Artykuły o New Horizons

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Planning the New Horizons Exploration of Ultima Thule
By: Alan Stern | December 4, 2018

Alan Stern, principal investigator of NASA's New Horizons mission, gives a detailed preview of what the spacecraft will be doing in the days up to, during, and after the impending flyby of the Kuiper Belt Object 2014 MU69.


The New Horizons spacecraft flies by the Kuiper Belt Object 2014 MU69 in this artist's illustration.
NASA / JHU-APL / SwRI / S. Gribben

As I wrote in this blog last month, NASA’s New Horizons spacecraft is on approach to conduct the first ever, close exploration of a Kuiper Belt Object (KBO) on January 1, 2019. The time of closest approach will be 5:33 Universal Time (33 minutes past midnight on the U.S. east coast), with a planned closest approach distance of 3,500 kilometers (2,200 miles). Our KBO, 2014 MU69, was discovered in a dedicated Hubble Space Telescope search for flyby targets that we conducted in 2014. After a naming contest, the mission team gave “MU69” the nickname “Ultima Thule,” a Latin phrase appropriately meaning “a distant unknown region; the extreme limit of discovery.”

The primary objectives of the flyby of Ultima are to map its surface features and composition, determine if it has an atmosphere, and to search for any satellites or rings it might possess. New Horizons, which was launched in 2006 and which made the first exploration of the Pluto system in 2015, carries seven powerful scientific instruments to carry out this exploration. All will be used in the exploration of Ultima.

Meet the science instruments


The experiments on New Horizons are designed with overlapping capabilities, so that if one fails the mission's scientific objectives can still be met. NASA / JHU-APL / SWRI

Three of the payload instruments are optical devices. LORRI, the Long Range Reconnaissance Imager, is comprised of a 20-cm diameter telescope that feeds a panchromatic CCD — a digital imaging device sensitive to all visible wavelengths — and is the highest resolution imager aboard New Horizons. A second imager named Ralph contains four CCDs with color filter channels and two CCDs for panchromatic imaging. Importantly, Ralph also contains an infrared spectrometer that will be used to map the surface composition of Ultima. The third optical instrument aboard New Horizons is Alice, an ultraviolet mapping spectrometer that will be used to search for gases emitted from Ultima and determine their density and composition.

The other instruments aboard New Horizons are: SWAP and PEPSSI, both charged-particle spectrometers; REX, a radio-science instrument that will be used to determine Ultima’s surface temperature and to measure its radar reflectivity; and SDC, a student-built interplanetary-dust counter.

Planning the encounter


This illustration shows the planned flyby trajectory of New Horizons as it passes the Kuiper Belt Object 2014 MU69 on January 1, 2019. NASA / JHU-APL / SWRI

Because Ultima is small — probably just 25 km (16 miles) or so in diameter — it will remain just a point of light to New Horizons until about 2 days before the close flyby. However, in the final hours around closest approach, New Horizons will be able to map Ultima at higher resolutions than we achieved at Pluto, because we will fly by Ultima at a much closer range than we did at Pluto

We will obtain geologic mapping resolutions as high as 35 meters (110 feet) per pixel using LORRI. By comparison, our highest resolution Pluto mapping was about 80 meters (260 feet) per pixel.

With the Ralph imager, we also plan to acquire color images of Ultima with resolutions as high as 330 meters (0.2 miles) per pixel, and composition mapping at a resolution of 1.8 km (1.1 miles) per pixel. Stereo imaging made on approach will map the surface topography of Ultima at about 80 meters (260 feet) per pixel.The first detailed imagery of Ultima will be downlinked to Earth once the spacecraft has completed its main flyby objectives late on January 1st, and will be released to the public after processing and image analysis on January 2nd. More images, as well as spectra and other data sets, will be downlinked on January 2nd, 3rd, and 4th — so get ready to learn a lot about Ultima in the first week of the new year! Then the spacecraft will slip behind the Sun as seen from Earth and image transmissions will cease for 5 days until the spacecraft reappears and can resume data transmissions.


This plan illustrates what the spacecraft will be up to in the days around the flyby. The bottom panel zooms in on the hours right around closest approach and shows what instruments will be active and when. NASA / JHU-APL / SWRI

The total data volume collected on the Ultima flyby will be close to 50 gigabits. Because New Horizons is so far from Earth, about 6 billion km (4 billion miles), its data transmission speed is now only about 1,000 bits per second. This limitation, and the fact that we share NASA’s Deep Space Network of tracking and communication antennas with over a dozen other NASA missions, means that it will take 20 months or more, until late in 2020, to send all of the data about Ultima and its environment back to Earth.

Looking ahead


This illustration provides a "big picture" view of New Horizon's trajectory from Earth to the Kuiper belt and beyond.
NASA / JHU-APL / SWRI

As you read these words, New Horizons is closing in on Ultima at a speed of nearly a million miles per day. The main tasks onboard the spacecraft now are navigation imaging that drives course corrections to home in on our aim point, and a three-week-long hazard search to determine if our close approach path is safe, or if we must divert to a greater distance of 10,000 km (6,000 miles) to avoid hazards such as dust or moons. We will make a final decision on the close approach distance on December 16th.

The flyby of Ultima will be orchestrated aboard New Horizons with a computer program called “command sequence” that will be uploaded by radio and will begin 7 days prior to the flyby, on Christmas day. This command sequence will direct all of the spacecraft and science instrument activities from then until 2 days after closest approach.

Our science team just completed its final meeting before the flyby. We’ll assemble for science operations beginning December 28th at our mission control, which is at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland. We’ll be reporting results in press conferences and news releases every day from December 30th to January 4th. You can follow New Horizons on NASA TV, and on a variety of social media such as Facebook and Twitter by just searching for “New Horizons”. Our mission web site is at http://pluto.jhuapl.edu.

I’ll blog here again the week before the flyby with an update on our hazard findings, our final selection of approach distance, and late-breaking other details. Stay tuned!

Source: Planning the New Horizons Exploration of Ultima Thule

[Orionid]

NASA’s New Horizons spacecraft heads for New Year’s encounter with distant world
December 28, 2018 William Harwood [Spaceflight Now]


Artist’s concept of the New Horizons spacecraft approaching a Kuiper Belt Object. Credit: NASA/JHUAPL/SWRI

Three years and a billion miles past Pluto, NASA’s New Horizons probe is on the verge of at least one more pioneering, once-in-a-lifetime milestone: a New Year’s Day flyby of a small body known as 2014 MU69, unofficially dubbed Ultima Thule — “beyond the known world” — in a NASA naming contest.

Like Pluto, Ultima Thule (pronounced TOO-lee) is a denizen of the remote Kuiper Belt, a vast realm beyond the orbit of Neptune populated by uncounted dwarf planets and a reservoir of frozen remnants left over from the birth of the solar system 4.6 billion years ago.

Little more than a dim point of light to even the Hubble Space Telescope, Ultima Thule will be the most distant object ever directly explored, a record that likely will stand for decades to come if not longer.

If all goes well, New Horizons will race by its target at a velocity of 32,000 mph — nearly nine miles per second — at 12:33 a.m. on New Year’s Day, passing within about 2,200 miles of Ultima Thule’s as-yet-unseen surface.

Four hours later, the spacecraft will turn to aim its dish antenna at Earth to confirm a successful encounter. A few hours after that, the first high-priority images and other data will begin making their way back to the inner solar system.

“Across the whole team, people are ready, they’re in the game, we can’t wait to go exploring,” Alan Stern, the New Horizons principal investigator, said Friday. “It’s been three-and-a-half years (since the Pluto flyby), we’ve worked so hard, people are ready to see that payoff and see what we can learn about the birth of our solar system.”

At Ultima Thule’s distance of 4.1 billion miles from Earth, it will take radio signals, traveling 186,000 miles per second, six hours seven minutes and 58 seconds to cross the gulf to waiting scientists at Johns Hopkins University’s Applied Physics Laboratory near Baltimore. The first high-resolution image is expected to be unveiled during a Jan. 2 news briefing.

Despite the ongoing government shutdown, the public is expected to be able to follow along on NASA’s satellite television channel. But just in case, the Applied Physics Laboratory, which built and operates New Horizons for NASA, plans to post images and other data on the New Horizons web page and the lab’s YouTube channel.

Only a handful of images and other high-priority data are expected before New Horizons moves behind the sun as viewed from Earth on Jan. 4, temporarily interrupting communications. But even when the downlink resumes, it will take about 20 months to bring in the entire treasure trove to Earth.

That’s because of the enormous distances involved, the faint signal from New Horizons’ 30-watt transmitter and other demands on NASA’s globe-spanning Deep Space Network antennas used to communicate with spacecraft across the solar system.

