Wednesday , January 20 2021

On the eve of New Horizon's flying city, Ultima Thule still holds its mysteries – Spaceflight Now



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

LAUREL, Maryland – One day before NASA's new horizons, spacecraft enters a frozen outpost named Ultima Thule 4.6 billion miles from Earth, the basic facts about the city-size object continued, researchers researched Sunday as the national team went to an abundance of data and imagery that must mask the unexplored world at the boundary of the solar system.

Ultima Thule – officially named 2014 MU69 – is one billion miles beyond Pluto, the last world New Horizons visited. It is reddish in color and the researchers have found their place with remarkable precision for an object that was just discovered in 2014.

In addition, Ultima Thule's appearance is devoted to the fantasies of scientists and documentaries. It will change speed when images snapped by New Horizon's spacecraft's black and white and color cameras start coming back to Earth on Tuesday and Wednesday.

"We don't know anything about MU69," said Alan Stern, New Horizon's principal researcher from the Southwest Research Institute. "We have never, in the history of space flight, gone to a goal that we knew less about, and it is remarkable that we are knowing a lot about this.

"Today I can't tell you more than five facts about it," Stern said in a briefing with journalists on Sunday. "We know its orbit, we know its color, we know a little about its shape and its reflexivity. We can't even get the rotation period. I thought we would have it 10 weeks ago."

While scientists knew that Ultima Thule would only reveal its secrets in the last days – or hours – of air travel, the issues still unanswered have caused New Horizon's team members to cope with their creative sides.

"Our team has made small clay figures (guesses). Here's what we think it looks like today, based on the current information we have," said Hal Weaver, New Horizon's project researcher at Johns Hopkins University Applied Physics Laboratory, where New Horizons was built and home to the mission control center.

Nevertheless, the researchers believe they are starting to see some details.

The Ultima Thule has just begun to be solved by the New Horizon's LORRI imaging camera, which so far has seen the object as just a bright spot – a single pixel in the camera's field of view. It will change quickly as the probe moves toward it at 32,000 mph (14 kilometers per second).

The goal is now almost 2 pixels across, but it's still not enough to solve its shape.

"How fast is it rotating? A few hours, tens of thousands or days?" Said Weaver.

"There is some indication, some hint that it might be a fast rotator," Weaver said. "The little we've been able to tease out suggests that it can rotate fairly quickly, but we've been up and down the team about whether we believe it."

New Horizon Project Researcher Hal Weaver speaks to journalists Sunday at Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. Credit: Stephen Clark / Spaceflight Now

If Ultima Thule spins relatively quickly, it would be good news for the scientists who are eagerly waiting for their first look at such a primitive world. A fast rotator would show more of its surface to the New Horizons during fly-by.

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

Scientists expected to see Ultima Thule cushioning and glare as it rotated, New Horizons has not found any change.

"We thought when we entered and began to observe it systematically from mid-September until now that we would get someting called a light curve, which enables us to see the variation in the lust of Ultima Thule that would tell us something about the shape, said Weaver.

"We systematically made these observations and hoped to convert these observations into a form model of Ultima Thule, but every time we went back and made observations, it was just plain flat.

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

"So it may be very elongated as we think of the star's occult measurements," he said, referring to observations made when Ultima Thule cards blocked the light of a background star viewed from Earth, allowing scientists to limit its shape and size.

Cathy Olkin, Deputy Project Researcher at the Southwest Research Institute, agreed.

"I believe, based on the results of the occultation, that we saw a clear signature that it is" either elongated or two lobes … I think we will not see anything around, "Olkin said.

"I think what we should see is that we look at pole-on to the object. It is a way to reconcile that we do not see a light curve on this object. We do not see a variation in light over time repeated times. "

Scientists believe that Ultima Thule is a relic of the early solar system 4.5 billion years ago, a type of object known as a "cold classic" because it remained in approximately the same orbit where it formed. The discoveries open up a new window on how all planetary systems are born and evolved, says Jason Kalirai, the leader of the civilian space mission at APL.

"It's absolutely basic breakthrough science," said Kalirai, an astrophysicist.

Weaver said that the New Year's meeting with Ultima Thule is once in the life of most people on the New Horizon team – due to the time it takes to prepare a space mission and make it travel from Earth to the Kuiper Belt.

