New Horizons: Revealing Pluto and the Kuiper Belt
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| Artist's illustration of New Horizons at Pluto and Charon. Credit: Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute |
New Horizons was the first mission to be sent past the orbit of Neptune, with the goal of studying the then last planet in the solar system: Pluto. After its successful flyby in 2015, New Horizons flew by another Kuiper belt object in 2019.
The Mission
Ever since the Voyager missions, scientists had been wanting to send a spacecraft to Pluto. In December of 2000, Stamatios "Tom" Krimigis and Alan Stern formed the New Horizons mission concept. In November of 2001, NASA selected New Horizons for Funding. Unfortunately, funding was cut by the new administrator Sean O'Keefe in 2003.
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| New Horizons under construction in 2005. Credit: NASA |
However, thanks to much lobbying from Stern, New Horizons made it to the top of medium-class missions in the Decadal Survey, and funding continued. The spacecraft was powered by a spare RTG from the Cassini mission, and its design resembled that of the Ulysses spacecraft. New Horizons also carried heritage hardware from CONTOUR and TIMED.
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| Launch of New Horizons. Credit: NASA/Kim Shiflett |
Shortly after launch, Pluto was reclassified as a Dwarf planet in an IAU forum, to much fanfare. As New Horizons left Earth's sphere of influence, it became the fastest object mankind had flown into space until the Parker Solar Probe surpassed its record.
As New Horizons approached the asteroid belt, the mission team looked for asteroids that would by chance approach the spacecraft. While no asteroid would come particularily close to New Horizons, it was able to image the asterod 13254 APL. The asteroid took its named from Johns Hopkins University Applied Physics Laboratory (APL).
In order to shorten the flight time to Pluto, New Horizons was planned to make a flyby of Jupiter. On February 28, 2007, the spacecraft made its closest approach of Jupiter. New horizons was able to obtain many images of Jupiter and its moons, including an eruption of the Tvashtar volcano on Io.
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| Tvashtar erupting on Io. Credit: NASA/JHUAPL/SwRI |
After the Jupiter flyby, New Horizons went into hibernation mode until it arrived at Pluto. During this time, two new moons were discovered around Pluto, named Kerberos, and Styx. The mission planners started to worry that New Horizons could encounter large amounts of dust sturred up from the moons. Contigency initiatives included using the antenna as a shield during th flyby, or diving into the edge of Pluto's thin atmosphere, were dust particles would be sparce.
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| Maps of Pluto and Charon. Credit: NASA/JHUAPL/SwRI |
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| Multiple views of Pluto's atmosphere. Credit: NASA/JHUAPL/SwRI |
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| Frozen lake of nitrogen on Pluto. Credit: NASA/JHUAPL/SwRI |
Watch an animation of the Pluto system flyby here.
New Horizons also obtained images of Pluto and Charon's minor moons, with the highest resolution images being of Nix and Styx. As New Horizons departed the Pluto/Charon system, the spacecraft was able to image Pluto's atmosphere backlit by the Sun.
The next goal afte the flyby was to download the 6.25 gigabytes of information collected. On October 25, 2016, New Horizons had finally transmitted all its Pluto encounter data. The New Horizons team recieved funding for a mission extension in 2016 to search for additional targets for the spacecraft to encounter.
Scientists had been looking for Kuiper Belt objects for New Horizons to flyby in 2011, with the Hubble Space Telescope eventually finding a suitable target in 2014. The chosen target was known as PT1, 1110113Y, or Kuiper Belt Object 486958. A provisional designation for the object was later given: 2014 MU69.
Those on the New Horizons nicknamed the object "Ultima Thule" on March 13, 2018, after an island from Greek inspired literature, that was located "beyond the borders of the known world." Later observations showed that the object was made of two lobes, so the larger one was nicknamed Ultima, and the smaller one Thule (these have officially been named Wenu and Weeyu respectively).
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| Stereoscopic animation of Arrokoth. Credit: NASA/JHUAPL/SwRI/Roman Tkachenko |
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| 3D shape-model of Arrokoth ("Ultima Thule"). Credit: James Tuttle Keane/NASA/JHUAPL/SwRI |
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| Geology of Arrokoth ("Utima Thule"), with comet 67P for comparison. Credit: NASA/JHUAPL/SwRI |
After the flyby, New Horizons studied deep space, and imaged nearby stars Proxima Centauri and Wolf 359, demonstrating for the first time an easily observable steller parallax. On April 17, 2021, New Horizons passed 50 Astronomical Units (AU) from the Sun.
The spacecraft currently has enough power to keep most of its instruments running until the 2030s, but as the years pass, instruments will start to be shut down like those on the Voyager spacecraft were decades previously. While the search for more future targets is currently ongoing, none have been fount to date.
NASA has crecently stated that it plans to turn New Horizons into a heliophysics mission, with much protest from Alan Stern and others. Currently the spacecraft is still active, and will likely transmit for decades to come until it's RTG power supply runs out.
The Targets
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| Richly detailed colour view of Pluto from New Horizons. Credit: NASA/JHUAPL/SwRI |
- Date Discovered: January 23, 1930
- Designation: 13434 Pluto (1930 BM)
- Mass: 1.309x10^22 Kilograms
- Radius: 1151 Kilometres
- Density: 2.05 g/cm^3
- Rotational Period: -6.387 Days*
- Orbital Period: 90487.28 Days (247.74 Years)
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| A beautiful image of Charon from New Horizons. Credit: NASA/JHUAPL/SwRI |
- Date Discovered: June 22, 1978
- Designation: I Charon
- Mass: 1.546625823x10^21 Kilograms
- Radius: 1151 Kilometres
- Density: 1.678 g/cm^3
- Rotational Period: -6.387 Days
- Orbital Period: -6.387 Days
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| Composite Image of Arrokoth from New Horizons. Credit: NASA/JHUAPL./SwRI |
- Date Discovered: June 26, 2014
- Designation: 486958 Arrokoth (2014 MU69) "Ultima Thule"
- Class: TransNeptunian Object [KBO]
- Radius: 9.13 Kilometres (Average)
- Rotational Period: 15.92 Hours
- Orbital Period: 107843.1 Days (295.26 Years)
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