For scientists eager to study an untouched remnant of the original cloud of rocky debris that coalesced to form the solar system, the long wait will be worth it.

“Everything that we have visited before has been warmed up at some point,” Stern said in an interview earlier this month. “Asteroids orbit close to the sun, the comets … were born cold, but we only have visited comets when they’re down near the Earth’s orbit, when they’re warm. The heat, the warmth causes chemical reactions to take place, it can drive surface processes, etc., that create an evolution.”

Ultima Thule, he said, “is completely unmarked by any of those things.” It is classified as a “cold classical,” that is, a Kuiper Belt body with a nearly circular orbit that is only slightly tilted to the plane of the solar system’s planets. Another major population of Kuiper Belt bodies, made up of material that originated closer to the Sun, was pushed outward by gravitational interactions in the distant past.

But not the cold classicals and Ultima Thule.

“It was born four billion miles from the sun, it has always been there, it’s temperature is just barely above absolute zero,” Stern said. “I don’t believe there’s any object we’ve ever visited that’s been kept that cold its entire existence. So this is really a time capsule, that’s the scientific value.”

New Horizons will fly more than two times closer to Ultima Thule than it did during the Pluto flyby, Stern said, “so the images are going to be much more detailed.”

“We’re going to find out how this thing is built, how much it’s evolved, what it’s made of, if it has an atmosphere, if it has moons, if it has rings, we’re going to take its temperature, we’re going to measure its radar reflectivity, we’re going to find out if it’s surrounded by a dust cloud left over from formation,” he said.

“All that stuff and more, because we’re not just going to take imagery,” he added. “We map its surface, we map it in color and in addition to that, we map it in stereo so we have topography everywhere. We’ll not just determine its composition, but we map it from place to place to see if it’s the same everywhere or if it’s made up of smaller building blocks.”

The encounter has five major objectives: to characterize the geology, morphology and topology of Ultima Thule; to map its surface color and composition; to determine its structure; to search for satellites and rings; and to look for any sort of a coma, or atmosphere.

“Ultima Thule could be heavily cratered, highly pitted or it could even be smooth from ancient flows and ancient activity,” said Carey Lisse, a New Horizons science team collaborator. “We don’t know. We simply aren’t going to know until we get there in January. I’m waiting to be surprised.”

Launched nearly 13 years ago in January 2006, New Horizons flew past Jupiter in February 2007, using the giant planet as a target to test its instruments and, more important, using its gravity to fling the craft onto a fast-track trajectory to Pluto.

Even so, moving 100 times faster than a jetliner throughout its voyage, it still took another eight long years to reach its target in July 2015, flying past at a distance of 7,800 miles to collect the first close-up pictures and a wealth of data about the solar system’s most famous dwarf planet.


This global mosaic of Pluto was created from imagery from the New Horizons spacecraft’s July 2015 flyby. Credit: NASA/JHUAPL/SWRI

While the Pluto encounter was the spacecraft’s primary goal, mission managers knew it would have left over propellant and that its nuclear power supply would keep the probe functioning through the 2020s. Well before the Pluto flyby, the team requested observing time on the Hubble Space Telescope to look for possible targets of opportunity past Pluto that might be close enough to New Horizons’ trajectory to enable another flyby.

Hubble discovered Ultima Thule in images captured on June 26, 2014. It was catalogued as 2014 MU69 and given the minor planet number 485968. An analysis of its orbit showed New Horizons could reach it with a post-Pluto trajectory correction maneuver.

After the Pluto encounter was complete, NASA managers approved a mission extension. A carefully planned rocket firing was carried out, adjusting New Horizons’ course to set up the upcoming encounter with Ultima Thule.

New Horizons did not spot its quarry until Aug. 15 this year, at a distance of more than 100 million miles. It was a barely visible pinpoint of light, and will remain little more than a brighter point of light until Monday, the day before the flyby.

Even so, scientists have at least some idea what to expect when New Horizons gets there. Based on occultation observations in which Ultima Thule passed in front of a background star as viewed from Earth, researchers believe the target is an elongated body measuring about 17 miles across. It may be made up of two bodies in close orbit or two lobes that are physically connected, a so-called “contact binary.”

Researchers know Ultima Thule receives only about 0.05 percent of the sunlight Earth does and they know it is reddish in color. But they don’t yet know its exact dimensions, whether it has any rings, moons or any trace of an atmosphere.

“Really, we have no idea what to expect,” Stern told planetary scientists during a conference in October. “We only discovered it in 2014 with the Hubble Space Telescope working at the very limit of its fantastic capabilities. We’ve been able to learn enough about its orbit to be able to intercept it and target it. But there’s very little else we know.”

Whatever they find out, it will happen very, very quickly. Ultima Thule’s small size means New Horizons’ cameras will not begin to resolve it until the day before the encounter.

On Sunday, for example, the best photos will have a resolution of about 6.2 miles per picture element, or pixel, and Ultima Thule will measure two to three pixels across. On New Year’s Eve, the resolution will improve to 3.4 miles per pixel and the body will measure five to six pixels across.

But by the evening of New Year’s Day, the resolution will have improved to 1,000 feet per pixel and the day after that, 500 feet per pixel with Ultima Thule stretching across 215 pixels.

“Although we’re traveling at about the same speed as we pass Ultima that we passed Pluto, Pluto’s about the size of a continent like North America,” Stern said. “And so, when we were 10 weeks out from Pluto we could already resolve its disk about as well as the Hubble Space Telescope, and each week we could see more and more detail.

“But Ultima 10 weeks out is just a dot in the distance. And it will remain as a dot in the distance until literally the day before the flyby when we start to resolve it. By the day after the flyby, we’ll have high resolution images, we hope even higher resolution than the best images of Pluto. So it’s going to be quick.”

New Horizons is equipped with six primary instruments: an imaging spectrometer known as Alice, a multi-spectral visible light camera called Ralph, a long-range reconnaissance imager — LORRI — incorporating an 8-inch telescope, a solar wind particle detector, an energetic particle spectrometer and a student-built dust counter.

In addition, its radio system includes circuity enabling precise analysis of changes caused when signals from Earth pass through an atmosphere.

Data is stored on redundant eight-gigabyte solid-state recorders and sent back to Earth with an X-band transmitter using an 83-inch-wide fixed dish antenna. Data transmission rates will be slightly better than 1,000 bits per second.

Stern said the encounter poses a much tougher challenge for New Horizons than Pluto did.

“This one is harder for a number of different reasons. First of all, it’s smaller and it’s fainter and so it’s harder to track, it’s harder to home in on,” he said. “It’s 100 times smaller, it’s 10,000 times fainter. Secondly, every year, the on board nuclear power supply produces less power. So now we have to much more carefully manage which instruments and avionics are on, we have to manage our power much more carefully.”


This image of Ultima Thule, or 2014 MU69, was captured by the Hubble Space Telescope in 2014. Credit: NASA/JHUAPL/SWRI

Thirteen years after launch, the spacecraft’s single radioisotope thermoelectric generator, or RTG, is producing only about 190 watts of power, roughly enough to energize three standard light bulbs.

In addition, because the science team does not know what to expect, New Horizons is going to carefully search the area around Ultima Thule, on the lookout for moons or other features, so “there are going to be a lot of images of blank sky simply because we’re trying to blanket the whole area in the event we discover a moon late.”

Four days after the flyby, communications with New Horizons will be suspended as the spacecraft moves behind the Sun as viewed from Earth. The science team has prioritized data playback to ensure a high-resolution image of Ultima Thule reaches Earth before the blackout begins.

“This is a much faster reveal than anything we’ve done on New Horizons before,” Stern said. “Essentially, it’s an overnight conversion from a dot in the distance to a real world. And I think that first week in January, when we’re getting the first detailed images back, is going to be breathtaking! Not just scientifically. I think for the people who follow the news just to see and think of what our race can do, what our species can do, is going to be amazing.”

Asked whether New Horizons can reach a third Kuiper Belt target down the road, Stern said he wants his team to stay focused on Ultima Thule in the near term. But after the encounter is complete, “we will look for another flyby target. I can’t promise anyone, you or NASA, that we will find one (but) I can tell you this: there’s nothing my team wants more than to get a second one.”

Editor’s note: Portions of this story were originally written for Astronomy Now magazine and are used here with permission.

Source: NASA’s New Horizons spacecraft heads for New Year’s encounter with distant world

[Orionid]

On eve of New Horizons flyby, Ultima Thule still holding onto its mysteries
December 30, 2018 Stephen Clark [Spaceflight Now]


This image shows the first detection of 2014 MU69 (nicknamed “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, each with an exposure time of 0.5 seconds, were combined to produce the image shown here. All three images were taken on Dec. 24, 2018. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

LAUREL, Maryland — A day before NASA’s New Horizons spacecraft closes in on a frozen outpost nicknamed Ultima Thule 4.1 billion miles (6.6 billion kilometers) from Earth, basic facts about the city-sized object continued to elude scientists Sunday as the ground team braced for a deluge of data and imagery that should unmask the unexplored world at the frontier of the solar system.

