A NASA space probe has become the second craft in history to reach interstellar space

  • NASA’s Voyager 2 is the second probe in history to leave the heliosphere.
  • Traveling for 41 years to date, the craft is the agency’s longest running mission.
  • Voyager 2 will use onboard instruments to collect data on the nature of interstellar space.
This illustration shows the position of NASA's Voyager 1 and Voyager 2 probes, outside of the heliosphere, a protective bubble created by the Sun that extends well past the orbit of Pluto. Voyager 1 exited the heliosphere in August 2012. Voyager 2 exited at a different location in November 2018. 
Source:  NASA/JPL-Caltech
This illustration shows the position of NASA's Voyager 1 and Voyager 2 probes, outside of the heliosphere, a protective bubble created by the Sun that extends well past the orbit of Pluto. Voyager 1 exited the heliosphere in August 2012. Voyager 2 exited at a different location in November 2018. 

A NASA spacecraft has become only the second manmade object in history to reach interstellar space.

NASA's Voyager 2 has now exited the heliosphere – the protective bubble of particles and magnetic fields created by the Sun – the space agency announced on Monday.

The craft is now 11 billion miles from Earth, in a boundary area known as the heliopause, where it will collect ground-breaking data.

Twin probe Voyager 1 crossed into the heliopause in 2012, but its Plasma Science Experiment (PLS) instrument – which Voyager 2 will use to gather information – was no longer working.

Launched weeks before Voyager 1 in 1977, Voyager 2 was originally built to last five years and conduct studies of Jupiter and Saturn. The craft has continued to travel however and after 41 years in space, is now NASA's longest-running mission.

Mission operators can communicate with Voyager 2, but information being transmitted from the probe takes more than 16 hours to reach Earth.

"Working on Voyager makes me feel like an explorer, because everything we're seeing is new," John Richardson, principal investigator for the instrument, said in a press release. "Even though Voyager 1 crossed the heliopause in 2012, it did so at a different place and a different time, and without the PLS data. So we're seeing things that no one has seen before."

"To have the Voyagers sending back information about the edge of the sun's influence gives us an unprecedented glimpse of truly uncharted territory," said Nicola Fox, director of the Heliophysics Division at NASA.

Voyager's science team will also study data collected by three other on-board instruments — the cosmic ray subsystem, the low energy charged particle instrument, and the magnetometer — all built to give a clearer picture of the environment Voyager 2 is traveling through.

NASA has said it is preparing another mission launch in 2024 to build on the observations from both Voyager spacecrafts.

Although the probes have left the heliosphere, neither Voyagers have yet left the solar system, which NASA considers to be beyond the edge of the Oort Cloud.

The Oort Cloud is a collection of small objects influenced by the sun's gravity. NASA said this boundary could take up to 30,000 years to fly through.