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New Horizons Approaches the Most Distant Object Ever Visited. ‘We Only Get One Shot.’ New Horizons Spacecraft Completes Flyby of Ultima Thule, the Most Distant Object Ever Visited
(35 minutes later)
LAUREL, Md. — As NASA’s New Horizons spacecraft zips past a small, distant icy world early on New Year’s Day, at 12:33 a.m. Eastern time, there will still be a nagging question for people working on the mission: Did the spacecraft’s cameras get the shot? LAUREL, Md. — Midnight at the Johns Hopkins Applied Physics Laboratory looked like any other New Year’s Eve party around the world. The scientists, engineers and well-wishers in attendance counted down and cheered the start of 2019.
New Horizons collected a wealth of fascinating pictures and data on Pluto when it flew by in 2015. Now it is set to speed past another object in the solar system’s mysterious Kuiper belt region, nicknamed Ultima Thule, which should yield clues about the early days of the solar system. Thirty-three minutes later, they counted down again, this time for the real reason they had gathered. The New Horizons spacecraft, operated by the laboratory for NASA, was approaching a small, icy world nicknamed Ultima Thule, which lies a billion miles farther from the sun than Pluto and could hold clues to the formation of the solar system as we know it.
[How to follow the New Horizons flyby of Ultima Thule, or watch the video player below.] “Are you psyched?” said S. Alan Stern, New Horizons’ principal investigator, surrounded by children waving American flags. “Are you jazzed?”
Getting the flyby right at a speed of 31,500 miles per hour is a challenging task that has taken years of planning. Despite the best efforts, Ultima Thule remains almost a complete mystery to the New Horizons’ managers and everyone else less than a day before the flyby. At the moment Dr. Stern marked the spacecraft’s closest approach, the crowd cheered, more loudly than they had for the new year.
“We don’t know a thing about MU69,” said S. Alan Stern, the principal investigator for the mission, referring to 2014 MU69, Ultima Thule’s official designation here at the Johns Hopkins Applied Physics Laboratory, which is operating the mission. “We’ve never in the history of spaceflight gone to a target we knew less about. It’s remarkable that we are on the verge of learning a great deal about it.” “Go, New Horizons!” Dr. Stern shouted.
Getting the shot will require taking many pictures of empty space. That’s necessary to ensure that at least some of the photographs do include the target the scientists are aiming to study. Although calculations by the mission's managers predicted that the spacecraft would pass within 2,200 miles of the small world, known by the designation 2014 MU69, at 12:33 a.m. Eastern time on Tuesday, scientists still have to wait hours to learn whether the mission was a success.
“We’re very confident in the spacecraft, and we’re very confident in the plan that we have for the exploration of Ultima,” Dr. Stern said on Monday. “But I’d be kidding you if I didn’t tell you that we’re also on pins and needles to see out how this turns out. We only get one shot at it.”
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Imagine driving along the New Jersey Turnpike, hoping to take a picture of the Manhattan skyline. But you don’t get to look through the camera viewfinder. In fact, you have to decide days in advance when you’re going to press the shutter button. Worse, you’re not exactly sure where Manhattan is. At that time of closest approach, the spacecraft was busy making its scientific observations. Only hours later was it scheduled to turn its antenna toward Earth to confirm whether everything had gone as planned. That 15-minute message, which does not contain images or other scientific data, would then take six hours to travel the 4.1 billion miles at the speed of light to Earth.
That essentially is the challenge faced by the New Horizons team. Except instead of Manhattan, New Horizons’ managers are trying to point their instruments at a 12- to 22-mile-wide world some four billion miles away. The New Horizons team will be waiting at 10:28 a.m. on Tuesday for the start of this “phone home” communication.
At closest approach, New Horizons will take nearly 900 images at the highest resolution. Ultima Thule is expected to appear in a few. Between the start of 2019 and the time of the flyby, the revelers were treated to Brian May, best known as the lead guitarist of the rock band Queen but also an astrophysicist collaborating with the mission’s science team, introducing a music video of a new song, “New Horizons,” which he wrote for the occasion at the request of Dr. Stern.
In many ways, this flyby is more difficult than the one for Pluto. Ultima Thule is about one-100th the diameter of Pluto and far dimmer. The spacecraft is to come within 2,200 miles of Ultima Thule’s surface, less than a third of the distance of the spacecraft’s closest approach to Pluto. New Horizons to exploreNew Horizons no one has ever seen before
While Pluto has been studied for decades, Ultima Thule was discovered only four and a half years ago by the Hubble Space Telescope, and none of the telescopes on Earth have been able to clearly spot it. Dr. May said he was initially reluctant when Dr. Stern asked. “I thought this is going to be hard, because I can’t think of anything that rhymes with Ultima Thule,” he said.
Still, the New Horizons team is confident that it has figured out where it will be. For most of the rest of his time here, Dr. May was working with other scientists. “I'm not here as a celebrity,” he said.
