyager is a triumph for the American unmanned space program and a testament to engineering and planning. In its 33 years of flight, the sturdy little spacecraft has successfully explored Jupiter, Saturn, Neptune, and Uranus, sending back memorable pictures of those planets and their moons and transmitting enormous amounts of new data that have dramatically increased our understanding of our home solar system.
When Voyager moves through the heliopause and continues on its journey toward the center of the Milky Way galaxy, it will become the first human-made object ever to leave our solar system. Let’s hope there will be many more.