NASA went into the New Year on Tuesday with a historic flight of the furthest and perhaps the oldest cosmic body ever explored by humanity – a small, distant world called Ultima Thule – hoping to find out more about how planets took shape.
A series of long-awaited "home" signals arrived after 10:30 am (1530 GMT), indicating that the spacecraft had made it intact through the risky, quick meeting.
"We have a healthy spacecraft," said Mission Operations Manager Alice Bowman, when the cheering broke out in the control rooms at Johns Hopkins Applied Physics Laboratory in Maryland.
About 10 hours earlier NASA celebrates the flyby of the new year, while mission managers – together with children dressed in space costumes – blew party horns to mark the moment at 12:33 (0533 GMT) when the New Horizons spacecraft's cameras Four billion miles (6.4 billion kilometers) were shot in space in a dark and ice-cold space known as the Kuiper Belt.
Images and data will arrive later on Tuesday and scientists will take a closer look at the first of an old building block of planets, Bowman said.
The flyby took place about one billion miles past Pluto, which until now was the most remote world ever visited by a spacecraft.
Realtime video of the actual flyby was impossible, because it takes more than six hours for a signal from the earth to reach the spaceship and another six hours before the answer arrives.
The spacecraft whizzed through space at a speed of 32,000 miles per hour and came closest to 2200 miles from the surface of Ultima Thule.
"This is an evening that none of us will forget", said guitarist Brian May – who also has an advanced degree in astrophysics – and who recorded a solo track to honor the spacecraft and its exploration.
Lead planetary scientist for New Horizons, Alan Stern, said Ultima Thule is unique because it is a remnant from the early days of the solar system and could offer answers about the origins of other planets.
"The object is in such a deep freeze that it has been perfectly preserved in the original formation," he said.
"Everything we are going to learn about Ultima – from composition to geology to how it was originally composed, whether it contains satellites and an atmosphere and stuff like that – will teach us about the original formation conditions of objects in the solar system."
– How does it look? –
Scientists do not know exactly what Ultima Thule (pronounced TOO-lee) looks like – whether it is crater or smooth, or even if it is a single object or a cluster.
It was discovered in 2014 with the help of the Hubble Space Telescope and is believed to be 12-20 miles.
A faded and pixelated image released on Monday, taken from 1.2 million miles away, has intrigued scientists because it appears to show an elongated glob, not a round space rock.
The spaceship had to collect 900 images in the course of a few seconds while it was passing by. Even clearer images should arrive in the next three days.
"Now it's only a matter of time to see the data drop," said vice-project scientist John Spencer of the Southwest Research Institute.
Scientists decided to study Ultima Thule with New Horizons after the spaceship, which was launched in 2006, ended its main mission with flying through Pluto in 2015, with the most detailed images ever returned from the dwarf planet.
Stern said the goal is to make images of Ultima that are three times the resolution that the team had for Pluto.
– Border of planetary science –
Ultima Thule is named after a mythical, northern island in medieval literature and cartography, according to NASA.
Project scientist Hal Weaver of the John Hopkins Applied Physics Laboratory said that people did not even know the Kuiper belt – a huge ring of relics from the formation days of the solar system – until the 1990s.
"This is the limit of planetary science," Weaver said.
Another NASA spacecraft, OSIRIS-REx, also laid a new record on Monday in a orbit around the asteroid Bennu, the smallest cosmic object – about 500 meters in diameter – once circled by a spacecraft.
NASA said that the orbit of some 70 million miles (110 million kilometers) marks "a leap for humanity" because no spacecraft ever circled so close to such a small space object – one with hardly enough gravity to keep a vehicle in a stable orbit. "
The double planetary delights coincided with the 50th anniversary of the first time people ever explored another world, when American astronauts circled around Apollo 8 in December 1968 around the moon.
"As you celebrate New Year's Day, you take a look and think about the amazing things that our country and our species can do when we focus on that," wrote Stern Monday in the New York Times.