No more than 20 miles (30 kilometers) long, Ultima Thule — officially named 2014 MU69 — is a billion miles beyond Pluto, the last world New Horizons visited. It’s reddish in color, and scientists have pinpointed its location with remarkable precision for an object just discovered in 2014.

Other than that, Ultima Thule’s appearance is relegated to the imaginations of scientists and space enthusiasts. That will change in a hurry once pictures snapped by the New Horizons spacecraft’s black-and-white and color cameras begin coming back to Earth on Tuesday and Wednesday.

“We don’t know a thing about MU69,” said Alan Stern, New Horizons principal investigator from the Southwest Research Institute. “We’ve never, in the history of spaceflight, gone to a target that we knew less about, and it’s remarkable that we’re on the verge of knowing a great deal about this.

“Today, I can’t tell you more than five facts about it,” Stern said in a briefing with reporters Sunday. “We know its orbit, we know its color, we know a little bit about its shape, and its reflectivity. We can’t even get the rotational period. I thought we’d have that 10 weeks ago.”

While scientists knew Ultima Thule would only reveal its secrets in the final days — or hours — of the flyby, the questions still unanswered have prompted New Horizons team members to tap into their creative sides.

“Our team has been making little clay figures (guessing) here’s what we think it looks like today based on the current information we have,” said Hal Weaver, the New Horizons project scientist at the Johns Hopkins University Applied Physics Laboratory, where New Horizons was built and home of the mission control center.

Nevertheless, scientists think they are beginning to see some details.

Ultima Thule is just starting to be resolved by New Horizons’s LORRI imaging camera, which so far has viewed the object as just a point of light — a single pixel in the camera’s field-of-view. That will change rapidly as the probe speeds toward it at 32,000 mph (14 kilometers per second).

The target is now nearly 2 pixels across, but that’s still not enough to resolve its shape.

“How fast is it rotating? A few hours, tens of hours, or days?” Weaver said.

“There’s some indication, some hint, that maybe this is a fast rotator,” Weaver said. “The little bit that we’ve been able to tease out suggests that it may be rotating pretty quickly, but we’ve been up and down on the team as to whether or not we believe that.”


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

If Ultima Thule is spinning relatively quickly, that would be good news for the researchers eagerly awaiting their first look at such a primitive world. A fast rotator would show more of its surface to New Horizons during the flyby.

One of the main mysteries so far in the 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 dimming and brightening as it rotated, New Horizons has not detected any change.

“We thought as we came in and started observing it systematically from mid-September up until now that we would get someting called a light curve, which allows us to see the variation in the brightness of Ultima Thule that would tell us something about the shape,” Weaver said.

“We were systematically making these observations hoping to be able to convert these observations into a shape model of Ultima Thule, but every time we went back and made observations it was just completely flat.

“So it’s possible that the rotation is maybe pointing towards us, which is a highly unusual… It could be anywhere in space — the rotational pole — but pointing toward us is an unusual circumstance,” Weaver says.

“So it may be that it’s highly elongated, which we think because of the stellar occultation measurements,” he said, referring to observations made when Ultima Thule briefly blocked the light of a background star as seen from Earth, allowing scientists to put constraints on its shape and size.

Cathy Olkin, deputy project scientist at the Southwest Research Institute, agreed.

“I think, based on the occultation result, we saw a clear signature that its’ either elongated or two lobes … I do believe that we’re not going to see something that’s round,” Olkin said.

“I think that what we’re going to see is that we’re looking pole-on to the object. That’s one way to reconcile the fact that we don’t see a light curve on this object. We don’t see a variation in light over time repeatably.”

Scientists believe Ultima Thule is a relic from the early solar system 4.5 billion years ago, a type of object known as a “cold classical” because it stayed in roughly the same orbit where it formed. The discoveries will open a new window into how all planetary systems are born and evolve, said Jason Kalirai, executive for the civil space mission area at APL.

“It’s absolutely foundational breakthrough science,” said Kalirai, an astrophysicist.

Weaver said the New Year’s encounter with Ultima Thule is a once-in-a-lifetime event for most people on the New Horizons team — due to the time it takes to prepare a space mission and have it travel from Earth to the Kuiper Belt.

New Horizons launched from Cape Canaveral on Jan. 19, 2006, got a gravitational assist by Jupiter on Feb. 28, 2007, then reached Pluto on July 14, 2015. Weaver called Pluto the gatekeeper to the Kuiper Belt, a ring of icy primordial worlds extending beyond the orbit of Neptune.

Pluto is the largest known object in the Kuiper Belt, where scientists think short-period comets originated.


The Kuiper Belt lies in the so-called “third zone” of our solar system, beyond the terrestrial planets (inner zone) and gas giants (middle zone). This vast region contains billions of objects, including comets, dwarf planets like Pluto and “planetesimals” like Ultima Thule. The objects in this region are believed to be frozen in time — relics left over from the formation of the solar system. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

“There’s nothing else on the books to do anything like this,” Weaver said.

“I don’t think I’ll be alive when the next cold classical Kuiper Belt Object is encountered, so we’re all looking forward to this flyby. In that respect, this is the frontier of planetary science … As a civilization, we’re stepping out into this third zone of the solar system that was not even discovered until the early 1990s.”

Scientists have brought sleeping bags, pillows, and even a tent to camp out here at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, as New Horizons speeds toward Ultima Thule — its next target after Pluto.

Alice Bowman, the mission operations manager for New Horizons, said she came into work at 3 a.m. EST Sunday to get the latest navigation update and help prepare a “knowledge update” for uplink to the spacecraft.

The update changed the timing of the sequence of images and data to be gathered during the flyby by just 2 seconds, but that’s enough to require some adjustment to ensure the cameras and sensors get the best information possible during the one-shot encounter with Ultima Thule.

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

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

New Horizons is right on course for its encounter with Ultima Thule, and Bowman tweeted Sunday night that the “knowledge update” was successfully received by the spacecraft after taking 6 hours and 8 minutes to traverse the distance from Earth at 186,000 mph, or 300,000 kilometers per second.

In fact, the latest navigation update from pictures of Ultima Thule captured by the LORRI camera on-board the spacecraft indicate New Horizons is around 18 miles (30 kilometers) off its aim point 2,200 miles (3,500 kilometers) away from the object.

Not bad for a mission that’s nearly 13 years off the launch pad.

No further commands are expected to be sent to the spacecraft before the flyby.

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

A giant 230-foot (70-meter) dish antenna part 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 spanning hundreds of pixels across — won’t arrive on Earth until late Tuesday, and are expected to be released to the public Wednesday afternoon.

The black-and-white LORRI camera is programmed to take around 1,500 pictures during the flyby. The other instruments aboard New Horizons will take color images, measure Ultima Thule’s composition, and take infrared data.

The flyby command sequence is already being executed by the spacecraft. Because of the vast distance between Earth and Ultima Thule, scientists and engineers are hands-off for the encounter.

New Horizons has instructions already loaded into its computer to handle any last-minute glitches and continue the data-gathering sequence.

“At this point, the navigation effort is effectively finished,” said Marc Buie, a member of the New Horizons team from Southwest Research Institute. “From here on out, it’s party time.”

The last thruster firing to actually tweak the trajectory of New Horizons was completed Dec. 18, and there are no more opportunities to do a course correction as the flyby fast approaches.

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

Those observations gave scientists an idea of the shape of Ultima Thule, which Buie suggested was possibly the shape of a peanut, at least according to the occultation data. Some scientists believe Ultima Thule could be a binary pair of objects, but Buie says he has ruled out that possibility, based on the most recent occultation measurements in August.

“We just have to be patient and wait for the images to come in, and we’re going see more and more pixels,” Buie said.

Source: On eve of New Horizons flyby, Ultima Thule still holding onto its mysteries

[Orionid]

New Horizons scientists elated as Ultima Thule’s shape comes into view
January 1, 2019 Stephen Clark [Spaceflight Now]


At left is a composite of two images taken by New Horizons’ high-resolution Long-Range Reconnaissance Imager (LORRI), which provides the best indication of Ultima Thule’s size and shape so far. Preliminary measurements of this Kuiper Belt object suggest it is approximately 20 miles long by 10 miles wide (32 kilometers by 16 kilometers). An artist’s impression at right illustrates one possible appearance of Ultima Thule, based on the actual image at left. The direction of Ultima’s spin axis is indicated by the arrows. Credits: NASA/JHUAPL/SwRI; sketch courtesy of James Tuttle Keane

LAUREL, Maryland — A fresh image from NASA’s New Horizons spacecraft released Tuesday showed the mission’s distant flyby target a billion miles beyond Pluto — nicknamed Ultima Thule — has an elongated shape like that of a peanut shell or a bowling pin, and the prospect of higher-resolution pictures arriving on Earth later in the day had scientists salivating for more.

