NASA’s New Horizons spacecraft successfully flew within 2,200 miles of Kuiper Belt object Ultima Thule, storing scientific data and transmitting the first close-up images to the mission team at 12:33 a.m. EST Jan. 1, 2019.

The images reached the Johns Hopkins Applied Physics Laboratory (APL) about 10 hours later, at 10:29 a.m. At left is a composite of two images taken by New Horizons' high-resolution Long-Range Reconnaissance Imager (LORRI). An artist's impression at right illustrates one possible appearance of Ultima Thule, based on the actual image at left. The direction of Ultima's spin axis is indicated by the arrows. Sources: NASA/JHUAPL/SwRI; sketch courtesy of James Tuttle KeaneEST. New Horizons will need 20 months to complete transferring all of the data it has accumulated about the small, dark object.

The initial images resolved two mysteries. Ultima’s shape resembles a bowling pin, with two differently sized lobes connected by a small neck. The object is approximately 20 miles long by 10 miles wide. Scientists had also wondered whether the object spins. Existing images supported both non-spinning and fast-spinning hypotheses. The verdict: Ultima spins like a propeller, with the spin axis perpendicular to its long axis (see image).

One member of the watch party waiting to hear from New Horizons was Queen guitarist and astrophysicist Brian May. Principal investigator Alan Stern of Southwest Research Institute (SWRI) asked May to compose a song about the mission. May collaborated with lyricist Don Black to produce “an anthem to human endeavor.”

Planetary scientists expect data from Ultima and elsewhere in the Kuiper Belt to help them learn about the origins of the solar system. New Horizons will continue to explore this region of space, which stretches from 2.5 billion to 4.5 billion miles from the sun, through 2021. APL manages the mission in collaboration with NASA and SwRI.