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NASA's New Horizons spacecraft has released the clearest images of Ultima Thule to date, taken during the historic Kuiper Belt overflight by the space probe on January 1, 2019.
This composite image combines nine individual images taken with the New Horizons Long Range Reconnaissance Imager (LORRI), each with an exposure time of 0.025 seconds, just 6½ minutes before the closest approach to the probe by Ultima Thule. The image was taken at 00:26 EST (0526 GMT) on 1 January 2019, while the satellite was 6,628 km from Ultima Thule and 6.6 billion km from the Earth. The angle between the Ultima Thule probe and the Sun – known as the phase angle – was 33 degrees. Image credit: NASA / Johns Hopkins Applied Physics Laboratory / Southwest Research Institute / National Observatory of Optical Astronomy.
"To get these images, we needed to know exactly where were the smaller Ultima and New Horizons, which intersected at a speed of more than 32,000 km / h (51,500 km / h) in the dim light of the belt from Kuiper, a billion miles away. Pluto, "said New Horizons principal investigator, Dr. Alan Stern, a researcher at the Southwest Research Institute.
"It was an observation much more difficult than anything we had attempted during our flyby of Pluto in 2015."
The higher resolution highlights many surface features not seen well in previous Ultima Thule images.
Among them are several clear, enigmatic and almost circular terrains.
In addition, many small dark pits near the terminator – the boundary between the sunny and dark sides of the body – are better resolved.
"Whether these features are craters produced by impactors, sublimation sinks, collapse wells or something completely different, our scientific team is discussing," said Dr. John Spencer, Deputy Scientist of the New Horizons Project. , also from the Southwest Research Institute.
"These sightings were risky because there was a real chance that we would only get some, if any, of Ultima Thule in the narrow field of view of the camera," said the Dr. Stern.
"But scientists, operations and navigation teams have understood and the result is a day on the ground for our science team!"
"Some of the details we see now on the surface of Ultima Thule do not look like anything ever explored before."
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