When it was thirty-three minutes past midnight in New York; when the ball had already dropped in Times Square to usher in 2019; when parties were in full swing across the city; history was being made four billion miles out in space.
Technically, history happened in the blink of an eye, as NASA spacecraft New Horizons zipped past Ultima Thule, a tiny Kuiper Belt object (KBO) in the outer reaches of our solar system, at a lusty speed of 32,280 miles per hour – that’s 9 miles in a second, to put things in perspective.
However, confirmation of the historic flyby came only after an agonizing wait of six hours and eight minutes.
That’s how long it took the radio signal from the robotic craft to travel through the void of space before it was plucked from the air by a NASA deep space radio dish in Madrid.
Mission controllers at the John Hopkins University Applied Physics Laboratory in Maryland broke out in applause and cheers as the good news reached them; happy at the success, relieved that the unbearable suspense was over.
“We have a healthy spacecraft,” said Mission Operations Manager Alice Bowman, adding, “We’ve just accomplished the most distant flyby.”
However, Principal Mission Investigator Alan Stern is somewhat concerned that something could go wrong with the space-weary craft.
“Even though the spacecraft has performed perfectly now for almost 13 years, there’s always the chance that something could go amiss,” said Stern in a Tuesday press briefing.
New images of 2014 MU69 (Ultima Thule’s official designation), taken when New Horizons was still about 500,000 miles away, looks like a blurry peanut pod.
However, it was enough to give the mission scientists a refined estimation of its size, which they worked out to be roughly 22 miles (35 kilometers) long and 9.3 miles (15 kilometers) wide.
“Even though it’s a pixelated blob still,” said Project Scientist Dr. Harold Weaver, Jr., adding, “it’s a better pixelated blob.”
“The [lower resolution] images that come down this week will already reveal the basic geology and structure of Ultima for us, and we’re going to start writing our first scientific paper next week,” Stern told reporters.
Another question that the low-res pics helped answer was why Ultima Thule emitted a steady light as the NASA probe approached, instead of rhythmically dimming and brightening as a spinning object is expected to do.
It was because the spacecraft’s onboard camera was front-on with one of the poles of Ultima Thule, meaning the reflected sunlight was coming from the same side all along.
“It’s almost like a propeller blade,” said Weaver, adding, “That explains everything.”
One burning question, however, remains unanswered: Is Ultima Thule a single object, or two separate bodies orbiting in a tight configuration, or, two connected KBO’s, like conjoined twins?
However, Stern and Weaver are of the opinion that Ultima Thule is more likely a single object.
“If I’m wrong, I’ll tell you tomorrow,” Dr. Stern said.
“If it’s two separate objects, this would be an unprecedented situation, in terms of how close they’re orbiting one another,” he said.
“It’d be spectacular to see, and I’d love to see it, but I think the higher probability is that it’s a single body,” Stern added.
As more and more data is beamed back in the days and months ahead, scientists will be able to understand a lot about this ancient object, like, for example, the number of craters it has, if any; the composition of its surface material; whether there are any moons orbiting it, or rings around it,’ and more.
The New Year’s Day flyby has made Ultima Thule, which dates back to our solar system’s origin 4.5 billion years ago, the most distant object ever to be visited by a human-made spacecraft.
As distant and tiny as it is, this KBO has largely remained a mystery for scientists, which they are hoping to unravel more of with each passing day as New Horizons continues its data gathering mission.
“There’s so much that we can learn from close-up spacecraft observations that we’ll never learn from Earth, as the Pluto flyby demonstrated so spectacularly,” John Spencer, New Horizons science team member, had said in a statement in August.
New Horizons has been traveling through space ever since it was launched thirteen years ago on a Pluto flyby and study mission, which it accomplished back in 2015.
On February 28, 2007, New Horizons flew by Jupiter at a distance of 1.4 million miles (2.3 million kilometers), successfully sending back data about the planet’s atmosphere, moons, and magnetosphere.
The solar system giant gave it the gravitational slingshot it needed to boost its speed for the onward journey, which was spent in hibernation mode to keep its onboard systems preserved for the mission ahead.
The systems were, however, brought back online for brief annual check-ups before being put back to sleep.
More than a month before the 2015 rendezvous with Pluto, the probe was brought online one final time for a complete instruments and systems checkout before the close encounter.
The mission was a success as New Horizons was able to provide close-ups of the dwarf planet as well as scientifically invaluable data about its atmosphere, terrain, and environments.
Ultima Thule was never part of the original mission; it was selected as New Horizons next flyby destination about six months after the Pluto encounter.
New Horizons is well equipped to map 2014 MU69 in every which way possible, and although nothing is certain, the KBO could possibly be pockmarked with impact craters, pits, and sinkholes or, conversely, it could present a smooth surface.