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New Horizons: Potential KBO Targets Identified

The welcome news that the Hubble Space Telescope has found three potential Kuiper Belt targets for New Horizons means that our hopes for an extended mission may be fulfilled. Pluto/Charon is an exciting target, but how much better to use the spacecraft to visit a Kuiper Belt object as well, a member of that vast ring of debris circling our Solar System. We’ve been to asteroids, of course, but KBOs are a different thing altogether, objects that have never been heated by the Sun, and thus give us a sample of the earliest days of the Solar System.


This was not an easy survey to complete, although when it began with the help of ground-based instruments — the 8.2-metre Subaru Telescope in Hawaii and the 6.5-metre Magellan Telescopes in Chile — a number of KBOs were identified. The problem was that none could be reached given the fuel available for course correction. Remember the observing conditions researchers had to deal with. Pluto is now in the direction of the constellation Sagittarius, which means observers were looking toward galactic center, a crowded starfield against which to identify targets. Says New Horizons science team member John Spencer (SwRI):

“We started to get worried that we could not find anything suitable, even with Hubble, but in the end the space telescope came to the rescue. There was a huge sigh of relief when we found suitable KBOs; we are ‘over the moon’ about this detection.”

Image: An artist’s impression of a Kuiper Belt object (KBO), located on the outer rim of our solar system at some 4 billion miles from the Sun. The Sun appears as a bright star at image center in this graphic, which represents the view from the KBO. The Earth and other inner planets are too close to the Sun to be seen in this illustration. The bright “star” to the left of the Sun is the planet Jupiter, and the bright object below the Sun is the planet Saturn. Two bright pinpoints of light to the right of the Sun, midway to the edge of the frame, are the planets Uranus and Neptune, respectively. The planet positions are plotted for late 2018 when the New Horizons probe reaches a distance of well over 6 billion kilometers from the Sun. The Milky Way appears in the background. Credit: NASA, ESA, and G. Bacon (STScI).

The ground search could not begin until 2011 to allow potential KBO candidates to be closing on the region that New Horizons will be able to reach after the Pluto/Charon flyby. With the ground-based search stalled, the New Horizons team was awarded observing time by the Space Telescope Science Institute in July, with the search ending in early September. With Hubble’s help we now have one KBO that has been called ‘definitely reachable’ and two other candidates that require additional observing time to determine whether they are in range. The ‘needle in a haystack’ search has revealed KBOs that are no more than one to two percent the size of Pluto. A KBO named 1110113Y or “PT1” looks to be the most likely candidate for a flyby.


Image: A Kuiper Belt object (KBO) that is potentially reachable by NASA’s Pluto-bound New Horizons probe is visible in multiple exposures taken with the Hubble Space Telescope. Hubble tracked the KBO (labeled PT1) moving against the crowded background field of stars in the summer constellation Sagittarius. The object is no bigger than 30 to 45 kilometers across, and it is a deep-freeze relic of what the outer solar system was like 4.6 billion years ago, during the period when the Sun formed. The image at right shows the KBO at an estimated distance of over six billion kilometers from Earth. As the KBO orbits the Sun, its position noticeably shifts between exposures taken approximately 10 minutes apart. Credit: NASA, ESA SwRI, JHU/APL, and the New Horizons KBO Search Team.

The New Horizons closest approach and flyby of Pluto/Charon takes place in July of 2015, and assuming NASA approves an extended mission, the spacecraft could reach one of the KBOs three to four years later, at a distance of well over six billion kilometers from the Sun. We’ve seen how valuable our Voyagers have been at charting the outer regions of the Solar System, an extended mission that has gone well beyond their original parameters. It’s clear that New Horizons can now become something of a ‘precursor to an interstellar precursor,’ returning data on a KBO even as we look toward missions explicitly designed to study the interstellar medium beyond the heliosphere.


Comments on this entry are closed.

  • Andrew LePage October 21, 2014, 13:19

    Phew!!! I was willing to wager that a suitable target for a close encounter after New Horizon’s Pluto flyby was not going to be found at this late date especially considering the quickly narrowing trajectory options. Now I can’t wait for 2019 for our first look at a Kuiper Belt object beyond Pluto. Still, given the observed range of properties of Kuiper Belt objects and the new questions about Pluto that will inevitably be raised by next July’s encounter with Pluto, it isn’t too early to start thinking about a followup mission to Pluto and beyond!