“I don’t know about all of you, but I’m really liking this 2019 thing so far,” said Alan Stern, the New Horizons mission’s principal investigator from the Southwest Research Institute. “We’re here to tell you that last night, overnight, the United States spacecraft New Horizons conducted the farthest exploration in the history of humankind, and did so spectacularly. Thousands of operations on board the spacecraft had to work correctly in order for us to be able to tell you this, and now we know that it all did.”

New Horizons phoned home hours after its encounter with Ultima Thule, and the ground team at the Johns Hopkins University Applied Physics Laboratory here confirmed the first signals from the probe since the flyby arrived on Earth at 10:31 a.m. EST (1531 GMT) Tuesday.

Subsystems aboard New Horizons looked good at first check, including the probe’s solid state recorders, indicating the spacecraft gathered the data intended during the flyby of Ultima Thule, the most distant planetary body ever explored up-close by a space mission.

“We have a healthy spacecraft, we’ve just accomplished the most distant flyby,” said Alice Bowman, mission operations manager, known by the acronym MOM.

An hour later, scientists gathered in a press conference to present a new image of Ultima Thule.

Alan Stern, the New Horizons mission’s principal investigator from the Southwest Research Institute, joked that it’s “OK to laugh” at the blurry image released Tuesday, which was the sharpest view the spacecraft’s Long-Range Reconnaissance Imager, or LORRI, black-and-white camera obtained of Ultima Thule before zipping past the object at a velocity of more than 32,000 mph (14 kilometers) per second at 12:33 a.m. EST (0533 GMT) New Year’s Day.

“But it’s better than the one we had yesterday,” Stern told an auditorium of scientists, reporters and space enthusiasts gathered at the Johns Hopkins University Applied Physics Laboratory, where the New Horizons spacecraft was built and home to the mission control center.

“In my line of work, we like to interpret even images like this. … First, we have a better handle on the size of Ultima, it’s about 35 by 15 kilometers (21 miles by 9 miles),” Stern said. “Secondly, you see its irregular shape. There are two possibilities here. One possibility is that it’s bilobate with the upper lobe being smaller than the lower lobe, so they would be asymmetric. Or it may be these are two things that are actually in orbit around each other and just blurred together because of their proximity. Tomorrow, we will know which of those is the case.”

Scientists have already been able to solve one mystery about Ultima Thule, which has an official name of 2014 MU69, designating its discovery by astronomers using the Hubble Space Telescope in 2014.

“Ultima is finally revealing its secrets to us,” said Hal Weaver, New Horizons project scientist at APL. “Even though it’s a pixelated blob still, it’s a better pixelated blob than the day before. In fact, these images have allowed us to resolve something that was really puzzling to the scientists.”

The axis of Ultima Thule’s rotation appears to be pointing roughly toward the direction of the New Horizons spacecraft’s approach, giving it the appearance of spinning like a propeller. That would explain why scientists did not see any significant change in Ultima Thule’s brightness as New Horizons homed in on the distant, icy world, which kept the team from determining its rotation rate.


This sequence of three images from New Horizons, received on Dec. 31, taken 70 and 85 minutes apart illustrates the rotation of Ultima Thule. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Before Tuesday’s flyby with New Horizons, scientists were uncertain whether Ultima Thule was actually one object, or perhaps two bodies orbiting in close proximity to one another. The latest image suggests it is more likely a single body, but scientists still did not rule out the binary explanation for Ultima Thule’s appearance.

“My bet would be it’s probably a single object, it’s bilobate, and if I’m wrong I’ll tell you tomorrow,” Stern said. “If it’s two separate objects, this would be an unprecedented situation in terms of how close they’re orbiting to one another. it would be spectacular to see, and I’d love to see it, but I think the higher probability is it’s a single body.”

Better images from the New Horizons spacecraft’s LORRI camera should be received by NASA’s Deep Space Network antennas beginning around 3 p.m. EST (2000 GMT) Tuesday. That communications downlink from New Horizons is expected to last until 6:35 p.m. EST (2335 GMT), according to Bowman, followed by another window to receive signals at 11 p.m. EST (0400 GMT Wednesday).

The transmissions will take roughly 6 hours and 8 minutes to travel the vast distance between New Horizons and Earth at light speed — 186,000 miles per second, or 300,000 kilometers per second.

The probe’s 15-watt transmitters can beam data down to scientists at 500 to 1,000 bits per second, so it will take 20 months to get all the data and imagery to the ground. The downlink will be interrupted from Jan. 4 until mid-January because New Horizons — located in the constellation Sagittarius as seen from Earth — will be too close to the sun in the sky for reliable communications.

“This mission has always ben about delayed gratification,” Stern said. “It took us 12 years to sell it (to NASA). It took us five years to build it, and it took us nine years just to get to the first target.”

Ultima Thule is part of the Kuiper Belt, a “third zone” of the solar system beyond the inner and outer planets, and New Horizons is the first space mission to visit objects residing so far from the sun, following its 2015 first-ever encounter with Pluto and this week’s flyby of Ultima Thule. Ultima Thule takes 298 years to complete one orbit around the sun, and scientists believe it has been in the same region of the solar system since the formation of the planets 4.5 billion years ago.


The Kuiper Belt lies in the so-called “third zone” of our solar system, beyond the terrestrial planets (inner zone) and gas giants (middle zone). This vast region contains billions of objects, including comets, dwarf planets like Pluto and “planetesimals” like Ultima Thule. The objects in this region are believed to be frozen in time — relics left over from the formation of the solar system. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

“There are really two attributes of Ultima Thule that make it so scientifically valuable for us,” Stern said.

“First, because it’s so far from the sun, and the sunlight is so weak out there that the temperatures are down near absolute zero,” he said. “As a result of that, chemical reactions are essentially frozen, so the object is in such a deep freeze thats it’s perfectly preserved from its original formation.

“When you combine that deep freeze with the fact that Ultima is a small body, only tens of kilometers across, it can’t have a strong geologic engine like Pluto, for example, which is also cold but you could see the activity on its surface and (in) its atmosphere. Ultima doesn’t have the ability to evolve that way.

“So everything we’re going to learn about Ultima, from its composition, to its geology, to how it was orginally assembled, whether it has satellites and an atmosphere, and those kinds of things, are going to teach us about the original formation conditions of objects in the solar system,” Stern said. “All the other things that we’ve gone out and orbited and flown by and landed on can’t tell us because they’re either large and they evolved, or they’re warm, and they evolved for that reason. Ultima is completely unique.”

Source: New Horizons scientists elated as Ultima Thule’s shape comes into view

[Orionid]

New Horizons completes flyby of Ultima Thule
by Jeff Foust — January 1, 2019 [SpaceNews]
Updated 1 p.m. Eastern with press conference comments.


Alan Stern, the principal investigator for New Horizons, high-fives Alice Bowman, mission operations manager, after controllers received a transmission from the spacecraft Jan. 1 confirming the success of the flyby. Credit: NASA/Bill Ingalls

LAUREL, Md. — NASA’s New Horizons completed a close approach to a small body in the distant Kuiper Belt early Jan. 1, collecting data that may reveal new insights about the formation of the solar system.

New Horizons made its closest approach to 2014 MU69, also known as Ultima Thule, at 12:33 a.m. Eastern, passing approximately 3,500 kilometers from the Kuiper Belt object. While the approach was celebrated at the time during an event at the Johns Hopkins University Applied Physics Laboratory (APL) here, the spacecraft was not in communications with the Earth.

NASA’s Deep Space Network received a signal from the spacecraft at 10:29 a.m. Eastern. That initial transmission contained no science data but rather telemetry about the health of the spacecraft and its performance during the flyby, including how much data it collected. Future downlinks, including one scheduled for later Jan. 1, will start returning science data.

“We have a healthy spacecraft,” said Alice Bowman, the New Horizons mission operations manager, after reviewing that initial burst of telemetry from the spacecraft, 6.6 billion kilometers from the Earth. “We’ve just accomplished the most distant flyby. We are ready for Ultima Thule science transmission.”

Prior to closest approach, project officials were optimistic that the spacecraft would perform the flyby as planned. “We’re very confident in the spacecraft and very confident in the plan that we have for the exploration of Ultima,” said Alan Stern, principal investigator for New Horizons, at a Dec. 31 press conference. “But I’d be kidding you if I didn’t tell you that we’re also on pins and needles to see how this turns out.”

