To Boldly Go where No Man has Gone Before

It has been twenty-six years since the Voyager spacecraft have been launches. They have traveled over eight billion miles, ninety time the distance from the Earth to the Sun. Now, scientists are debating whether these craft have become the first manmade object to leave our Solar System and head out into the final frontier.
	The Voyager spacecraft have flown farther than any manmade object. Voyager1 is now leaving the Solar System.

What is not questionable is that Voyager 1 and 2 have traveled further than any other manmade object. But scientists can't quite agree about just where the boundaries of our Solar System is. So the Voyagers may, or may not have actually headed out into that final frontier.

The boundary of the Solar System is called the termination shock and it exists somewhere between 8 and 9.5 billion miles from the Sun, far beyond the most distant planet, Pluto. It isn't a distinct boundary, just a place where the solar wind drastically slows down and meets the gas and dust of interstellar space.

For over a year the instruments on board Voyager 1 have been sending back some interesting readings. The energetic particle instruments have indicated that the spacecraft has entered a different part of space. Some scientists think that this means that Voyager 1 has passed the termination shock while others argue it has only crossed a sort of "foreshock", a turbulent region which exists just before the actual termination shock.

The fuel for the debater is that it isn't really known just where the termination zone is exactly. No spacecraft has actually been there, so we can't say just where it is. Scientists also theorize that the termination shock can expand and contract and even ripple!

If, in fact, Voyager 1 has crossed the termination shock, it will have entered a region called the heliopause, where the solar winds and interstellar winds are balanced. Voyager 1 will then be able to measure the conditions of interstellar space without the influence of the solar winds.

The debate could have been settled by using Voyager 1's solar wind detector - but unfortunately, the detector broke in 1990.

Voyager 1 and 2 were launched sixteen days apart in the summer of 1977 and were designed to explore the giant planets Jupiter and Saturn and provide the first ever close-up images of these worlds. Voyager 1 reached Jupiter in March of 1979 and Saturn in November of 1980. After passing Saturn, Voyager 1 flung itself out of the planetary plane and began its trip out of the solar system.

Initially, both spacecraft were designed to investigate Jupiter and Saturn. Later it was revealed that Voyager 2 could also slingshot around Uranus and Neptune. This was a real bonus as we had very limited information about these outer worlds. Between the two spacecraft, they have discovered twenty-two new moons around Jupiter, Saturn, Uranus and Neptune. Both also carry a gold disk containing information about Earth and the life which inhabits it.

The spacecraft are still exactly on time, being just when and where their original schedule predicted them to be! Both have adequate amounts of plutonium to continue operating until around 2020, when the electrical power generated by the craft will not be enough to keep the instruments powered. After that, they will glide between the stars, as silent ambassadors from a race hoping to reach out into the cosmos.

For more information about the Voyager missions visit: http://voyager.jpl.nasa.gov/.

For more information about the gold plaques that Voyagers carry please read the book Murmurs of Earth by the late astronomer Dr. Carl Sagan: originally published in 1978, but reissued in 1992 by Warner News Media and includes a CD-ROM that replicates the Voyager record.

Constellations

The Solar System