When NASA’s New Horizons spacecraft flew by a small distant world on New Year’s Eve, it tried to use one of its cameras to capture the highest-resolution images that were possible. Pulling this off presented risks.
Mission officials cautioned that even a slight error in pointing the camera could result in the spacecraft sending pictures of just empty space back to Earth.
On Friday, mission scientists announced success.
“It's a technical accomplishment,” said S. Alan Stern, the principal investigator for New Horizons. “It was incredible how accurately our navigators put us on target.”
New Horizons passed within 2,200 miles of the object, officially designated 2014 MU69 and nicknamed Ultima Thule. Orbiting four billion miles from the sun and a billion miles beyond Pluto, Ultima Thule is a pristine leftover from the earliest days of the solar system.
The images have a resolution of about 33 meters, or 110 feet, per pixel. However, the spacecraft was traveling so fast — more than 32,000 miles per hour — that the images were taken with a short exposure time of 1/40th of a second to minimize blurring.
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“It’s a subtle improvement” over earlier images taken at about one-fourth the resolution, said John R. Spencer, one of the deputy project scientists. “It’s grainier because of underexposure.”
Still, even the subtle improvements will give better understanding of the pits and bright patterns on Ultima Thule’s surface. A clearer look at the rims of the pits might help tell whether they are small impact craters or they formed from erosion, for example. Counting craters could reveal the rate of collisions in this distant part of the solar system, while erosion would hold clues to what Ultima Thule is made of.
“We can see much smaller features,” Dr. Stern said. “That brings out much more detail.”