“The New Horizons team makes it look easy. It’s not easy,” Stern said at a press conference here Jan. 1 after hearing back from the spacecraft. “From everything that we can tell, they scored a 100 on the test.”

While the signal contained no science data, project scientists did release some findings from data collected prior to closest approach and transmitted to Earth Dec. 31. That includes a better image of Ultima Thule, which appears similar in shape to a peanut or bowling pin, about 35 kilometers long and 15 kilometers wide.


A composite image (left) of 2014 MU69, aka Ultima Thule, taken by New Horizons Dec. 31, along with a sketch showing the estimated rotation axis of the object. Credit: NASA/JHUAPL/SwRI; James Tuttle Keane

Stern said scientists can’t rule out that Ultima Thule is a binary object, with two bodies orbiting very close to each other, but believe it’s more likely it is a single body with two distinct lobes.

That shape would not be surprising. “Most of the small bodies in the solar system are highly elongated,” said Hal Weaver, New Horizons project scientist, because the objects aren’t massive enough that gravity can shape them into something more spherical. “We were expecting to have something along these lines.”

Those pre-flyby observations also resolved a mystery about the lack of brightness variations as it rotated. Weaver said images taken as New Horizons approached revealed that the rotational pole of Ultima Thule was pointed almost directly at the spacecraft, as some scientists speculated in recent days. “It was almost like a propeller blade,” Weaver said, showing the same profile as it spun around. “There’s no change in the brightness because we’re always seeing the same side.”

What’s not yet clear, he added, is the rotation rate of the object. The observations so far can be explained by rotation periods of 15 and 30 hours, but upcoming data should resolve that difference.

Better images of Ultima Thule will come in the next few days, with at least one such image scheduled for release at a Jan. 2 briefing. “It’s going to be dramatically different,” Weaver said. “Ultima Thule will be turned into a real world.”

It will take about 20 months for New Horizons to transmit the estimated seven gigabytes of data it collected during the flyby. The next few days will see some high-resolution images, Stern said, although the sharpest images — with an estimated resolution as good as 33 meters per pixel — won’t come down until February. Some initial spectral data will also be returned this week.

The science team will work with those data this week, then take a break next week when the spacecraft is in solar conjunction, with the sun blocking communications with the spacecraft. The science team will reconvene around Jan. 15, Stern said, after communications resume.

“The images that will start to come down this week will already reveal the basic geology and structure of Ultima,” Stern said. “We’re going to start writing our first scientific paper next week.”

What makes Ultima Thule interesting to scientists is that is part of a population of “cold classical” Kuiper Belt objects whose orbits, with low inclinations and eccentricities, suggest that they are pristine objects unaltered since the formation of the solar system 4.6 billion years ago.

“Nothing has happened to these things since they formed,” said John Spencer, a member of the New Horizons science team, at a pre-flyby briefing. “It’s a very special region that we’re very excited to explore.”

Source: New Horizons completes flyby of Ultima Thule

[Orionid]

New Horizons shows Ultima Thule looks like a snowman, or maybe BB-8
The Kuiper Belt object is probably two rocks stuck together
BY LISA GROSSMAN 5:42PM, JANUARY 2, 2019 [ScienceNews]


A JOLLY HAPPY SOUL  New Horizons snapped this picture of 2014 MU69 (nicknamed Ultima Thule) from a distance of about 28,000 kilometers, about half an hour before the spacecraft’s closest approach to the space rock. Clearer pictures should arrive in the next few days.

The results are in: Ultima Thule, the distant Kuiper Belt object that got a close visit from the New Horizons spacecraft on New Year’s Day, looks like two balls stuck together.

“What you are seeing is the first contact binary ever explored by a spacecraft, two separate objects that are now joined together,” principal investigator Alan Stern of the Southwest Research Institute in Boulder, Colo., said January 2 in a news conference held at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.

“It’s a snowman, if it’s anything at all,” Stern said. (Twitter was quick to supply another analogy: the rolling BB-8 droid from Star Wars.)

https://twitter.com/JoAnnaScience/status/1080541996102680576

That shape is enough to lend credence to the idea that planetary bodies grow up by the slow clumping of small rocks. Ultima Thule, whose official name is 2014 MU69, is thought to be among the oldest and least-altered objects in the solar system, so knowing how it formed can reveal how planets formed in general (SN Online: 12/18/18).

“Think of New Horizons as a time machine ... that has brought us back to the very beginning of solar system history, to a place where we can observe the most primordial building blocks of the planets,” said Jeff Moore of NASA’s Ames Research Center in Moffett Field, Calif., who leads New Horizons’ geology team. “It’s gratifying to see these perfectly formed contact binaries in their native habitat. Our ideas of how these things form seem to be somewhat vindicated by these observations.”

The view from about 28,000 kilometers away shows that MU69 is about 33 kilometers long and has two spherical lobes, one about three times the size of the other. The spheres are connected by a narrow “neck” that appears brighter than much of the rest of the surface.


RUSTY HUES The Kuiper Belt object’s reddish color could be from radiation altering exotic ices like methane or nitrogen. SWRI/JHU-APL/NASA

That could be explained by small grains of surface material rolling downhill to settle in the neck, because small grains tend to reflect more light than large ones, said New Horizons deputy project scientist Cathy Olkin of the Southwest Research Institute. Even the brightest areas reflected only about 13 percent of the sunlight that hit them, though. The darkest reflected just 6 percent, about the same brightness as potting soil.

Measurements also show that MU69 rotates once every 15 hours, give or take one hour. That’s a Goldilocks rotation speed, Olkin said. If it spun too fast, MU69 would break apart; too slow would be hard to explain for such a small body. Fifteen hours is just right.

The lobes’ spherical shape is best explained by collections of small rocks glomming together to form larger rocks, Moore said. The collisions between the rocks happened at extremely slow speeds, so the rocks accreted rather than breaking each other apart. The final collision was between the two spheres, which the team dubbed “Ultima” (the bigger one) and “Thule” (the smaller one).

That collision probably happened at no more than a few kilometers per hour, “the speed at which you might park your car in a parking space,” Moore said. “If you had a collision with another car at those speeds, you may not even bother to fill out the insurance forms.”

New Horizons also picked up MU69’s reddish color. The science team thinks the rusty hue comes from radiation altering exotic ice, frozen material like methane or nitrogen rather than water, although they don’t know exactly what that ice is made of yet.

The spacecraft is still sending data back to Earth, and will continue transmitting details of the flyby for the next 18 months. Even as the New Horizons team members shared the first pictures from the spacecraft’s flyby, data was arriving that will reveal details of MU69’s surface composition.

“The real excitement today is going to be in the composition team room,” Olkin said. “There’s no way to make anything like this type of observation without having a spacecraft there.”

Source: New Horizons shows Ultima Thule looks like a snowman, or maybe BB-8

[Orionid]

New Horizons' Historic Flyby of Ultima Thule Reveals 'Entirely New Kind of World'
By Paul Scott Anderson, on January 2nd, 2019 [AmericaSpace]


The first detailed image of Ultima Thule, showing two rounded lobes with a bright “neck” connecting them. It was taken at 5:01 Universal Time on Jan. 1, 2019, just 30 minutes before closest approach from a range of 18,000 miles (28,000 kilometers), with an original scale of 730 feet (140 meters) per pixel. Image Credit: NASA/JHUAPL/SwRI

NASA’s New Horizons spacecraft has just completed its newest flyby – of the Kuiper Belt Object (KBO) called Ultima Thule (aka 2014 MU69). New Horizons sped past the small but intriguing little world at 12:33 a.m. EST on Jan. 1, 2019. The event marks a milestone for the most distant object in the Solar System ever to be visited by a spacecraft from Earth. The good news was first reported during a NASA press conference on January 1. The flyby has revealed an “entirely new kind of world” according to today’s follow-up press conference.

“This flyby is a historic achievement,” said New Horizons Principal Investigator Alan Stern of the Southwest Research Institute in Boulder, Colorado. “Never before has any spacecraft team tracked down such a small body at such high speed so far away in the abyss of space. New Horizons has set a new bar for state-of-the-art spacecraft navigation.”

“Congratulations to NASA’s New Horizons team, Johns Hopkins Applied Physics Laboratory and the Southwest Research Institute for making history yet again. In addition to being the first to explore Pluto, today New Horizons flew by the most distant object ever visited by a spacecraft and became the first to directly explore an object that holds remnants from the birth of our solar system,” said NASA Administrator Jim Bridenstine. “This is what leadership in space exploration is all about.”


