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On the eve of New Horizons, Ultima Thule continues to maintain its mysteries: Spaceflight Now


This image shows the first detection of the 2014 MU69 (dubbed "Ultima Thule"), using the highest resolution mode (known as "1 × 1") of the Long Range Reconnaissance Imager (LORRI) aboard the New Horizons spacecraft. Three separate images were combined, each with an exposure time of 0.5 seconds, to produce the image shown here. The three images were taken on December 24, 2018. Credits: Laboratory of Applied Physics at the University of NASA / Johns Hopkins / Southwest Research Institute

LAUREL, Maryland – A day before the NASA Space Shuttle New Horizons closes to a freezing site called Ultima Thule at 4.1 million kilometers (6.6 billion kilometers) of Earth, the basic facts about The object of the city continued to evade scientists on Sunday, a flood of data and images that should unmask the unexplored world at the border of the solar system.

No more than 20 miles (30 miles) long, Ultima Thule, officially named 2014 MU69, is one billion miles past Pluto, the last world that New Horizons visited. It is reddish, and the scientists have pointed out their location with a remarkable precision for an object that we have just discovered in 2014.

Apart from that, the appearance of Ultima Thule is relegated to the imagination of scientists and space enthusiasts. This will change quickly, once photos burned by the black and white cameras of the New Horizons ship begin to return to Earth on Tuesdays and Wednesdays.

"We do not know anything about MU69," said Alan Stern, senior researcher of New Horizons at the Southwest Research Institute. "Never, in the history of the space flight we did not reach a goal that we knew less, and it is remarkable that we are about to know a lot about it.

"Today, I can not tell you more than five facts about it," Stern said in a meeting with journalists on Sunday. "We know its orbit, we know its color, we know a little about its shape and its reflectivity. We can not even get the period of rotation. I thought we would have it ten weeks ago."

Although scientists knew that Ultima Thule only revealed their secrets in the last days or hours of the steering wheel, questions still unanswered caused the members of the New Horizons team to take advantage of their creative sides.

"Our team is making small clay figures," said Hal Weaver, a New Horizons project scientist at the Johns Hopkins University Applied Physics Laboratory, where New Horizons was built and headquartered in the control center of the mission

However, scientists believe they are starting to see some details.

Ultima Thule is beginning to solve the New Horizons LORRI image camera, which has so far seen the object as a point of light: a single pixel in the field of vision of the camera. This will change quickly as the probe accelerates to 32,000 mph (14 kilometers per second).

The goal now has almost 2 pixels in width, but that is not enough to solve the way.

"How fast is it turning? Some hours, dozens of hours or days?" Said Weaver.

"There is some indication, some clue, that it may be a fast rotator," Weaver said. "The little we've been able to prove suggests that it can be spinning very quickly, but we've been up and down in the team about whether we believe it or not."

New Horizons project scientist Hal Weaver talks to Sunday journalists at the Applied Physics Laboratory at the Johns Hopkins University in Laurel, Maryland. Credit: Stephen Clark / Spaceflight Now

If Ultima Thule turns relatively quickly, this would be good news for researchers who eagerly awaited their first look at such a primitive world. A fast rotator showed more of its surface in New Horizons during the flyby.

One of the main mysteries so far in the Last Thule approach has been that New Horizons has not observed any curve of light, or change of brightness, from the object.

Scientists expected to see that Ultima Thule became thermal and bursting as it turned, New Horizons did not detect any change.

"We thought that we entered and we began to observe it systematically from mid-September until now that we will achieve a bright curve that will allow us to see the variation of the Ultra Thule shine that would say something to us thing about the way, Weaver said.

"We were systematically doing these observations with the hope of turning these observations into a model of Ultima Thule, but every time we return and perform observations it was completely flat.

"So it is possible that rotation can point to us, which is very unusual … It could be anywhere in the space – the rotary pole – but pointing to us is an unusual circumstance," says Weaver.

"As far as it may be that it is very lengthy, we think of the stellar measures of concealment," he said, referring to the observations made when Ultima Thule briefly blocked the light from a Star background viewed from Earth, allowing scientists to put restrictions on their shape and size.

Cathy Olkin, deputy director of the Southwest Research Institute project, agreed.

"I think that, depending on the result of the concealment, we saw a clear sign that it is" elongated or two lobes … I think we will not see anything, "said Olkin.

"I think that what we are going to see is that we are looking for pole-on the object. This is a way to reconcile the fact that we do not see a bright curve on this object. We do not see a variation of light over time repeatably ".

Scientists believe that Ultima Thule is an early solar system relic, 4,500 million years ago, a type of object known as a "cold classic" because it was kept in the same orbit where it goes to form The discoveries will open a new window on how all planetary systems are born and evolved, said Jason Kalirai, executive of the mission area of ​​the civil space mission to APL.

