After travelling for more than nine years and three billion kilometres, NASA’s New Horizons spacecraft has successfully sailed past Pluto on Tuesday. At 7:50 a.m. ET, the spacecraft swept past Pluto’s surface at a distance of about 7,706 miles, closer to the tiny world than most GPS satellites get to Earth.
The event culminated an initiative to survey the solar system that the space agency embarked upon more than 50 years ago.
New Horizons’s fly-by is hugely important because it is giving us a first glimpse into the unseen world of a third class of objects in the Kuiper belt – the building blocks of the outer solar system, located beyond the terrestrial and gas-giant planets. Fly-bys such as this are very exciting as they provide just one chance for unique measurements at the target.
New Horizons launched from Cape Canaveral atop an Atlas V rocket in 2006, after a speedy four-year construction. Prior to that, the so-called Pluto Underground spent more than 15 years trying to get NASA to greenlight the project. It was designed to complete our first look at the solar system’s original nine planets – as the term “planet” was understood then. More importantly, scientists said, it is the first effort to explore a poorly understood domain beyond the orbit of Neptune where thousands of icy bodies, some nearly as large as Pluto, harbour clues to the solar system’s formation and history.
The first indication that New Horizons succeeded in its quest was picked up by NASA’s Deep Space Network on Tuesday at about 9 p.m. ET. The signal was relayed to the mission’s operations centre at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.
Also in attendance were Alden and Annette Tombaugh, the adult children of astronomer Clyde Tombaugh, who discovered Pluto in 1930 and who died in 1997. A small quantity of his ashes are aboard New Horizons and will leave the solar system with the spacecraft, the first human remains to do so.
As planned, New Horizons’ first contact after the Pluto encounter lasted less than 20 minutes, but it allowed mission controllers to verify that the spacecraft is functioning well. Scientists hope its computer memory is loaded with data that can be reconstituted into dazzling images taken during the closest approach.
It will take about 16 months for New Horizons to transmit back all the thousands of images and measurements taken during its pass by Pluto. By then, the spacecraft will have traveled even deeper into the Kuiper Belt, heading for a possible follow-on mission to one of Pluto’s cousins.
New Horizons will never return, but its achievement has left an indelible mark – it is a historic first that mission scientists say links New Horizons directly to the golden age of the space program.