In this earlier lower-resolution pre-flyby image (January 1) , the general shape of Ultima Thule can be seen, resembling a bowling pin or peanut. The diagram shows the rotation direction of the object. Image Credit: NASA/JHUAPL/SwRI; sketch courtesy of James Tuttle Keane


And the image from the next day (January 2). Image Credit: Image Credit: NASA/JHUAPL/SwRI


Some of the basic surface features seen so far. Image Credit: Image Credit: NASA/JHUAPL/SwRI


Color variation seen in the early images. At left is an enhanced color image taken by the Multispectral Visible Imaging Camera (MVIC), produced by combining the near infrared, red and blue channels. The center image taken by the Long-Range Reconnaissance Imager (LORRI) has a higher spatial resolution than MVIC by approximately a factor of five. At right, the color has been overlaid onto the LORRI image to show the color uniformity of the Ultima and Thule lobes. Note the reduced red coloring at the neck of the object. Image Credit: Image Credit: NASA/JHUAPL/SwRI


The topography of Ultima Thule isn’t clear yet, but there are interesting hints, such as the “divots” connected by a long, dark marking. Image Credit: Image Credit: NASA/JHUAPL/SwRI

The new images – taken from as close as 17,000 miles (27,000 kilometers) during approach – revealed Ultima Thule to be a “contact binary,” consisting of two connected spheres. End to end, the little world measures 19 miles (31 kilometers) in length. The team has dubbed the larger sphere “Ultima” (12 miles/19 kilometers across) and the smaller sphere “Thule” (9 miles/14 kilometers across).

One of the most prominent features is a distinct brighter “band” circling the “neck” where the two spheres connect. Scientists don’t know how it formed yet, but it may be composed of smaller grains of material that accumulated in the neck crevice. Scientists said the two lobes probably came into contact with each other very, very slowly, no faster than two cars in a fender-bender.

This is the first time ever that humanity has explored an object in the Kuiper Belt, the region of asteroid-like bodies in the outer Solar System, out past the orbit of Neptune.

Signals from the spacecraft reached the mission operations center at the Johns Hopkins Applied Physics Laboratory (APL) yesterday at 10:29 a.m. EST, almost exactly 10 hours after New Horizons’ closest approach to the object.

“New Horizons performed as planned today, conducting the farthest exploration of any world in history – 4 billion miles from the Sun,” said Principal Investigator Alan Stern, of the Southwest Research Institute in Boulder, Colorado. “The data we have look fantastic and we’re already learning about Ultima from up close. From here out the data will just get better and better!”


The New Horizons team provides the latest updates on the historic flyby of Ultima Thule, the farthest exploration of any world, ever.


A successful flyby! Image Credit: Image Credit: NASA/JHUAPL/SwRI

Images and other science data are currently being sent back to Earth. The first images showed Ultima Thule in low resolution, as expected, but they were good enough to see that the object was shaped kind of like a bowling pin or peanut, with two distinct lobes, and is approximately 20 by 10 miles (32 by 16 kilometers) in size.

“New Horizons is like a time machine, taking us back to the birth of the solar system. We are seeing a physical representation of the beginning of planetary formation, frozen in time,” said Jeff Moore, New Horizons Geology and Geophysics team lead. “Studying Ultima Thule is helping us understand how planets form – both those in our own solar system and those orbiting other stars in our galaxy.”

A previous mystery reported on earlier – the puzzling lack of a light curve – has also been solved. Ultima Thule is “spinning” like a propeller, with its axis tinted in the direction of the spacecraft. This explains why its brightness didn’t seem to change as it rotated.

“New Horizons holds a dear place in our hearts as an intrepid and persistent little explorer, as well as a great photographer,” said Johns Hopkins Applied Physics Laboratory Director Ralph Semmel. “This flyby marks a first for all of us — APL, NASA, the nation and the world — and it is a great credit to the bold team of scientists and engineers who brought us to this point.”


Ultima Thule is the most distant object ever visited by a spacecraft from Earth – about a billion miles past Pluto. Image Credit: Image Credit: NASA/JHUAPL/SwRI

The flyby itself may be over now – almost 13 years after its launch – but New Horizons will continue to send back images and science data in the days and months ahead. It will take about 20 months for all of the data to be sent to Earth. Scientists will also look for a possible next target, another KBO, for a flyby sometime in the 2020s.

“Reaching Ultima Thule from 4 billion miles away is an incredible achievement. This is exploration at its finest,” said Adam L. Hamilton, president and CEO of the Southwest Research Institute in San Antonio. “Kudos to the science team and mission partners for starting the textbooks on Pluto and the Kuiper Belt. We’re looking forward to seeing the next chapter.”

“In the coming months, New Horizons will transmit dozens of data sets to Earth, and we’ll write new chapters in the story of Ultima Thule – and the Solar System,” said Helene Winters, New Horizons Project Manager.

All of the press conference slides can be seen here and here and all raw images from the flyby are available here.

More information about New Horizons is available on the mission website.

Source: New Horizons' Historic Flyby of Ultima Thule Reveals 'Entirely New Kind of World'

[Orionid]

Most distant object ever visited resembles a snowman
January 2, 2019 Stephen Clark [Spaceflight Now]


The Kuiper Belt Object 2014 MU69 — nicknamed “Ultima Thule” — appears as a dual-lobe contact binary in this photo captured by NASA’s New Horizons spacecraft at a distance of around 18,000 miles (28,000 kilometers). Credit: NASA/SWRI/JHUAPL

LAUREL, Maryland — The first well-resolved image of the faraway chunk of rock fleetingly visited by NASA’s New Horizons spacecraft on New Year’s Day reveals the object — officially named 2014 MU69 but nicknamed Ultima Thule — is made of two lobes scientists say came together in an ancient slow-speed collision just as the solar system’s planets were forming.

Roughly the size of a large metropolitan area, the frozen world located 4.1 billion miles (6.6 billion kilometers) is a relic left over from the birth of the solar system some 4.5 billion years ago. The plutonium-powered New Horizons spacecraft targeted Ultima Thule after zipping past Pluto in July 2015.

Scientists revealed the sharpest image of Ultima Thule, nicknamed for an ancient term meaning “beyond the known world,” in a press conference Wednesday at the Johns Hopkins University Applied Physics Laboratory here, where New Horizons was built and home of the mission control center. The new images, taken just before the craft’s closest approach, were the first to reveal details about Ultima Thule’s shape, a day after the previously-best picture only resolved the object as a fuzzy blob.

“That image is so 2018,” said Alan Stern, New Horizons principal investigator from the Southwest Research Institute, referring to the New Year’s Eve pre-flyby picture. “Meet Ultima Thule! Just like with Pluto, we could not be happier. What you’re seeing is the first contact binary ever explored by spacecraft. It’s two completely separate objects that are now joined together.”

The bigger of the two lobes has been nicknamed Ultima, and the smaller one Thule, Stern said. The bigger section is around three times the volume of the smaller one.

Shaped like a charcoal-colored snowman in black-and-white images, Ultima Thule actually appears reddish in color imagery captured by the New Horizons spacecraft, according to Carly Howett, a co-investigator on the mission from the Southwest Research Institute.

Scientists have also nailed down Ultima Thule’s rotation rate, a basic characteristic that eluded the New Horizons team during the spacecraft’s approach.

“We now know that Ultima rotates with a period of 15 hours, give or take one hour,” said Cathy Olkin, the mission’s deputy project scientist from the Southwest Research Institute.

Olkin said the object’s rotation axis was tilted about 30 degrees from the spacecraft’s approach vector, meaning much of the same face of Ultima Thule always faced New Horizons as it sped toward the New Year’s Day Encounter.


The first color image of Ultima Thule, taken at a distance of 85,000 miles (137,000 kilometers) at 0408 GMT on Jan. 1, 2019 (11:08 p.m. EST on Dec. 31), highlights its reddish surface. At left is an enhanced color image taken by the Multispectral Visible Imaging Camera (MVIC), produced by combining the near infrared, red and blue channels. The center image taken by the Long-Range Reconnaissance Imager (LORRI) has a higher spatial resolution than MVIC by approximately a factor of five. At right, the color has been overlaid onto the LORRI image to show the color uniformity of the Ultima and Thule lobes. Note the reduced red coloring at the neck of the object. Credit: NASA/SWRI/JHUAPL

Stern said the spacecraft’s one-shot encounter went according to plan, with the probe zooming past Ultima Thule at a distance of around 2,200 miles (3,500 kilometers) at 12:33 a.m. EST (0533 GMT) on New Year’s Day. He called the flyby “a technical success beyond anything ever attempted before in spaceflight.”

