Home / Science / In the evening at New Horizon's flyby, Ultima Thule still keeps its mysteries – Spaceflight Now

In the evening at New Horizon's flyby, Ultima Thule still keeps its mysteries – Spaceflight Now



This image shows the first discovery of the 2014 MU69 (named "Ultima Thule"), with the highest resolution mode (known as "1 × 1") in the Long Range Reconnaissance Imager (LORRI) aboard the spacecraft New Horizons. 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 closes on a frozen outpost called Ultima Thule 4.1 billion miles from the earth, basic facts about the urban object continued to avoid the scientists on Sunday, when the ground team slowed down a flood of data and imagery that would unleash the unscathed world at the sun's border. 19659003] Ultima Thule, officially named 2014 MU69, is more than 20 miles (30 kilometers) long, one billion miles beyond Pluto, the last world New Horizons visited. It is reddish, and researchers have identified their location with remarkable precision for an object discovered in 2014.

In addition to that, Ultima Thule's appearance has shifted to the fantasies of researchers and space enthusiasts. It will hurry when the images in the New Horizon spacecraft's black and white camera begin to come back to Earth on Tuesday and Wednesday.

"We don't know anything about MU69," says Alan Stern, New Horizon's lead researcher from the Southwest Research Institute. "We have never, in the history of the space shuttle, gone to a goal we knew less about, and it is noteworthy that we are about to know much about this.

" Today I cannot tell more than five facts about it , Stern says in a meeting with reporters Sunday. "We know their orbit, we know their color, we know a little about their shape and its reflectivity. We can't even get the rotation period. I thought we would have it 10 weeks ago."

While scientists knew Ultima Thule would only reveal his secrets on the last days – or the hours – in the airfield, the issues that have not yet been answered have led to new horizons of team members beating their creative sides.

"Our team has made some clay figures (guess) here is what we think it looks like today based on the current information we have," says Hal Weaver, project scientist at New Horizons at Johns Hopkins University Applied Physics Laboratory, where New Horizons was built and was home to the mission control center.

Although researchers believe they are starting to see some details.

Ultima Thule just begins to be solved by New Horizon's LORRI imaging camera, which has so far looked at the object as just a bright spot – a single pixel in the camera's field of view. It will change quickly when the probe reaches 32,000 mph (14 km per second).

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

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

"There's an indication, a clue that maybe it's a fast rotator," Weaver said. "The little bit that we have been able to tear out indicates that it can rotate fairly quickly, but we have gone up and down on the team as to whether we believe it."

Project researcher New Horizons Hal Weaver speaks with reporters 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 scientists while awaiting their first glance at such a primitive world. A fast rotator would show more of its surface to New Horizons during flyby.

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

Researchers were expecting to see Ultima Thule cushioning and brightening when rotated. New Horizons have not discovered any change.

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

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

"So it is possible that the rotation may point to us, which is a loud you nusual … It may be anywhere in space – the rotational bar – but pointing to us is an unusual circumstance," says Weaver.

"So it may be that it is very elongated, which we think because of the stellar occult measurements," he said, referring to observations made when Ultima Thule cards blocked the light from a background star as seen from the earth, so that scientists could place restrictions in shape and size

Cathy Olkin, Assistant Project Researcher at the Southwest Research Institute, agreed

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

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

Researchers believe that Ultima Thule is a relic from the early solar system 4.5 billion years ago, a type of object called" cold classical "because it stalled in roughly the same orbit as it was formed. The discoveries will open a new window on how all planetary systems are born and developed, says Jason Kalirai, director of the Civil Space Mission at APL.

"It is absolutely fundamental breakthrough science," says Kalirai, an astrophysicist. [19659003] Weaver said the New Year's meeting with Ultima Thule is once in life for most of the New Horizons team – because of the time it takes to prepare a space mission and make it travel from Earth to the Kuiper belt.

New Horizons launched from Cape Canaveral on January 19, 2006, received a gravity aid from Jupiter on February 28, 2007 and then reached Pluto on July 14, 2015. Weaver called Pluto gatekeeper to Kuiper Belt, a

Pluto is the largest known item in the Kuiper belt, where researchers believe that short-lived comets originate.

The Kuiper belt lies in the so-called "third zone" "Of our solar system, bey on the terrestrial planets (inner zone) and the gas giants (middle zone). This large region contains billions of objects, including comets, dwarf planets such as Pluto and" planetesimals " as Ultima Thule The objects in this region are believed to be frozen in time – leftovers 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 , "said Weaver. In this respect, this is the boundary of planetary science … As a civilization, we go into this third zone of the solar system, which was not even discovered until the early 1990s. "

Scientists have taken sleeping bags, pillows, and even a tent to read out here at Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, which new horizons accelerate toward Ultima Thule – its next goal after Pluto.

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

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

"This last day has probably been but that most intense for us, says Bowman.

"Whatever is required, we are here for the exploration and we are happy to spend the night, if that is what it takes," she said.

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

In fact, the latest navigation update from images from the Ultima Thule captured by the LORRI camera aboard the spacecraft shows that New Horizons is about 30 miles off its target point 2,200 miles (3,500 kilometers) away from objects.

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

No additional commands are expected to be sent to the spacecraft before flying.

As a result of astrodynamics, New Horizons will reach its closures t pointing to Ultima Thule at 12:33 AM EST (0533 GMT) on Tuesday, New Year's Day. About four hours later, the spacecraft will pause its observations to turn its antenna by 6.9 meters (2.1 meters) to the ground to call home.

A giant 230 meter long antenna portion of NASA's Deep Space Network near Madrid will receive the signals more than six hours later at 10:29 EST (1529 GMT). But the best pictures – with Ultima Thule spanning hundreds of pixels everywhere – are not coming to Earth until the end of Tuesday and are expected to be released to the public on Wednesday afternoon.

The black-and-white LORRI camera is programmed to take approximately 1500 images during fly-by. The other instruments on board New Horizons will take color images, measure Ultima Thule's composition and take infrared data.

The Flyby command sequence is already performed by the spacecraft. Due to the great distance between Earth and Ultima Thule, researchers and engineers are suspended for the meeting.

New Horizons has instructions already loaded into the computer to handle any last-minute errors and continue the data collection sequence. [19659003] "At this point, navigation work is effectively completed," said Marc Buie, a member of the New Horizon team from the Southwest Research Institute. "From here it is festive times."

The last recorder that actually tweaks New Horizon's course was completed December 18, and there are no more opportunities to do a course correction as flyby fast approaches. 19659003] Buie led the team that observed Ultima Thule during a couple of star cultures when the object passed between two stars and the earth in July 2017 and August 2018.

These observations gave researchers an idea of ​​the shape of Ultima Thule, which Buie suggested was possibly the form of a peanut, at least according to occult data. Some researchers believe that Ultima Thule may be a binary pair of objects, but Buie says he has excluded that possibility, 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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