NASA is now two for two in regard to a huge achievement in space. Voyager 2 has become only the second man-made object to enter interstellar space, or the "space between the stars," as a release from the agency's Jet Propulsion Laboratory puts it. The first was its sister ship, Voyager 1, which crossed the boundary in 2012. Details and developments:
- Long mission: Voyager 2 launched in August of 1977 on a mission to study the outer planets in our solar system. (Voyager 1 went up about two weeks later, but on a different trajectory.) In fact, Voyager 2 is the only spacecraft to have studied the gas giants Jupiter, Saturn, Uranus, and Neptune, reports Space.com. After that part of the mission wrapped up decades ago, NASA steered the craft toward deep space.
- Still transmitting: One key difference between Voyagers 1 and 2 is that 2 still has a working instrument that is expected to provide "first-of-its-kind observations" from the journey, per JPL. The same instrument (the Plasma Science Experiment) conked out on Voyager 1 long before it crossed the boundary.
- Video: NASA scientists explain the mission and the milestone in this video.
- Where it is: Voyager 2 is now about 11 billion miles from Earth, traveling at 34,000mph, reports the BBC. Scientists say it crossed into interstellar space on Nov. 5. It had been detecting particles emitted by the sun, and the data suddenly dropped on that day.
- Left the solar system? Though some stories say the spacecraft has left the solar system, project scientist Ed Stone avoids the phrase. More specifically, the spacecraft reached the edge of what's known as the heliosphere, "the bubble of particles and magnetic fields" from our sun, per JPL. It then crossed the boundary known as the "heliopause," which "is where the tenuous, hot solar wind meets the cold, dense interstellar medium."
- Onto the Oort: Here's how NASA's JPL addresses the above issue: "While the probes have left the heliosphere, Voyager 1 and Voyager 2 have not yet left the solar system, and won't be leaving anytime soon. The boundary of the solar system is considered to be beyond the outer edge of the Oort Cloud, a collection of small objects that are still under the influence of the sun's gravity." It could take Voyager 2 another 300 years to reach the cloud and 30,000 years to go beyond it, reports CBS News.
- Power supply: Both Voyagers have a plutonium power source, which will eventually be depleted and render the onboard equipment useless. But the spacecraft themselves could last billions of years, says JPL.
(Both Voyagers carry recordings from Earth, including a Chuck Berry song