Discovered by the Hubble Space Telescope in 2014, Ultima Thule is the most distant planetary body ever explored up-close, and a building block of planetary formation scientists said has been undisturbed for billions of years, holding clues about the conditions in the early solar system.

“What this spacecraft and this team accomplished is unprecedented,” Stern said Wednesday. “The object that we rendezvoused with at midnight on New Year’s Day wasn’t even known until the summer of 2014.

“It’s only really the size of something like Washington D.C., and it’s about as reflective as garden variety dirt, and it’s illuminated by a sun that’s 1,900 times fainter than it is outside on a sunny day here on the Earth,” Stern continued. “So we were basically chasing it down in the dark at 32,000 mph (14 kilometers per second), and all that had to happen just right, as did the entire sequence.”

The results discussed in Wednesday’s press conference are preliminary. According to Stern, far less than 1 percent of the data collected during the flyby has been downlinked to Earth, a time-consuming process expected to take 20 months because of the slow transmission rate over the vast distance to New Horizons.

Jeff Moore, New Horizons geology and geophysics team lead from NASA’s Ames Research Center, said Ultima Thule likely formed by a low-speed merger between two bodies more than 4 billion years ago, at the earliest stages of the birth of the solar system’s planets.

“We think what we’re looking at is perhaps the most primitive object that has yet been seen by any spacecraft, and may represent a class of objects which are the oldest and most primitive objects that can be seen anywhere in the present solar system,” Moore said.

“What we think we’re looking at is the end product of a process which probably took place in only a few hundred thousand or maybe a few million years at the very beginning of the formation of the solar system, where initially you have innumerable small particles or pebbles that swirl together into little nodes,” Moore said.


Credit: NASA TV/Spaceflight Now

Through collisions and gravitational interactions, the debris grew into larger clumps, forming the two bodies that make up Ultima Thule, and countless similar objects that formed the planets.

“Maybe that’s how Ultima and Thule, as separate objects, formed, and then as the last few bits and pieces of their local swirl are ejected or else collide, the amount of energy that’s still left in the system is so little that the two lobes come together,” Moore said.

The two bodies that formed Ultima Thule must have merged at slow speeds — likely at only a few miles per hour — to neatly come together without disturbing their individual near-spherical shapes, Moore said.

Pluto’s small moons are the shard-like leftovers from a violent collision, whereas Ultima Thule’s lobes retain their original shape.

“So what we’re looking at is basically the first planetesimals, and these first planetesimals, where they were more commonly found in the inner solar system, came together to form the planets and the moons and everything else we see,” Moore said. “But these are the only remaining basic building blocks in the backyard of the solar system that everything else we live on, or can see with our telescopes, or visit with our spacecraft, were formed from.

“I think we should think about New Horizons as a time machine, like the ‘wayback machine’ that we set to time zero that has brought us back to the very beginning of solar system history, to a place where we can observe the most primordial building blocks of the planets,” he said.

Even better images are expected to be sent back to Earth by New Horizons in the coming weeks, including views from different angles that will help scientists sort out the topography, cratering and roughness of Ultima Thule. At first glance, no obvious craters are visible on the object.

The first glimpse at Ultima Thule’s chemical composition should be available as soon as Thursday, when scientists plan to hold another press conference.

“It’s just going to get better and better,” Stern said.

The mission’s chief scientist also addressed a controversy over the nickname Ultima Thule during Wednesday’s press briefing. Ultima Thule’s roots are in Latin, but Nazis used the term to refer to the mythological birthplace of the Aryan race.

“I think New Horizons is an example, one of the best examples of our time, of raw exploration,” Stern said.

Stern noted the name’s ancient origins, and called it a “wonderful meme for exploration.”

“That’s why we chose it,” he said. “Just because some bad guys once liked that term, we’re not going to let them hijack it.”

Formally known as 2014 MU69, the object’s official name — and the names of its surface features — must be approved by the International Astronomical Union, and Stern told reporters there are plans to begin submitting names to the IAU later this year.

Source: Most distant object ever visited resembles a snowman

[Orionid]

New Horizons reveals Kuiper Belt object is a contact binary
by Jeff Foust — January 2, 2019 [SpaceNews]


An image of 2014 MU69, aka Ultima Thule, taken by NASA's New Horizons spacecraft on approach shows the object is a "contact binary," two separate objects touching each other. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

LAUREL, Md. — The distant object that NASA’s New Horizons spacecraft flew past Jan. 1 is now taking shape as a body — or bodies — unlike any visited by a spacecraft to date.

At a Jan. 2 press conference at the Johns Hopkins University Applied Physics Laboratory (APL) here, scientists working on the mission released new images showing that the Kuiper Belt object known as 2014 MU69, and nicknamed Ultima Thule, is a “contact binary,” two objects touching one another, with an appearance some likened to a snowman.

“Just like with Pluto, we could not be happier,” Alan Stern, the principal investigator for New Horizons, said, recalling the spacecraft’s 2015 flyby of that world. “What you’re seeing is the first contact binary ever explored by spacecraft: two completely separate objects that are now joined together.”

The shape of Ultima Thule had been the subject of speculation for years leading up to the flyby. The small object appeared as a point source in Hubble Space Telescope images, where it was discovered in 2014, and in images from New Horizons itself until a couple days before the flyby. Scientists speculated that it could be single, likely elongated object, or two objects closely orbiting each other.

The contact binary shape of Ultima Thule is consistent with models of the formation of the Kuiper Belt. “What we think we’re looking at is the end product of a process that probably took place only a few hundred thousand or maybe a few million years at the very beginning of the formation of the solar system,” said Jeff Moore of NASA’s Ames Research Center.

At that time the outer fringes of the solar system consisted of “innumerable small particles or pebbles,” Moore explained, that slowly coalesced into larger ones. That created the two bodies seen at Ultima Thule: a larger one, dubbed simply “Ultima,” that is 19 kilometers across, and a smaller one, “Thule,” 14 kilometers across.

The two bodies came together at a very low speed, he said, on the order of a few kilometers per hour, slow enough to preserve each object. “If you had a collision with another car at those speeds, you may not even bother to fill out the insurance forms,” he said.

That means that Ultima Thule is likely an object that dates back to the formation of the solar system, as scientists suspects prior to the flyby. “What we’re looking at is basically the first planetesimals,” Moore said. “These are the only remaining basic building blocks.”

There is some dispute among scientists, though, about whether Ultima Thule is the first contact binary seen. The nucleus of comet 67P/Churyumov–Gerasimenko, as seen by ESA’s Rosetta spacecraft, has two lobes that appear connected by a narrow “neck” region. Moore said that the shape of that cometary nucleus could also be explained by activity as cometary ice sublimates.

Besides the improved images, scientists also refined other knowledge of the object. Cathy Olkin, deputy project scientist, said the object has a rotation period of approximately 15 hours. The images, she said, also showed some brightness variations on the surface, including a brighter area in the neck where the two bodies meet. That could be explained if the neck contains fine-grained particles that settle there from both lobes.

The first color images, taken at lower resolution, show that Ultima Thule has a red color. That color can be explained by irradiation of ices on its surface, said Carly Howett of the Southwest Research Institute.

The images don’t yet reveal much information about topography given the sun angle at the time New Horizons took the image, on approach to Ultima Thule at a distance of about 50,000 kilometers. That will change as later images, taken at different angles, are sent back, Moore said.

Also on its way back to Earth are spectral data collected by the spacecraft. Olkin said the initial data will focus on specific bands that could help scientists identify water ice or other volatiles.

The only issue with the flyby so far has nothing to do with the spacecraft or the object but rather the Ultima Thule nickname that the mission, with NASA’s concurrence, applied to the object. In just the last day some members of the public expressed reservations about the name because of ties to Nazi ideology.

Stern defended the choice of the name, noting that it dates back to the classical era, referring to the most distant northern lands. The name, he said, “is a wonderful meme for exploration, and that’s why we chose it.”

“And I would say that just because some bad guys once liked that term, we’re not going to let them hijack it,” he said, prompting a round of applause from team members and guests in the APL auditorium.

Thomas Zurbuchen, NASA associate administrator for science, defended the name as well. “If there is a connection, it is very tenuous,” he said of any Nazi ties to the name, emphasizing the “positive message” of the name. He added that searches for the term online turn up other, innocuous uses the name.

A Google search for “Ultima Thule” found not just references to the Kuiper Belt object and the mission but also a lodge in Alaska, Finnish glassware and an Australian radio show, among other citations.

