http://photos.state.gov/libraries/amgov/3234/Week_1/09072012_Neptune-from-Vyger-1-300.jpg

Voyager 1 sent back this photo of Neptune, taken from about 5,000 kilometers away.

Washington — Humankind sent two emissaries on a distant journey 35 years ago, and the most exciting chapter is just about to begin.

The Voyager spacecraft — 1 and 2 — left the launch pad and began a trip through the solar system in late August 1977 and early September 1977. The two craft have each earned superlatives as they approach interstellar space. Voyager 2, launched first in August 1977, is the longest-operating spacecraft ever. Voyager 1 is the most distant object ever sent from Earth.

The two craft also provided the first views humans ever had of the distant neighbors of our system.

“Voyager results turned Jupiter and Saturn into full, tumultuous worlds, their moons from faint dots into distinctive places, and gave us our first glimpses of Uranus and Neptune up close,” said Ed Stone, the Voyager project scientist and a physics professor at the California Institute of Technology in Pasadena, the institution which is home to NASA's Jet Propulsion Laboratory (JPL).

 

The images returned by these craft include the tipped magnetic poles of Uranus and Neptune, geysers on Neptune’s frozen moon Triton, the volcanoes of Jupiter’s moon Io, and the hazy Saturn moon Titan.

“We continue to listen to Voyager 1 and 2 nearly every day,” said Suzanne Dodd, the Voyager project manager at JPL. “The two spacecraft are in great shape for having flown through Jupiter’s dangerous radiation environment and having to endure the chill of being so far away from our sun.”

Dodd and her team keep the craft flying toward interstellar space by carefully managing the use of power from their diminishing energy sources. The team calculates that the two spacecraft will have enough energy to continue data collection and transmission to Earth through 2020 and possibly through 2025.

The actual boundary between our solar system and space is not clearly defined, but, for several years, data from the craft have recorded their voyage through a turbulent region of charged particles. Now scientists are seeing a prevalence of high-energy particles streaming into Voyager’s paths from outside the solar system, and a lower level of energy particles originating from inside our solar system. The team is analyzing data on the direction of the magnetic field, which they predict will change when the vehicles cross into interstellar space.

The Voyagers carry some interesting and carefully planned cargo on their mission that is aimed at introducing other life forms to the people of planet Earth. Each craft carries an object known as the Golden Record, a 30-centimeter, gold-plated copper disc inscribed with sounds and images selected to portray the diversity of life and culture on Earth. They may one day tell the story of humanity and our world to extraterrestrials.