NASA's New Horizons spacecraft has taken the first true color photograph of Pluto and its largest moon Charon – all while speeding toward the dwarf planet at four kilometres a second (8,950 miles per hour).
The pictures were taken from around 115 million kilometres (71 million miles) away and so are somewhat blobby to say the least. They were snapped by the probe's 6cm telescope, called Ralph after the spouse-threatening Mr Kramden in The Honeymooners; the sensor is a bank of seven charge-coupled devices to get color shots of the objects.
"Scientific literature is filled with papers on the characteristics of Pluto and its moons from ground based and Earth orbiting space observations, but we’ve never studied Pluto up close and personal,” said John Grunsfeld, associate administrator of the NASA Science Mission Directorate.
“In an unprecedented flyby this July, our knowledge of what the Pluto system is really like will expand exponentially and I have no doubt there will be exciting discoveries."
The New Horizons probe set off nine years ago (when Pluto was still classified as a planet), and so far has travelled more than three billion miles to get into position to take the shot. The craft is the fastest human-made object to leave Earth's orbit, and picked up extra speed thanks to a gravity-assist flyby of Jupiter. It will whizz past Pluto on July 14 this year.
"This is pure exploration; we’re going to turn points of light into a planet and a system of moons before your eyes!” said Alan Stern, the New Horizons principal investigator from the Southwest Research Institute in Texas. “This 21st century encounter is going to be an exploration bonanza unparalleled in anticipation since the storied missions of Voyager in the 1980s.”
As the probe flies by, the Ralph telescope should be able to pick up ground features on Pluto and Charon, as well as the dwarf planet's other four moons. The spacecraft also has a larger monochrome camera for detail, as well as spectrometers, an ion analyzer, and a dust analysis unit.
The probe also carried a more unusual piece of cargo – human remains. Pluto was discovered by American astronomer Clyde Tombaugh in 1930, and New Horizons will carry an ounce of his ashes past his discovery, and out into the rest of the universe.
We can expect to get much better pictures of Pluto as the probe approaches, although getting them back to Earth is a slow and arduous process. Due to the huge distances involved, the probe can only send back data at a about 1Kbps, and the signal takes more than four hours to get back to Earth.
Once past Pluto, the probe will explore the rest of the Kuiper Belt. NASA is using the Hubble telescope to scout out a possible route to other objects of interest, and the craft should be able to send data back for up to a decade to come. ®