  • Alex Tolley October 21, 2014, 17:46

    I hope that the instruments will be good enough to give us surface composition of the target KBO, as well as imagery and bulk properties estimates.

  • Christopher Phoenix October 22, 2014, 2:33

    Exciting new, July 2015 is going to be like Christmas for us deep space buffs, ha ha! We are quite lucky that our space hardware has proven resilient enough to not only outlast the original mission but continue to carry our a second one on so many probe missions.

  • John Cody October 23, 2014, 4:36

    As much as I’m anticipating the results of the Pluto flyby, I doubt they’ll be much call for a followup. I’d much rather get a look at places like Sedna, Eris, Haumea…

  • Mark Zambelli October 23, 2014, 12:21

    I’m with you Alex and I had read that depending on the trajectory choices, any images may show PT1 to cover between 100 and 1000 pixels so that should hopefully allow for a fair amount of surface data re composition, temperature profiles etc. I cannot wait :)

  • ljk November 19, 2014, 10:40

    New Horizons Ready for Last Wake-Up Call Prior to Start of Historic Pluto Encounter Operations

    By Leonidas Papadopoulos

    They say that practice makes perfect, and the New Horizons mission has had much time in its hands to do just that. After more than eight years of silently cruising through the entirety of the Solar System toward its ultimate destination, the intrepid spacecraft is almost there: Currently located just over 1.5 times the Earth-Sun distance away from mysterious Pluto, New Horizons is set to come out of hibernation for the very last time three weeks from now, prior to the start of its historic encounter operations in January 2015 with this distant world in the outer reaches of the Solar System.

    Staying true to the nature of its mythological namesake, Pluto is a mysterious planet which is currently holding the keys to the Solar System’s gates of the unknown, beyond which lies a vast expanse we know very little about. In large part due to its great distance from the Sun, which on average is approximately 5.8 billion km, Pluto is the only planetary body from the Solar System’s total real estate that has never been examined up close by any visiting spacecraft during the 50-year history of planetary exploration, thus essentially remaining remote and exotic, ever since it was discovered by American astronomer Clyde Tombaugh in 1930.

    The revolutionary discovery since the early 1990s of thousands of minor icy planetary bodies beyond the orbit of Neptune, known as Kuiper Belt Objects, or KBOs, revealed the existence of a previously unknown third region of the Solar System beyond those of the terrestrial and gas giant planets—that of the Kuiper Belt, which comprises a completely uncharted territory of Solar System real estate. This finding also proved to be the important catalyst which prompted the U.S. National Research Council to ultimately propose a dedicated mission concept to the Pluto system in the early 2000s as the highest priority for the then-upcoming 2003-2013 Planetary Science Decadal Survey, resulting to the New Horizons mission finally been selected for implementation by NASA in November 2001, representing the culmination of decades’ worth of efforts by the space agency and the planetary science community alike for the exploration of Pluto and the vast expanses of the Kuiper Belt in the outer regions of the Solar System.

    Full article here:


  • ljk December 2, 2014, 11:10

    Probing Pluto’s Paltry Atmosphere Using A Solar Eclipse And Spacecraft


    Pluto is so far away from us and so tiny that it’s hard to glean even basic facts about it. What is its tenuous atmosphere made of? And how to observe it during NASA’s New Horizons very brief flyby next July? A recent Johns Hopkins blog post explains how a careful maneuver post-Pluto will let investigators use the Sun to examine the dwarf planet’s true nature.

    Investigators will use an instrument called Alice, an ultraviolet spectrometer, to look at the atmosphere around Pluto and its largest moon, Charon. Alice is capable of examining the gases in the atmosphere using a large “airglow” aperture (4 by 4 centimeters) and also using the Sun for observation with a smaller, 1-mm solar occultation channel.

    “Once New Horizons flies past Pluto, the trajectory will conveniently (meaning, carefully planned for many years) fly the spacecraft through Pluto’s shadow, creating an effect just like a solar eclipse here on Earth,” wrote Joel Parker, New Horizons co-investigator, in a blog post.

