Although the flyby occurred at 12:33 a.m. ET on Tuesday, the spacecraft is so far from Earth that the “phone-home” signal didn’t reach us until about 10:30 a.m. ET. Mission scientists were relieved about the success because there was only one chance to get it right as New Horizons screamed past Ultima at 31,500 miles per hour. This incredible feat was possible because thousands of operations on the spacecraft worked in sync. “We’ve just accomplished the most distant flyby,” mission operations manager Alice Bowman said. “This science will help us understand the origins of our solar system.” New Horizons has...