Launched from Cape Canaveral on January 19, 2006, New Horizons received a Jupiter gravity aid on February 28, 2007 and reached Pluto on July 14, 2015. Weaver called Pluto the gatekeeper for the Kuiper Belt, a ring of icy primordial worlds stretching over Neptune's path.

Pluto is the largest known object in the Kuiper Belt, where researchers believe that card memory has emerged.

The Kuiper Belt lies in the so-called "third zone" of our solar system, in addition to the terrestrial planets (inner zone) and gas giants (middle zone). This large region contains billions of objects, including comets, dwarf planets such as Pluto and "planetary decimal" such as Ultima Thule. The objects in this region are believed to be frozen in time – remains left from the formation of the solar system. Credit: NASA / Johns Hopkins University Applied Physics Laboratory / Southwest Research Institute

"There is nothing else on the books to do something like this," Weaver said.

"I do not think I will be alive when the next cold classic Kuiper Belt Object has come, so we are all looking forward to this fly city. In this respect, this is the limit of planetary science … As a civilization, we go into this third zone of the solar system that was not even discovered until the early 1990s. "

Researchers have brought sleeping bags, pillows and even a tent to camp here at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, as New Horizon's speeds toward Ultima Thule – the next target after Pluto.

Alice Bowman, New Horizons Mission Operations Manager, said she came to work at. 3:00 EST Sunday to get the latest navigation update and help prepare a "knowledge update" for the uplink spacecraft.

The update changed the timing of the sequence of images and data to be collected during air travel by only 2 seconds, but this is enough to require some adjustment to ensure that the cameras and sensors get the best information possible during one shot the meeting with Ultima Thule.

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

"Whatever it takes, we're here for exploration, and we're happy to spend the night if that's what it takes," she said.

New Horizons is right on the course for his meeting with Ultima Thule, and Bowman tweeted Sunday night that "Knowledge Update" was received with the spacecraft after taking 6 hours and 8 minutes to cross the distance from the Earth at 186,000mph or 300,000 miles per second.

In fact, the latest navigation update from pictures of Ultima Thule, captured by the LORRI camera on board, indicates the spacecraft. New Horizons is about 18 miles away from its destination 2100 kilometers away from the object.

Not bad for a mission that is almost 13 years away from the launch pad.

As a result of astrodynamics, New Horizons will reach its closest point to Ultima Thule at. 12.33 EST (0533 GMT) on Tuesday, New Year's Day. About four hours later, the spacecraft will pause its observations to turn its 6.9-meter (2.1-meter) antenna toward the ground to call home.

A huge 230-foot satellite dish part of NASA's Deep Space Network near Madrid receives the signals more than six hours later at. 10:29 am (1529 GMT). But the best pictures – with the Ultima Thule spanning hundreds of pixels across – don't come to the ground until the end of Tuesday and are expected to be published on Wednesday afternoon.

The black-and-white LORRI camera is programmed to take about 1,500 images during air travel. The other instruments on board the New Horizons will take color images, measure Ultima Thule's composition and take infrared data.

The Flyby command sequence is already executed by the spacecraft. Due to the great distance between Earth and Ultima Thule, scientists and engineers are handling the meeting.

New Horizons has instructions already loaded into its computer to handle any last-minute errors and continues the data collection sequence.

"At this point, the navigation effort is effectively done," said Marc Buie, a member of the New Horizon team from the Southwest Research Institute. "From here it's party time."

The last thruster firing to actually customize the course of New Horizons was completed on December 18, and there are no more options for making a course correction as flying fast approaches.

Buie led the team, observing Ultima Thule during a few star occultations, as the object went between two stars and the ground in July 2017 and August 2018.

These observations gave scientists an idea of ​​the formula for Ultima Thule, which Buie suggested might be the form of a peanut, at least according to the occult data. Some researchers believe that Ultima Thule could be a binary pair of objects, but Buie says he has excluded this opportunity based on the latest occult measurements in August.

"We just have to be patient and wait for the pictures to come in and we'll see more and more pixels," Buie said.

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Follow Stephen Clark on Twitter: @ StephenClark1.


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