More than just sharing the most detailed photo of Pluto we've ever seen, NASA's New Horizons probe has another mission: it's gathering data on the Plutonian surface on a flyby 12,600km above the dwarf planet, then continuing out further through the solar system to run more studies.
New Horizon's close flyby of Pluto was due to start sending data back to NASA and the world's space agencies, including Canberra's Deep Space Communications Complex, around two hours ago at 6:27AM AEST (8:27PM GMT). But the 5.7 billion kilometre distance between Pluto and Earth means that even at the speed of light (the rate at which radio-wave communications travel in a vacuum) there's a wait of around four hours and 25 minutes before we start receiving flyby data.
That means at around 10:52AM AEST (11:52PM GMT) today, we'll start to know just how well the space probe's main mission has gone, and what data it has started to gather about the surface of our solar system's most distant planetoid. Until then, it's radio silence from New Horizons. The gap in communications occurred because the probe's communications array had to be pointed at Pluto, not Earth, to gather more data which it could then send back after the array re-oriented itself.
Also on the way are high resolution images of Pluto and the dwarf planet, close up and in more detail than we've ever seen before. The same amazing photo will come back to Earth in a much higher resolution, and the LORRI imager will capture images of the Plutonian surface at up to 50 megapixels. One issue is transmission size -- the spacecraft's X band communications with Earth are expected to run at approximately 1Kbps.
After the Pluto flyby -- which has hopefully gone to plan and come off without a hitch -- New Horizons will continue on through the Kuiper Belt to study any one of three trans-Neptunian objects, designated PT1, PT2 and PT3, that were detected by the Hubble Space Telescope in 2014. It's most likely that the probe will pass PT1, the object 2014 Mu69, in January 2019.
When it completes its flyby study of whichever of those bodies NASA and JPL decide to task it with, New Horizons will continue on its ballistic trajectory out towards the heliosphere. As it passes 55 AU of distance from Earth, the probe's onboard plutonium RTG will not be providing enough wattage to power all onboard components sufficiently simultaneously, so the opportunity for data transmission back to Earth will be limited. Power sharing will mean observations can be made intermittently, but New Horizon's projected mission lifespan ends in 2026.
If it is still functioning over a decade later in 2038, the plucky Pluto probe will be 100 AU away from Earth and can study the outer heliosphere.