Probe unveils Pluto as solar system's second 'Red Planet'

Tuesday, July 7, 2015, 10:28 AM - The latest detailed images of Pluto are in from NASA's New Horizons team, and while a large dark spot is drawing plenty of attention, the dwarf planet's colour is strangely familiar.

With NASA's deep-space Pluto probe now recovered from a glitch it suffered over the weekend, the mission team released new images the spacecraft captured between July 1-3. The first reveals three pictures in sequence, covering roughly one quarter of Pluto's globe, which reveals a curious dark patch of terrain in the dwarf planet's southern hemisphere.

According to NASA's update from Monday, July 6:

The left image shows, on the right side of the disk, a large bright area on the hemisphere of Pluto that will be seen in close-up by New Horizons on July 14. The three images together show the full extent of a continuous swath of dark terrain that wraps around much of Pluto’s equatorial region. The western end of the swath (right image) breaks up into a series of striking dark regularly-spaced spots, each hundreds of miles in size, which were first detected in New Horizons images taken in late June. Intriguing details are beginning to emerge in the bright material north of the dark region, in particular a series of bright and dark patches that are conspicuous just below the center of the disk in the right image. In all three black-and-white views, the apparent jagged bottom edge of Pluto is the result of image processing. The inset shows Pluto’s orientation, illustrating its north pole, equator, and central meridian running from pole to pole.

Credit: NASA/JHUAPL/SWRI

More remarkable, though, is the zoomed-in, colour image that shows off the reddish hue of the surface - making Pluto strangely reminiscent of our neighbouring world, Mars.

Credit: NASA/JHUAPL/SWRI

This latest image of Pluto certainly settles things regarding what colour the internet thinks Pluto is (follow the link to planetary astronomer Alex Parker's detailed analysis of the trending hues).

Also, some of the more intriguing questions that have risen with New Horizons' approach to the system revolve around exactly how Pluto gained this particular colour, and why the surface of its largest moon, Charon - if it was formed from an ancient impact, similar to how Earth's Moon came to be - is not only much darker, but appears to be almost entirely made up of shades of gray.

The co-rotation of Pluto and Charon, taken between June 23 and June 29, 2015, with data from New Horizons' Ralph instrument added to show colour. Credit: NASA/JHUAPI/SWRI

With the apparent similarities between the origins of Charon and Earth's Moon, uncovering the reason for the difference between Pluto and Charon may lead to discoveries that reveal new findings closer to home as well.

RELATED: Two faces of Pluto emerge in latest NASA photographs

Worrying failure, but team remains steadfast

Engineers and scientists on the New Horizons team suffered through a few hours of silence from their distant explorer on the afternoon of Saturday, July 4, as a problem with the probe's primary computer sent it into a condition known as safe mode.

At a press conference on Monday, July 6, Glen Fountain, the New Horizons project manager at Johns Hopkins University Applied Physics Laboratory, explained that the spacecraft's computer's processor became overloaded by two sets of complex commands.

One of those sets of commands was for the computer to compress the data that was still in memory, to ensure enough space for the upcoming science observations. When the processor became overloaded, it shut down automatically, and the computer's controller put the system in safe mode, switching over to the backup computer in the process.

During "safe mode" a spacecraft or robotic rover will cease all science-based activities, even imaging, and maintain only the essentials - keeping its computers and instruments at the correct temperature, staying on course for its destination, and remaining in contact with Earth.

Although the spacecraft shutting down interrupted the stream of images that have been arriving back on Earth, New Horizons is still on course for its pass through the Pluto system, as all course-correction maneuvers have already been performed.

RELATED: Check out New Horizon's planned path for its pass through the Pluto system

As of Monday, July 6, New Horizons is now out of safe mode, however it has yet to resume its science observations. The New Horizons team plans for the spacecraft to enter into Encounter Mode starting at 12:45 p.m. EDT on Tuesday, July 7, which will last until after the probe has passed through the Pluto system on July 14.

"I'm pleased that our mission team quickly identified the problem and assured the health of the spacecraft," said Jim Green, NASA’s Director of Planetary Science, in a NASA press release. "Now – with Pluto in our sights – we're on the verge of returning to normal operations and going for the gold."

If another failure were to result sometime during that period, the team says that the spacecraft will not enter into safe mode. Instead, New Horizons' computer would simply reboot and continue on with its flight plan.

What have we missed due to this glitch?

According to the team, 30 observations by New Horizons' LORRI instrument (the Long Range Reconnaissance Imager) were sacrificed during the safe mode downtime, however, this only represents about six per cent of the total number of observations that would have taken place between the start of safe mode and Pluto flyby.

"In terms of science, it won’t change an A-plus even into an A," said New Horizons Principal Investigator Alan Stern of the Southwest Research Institute.

Sources: NASA | The Planetary Society | NASA | NASA