Pluto Comes Into Focus in Latest Images as New Horizons Approaches Ever Closer

NASA's New Horizons spacecraft took a series of images of Pluto in 8-12 May from a decreasing distance of 110 million to 75 million km away, which provide fascinating new views of the distant planet's largely varied surface topography. Compared to images taken one month earlier, Pluto appears to get larger as the spacecraft gets closer, with the planet's apparent size increasing by approximately 50 percent. These images are displayed at four times their native image size and have been processed using a method called deconvolution, which sharpens the original images to enhance Pluto's surface features. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

NASA’s New Horizons spacecraft took a series of images of Pluto in 8-12 May from a decreasing distance of 110 million to 75 million km away, which provide fascinating new views of the distant planet’s largely varied surface topography. Compared to images taken one month earlier, Pluto appears to get larger as the spacecraft gets closer, with the planet’s apparent size increasing by approximately 50 percent. These images are displayed at four times their native image size and have been processed using a method called deconvolution, which sharpens the original images to enhance Pluto’s surface features. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Up till now, 2015 has been a year of historic, ever bigger revelations regarding some of the Solar System’s “lesser bodies,” with ESA’s Rosetta spacecraft returning breath-taking close-up images of comet 67P/Churyumov-Gerasimenko and NASA’s Dawn mission providing stunning views of dwarf planet Ceres in the vast expanses of the asteroid belt between Mars and Jupiter. More than 5 billion km farther out from the Sun, as if not wanting to be left out from all the buzz, the New Horizons spacecraft has beamed back the first focused images of Pluto, finally transitioning this last unexplored planetary body of the Solar System from an astronomical object to a geological one.

As detailed in a recent AmericaSpace article, the New Horizons mission is currently in the middle of a six-month-long, long-range reconnaissance of Pluto, in preparation for its historic and eagerly awaited first close flyby of the distant dwarf planet in July 14. Throughout this time the spacecraft has returned tantalising glimpses of the entire Pluto system from afar, which have revealed the graceful orbital ballet between the dwarf planet and its menagerie of five known moons. In most of the images that New Horizons has beamed back during its approach phase, Pluto has occupied just a couple of pixels with each pixel covering an area more than 2,000 km wide, which is almost the diameter of the planet itself, resulting in poor quality images where the planet was barely resolved at all.

This started to change in mid-May, when New Horizons while being at a distance of approximately 77 million kilometers away from Pluto, imaged the latter with almost double the resolution, revealing a series of finer details of the distant planet’s surface features for the first time. Whereas the previous set of images that had been taken by the spacecraft one month earlier had shown a series of interesting surface brightness variations on Pluto which indicate the possible existence of a broad northern highly reflective polar ice cap, in the latest ones the distant world appears almost 50 percent bigger, allowing scientists to discern finer details throughout most of the planet’s surface during the latter’s week-long rotation along its axis, including what appears to be as a series of fascinating bright and dark areas.

“These new images show us that Pluto’s differing faces are each distinct; likely hinting at what may be very complex surface geology or variations in surface composition from place to place,” explains Dr. Alan Stern, Principal Investigator for the New Horizons mission at the Southwest Research Institute in Boulder, Colo. “These images also continue to support the hypothesis that Pluto has a polar cap whose extent varies with longitude; we’ll be able to make a definitive determination of the polar bright region’s iciness when we get compositional spectroscopy of that region in July.”

A composite of the latest Pluto images by the New Horizons spacecraft. Image Credit: NASA/JPL-Caltech/Paul Scott Anderson

A composite of the latest Pluto images by the New Horizons spacecraft. Image Credit: NASA/JPL-Caltech/Paul Scott Anderson

Despite this increase in image quality, these latest raw images that were taken with the onboard Long Range Reconnaissance Imager, or LORRI, had to be processed with the use of a technique called image deconvolution in order for the additional details to come out, in a similar way to the one that had been previously used to sharpen the images of the Hubble Space Telescope in the early 1990s prior to its first servicing mission, when it was determined that the primary mirror of the space observatory suffered from spherical aberration which greatly reduced its observing capabilities. Nevertheless, the resolution in this latest batch of images of Pluto from New Horizons is already exceeding those that have been previously taken by Hubble and are only bound to get better from now on as the spacecraft approaches closer to its destination by about 1.2 million kilometers with each passing day. “As New Horizons closes in on Pluto, it is transforming it from a point of light to a planetary object of intense interest,” says Dr. Jim Green, Director of Planetary Science at NASA’s Headquarters in Washington, D.C. “We’re in for an exciting ride for the next seven weeks.”

Another very importance task for the New Horizons mission that was successfully completed during this past month’s imaging session has been the first in a series of searches for any as-of-yet undetected hazardous moonlets, rings, and dust debris that may lie along the spacecraft’s planned trajectory through the Pluto system. The results of the analysis of the images that were taken in mid-May have revealed no such hazardous objects so far. New Horizons is close enough to Pluto now that its onboard cameras have the ability to detect any object with a brightness half that of Styx, Pluto’s smallest and faintest known moon, that could pose a threat to the mission. This means that if any such objects lie ahead they should be less than 10-20 km wide, which is the estimated size for Styx.

