Happy New Year!
As the world celebrated the start of 2019, scientists with NASA's New Horizons spacecraft partied with them. But the bigger celebration came just over 30 minutes later, when New Horizons made history with the flyby of Ultima Thule, a mysterious object 4.1 billion miles (6.6 billion kilometers) from Earth in the Kuiper Belt, home to frozen relics left over from the birth of the solar system. It's the farthest flyby of an object in our solar system; and the second rendezvous for New Horizons, which visited Pluto in July 2015.
"We set a record! Never before has a spacecraft explored something so far away," New Horizons principal investigator Alan Stern, of the Southwest Research Institute (SwRI) in Boulder, Colorado, said after the flyby today (Jan. 1). "I mean, think of it. We're a billion miles further than Pluto, and now we're going to keep going into the Kuiper Belt. [New Horizons at Ultima Thule: Full Coverage]
New Horizons flew by Ultima Thule at 12:33 a.m. EST (0533 GMT), hurtling past at a mind-boggling 32,000 mph (51,500 km/h) as it captured the first close-up views of a Kuiper Belt object. The cosmic rendezvous occurred so far from Earth, it'll take more than 6 hours for a signal from New Horizons to reach Earth. NASA expects to hear back from the probe at 10:30 a.m. EST (1530 GMT).
"And I can't promise you success," Stern said hours before the flyby, adding that the flyby is much harder than the Pluto rendezvous. "We are straining the capabilities of this spacecraft."
NASA and JHUAPL were able to stream live webcasts and photos of the flyby. Thomas Zurbuchen, NASA's associate administrator for science, even received special dispensation from NASA chief Jim Bridenstine to attend.
"I think it is fitting that this flyby of Ultima Thule is at the interface of the 60th anniversary of Explorer 1 [the first U.S. satellite] in 2018 and the 50th anniversary of Apollo 11 in 2019," Zurbuchen said in an email that Stern read aloud Monday. "To me, this milestone for New Horizons is full of everything that NASA and NASA science is about."
Another NASA mission also hit a milestone on New Year's Eve. The space agency's sample-return probe OSIRIS-REx officially began orbiting its target asteroid Bennu on Monday (Dec. 31), making it a banner 24 hours for planetary science.
https://www.space.com/42871-new-horizons-ultima-thule-flyby-success.html?utm_source=notification
When it launched, New Horizons made the fastest departure ever from Earth, at 36,000 mph. This was possible using a standard Lockheed Martin Atlas V with an unusually powerful third stage, supplied by Boeing.
The spacecraft got even faster when it made a pass by Jupiter in 2006, gaining another 9,000 mph. The Jupiter flyby also served as a practice run for the team to take pictures and do measurements with the spacecraft's instruments. Despite getting only a very quick look at Jupiter, New Horizons did find firsts: the first close-up look at lightning at Jupiter's poles, and the first sequence of pictures showing an eruption on the volcanic moon Io.
Pluto and its moon Charon began getting bigger in New Horizons' pictures in January 2015. At first the worlds were used for navigational purposes, but as New Horizons drew closer it was possible to see details of the terrain.
As early as 2003, the National Academy of Sciences' Planetary Decadal Survey strongly recommended that the visit to Pluto include flybys of small Kuiper Belt objects (KBOs). Observing multiple targets would provide greater insight into the previously unexplored segment of the solar system. New Horizons launched in 2006 with extra fuel for such a flyby, and its power and communications systems are prepared to work at distances beyond Pluto's orbit for years to come.
In 2011, mission scientists used ground-based telescopes to begin searching for a second target, but none of the new discoveries lay within the reach of New Horizons. In 2014, the Hubble Space Telescope joined the search, locating five potential objects. One of them was 2014 MU69, which was labeled 1110113Y after its June 26, 2014, discovery and PT1 ("potential target 1") after its elevation to one of two possible destinations. In August 2015, the mission team selected 2014 MU69 as its next potential target.
"2014 MU69 is a great choice because it is just the kind of ancient KBO, formed where it orbits now, that the Decadal Survey desired us to fly by," New Horizons principal investigator Alan Stern, of the Southwest Research Institute (SwRI) in Boulder, Colorado, said in a statement. "Moreover, this KBO costs less fuel to reach [than other candidate targets], leaving more fuel for the flyby, for ancillary science, and greater fuel reserves to protect against the unforeseen."
New Horizons' final target lies about 1 billion miles (1.6 billion kilometers) beyond Pluto.
In 2017, the New Horizons team requested suggestions for nicknames from the public as part of an outreach campaign. The final decision, Ultima Thule, is a term used in medieval times to mean "beyond the known world." The nickname was submitted by about 40 different people, NASA officials said.
"MU69 is humanity's next Ultima Thule," Stern said.
It will take about 20 months for New Horizons to beam back all of its images and other observations of Ultima Thule. That's because it has just a small 15-watt transmitter to beam a vast amount of data home.
"I am in awe that we can even do this," Stern said. "The spacecraft has a 15-watt transmitter on it...that's a quarter of a light bulb. And we're receiving it from 4 billion miles away."
But the New Horizons team won't be idle during that time. Scientists are actively searching for a third Kuiper Belt object for New Horizons to potentially visit.
