Voyager 2 then journeyed to Uranus and Neptune. It remains the only spacecraft to fly by these two outer planets. Voyager 1 used Saturn as a gravitational slingshot to catapult itself toward the edge of the solar system.
“Time after time, Voyager revealed unexpected – kind of counterintuitive – results, which means we have a lot to learn,” said Stone, Voyager’s chief scientist and a professor of physics at the California Institute of Technology.
These days, a handful of engineers diligently listen for the Voyagers from a satellite campus not far from the NASA Jet Propulsion Laboratory, which built the spacecraft.
The control room, with its cubicles and carpeting, could be mistaken for an insurance office if not for a blue sign overhead that reads “Mission Controller” and a warning on a computer: “Voyager mission critical hardware. Please do not touch!”
There are no full-time scientists left on the mission, but 20 part-timers analyze the data streamed back. Since the spacecraft are so far out, it takes 17 hours for a radio signal from Voyager 1 to travel to Earth. For Voyager 2, it takes about 13 hours.
Cameras aboard the Voyagers were turned off long ago. The nuclear-powered spacecraft, about the size of a subcompact car, still have five instruments to study magnetic fields, cosmic rays and charged particles from the sun known as solar wind. They also carry gold-plated discs containing multilingual greetings, music and pictures – in the off chance that intelligent species come across them.
Since 2004, Voyager 1 has been exploring a region in the bubble at the solar system’s edge where the solar wind dramatically slows and heats up. Over the last several months, scientists have seen changes that suggest Voyager 1 is on the verge of crossing over.
When it does, it will be the first spacecraft to explore between the stars. Space observatories such as the Hubble and Spitzer space telescopes have long peered past the solar system, but they tend to focus on far-away galaxies.
As ambitious as the Voyager mission is, it was scaled down from a plan to send a quartet of spacecraft to Jupiter, Uranus, Neptune and Pluto in what was billed as the “grand tour” of the solar system. But the plan was nixed, and scientists settled for the Voyager mission.
American University space policy expert Howard McCurdy said it turned out to be a boon.
They “took the funds and built spacecraft robust enough to visit all four gas giants and keep communicating” beyond the solar system, McCurdy said.
The double missions so far have cost $983 million ((euro) 782.15 million) in 1977 dollars, which translates to $3.7 billion ((euro) 2.94 billion) now. The spacecraft have enough fuel to last until around 2020.<< previous 1 2