Follow Voyager's Epic Interstellar Mission Online

The twin deep-space exploring spacecraft Voyager 1 and 2 continue their travel where nothing from Earth has flown before, and are now on the verge of leaving our Solar System for interstellar space! In the 34th year after their 1977 launches, they each are much farther away from Earth and the Sun than Pluto. Voyager 1 and 2 are now in the "Heliosheath" - the outermost layer of the heliosphere where the solar wind is slowed by the pressure of interstellar gas. Both spacecraft are still sending scientific information about their surroundings through the Deep Space Network (DSN).

This data can now be followed live online on the Voyager home page, where a gauge tracks levels of two of the three key signs scientists believe will appear when the spacecraft leave our solar neighborhood and enter interstellar space. When the three signs are verified, scientists will know that one of the Voyagers has hurtled beyond the magnetic bubble the sun blows around itself, which is known as the heliosphere.

The gauge indicates both the level of fast-moving charged particles coming from outer space, and the level of slower-moving charged particles (both are mainly protons), from inside the heliosphere. If the level of outside particles jumps dramatically and the level of inside particles drops precipitously, and these two levels hold steady, that means one of the spacecraft is closing in on the edge of interstellar space. These data are updated every six hours.

Scientists then need only see a change in the direction of the magnetic field to confirm that the spacecraft has sailed beyond the breath of the solar wind and finally arrived into the vast cosmic ocean between stars.

Voyager 1 is now exactly 18,462,319,287 kilometers away from Earth, about 123 times the distance between our planet and the Sun (123 AU, astronomical units) and is believed to be within the last region before interstellar space, which scientists have called "the magnetic highway." Inside particles are zooming out and outside particles are zooming in. However, Voyager 1 has not yet seen a change in the direction of the magnetic field, so the consensus among the Voyager team is that it has not yet left the heliosphere.

Voyager 2, the longest-operating spacecraft, but not as distant as Voyager 1, does not yet appear to have reached the magnetic highway, though it has recently seen some modest drops of the inside particle level.

The mission objective of the Voyager Interstellar Mission (VIM) is to extend the NASA exploration of the solar system beyond the neighborhood of the outer planets to the outer limits of the Sun's sphere of influence, and possibly beyond. Penetration of the heliopause boundary between the solar wind and the interstellar medium will soon allow measurements to be made of the interstellar fields, particles and waves unaffected by the solar wind.