The latest images from Nasa’s New Horizons Pluto mission are helping engineers fine tune the spacecraft’s approach to the icy dwarf planet.
The probe is still three months away from a close encounter, but new photos show it is already in viewing range though Pluto still looks like little more than a bright dot in colour images released by Nasa.
But with no fuel for a braking burn to put itself into orbit around Pluto after a five billion km journey that started in January 2006, the spacecraft will make its observations on the fly so the images are providing a vital roadmap for control teams tweaking New Horizon's approach.
Calculations to orient the spacecraft and its science instruments are based on knowing the exact time and location that New Horizons passes Pluto. Engineers are using the latest views to refine their knowledge of the dwarf planet’s location and navigate the probe towards a precise target point 12,500 km from the surface.
"Our team has worked hard to get to this point, and we know we have just one shot to make this work," Alice Bowman, New Horizons mission operations manager at the Johns Hopkins University Applied Physics Laboratory, said in a statement.
"We've plotted out each step of the Pluto encounter, practiced it over and over, and we're excited the 'real deal' is finally here."
The spacecraft has a suite of seven science instruments, including cameras, spectrometers, and plasma and dust detectors, that will allow it to map the geology of Pluto and its primary moon Charon.
During its flyby on 14 June the spacecraft will also map the two bodies' surface compositions and temperatures; examine Pluto’s atmosphere and search for one around Charon; study Pluto’s smaller satellites; and look for rings and additional satellites around Pluto.
The probe will collect 100 times as much data on close approach as it can send home before flying away. Although the spacecraft will send high-priority datasets home in the days just before and after close approach, the mission will continue returning data stored in on-board memory for a full 16 months.
New Horizons is the fastest spacecraft ever launched and has travelled further than any previous space mission to reach its primary target.
Since blasting off, Pluto has been demoted from the ninth planet in the solar system to dwarf planet status after the discovery of similar icy bodies in eccentric, distant orbits around the sun, but the mission will complete humankind’s initial reconnaissance of the classical solar system.
After close-up studies of Pluto and its five known satellites, the probe will continue out into the Kuiper Belt, a region peppered with what are believed to be frozen remnants from the formation of the solar system some 4.6 billion years ago.
“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, New Horizons principal investigator from Southwest Research Institute in Boulder, Colorado.
“New Horizons is flying to Pluto – the biggest, brightest and most complex of the dwarf planets in the Kuiper Belt. This 21st century encounter is going to be an exploration bonanza unparalleled in anticipation since the storied missions of Voyager in the 1980s.”
The team plans to petition Nasa for additional funds for a flyby of a second Kuiper Belt object in 2019.