    Full article here:


  • ljk January 14, 2015, 13:41

    The first man on PLUTO: New Horizon probe on mission to dwarf planet is carrying astronomer Clyde Tombaugh’s ashes

    American astronomer Clyde Tombaugh discovered the icy world in 1930

    Upon his death in 1997 he requested that his ashes be carried into space

    His remains are inside a container fixed to Nasa’s New Horizon’s probe

    They have spent nine years travelling 3.67 billion miles towards Pluto

    The £460 million mission will be mankind’s closest encounter with Pluto

    Pluto was officially downgraded as a planet by astronomers in 2006

    It is now known as a dwarf planet along with several similar rocky worlds


    PUBLISHED: 13:28 EST, 12 January 2015 | UPDATED: 13:36 EST, 12 January 2015

    Full article here:


    This “news” has been publicly known since 2008. I am glad to see that if some human had to be the first to travel beyond the Sol system in some form or another that it was Dr. Tombaugh.

  • ljk January 16, 2015, 10:20

    Coming Down the Home Stretch: New Horizons Begins Historic Long-Range Reconnaissance of Pluto, Prior to Closest Approach in July

    By Leonidas Papadopoulos

    Nine years ago this week, one of the longest and most historic missions ever in the annals of planetary exploration began, with the launch of NASA’s New Horizons spacecraft towards one of the last unexplored destinations in the Solar System that haven’t been witnessed still by human eyes.

    Today, more than 5 billion kilometers away from home, the small piano-sized robotic spacecraft has finally began its much-anticipated long-range reconnaissance of Pluto, while approaching ever closer to the mysterious dwarf planet, marking the official start of humanity’s first close-up study of one of the largest planetary bodies in the expansive Kuiper Belt that dominates the outer Solar System.

    The New Horizons mission represents the culmination of decades worth of efforts by NASA and the planetary science community to explore this completely unknown part of the Sun’s planetary family. Going back to the days of the space agency’s Voyager Grand Tour of the 1970s and ’80s, scientists and engineers had briefly considered at the time sending Voyager 1 toward Pluto following its encounter with Saturn in 1980. Yet, doing so would mean putting the spacecraft toward a trajectory that would prohibit a close examination of Titan, and Saturn’s largest and more intriguing moon was eventually chosen instead, as it represented a more interesting scientific target.

    As Pluto was approaching perihelion in 1989, many proposals calling for a dedicated mission to the distant dwarf planet were sent to NASA, with none of them ever advancing beyond the mission concept phase. One of them, the Pluto Kuiper Express, held much potential of being realised in the 1990s, but the space agency eventually cancelled the mission in 2000, reacting to a series of cost overruns and budget cuts imposed by the White House at the time. An intense lobbying campaign on Congress that was coordinated by the planetary science community, led to a re-authorisation by the Senate which allowed NASA to continue with a Pluto-dedicated mission. It was out of this campaigning effort that New Horizons arose, as the first of a New Frontiers-class of missions, with a cost of $650 million throughout its operational cycle.

    Full article here:


  • ljk January 19, 2015, 17:05

    ‘Radiation hardened’ PlayStation chip guides probe to Pluto

    Published time: January 16, 2015 22:37

    NASA has repurposed a PlayStation chip – the same processor used in the original Sony PlayStation model back in 1994-95 – to help guide one of its probes to Pluto.

    The chip is the MIPS R3000 CPU; it was used in the original Sony PlayStation, which ran games from the Final Fantasy and Metal Gear Solid franchises.

    It is being used to control thrusters, guidance, and other systems in order to help direct the probe to Pluto. This particular chip is “radiation hardened,” Escapist magazine reported.

    While the PlayStation uses a 33 MHz R3051 CPU, the New Horizons spacecraft uses a 12 MHz Mongoose-V CPU.

    “It is found in workstations and servers designed by companies such as Evans & Sutherland, DEC, Silicon Graphics, Tandem Computers and Whitechapel Workstation. Most notably, it was the CPU chosen for the original PlayStation game console from Sony,” an Imagination spokesman told Electronics Weekly, “and is still being used by Toshiba in a range of microcontrollers.”

    Full article here: