New Horizons Successfully Explores the Kuiper Belt object ‘Ultima Thule’

This image taken by the Long-Range Reconnaissance Imager (LORRI) is the most detailed of Ultima Thule returned so far by the New Horizons spacecraft. It was taken at 5:01 Universal Time on January 1, 2019, just 30 minutes before closest approach from a range of 28,000 kilometers, with an original scale of 140 meters per pixel.
Credit : NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
NASA’s New Horizons spacecraft flew past Ultima Thule in the early hours of New Year’s Day, ushering in the era of exploration from the enigmatic Kuiper Belt, a region of primordial objects that holds keys to understanding the origins of the solar system. In addition to being the first to explore Pluto, New Horizons flew by the most distant object ever visited by a spacecraft and became the first to directly explore an object that holds remnants from the birth of our solar system.

New Horizons came within about 3,500 kilometers of Ultima Thule at 6:33 a.m. on Jan. 1, zooming past the object at more than 51,000 kilometers per hour.

Scientists from NASA’s New Horizons mission [1], including three researchers from the Institut de Planétologie et Astrophysique de Grenoble (IPAG/OSUG, UGA/CNRS) [2], released the first detailed images of the most distant object ever explored (6.5 billions km from the Sun) — the Kuiper Belt object 2004 MU69, nicknamed Ultima Thule. Its remarkable appearance, unlike anything we’ve seen before, illuminates the processes that built the planets four and a half billion years ago.
The new images — taken from as close as 28,000 kilometers on approach — revealed Ultima Thule as a "contact binary," consisting of two connected spheres. End to end, the world measures 31 kilometers in length. The team has dubbed the larger sphere "Ultima" (19 kilometers across) and the smaller sphere "Thule" (14 kilometers across).

The first color image of Ultima Thule, taken at a distance of 137,000 kilometers at 4:08 Universal Time on January 1, 2019, highlights its reddish surface. At left is an enhanced color image taken by the Multispectral Visible Imaging Camera (MVIC), produced by combining the near infrared, red and blue channels. The center image taken by the Long-Range Reconnaissance Imager (LORRI) has a higher spatial resolution than MVIC by approximately a factor of five. At right, the color has been overlaid onto the LORRI image to show the color uniformity of the Ultima and Thule lobes. Note the reduced red coloring at the neck of the object.
Credit : NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
The first color image of Ultima Thule, taken at a distance of 137,000 kilometers at 4:08 Universal Time on January 1, 2019, highlights its reddish surface. At left is an enhanced color image taken by the Multispectral Visible Imaging Camera (MVIC), produced by combining the near infrared, red and blue channels. The center image taken by the Long-Range Reconnaissance Imager (LORRI) has a higher spatial resolution than MVIC by approximately a factor of five. At right, the color has been overlaid onto the LORRI image to show the color uniformity of the Ultima and Thule lobes. Note the reduced red coloring at the neck of the object.
Credit : NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Among the findings made by the mission science team in the first days after the flyby are :

  • Initial data analysis has found no evidence of rings or satellites larger than 1.8 kilometer in diameter orbiting Ultima Thule.
  • Data analysis has also not yet found any evidence of an atmosphere.
  • The color of Ultima Thule matches the color of similar worlds in the Kuiper Belt, as determined by telescopic measurements.
  • The two lobes of Ultima Thule — the first Kuiper Belt contact binary visited — are nearly identical in color. This matches what we know about binary systems which haven’t come into contact with each other, but rather orbit around a shared point of gravity.
  • The New Horizons spacecraft will continue uploading images and other data in the days and months ahead, with much higher resolution images yet to come. Complete return of all science data will span over the next 20 months.

Live updates and links to mission information are available on http://pluto.jhuapl.edu and www.nasa.gov.

Local scientific contacts

- Bernard Schmitt, IPAG/OSUG, bernard.schmitt univ-grenoble-alpes.fr | 06 07 62 25 05
- Eric Quirico, IPAG/OSUG, eric.quirico univ-grenoble-alpes.fr | 07 82 10 94 35


[1The Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, designed, built and operates the New Horizons spacecraft, and manages the mission for NASA’s Science Mission Directorate. The Southwest Research Institute, based in San Antonio, 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 in Huntsville, Alabama.

[2The IPAG team is composed of : Bernard Schmitt, Eric Quirico, Leila Gabasova