New Horizons’ next observing session of the Pluto system is scheduled to begin today (May 29), by which time the image resolution will be almost double that of the ones that were taken in mid-May, allowing for even more crisp views of the mysterious distant world in the edges of the Solar System. The reason for these long gaps between the mission’s observing sessions, is the agonizingly slow data rates of 1 kilobit per second with which the spacecraft transmits its data back to Earth. At its current distance of more than 5 billion km away, New Horizons’ signals are so weak that can only be picked up by the largest, 70-m-wide antennas of NASA’s Deep Space Network in the U.S., Spain, and Australia. Furthermore, the spacecraft has to periodically empty its data recorders in order to be able to collect as much data as possible during its closest approach of Pluto in July. As a result, the mission’s team have devised a timetable during which New Horizons stops observing Pluto in order for it to transmit all of the data that it has accumulated up to that point back to Earth. With the very slow data rates that the spacecraft can achieve at its current distance of more than 30 Astronomical Units away, it takes weeks before New Horizons has cleared its data recorders and begin observations again.

The New Horizons science team conducted a search for potentially hazardous material around Pluto, based on a total of 144 10-second exposures of the Pluto system that were taken by the spacecraft between May 11-12 from a distance of 76 million km away. The results indicated no immediate threat for the spacecraft this far. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

The New Horizons science team conducted a search for potentially hazardous material around Pluto, based on a total of 144 10-second exposures of the Pluto system that were taken by the spacecraft between May 11-12 from a distance of 76 million km away. The results indicated no immediate threat for the spacecraft this far. Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

This long hiatus means the data being returned with each observing session are of far superior quality than those of the previous ones. From here on, New Horizons’ image resolution will by far exceed that of the images of Pluto that have been taken with the Hubble space telescope, which up till recently were the best ones ever we had of the distant planet, allowing scientists to unveil ever more fascinating details about this fascinating world that has remained a complete mystery ever since it was discovered almost a century ago. “By late June the image resolution will be four times better than the images made May 8-12, and by the time of closest approach, we expect to obtain images with more than 5,000 times the current resolution,” says Hal Weaver, project scientist for New Horizons at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md.

The time has finally arrived, when everyone alive today will have a front-row seat to humanity’s first-ever, close-up exploration of Pluto and its moons. The seven weeks that separate us from this historic event will be a thrilling time indeed.

 

For up-to-the-minute information, regular updates & live coverage of the Pluto New Horizons flyby in July, be sure to bookmark our New Horizons Mission Tracker!

The author would like to thank AmericaSpace colleague Paul Scott Anderson for his kind permission to use his composite of the new LORRI images from the New Horizons mission.


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6 comments to Pluto Comes Into Focus in Latest Images as New Horizons Approaches Ever Closer

  • Karol

    According to the 29 May edition of the AIAA “Daily Launch”, no small moons, rings or other objects that could pose a navigation problem have been discovered to date, clear sailing ahead, so you’re right Leonidas, it’s going to be a thrilling time indeed! 🙂 I wonder how many individuals the world over are aware of the very unusual Clyde Tombaugh-related item that New Horizons will be carrying as it passes Pluto? It would most certainly garner some interest. Thanks for the update Leonidas, your efforts on our behalf are always greatly appreciated.

    • Leonidas Papadopoulos

      Clear Sailing Ahead indeed Karol! And what a great phrase! Could I borrow it for a future article title for New Horzons? 🙂

      Yes, Clyde Tombaugh’s remains on board NH is only fitting. And thank you for your always great commentary on AmericaSpace. You and Tom are some of my greatest online friends for all things space 🙂

      My best regards!

    • I’m glad you brought that up Karol, would make for a great story. I think you just assigned Leo a new article! Ha

  • Karol

    Thank you very much Leonidas and Mike for your kind and gracious consideration. Many of us in the space advocacy community are in your debt for the countless hours of highly informative, educational, and yes, entertaining work with which you have so generously gifted us. All that is needed to make it complete is when the AmericaSpace crew (Tom and I included) get together for an “Orion/Space Launch System Launch Party”. 😀 Got that “top shelf” bottle of scotch picked out already! Please feel free to use “Clear Sailing Ahead” or anything else you might find suitable Leonidas my friend, you’re always welcome to it! If you are typical of the exceptionally high caliber of researchers and writers produced by the Greek school system, I think we need to start importing teachers from Greece immediately! (. . . and England too, considering the number of books by Ben Evans on my bookshelf – gotta remember to bring them to the launch party for him to autograph!) Best wishes always! Karol

  • […] observations are bound to come just 40 days from now, when NASA’s New Horizons spacecraft will speed through the Pluto system in 14 July, for its eagerly anticipated and historic flyby of this distant realm of the Solar System. […]

  • […] As described in AmericaSpace’s previous mission update, New Horizons is currently in the middle of its second of three Approach Phases to the Pluto system. Covering more than 1 million km with each passing today towards reaching its target, the intrepid robotic explorer has started sending back images of Pluto and its assortage of moons at regular intervals, ever since it was awakened from its final hibernation period in early December of last year. With anticipation and excitement running high among scientists and the general public alike, everyone has been eagerly anticipating to see what this mysterious world in the outer reaches of the Solar System actually looks like. Now, with just over five weeks remaining before the day of closest approach New Horizons has provided with our first treat of what’s to come, by returning images which reveal a tantalising set of brightness variations of very bright and dark patches across the surface of Pluto which hint at very interesting and diverse geological features on the surface of the distant world. “Even though the latest images were made from more than 30 million miles away, they show an increasingly complex surface with clear evidence of discrete equatorial bright and dark regions—some that may also have variations in brightness,” says Dr. Alan Stern, Principal Investigator for the New Horizons mission at the Southwest Research Institute, in Boulder, Co. “We can also see that every face of Pluto is different and that Pluto’s northern hemisphere displays substantial dark terrains, though both Pluto’s darkest and its brightest known terrain units are just south of, or on, its equator. Why this is so is an emerging puzzle.” […]