"It is a fundamentally foundly advanced science," said Kalirai, an astrophysicist.

Weaver said the New Year's encounter with Ultima Thule is an event once for most of the New Horizons team, due to the time it takes to prepare a space mission and make traveling from the Earth to the Kuiper belt.

New Horizons launched from the head of Canaveral on January 19, 2006, obtained gravitational assistance from Jupiter on February 28, 2007, and reached Pluto on July 14, 2015. Weaver called Pluto the guardian of Kuiper belt, a world primordial frost ring that extends beyond the Neptune orbit.

Pluto is the best known object of the Kuiper belt, where scientists believe that short-term quotes originated.

The Kuiper belt is located in the "third zone" of our solar system, beyond the terrestrial planets (inner zone) and the gas giants (middle zone). This vast region contains billions of objects, including quotes, dwarf planets such as Pluto and "planetesimals" such as Ultima Thule. The objects of this region are frozen in time: relics left of the formation of the solar system. Credit: Applied Physics Laboratory of the University of NASA / Johns Hopkins / Southwest Research Institute

"There's nothing else in the books to do anything like this," Weaver said.

"I do not think it's alive when the next cool classic of Kuiper waist objects is found, so we all hope this flight. In this sense, this is the frontier of planetary science … As a civilization, we are leaving to this third area of ​​the solar system that was not even discovered until the early nineties. "

Scientists have brought sleeping bags, pillows and even a tent to camp here at the Applied Physics Laboratory at the Johns Hopkins University in Laurel, Maryland, as New Horizons advances to Ultima Thule, his next goal after Pluton

Alice Bowman, the director of New Horizons mission operations, said she was going to work at 3 o'clock in the morning this Sunday to get the latest browsing update and help her prepare for a "knowledge update" for the upstream link to the spacecraft.

The update has changed the time of the sequence of images and data that will be collected during the flight with only 2 seconds, but this is sufficient to require a certain adjustment to guarantee that the cameras and the sensors obtain the best Possible information during the meeting with Ultima Thule.

"This last day has probably been the most intense for us," Bowman said.

"Whatever it is, we are here for the exploration and we are happy to spend the night if that's what is needed," he said.

New Horizons is right in the course of his encounter with Ultima Thule, and Bowman tweeted on Sunday night that the "knowledge update" was successfully received by the spacecraft after taking 6 hours and 8 minutes to go through the Distance from Earth at 186,000 mph or 300,000 kilometers per second.

In fact, the latest navigation update of the Ultima Thule images captured by the LORRI camera on board the ship indicates that New Horizons is about 18 miles (30 kilometers) of its 2,600 mile target (3,500 kilometers) away from the object.

Not bad for a mission that is almost 13 years out of the launching pad.

No additional command is required in the spacecraft before the flight.

Purely as a consequence of the astrodynamics, New Horizons will reach the nearest point to Ultima Thule at 12:33 a.m. EST (0533 GMT) on Tuesday, Day of the New Year. About four hours later, the spacecraft will pause for its observations to turn its 6.9-foot (2.1m) antenna to the Earth to call home.

A giant 230-foot (70m) giant dish antenna of NASA's deep space network near Madrid will receive the signals more than six hours later at 10:29 a.m. EST (1529 GMT). But the best images – with Ultima Thule that will cover hundreds of pixels – will not arrive on Earth until Tuesday afternoon and it is expected to be released to the public Wednesday afternoon.

The LORRI camera in black and white is programmed to carry around 1,500 images during the flyby. The other instruments on board New Horizons will bring color images, measure the composition of Ultima Thule and bring infrared data.

The space probe already runs the flyby script. Due to the great distance between Earth and Ultima Thule, scientists and engineers are ready for the meeting.

New Horizons has instructions already loaded on the computer to deal with the last-minute faults and continue with the data collection sequence.

"At this time, the navigation effort is effective," said Marc Buie, a member of the New Horizons team at the Southwest Research Institute. "From here on, it's time to party."

The last propeller to shoot the New Horizons trajectory was completed on December 18, and there are no more opportunities to make a correction of the course as fast as possible.

Buie led the team who watched Ultima Thule during a couple of stellar occultations when the object passed between two stars and the Earth in July 2017 and August 2018.

These observations gave scientists an idea of ​​the Last Thule form, which Buie suggested was possibly the form of a peanut, at least according to the occultation data. Some scientists believe that Ultima Thule could be a pair of binary objects, but Buie says it has ruled out this possibility, based on the most recent occlusion measures in August.

"We just have to be patient and wait for the images to go in, and we're going to see more and more pixels," said Buie.

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Follow Stephen Clark on Twitter: @ StephenClark1.

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