Pluto has long been a source of fascination for science – partly because, at a minimum of 4.4 billion kilometres (2.7 billion miles) at its closest orbital approach to the Sun, it has been beyond the effective reach of all but one spacecraft: Voyager 1. NASA instead opted for a close flyby of Titan (Saturn’s biggest moon), which put it beyond a compatible trajectory for Pluto.
That’s one reason why, in 2006, NASA sent the New Horizons spacecraft off to Pluto tasked with a double-reconnaissance of the dwarf planet and its largest satellite, Charon, as well as an extended mission into the most distant parts of the Solar System to investigate objects in the mysterious Kuiper Belt.
At the time of writing, New Horizons has taken its payload of scientific instruments 25 astronomical units (which is approximately 3.7 billion kilometres/2.3 billion miles) and is scheduled to begin its Pluto flyby in July 2015.
Piggybacking an Atlas V rocket (the same kind used for NASA’s Mars Reconnaissance Orbiter and Mars Science Laboratory) for launch, New Horizons achieved the fastest escape velocity ever at 57,600 kilometres (35,800 miles) per hour, on a trajectory that should see it reach Pluto around July 2015.
Among them, an instrument called ‘Ralph’ will take care of map-making, ‘Alice’ will provide atmospheric data via an ultraviolet spectrometer and REX is primarily responsible for making sure all the data collected is transmitted safely across the five light hours it takes to reach Earth from Pluto.
Deep-space dangers
Exploring the Kuiper Belt
Many short-period icy comets (those with orbital periods of less than 200 years) are thought to have originated from the Kuiper Belt, including the space rock that is suspected to have made the Chicxulub impact that triggered the dinosaur-slaying mass-extinction event 65.5 million years ago. We have very little knowledge of the Kuiper Belt and hope to get a better picture of how the Solar System formed once New Horizons has investigated it.