Yesterday, on the very edge of our solar system, its mission reached its climax when the New Horizons probe hurtled past a mass of rock that has drifted undisturbed for four billion years.
"We finally have reached the outskirts of the solar system, these things that have been there since the beginning and have hardly changed - we think".
Stern and other members of the team at Johns Hopkins University's Applied Physics Laboratory, which NASA chose to carry out the mission, were very pleased with the performance of the almost 13-year-old space probe. Researchers discovered Ultima in 2014, hoping to find an object on New Horizon's existing flight path, and have been counting down to this rendezvous for years.
"We have a healthy spacecraft". Later, she added to more applause: "We did it again". Cheers erupted at Johns Hopkins University's Applied Physics Laboratory, home to Mission Control. Scientists and other team members embraced, while hundreds of others gave a standing ovation.
An anxious spill-over crowd in a nearby auditorium joined in the loud celebration, cheering each green, or good, status update.
Stern said the science team expects to use the data to map the surface and look for satellites and rings around Ultima Thule, Stern said.
Scientists do not yet have a clear picture of exactly what Ultima Thule is, whether a single object or a cluster, spanning about 19 miles (30 kilometers) in diameter.
Ultima Thule is either one object with two connected lobes, sort of like a spinning bowling pin or peanut still in the shell, or two objects orbiting surprisingly close to one another.
It was initially believed that Ultima Thule was a "binary" minor planet which consisted of two bodies locked in orbit around each other.
But the best colour close-ups will not be available until later in January and February.
Whether Ultima's surface is heavily cratered and if it has a rich surface geology - like that of Pluto - remains to be seen. Radio signals take over six hours to cover the distance to Earth.
Images and data will start arriving later Tuesday, "science to help us understand the origins of our solar system", Bowman said. It's scheduled to continue exploring the Kuiper Belt until at least 2021.
The answer is one that scientists already suspected: Ultima Thule's spin axis is roughly pointed toward Earth, so that it appears somewhat like a turning propeller with the illuminated side constantly facing earthbound telescopes.
"This mission's always been about delayed gratification", Stern reminded reporters.
Deep inside the so-called Kuiper Belt, a frigid expanse beyond Neptune that is also known as the Twilight Zone, Ultima Thule is believed to be a preserved relic dating back 4.5 billion years to the formation of our solar system.
It is the farthest away from the Sun any spacecraft has ever investigated an object, with New Horizons taking over 13 years to reach the rock.
The night before, after ringing in the new year, team members had counted down and celebrated the moment they expected New Horizons would make its closest approach to its target based on their knowledge of its trajectory.
"Celebrating the whole 12-year Journey of New Horizons probe", the text about the song and music video on YouTube said.