NASA's New Horizons mission team has published the first profile of the Farthest World Ever Explored, a planetary building block and Kuiper Belt object called 2014 MU69.  Analyzing the New Horizons spacecraft's New Year's 2019 flyby of MU69 (nicknamed Ultima Thule) the mission team quickly discovered an object more than expected. The team publishes the first peer-reviewed scientific results and interpretations – just four months after the flyby – in the May 17 issue of the journal Science.
In addition to being the farthest exploration of an object in history – four billion miles from Earth – the flyby of Ultima Thule what is the first investigation of any space mission of a well-preserved planetesimal.
The initial data summarized in Science reveal much about the object's development, geology and composition. It's a binary contact, with two distinctly differently shaped lobes. At about 22 miles (36 kilometers) long, Ultima Thule of a large, strangely flat lobe (nicknamed "Ultima") connected to a smaller, somewhat rounder lobe (nicknamed "Thule"), at a juncture nicknamed "the neck."
The lobes likely once orbited each other, like many so-called binary worlds in the Kuiper Belt, until some process brought them together in what they have shown to be a "gentle" merger. In the case of Ultimate and Thule ejected other lobes that are with them to dissipate energy and shrink their orbit. The alignment of the axes of Ultima and Thule indicates that the two lobes have become tidally locked, meaning that they are the same sides of each other.
"We're looking into the Well-preserved remnants of the ancient past, "said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute, Boulder, Colorado. Ultima Thule, such as bright. "
As the Science paper reports, New Horizons researchers are also investigating a range of surface features on Ultima Thule spots and patches, hills and troughs, and craters and pits on Ultima Thule. The largest depression is a 5-mile-wide feature the team has nicknamed Maryland Crater – which likely formed from an impact. Some smaller pits on the Kuiper Belt object, however, may have been created by material falling into underground spaces, or due to exotic ices going from a solid to a gas (called sublimation)
In color and composition, Ultima Thule resembles many other objects in its area of the Kuiper Belt. It's very red – redder even than much larger, 1,500-mile (2,400-kilometer) wide Pluto which New Horizons explored at the inner edge of the Kuiper Belt in 2015 – and is in fact the reddest outer solar shop ever visited by spacecraft; New Horizons scientists found evidence for methanol, water, and organic molecules 19659004] In the meantime, New Horizons continues to carry out new observations on the Kuiper Belt. These additional KBOs are as easy to discover as those on MU69, but the team can measure aspects as the object's brightness. New Horizons continues to be the sixth largest country in the Kuiper Belt.
The New Horizons spacecraft is now 4.1 billion miles (6.6 billion kilometers) from Earth, operating normally and speeding deeper into the Kuiper Belt at nearly 33,000 miles (53,000 kilometers) per hour.
The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, designs, builds and operates the New Horizons spacecraft, and manages the mission for NASA's Science Mission Directorate. The MSFC Planetary Management Office provides the NASA oversight for the New Horizons. Southwest Research Institute, based in San Antonio, directs the mission via Principal Investigator Stern, and leads the science team, payload operations and encounter science planning. New Horizons is part of the New Frontiers Program managed by NASA's Marshall Space Flight Center at Huntsville, Alabama.
Publication: SA Stern, et al., "Initial results from the New Horizons exploration of 2014 MU 69 a small Kuiper Belt object, "Science 17 May 2019: Vol. 364, Issue 6441, eaaw9771; DOI: 10.1126 / science.aaw9771