Voyager Forges a New Frontier
No spacecraft in history has gone as far or traveled as many miles as NASA's Voyager 1. During its 26 year journey Voyager was propelled into deep space with the help of Jupiter's and Saturn's gravity and is now verging on the edge of the solar system.
Voyager 1 is about 8 billion miles away from the sun traveling at a speed of about 3.6 Astronomical Units (AU), while Voyager 2 is about 6.5 AU from the sun, traveling at about 3.3 AU per year. One 'AU' equals the distance between the Sun and the Earth, or 93 million miles.
Penetration of the heliopause boundary between the solar wind and the interstellar medium will allow measurements to be made of the interstellar fields, particles and waves unaffected by the solar wind.
What's really on the other side of the solar system remains to be seen. Voyager will enter a fluid region of space known as the heliosheath, which is past the boundaries of the termination shock. This is a violent zone where interstellar gas and solar wind start to mix. It is possible that before its electrical power is exhausted, Voyager 1 will pass through the heliopause region and into interstellar space.
There's a debate going on between scientists, depending on how they've analyzed Voyager's data, about whether it has passed beyond the termination shock or not. According to Dr. Stamatios Krimigis, who argues that Voyager 1 has crossed the termination shock, scientists are going to be re-writing a lot of textbooks based on the new data. On the other hand, Dr. Frank McDonald of the University of Maryland, says that the Voyagers are on the threshold of the termination shock, but have not left the solar wind.
During the next 20 years as Voyager continues on its travels, new discoveries are bound to be made. Even after they are no longer able to communicate with Earth, the Voyagers will continue to travel the Milky Way. If discovered by alien life forms each Voyager has a 12-inch gold-plated copper disc mounted on its body. The disk has recorded sounds and images of Earth designed to portray the diversity of life and culture on the planet. Instructions explaining where the spacecraft originated and how to play the disc are engraved onto an accompanying cover.
The contents of the record selections were chosen for NASA by a committee chaired by Carl Sagan of Cornell University. Dr. Sagan and his associates assembled 115 images and a variety of natural sounds. To this they added musical selections from different cultures and eras and spoken greetings from Earth-people in fifty-five languages.
NASA's Deep Space Network, a global tracking system, will keep its antennas trained on Voyager as it speeds closer to the unknown. There's no question that Voyager will continue to make studying the Universe a fascinating subject.
For further information please visit:
NASA's Jet Propulsion Laboratory and John F. Kennedy Space Center