New Horizons: Maneuvering for Kuiper Belt target + Family portrait of Pluto’s moons

The New Horizons probe, which is still returning data from its encounter with Pluto, will fly by another distant object on January 1, 2019 if everything goes as planned. The spacecraft has just carried out

the second in a series of four maneuvers propelling it toward an encounter with the ancient Kuiper Belt object 2014 MU69, a billion miles farther from the sun than Pluto.

More about this at:

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On Course: Projected path of NASA’s New Horizons spacecraft toward 2014 MU69, which orbits in the Kuiper Belt about 1 billion miles beyond Pluto. Planets are shown in their positions on Jan. 1, 2019, when New Horizons is projected to reach the small Kuiper Belt object. NASA must approve an extended mission for New Horizons to study MU69.

Meanwhile, the data from the flyby continues to flow back to earth. (It will take over a year to return all the data due to the low data transmission rate from the distant probe.) Here is a report on one of Pluto’s moons:

Last of Pluto’s Moons – Mysterious Kerberos
– Revealed by New Horizons

Images of Pluto’s tiny moon tiny Kerberos taken by NASA’s New Horizons spacecraft – and just sent back to Earth this week – complete the family portrait of Pluto’s moons.

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Family Portrait of Pluto’s Moons: This composite image shows a sliver of Pluto’s large moon, Charon, and all four of Pluto’s small moons, as resolved by the Long Range Reconnaissance Imager (LORRI) on the New Horizons spacecraft. All the moons are displayed with a common intensity stretch and spatial scale (see scale bar). Charon is by far the largest of Pluto’s moons, with a diameter of 751 miles (1,212 kilometers). Nix and Hydra have comparable sizes, approximately 25 miles (40 kilometers) across in their longest dimension above. Kerberos and Styx are much smaller and have comparable sizes, roughly 6-7 miles (10-12 kilometers) across in their longest dimension. All four small moons have highly elongated shapes, a characteristic thought to be typical of small bodies in the Kuiper Belt. Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Kerberos appears to be smaller than scientists expected and has a highly-reflective surface, counter to predictions prior to the Pluto flyby in July. “Once again, the Pluto system has surprised us,” said New Horizons Project Scientist Hal Weaver, of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.

The new data, downlinked from the New Horizons spacecraft on Oct. 20, show that Kerberos appears to have a double-lobed shape, with the larger lobe approximately 5 miles (8 kilometers) across and the smaller lobe approximately 3 miles (5 kilometers) across. Science team members speculate from its unusual shape that Kerberos could have been formed by the merger of two smaller objects. The reflectivity of Kerberos’s surface is similar to that of Pluto’s other small moons (approximately 50 percent) and strongly suggests Kerberos, like the others, is coated with relatively clean water ice.

Before the New Horizons encounter with Pluto, researchers had used Hubble Space Telescope images to “weigh” Kerberos by measuring its gravitational influence on its neighboring moons.  That influence was surprisingly strong, considering how faint Kerberos was. They theorized that Kerberos was relatively large and massive, appearing faint only because its surface was covered in dark material.  But the small, bright-surfaced, Kerberos now revealed by these new images show that that idea was incorrect, for reasons that are not yet understood.

“Our predictions were nearly spot-on for the other small moons, but not for Kerberos,” said New Horizons co-investigator Mark Showalter, of the SETI Institute in Mountain View, California. The new results are expected to lead to a better understanding of Pluto’s fascinating satellite system.

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Kerberos Revealed. This image of Kerberos was created by combining four individual Long Range Reconnaissance Imager (LORRI) pictures taken on July 14, approximately seven hours before New Horizons’ closest approach to Pluto, at a range of 245,600 miles (396,100 km) from Kerberos. The image was deconvolved to recover the highest possible spatial resolution and oversampled by a factor of eight to reduce pixilation effects. Kerberos appears to have a double-lobed shape, approximately 7.4 miles (12 kilometers) across in its long dimension and 2.8 miles (4.5 kilometers) in its shortest dimension. Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute