The team of spacecraft that take us from near Pluto will ring in the new year by exploring a more distant and mysterious world.
NASA's New Horizons spacecraft will pass thin objects and ice dubbed Ultima Thule (TOO-lee) immediately after the midnight break.
A billion miles outside of Pluto and a staggering 4 billion miles from Earth (1.6 billion kilometers and 6.4 billion kilometers), Ultima Thule will be the furthest world ever explored by mankind. That's what makes this freezing target so interesting; this is a preserved relic that originated from our solar system 4.5 billion years ago. There is no spacecraft that visits something primitive.
"What can be more interesting than that?" said project scientist Hal Weaver from Johns Hopkins University, part of the New Horizons team.
Leading scientist Alan Stern of the Southwest Research Institute in Boulder, Colorado, hopes that the New Year meeting is more risky and more difficult than meeting Pluto: Older spacecraft, smaller targets, closer flyby and greater distance from us.
NASA launched a spacecraft in 2006; it's about the size of a baby grand piano. It flew past Pluto in 2015, giving the planet's first close-up view. With a very successful flight path behind them, mission planners won an extension from NASA and turned their gaze to destinations deep within the Kuiper Belt. So far, Pluto is barely on the Kuiper Belt, called the Twilight Zone that stretches beyond Neptune. Ultima Thule is in the heart of the Twilight Zone.
This Kuiper Belt Object was discovered by the Hubble Space Telescope in 2014. Officially known as 2014 MU69, it was nicknamed Ultima Thule in online voting. In classical and medieval literature, Thule is the farthest, most northerly outside world known. When New Horizons first saw a rocky ice ball in August, that was just a point. A good close-up image must be available the day after flying.
Have we arrived?
New Horizons will take the closest approach in the early hours of January 1 – 12:33 am EST. The spacecraft will enlarge in 2,200 miles (3,500 kilometers) from Ultima Thule, seven science instruments that will explode. The beach must be clear: Scientists have not found a ring or moon around it that can destroy the spacecraft. New horizons shot through the sky at a speed of 31,500 mph (50,700 kph), and even something very small like a grain of rice could destroy it. "There are some dangers and tensions," Stern said at the autumn meeting of astronomers. It took about 10 hours to get confirmation that the spacecraft had finished – and survived – from the meeting.
Ultima Thule speculated scientists could be two objects that orbit each other. If it is solo, it is possible to have a maximum length of 20 miles (32 kilometers). Imagine baked potatoes. "Cucumber, whatever. Choose your favorite vegetables," said astronomer Carey Lisse from Johns Hopkins. It can even be two bodies connected by a neck. If twins, each can be 9 miles to 12 miles in diameter (15 kilometers to 20 kilometers).
Scientists will map Ultima Thule in all possible ways. They anticipate the impact of the crater, maybe also holes and drainage holes, but the surface can also be proven smooth. As for color, Ultima Thule must be darker than coal, burned by thousands of years of cosmic rays, with a reddish hue. However, nothing is certain, including its orbit, which is so large that it takes almost 300 of our Earth years to circle the sun. Scientists say they know enough about orbit to intercept it.
New Horizons will be much closer to Ultima Thule than in Pluto: 2,220 miles versus 7,770 miles (3,500 kilometers vs. 12,500 kilometers). At the same time, Ultima Thule is 100 times smaller than Pluto and therefore more difficult to trace, making everything more challenging. It takes 4 ½ hours, one way, for flight controllers at Johns Hopkins Applied Physics Lab in Laurel, Maryland, to get messages to or from New Horizons on Pluto. Compare this with more than six hours at Ultima Thule.
It took almost two years for New Horizons to send all data back to Ultima Thule. A flight from an even farther world might soon arrive in the 2020s, if NASA approves the extension of other missions and the spacecraft remains healthy. At the very least, nuclear-powered New Horizons will continue to observe objects from a distance, because they push deeper into the Kuiper Belt. There are lots of things out there, waiting to be explored.