Source: New Horizons reveals Kuiper Belt object is a contact binary

[Orionid]

Discoveries at solar system’s distant frontier shed light on how planets form
February 13, 2020 Stephen Clark [SFN]


The uniform color and composition of Arrokoth’s surface shows the Kuiper Belt object formed from a small, uniform, cloud of material in the solar nebula, rather than a mishmash of matter from more separated parts of the nebula. The former supports the idea that Arrokoth formed in a local collapse of a cloud in the solar nebula. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Roman Tkachenko

Data from the encounter of NASA’s New Horizons spacecraft with a frozen reddish snowman-shaped object a billion miles beyond Pluto last year suggest the building blocks of planets may have formed less violently than many scientists expected, officials said Thursday.

When new New Horizons zipped past the distant world Jan. 1, 2019, the probe captured imagery that showed it was formed of two smooth connected lobes, both reddish in color with little sign of structural damage, cracks or other evidence of a violent collision.

The appearance led scientists to hypothesize that the two lobes likely formed near one another soon after the birth of the solar system 4.5 billion years ago, then merged together at a relatively slow relative velocity. Modeling of data gathered by New Horizons during last year’s New Year’s Day flyby has confirmed the low-speed merger hypothesis.

Named Arrokoth, the dual-lobe world measures about 22 miles (36 kilometers) long, 12 miles (20 kilometers) wide, and around 6 miles (10 kilometers) thick. Scientists have compared its shape to a partially flattened snowman.

Arrokoth orbits the sun once every 293 years, and is located some 4.1 billion miles (6.6 billion kilometers) from Earth in the Kuiper Belt, a ring of small, icy worlds beyond the orbit of Neptune.

The New Horizons published three papers in the journal Science this week discussing the latest findings.

“Arrokoth is the most distant, most primitive and most pristine object ever explored by spacecraft, so we knew it would have a unique story to tell,” said Alan Stern, principal investigator on the New Horizons mission from the Southwest Research Institute in Boulder, Colorado. “It’s teaching us how planetesimals formed, and we believe the result marks a significant advance in understanding overall planetesimal and planet formation.”

Scientists formally named the object Arrokoth in November after initially giving it the nickname Ultima Thule, a term in medieval mythology that meant “beyond the borders of the known world.” Although the name “Ultima Thule” is centuries old, Nazis used the term to refer to the mythological birthplace of the Aryan race, prompting protests from numerous members of the scientific community and beyond.

Arrokoth means “sky” in the Powhatan/Algonquian language. With consent from Powhatan Tribal elders and representatives, NASA’s New Horizons team proposed the new name to the International Astronomical Union, which oversees the formal naming of planetary objects and astronomical features.

Planetesimals are the building blocks of planets, many of which accreted into ever-larger clumps to create worlds like Earth. But some of the would-be planets stopped growing as other planet-forming materials coalesced elsewhere, leaving behind time capsules like Arrokoth ripe for research using modern spacecraft, instrumentation and computer modeling.

The results show the two pieces that formed Arrokoth formed close together, orbited one another, and then finally merged at a speed equivalent to a brisk walking pace.

That evidence suggests Arrokoth was created in a much less violent way than some scientists theorized.

“Just as fossils tell us how species evolved on Earth, planetesimals tell us how planets formed in space,” said William McKinnon, a New Horizons co-investigator from Washington University in St. Louis, and lead author of an Arrokoth formation paper in Science this week. “Arrokoth looks the way it does not because it formed through violent collisions, but in more of an intricate dance, in which its component objects slowly orbited each other before coming together.”



Scientists have come up with two major competing theories explaining planetesimal formation. One is called the cloud collapse model, and other is known as hierarchical accretion.

Data from the New Horizons mission supports the cloud collapse theory, indicating Arrokoth formed as solid particles in the primordial solar nebula gently collapsed onto one another under the tug of gravity. The competing theory of hierarchical accretion supposes that planetesimals collided with each other at high speed like billiard balls to accrete into larger bodies.

Visual evidence from the New Horizons flyby last year supports modeling suggesting the two lobes came together at slow speeds.

There is no sign of visible damage at the surface of Arrokoth, and both lobes appear the same color with the same mineral composition, suggesting they formed from the same type of material in the same region of the ancient solar system.

“Arrokoth has the physical features of a body that came together slowly, with ‘local’ materials in the solar nebula,” said Will Grundy, New Horizons composition theme team lead from Lowell Observatory in Flagstaff, Arizona, and the lead author of another Science paper. “An object like Arrokoth wouldn’t have formed, or look the way it does, in a more chaotic accretion environment.”

Scientists said the flattened shape of Arrokoth and close alignment of the equators and poles on each lobe also supports the conclusion that the two segments did not collide chaotically.

“All of the evidence we’ve found points to particle-cloud collapse models, and all but rule out hierarchical accretion for the formation mode of Arrokoth, and by inference, other planetesimals,” Stern said in a statement.

The new papers published in Science are follow-ups to a paper from May 2019 that laid out the New Horizons team’s initial conclusions from the Arrokoth flyby. The information released Thursday is based on 10 times as much data as the May 2019 report.

New Horizons flew by Arrokoth at a relative velocity of roughly 32,000 mph, or 9 miles per second (14 kilometers per second), obtaining a snapshot view the faraway world.

The fresh data downlinked New Horizons since last May also produced refined estimates of Arrokoth’s dimensions.

Scientists estimate Arrokoth’s larger lobe is about 12.8 miles (20.6 kilometers) by 12.4 miles (19.9 kilometers) by 5.8 miles (9.4 kilometers). The smaller lobe is roughly 9.6 miles (15.4 kilometers) by 8.6 miles (13.8 kilometers) by 6.1 miles (9.8 kilometers).

The updated dimensions give Arrokoth a volume about 30 percent larger than the previous estimate, the New Horizons team wrote in one of the Science papers this week.

Launched in 2006, the New Horizons spacecraft obtained the first up-close glimpse of Pluto and its moons in July 2015. Ground controllers steered the probe toward a second, more distant flyby target with leftover fuel after scientists discovered Arrokoth with the Hubble Space Telescope.

New Horizons is now in an extended mission, using its instruments to make long-range observations of other Kuiper Belt Objects and collect data on the radiation and dust environment more than 4 billion miles from the sun.

Scientists plan to use ground-based telescopes later this year to search for another target in the Kuiper Belt that New Horizons could reach for a close-up flyby in the coming years.

Source: https://spaceflightnow.com/2020/02/13/discoveries-at-solar-systems-distant-frontier-shed-light-on-how-planets-form/

[Orionid]

Debate rages about future of New Horizons
Jeff Foust May 4, 2023 [SN]



LAUREL, Md. — NASA and the science team for a spacecraft in the outer reaches of the solar system are locked in a dispute about the future of that mission and the science it can perform.
https://spacenews.com/debate-rages-about-future-of-new-horizons/

NASA ogłosiła 29 września ​​przedłużenie  misji sondy New Horizons do końca lat dwudziestych, kiedy to spodziewane jest opuszczenie przez sondę Pasa Kuipera.
Oznacza to potencjalnie możliwość przyszłego bliskiego przelotu w pobliżu obiektu Pasa Kuipera pod warunkiem, że uda się wcześniej taki obiekt zidentyfikować.
NASA wydała 9,5 mln dol. na misję New Horizons w 2022 roku i zaproponowała wydanie 9,7 mln. dol. na misję w swojej propozycji budżetu na rok budżetowy 2024.

NASA to extend New Horizons mission through late 2020s
Jeff Foust September 29, 2023 [SN]


The new extended mission for New Horizons keeps open the option of another Kuiper Belt object flyby if a suitable one is discovered. Credit: JHUAPL/SwRI

WASHINGTON — NASA has agreed to extend operations of its New Horizons spacecraft through late this decade to support “multidisciplinary” science that could include another Kuiper Belt object flyby. (...)

NASA announced Sept. 29 that it would extend New Horizons, currently approved for operations through the end of fiscal year 2024, until the spacecraft exits the Kuiper Belt, which is expected around the end of the decade. The focus of the mission, starting in fiscal year 2025, will be collecting heliophysics data as the spacecraft heads out of the solar system.

The arrangement, though, would allow the spacecraft to perform another Kuiper Belt flyby, like the flyby of Arrokoth it conducted in early 2019. While there are currently no known objects within range of New Horizons, “this new path allows for the possibility of using the spacecraft for a future close flyby of such an object, should one be identified,” NASA said in a statement announcing the extension.

“The New Horizons mission has a unique position in our solar system to answer important questions about our heliosphere and provide extraordinary opportunities for multidisciplinary science for NASA and the scientific community,” said Nicola Fox, associate administrator of science at NASA, in the agency statement. “The agency decided that it was best to extend operations for New Horizons until the spacecraft exits the Kuiper Belt, which is expected in 2028 through 2029.” (...)
https://spacenews.com/nasa-to-extend-new-horizons-mission-through-late-2020s/
https://twitter.com/AlanStern/status/1707830560666923048