NASA snaps first full family photo of Pluto and its five moons
The dwarf and its big family
The New Horizons probe, currently speeding towards a July rendezvous with Pluto, has sent back the first images of the dwarf planet and the five moons that orbit it.
"New Horizons is now on the threshold of discovery," said mission science team member John Spencer, of the Southwest Research Institute in Boulder, Colorado. "If the spacecraft observes any additional moons as we get closer to Pluto, they will be worlds that no one has seen before."
Pluto itself was only discovered in 1930 and its first moon, Charon, wasn't found until 1978. Two more moons, Nix and Hydra, were spotted in 2005. And the Hubble space telescope identified two more, Kerberos and Styx in 2011 and 2012, respectively, as NASA scouted out New Horizons' future path.
So it's not outside of the realm of possibility that New Horizons does discover more material orbiting Pluto. We'll get a better idea what might be out there as the spacecraft approaches, and it'll make its closest flyby on July 14 – provided it doesn't hit anything on the way there.
The probe is currently 55 million miles away from its target and is speeding onwards at four kilometers per second (8,950 miles per hour). It snapped its first images between April 25 and May 1 using the spacecraft's Long Range Reconnaissance Imager (LORRI), and NASA astroboffins later processed them and strung them together into an animated film.
LORRI is a black-and-white high-resolution camera telescope with a 20.8cm mirror and an angular resolution of about 5 microradians. The probe transmits its images using a 1Kbps data link and, because of the distances involved, the data takes more than four hours to reach Earth.
This poses something of a problem for the scientists involved, because New Horizons is going to slide past Pluto very quickly – there isn't enough fuel to slow it down and nothing with an atmosphere nearby that would allow the scientists to try aero-braking the spacecraft.
As New Horizons gets closer to the dwarf planet, all of its instruments will get switched on to full operating speeds to try and grab as much information as possible in the short time available. It then has to be sent back and laboriously analyzed.
In the meantime, the spacecraft will continue on to the Kuiper Belt, the vast collection of rocks and minor planets that encircle the Solar System. After that it'll head out to the heliosphere, carrying with it one ounce of the ashes of Pluto's discoverer, Clyde Tombaugh. ®