NASA's spacecraft, New Horizons, which is set to travel close to Pluto next year, has just successfully passed Neptune's orbit. This is its last big object to cross before it reaches Pluto on July 14, 2015. In a bit of history, this is also the 25th anniversary of NASA's Voyager 2 craft's encounter with Neptune. The Voyager 2 reached Neptune of August 25, 1989.
"It's a cosmic coincidence that connects one of NASA's iconic past outer solar system explorers, with our next outer solar system explorer," said Jim Green, who directs NASA's Planetary Science Division at the NASA Headquarters in Washington. "Exactly 25 years ago at Neptune, Voyager 2 delivered our 'first' look at an unexplored planet. Now it will be New Horizons' turn to reveal the unexplored Pluto and its moons in stunning detail next summer on its way into the vast outer reaches of the solar system."
The New Horizons craft is about as large as a piano. It will be the first spacecraft to reach close to Pluto. The ship left Earth in January 2006, beginning an epic voyage to reach Pluto, one of the farthest celestial bodies in our solar system. So far, as of today, New Horizons has traveled almost 2.75 billion miles to reach Neptune. New Horizons took eight years and eight months to reach the planet, breaking the record for time. Voyager 2 launched in August 20, 1977 and didn't reach Neptune until August 25, 1989, twelve years later!
New Horizons is passing through Neptune's orbit at a distance of about 2.48 billion miles from the planet, but it was still able to capture some amazing photos of the planet with a wide telescopic lens on a camera. It took those photos on July 10. You can see them here.
"NASA's Voyager 1 and 2 explored the entire middle zone of the solar system where the giant planets orbit," said Alan Stern, the principal investigator of New Horizons. "Now we stand on Voyager's broad shoulders to explore the even more distant and mysterious Pluto system."
Some people who are working now on the New Horizons as senior members also worked on Voyager 2 in 1989, and they remember the excited feeling of the approach of Neptune back then. Many of them are equally excited for New Horizons to approach Pluto in the year to come.
"The feeling 25 years ago was that this was really cool, because we're going to see Neptune and Triton up-close for the first time," said Ralph McNutt, a New Horizons science team member who also worked on the Voyager team. "The same is happening for New Horizons. Even this summer, when we're still a year out and our cameras can only spot Pluto and its largest moon as dots, we know we're in for something incredible ahead."
McNutt said that we don't know what we will see next year when New Horizons is able to take close-up photos of Pluto, giving us a close look at the planet for the very first time. However, he says that we will know enough to expect to be "very surprised".