“I think we're good,” said Marc W. Buie, an astronomer working to pin down Ultima Thule’s position. “I think we're better than good.” There was plenty of work to be done. In many ways, this flyby was more difficult than the one for Pluto in 2015, which collected a wealth of fascinating pictures and data. Ultima Thule is about one-100th the diameter of Pluto and far dimmer. While Pluto has been studied for decades, Ultima Thule was discovered only four and a half years ago by the Hubble Space Telescope, and none of the telescopes on Earth have been able to clearly spot it.
If Ultima Thule was not where the scientists thought it was, the cameras and other instruments could have been pointing at empty space instead. At closest approach, New Horizons snapped a swath of almost 900 of the highest-resolution images to make sure that the object shows up in a few.
Still, the New Horizons team was confident that it had pinned down where it would be.
“I think we're good,” said Marc W. Buie, an astronomer working to identify Ultima Thule’s position, during a news conference on Sunday. “I think we're better than good.”
In the last couple of years, there were several fortuitous times when Ultima Thule passed in front of a distant star, causing the starlight to vanish briefly, what astronomers call an occultation. That tells them that Ultima Thule was along the line of sight between Earth and the star.In the last couple of years, there were several fortuitous times when Ultima Thule passed in front of a distant star, causing the starlight to vanish briefly, what astronomers call an occultation. That tells them that Ultima Thule was along the line of sight between Earth and the star.
Using the information from the occultations, the spacecraft navigators believe they have calculated the time of the nearest approach to Ultima Thule to within six or seven seconds, Dr. Buie said. Using the information from the occultations, the spacecraft navigators believe they had calculated the time of the nearest approach to Ultima Thule to within six or seven seconds, Dr. Buie said.
That is better than was possible for Pluto, even though astronomers have been studying Pluto for decades. “We had a lot of trouble with Pluto, believe it or not,” Dr. Buie said.
Those occultation observations also showed that the object is not a sphere, but rather elongated like a long potato or perhaps two bodies touching each other.Those occultation observations also showed that the object is not a sphere, but rather elongated like a long potato or perhaps two bodies touching each other.
New Horizons itself was able to spot Ultima Thule beginning in August, although as no more than a speck of light until this weekend. As the spacecraft approached, scientists hoped to spot a rhythmic brightening and dimming of Ultima Thule, which would reveal how fast it is spinning. Instead, the brightness seems to have remained steady the whole time. New Horizons itself was able to spot Ultima Thule beginning in August, although as no more than a speck of light until this weekend. As the spacecraft approached, scientists had expected to see a rhythmic brightening and dimming of Ultima Thule, which would reveal how fast it is spinning. Instead, the brightness seems to have remained steady the whole time.
“It’s really puzzling, because we know the shape is irregular,” Dr. Stern said.“It’s really puzzling, because we know the shape is irregular,” Dr. Stern said.
While the partial federal government shutdown has little direct effect on the flyby — it is considered an essential government activity, plus most of the people working on the mission are employees of the Johns Hopkins laboratory, not NASA — it has been a bureaucratic hassle. On Monday, scientists showed an image where Ultima Thule was finally larger than a single dot of light, again indicating an elongated shape.
The laboratory has to take over some communications responsibilities usually handled by NASA, and two members of the mission’s science team who work at the NASA Ames Research Center in California needed a special exemption to come to Maryland and take part.
Final tweaks to the instructions for the flyby choreography, adjusting the time of the closest approach by a couple of seconds, were sent on Sunday to New Horizons.
Now all anyone can do at this point is watch and wait.
Early on Monday, a science fair-like atmosphere prevailed as specialists from New Horizons presented overviews of the mission and science to friends and families who came to share in the excitement. They will celebrate the start of the new year at midnight and then the closest approach of the flyby 33 minutes later, but they will not know how New Horizons, which will be busy making its scientific observations, will be doing at that moment.
“We’re very confident in the spacecraft, and we’re very confident in the plan that we have for the exploration of Ultima,” said Dr. Stern, the principal investigator for the mission. “But I’d be kidding you if I didn’t tell you that we’re also on pins and needles to see out how this turns out. We only get one shot at it.”
Hours later, the spacecraft will turn back to Earth and send a 15-minute message that will confirm that the encounter occurred, but will not include any photographs or scientific data. If all goes well, that data — which takes six hours to reach Earth — will arrive at 10:28 a.m. on Tuesday.
Over the next couple of days, preliminary looks at the data, including what the scientists hope will be striking images of Ultima Thule, will be beamed back to Earth. Twenty months will pass before scientists have the full set of measurements. And they will be eagerly awaiting every bit of that stream.Over the next couple of days, preliminary looks at the data, including what the scientists hope will be striking images of Ultima Thule, will be beamed back to Earth. Twenty months will pass before scientists have the full set of measurements. And they will be eagerly awaiting every bit of that stream.
“We are ready to science the heck out of Ultima Thule,” Dr. Stern said.“We are ready to science the heck out of Ultima Thule,” Dr. Stern said.