Tuesday , August 3 2021

On the eve of the new horizons, Ultima Thule still holds its mysteries – Spaceflight Now

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

LAUREL, Maryland – A day before the spacecraft NASA "New Horizons" closed on a frozen asteroid called Ultima Thule, which is 4.6 billion kilometers from Earth, the basic facts about the large building in the city continued to eliminate scientists on Sunday, a flood of data and images that need to unmask the unexplored world at the frontier of the solar system.

Not more than 30 kilometers long, Ultima Thule – officially named 2014 MU69 – is a billion miles away from Pluto, visited the last world New horizons. It is reddish in color, and scientists pinpointed its location with outstanding precision for an object that was only discovered in 2014.

In addition, the look of Ultima Thule is portrayed in the fantasy of scientists and space enthusiasts. It will change in a hurry after returning to Earth on Tuesday and Wednesday photos taken by black and white and cameras on the New Horizons spacecraft.

"We do not know anything about MU69," said Alan Stern, chief researcher at New Horizons at the Southwest Research Institute. "We are never in the spacecraft's history, we went to the goal for which we knew less, and it is remarkable that we are on the brink of knowledge a lot about this.

"Today, I can not tell you more than five facts about it," Stern said at a briefing with reporters on Sunday. "We know its orbit, we know its color, we know little about its shape and its reflection, we can not even get the rotational period, I thought we would have it 10 weeks ago."

While the scientists knew that Ultima Thule would reveal their secrets only in the last days – or hours – of flight, questions that had not yet been answered prompted the members of the New Horizons team to join their creative pages.

"Our team makes small clay figures (guessing) here we think it looks today based on the current information we have," said Hal Wever, a New Horizon Project at the University of Applied Physics at Johns Hopkins University, where New Horizons were built and the home of the mission's control center.

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

Ultima Thule is just beginning to deal with the LORRI camera on new horizons, which has so far seen the object as the only point of light – one pixel in the field of camera viewing. It will quickly change with the speed of the probe to 32,000 km / h (14 kilometers per second).

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

"How fast is it rotating? A few hours, dozens of hours, or days?" Said Wyver.

"There are some indications, some hints that maybe this is a quick rotator," said Wyver. "The few that we can drive out suggest that it can be rotated pretty fast, but we've been up and down in the team as to whether or not we believe it."

New horizon scientist Hal Wever speaks to reporters at the University of Applied Physics at Johns Hopkins University in Laurel, Maryland. Credit: Stephen Clark / Spaceflight Now

If Ultima Thule turns relatively fast, it will be good news for researchers who are eagerly awaiting their first glimpse of such a primitive world. A quick rotator will show more of its surface to the New Horizons during the flight.

One of the main mysteries ever in the approach to Ultima Thule is that New Horizons did not notice any curve of light or change in the brightness of the object.

Scientists expected to see Ultima Thule darken and be illuminated while rotating, New Horizons did not reveal any changes.

"We thought how we entered and began to observe systematically from mid-September to the present, when we get something called a curve of light, which allows us to see the variation in the brightness of Ultima Thule that tells us something about the shape, said Viver.

"We systematically made these observations hoping to be able to turn these observations into a shaped Ultima Thule model, but whenever we came back and made notes, it was quite flat.

"So it's possible that the rotation will direct us towards us, which is very unusual … It can be anywhere in space – the rotation pillar – but pointing to us is an unusual circumstance," Weaver says.

"So it may be that it's very elongated, what we mean because of the stellar measurements of an oculus," he said, referring to the observations made when Ultima Thule briefly blocked the light of the background star as seen from Earth, allowing scientists to put restrictions on its shape and size.

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

"I think that, based on the result of an occult, we have seen a clear signature that his" or elongated or two lobes … I believe that we will not see anything that is circular, "said Olkin.

"I think what we will see is that we are looking for a pole of an object. It's one way to make up for the fact that we do not see the curve of the light of this object. We do not see variation with light over time."

Scientists believe Ultima Thule is a remnant of the early solar system 4.5 billion years ago, a kind of object known as "cold classic", because it remained at approximately the same orbit where it was formed. The findings will open a new window on how all planetary systems are being born and evolving, said Jason Kalirai, executive director for space for civilian space mission in the APL.

"It's an absolutely groundbreaking scientific research," said Kalirai, an astrophysicist.

Wyver said the New Year's encounter with Ultima Tule was a life event for most people in the New Horizons team – due to the time needed to prepare a space mission and travel from Earth to the Kuiper Belt.

The new horizons started from Cape Canaveral on January 19, 2006, received gravity assistance from Jupiter on February 28, 2007, and then reached Pluto on July 14, 2015. The vice-president called Pluto a companion on the Kuiper peak, a ring of frozen primordial worlds out of the orbit of Neptune.

Pluto is the largest known object in the Kuiper Belt, where scientists believe that comets from a short period originate.

The couper belt lies in the so-called "third zone" of our solar system, outside the terrestrial planets (inner zone) and gas giants (middle zone). This vast region contains billions of objects, including comets, dwarf planets like Pluto and "planets", such as Ultima Tule. The objects in this region are believed to be frozen with time relics left from the formation of the solar system. Credit: NASA / University of Applied Physics at Johns Hopkins University / Southwest Research Institute

"There is nothing else in the books to do anything like that," Wyver said.

"I do not think I'll be alive when I meet with the next cool classic Kuiper Belt Object, so we all hope for this overflow. In this sense, this is the boundary of planetary science … As a civilization, we are stepping into the third zone of the Solar System, which was not discovered until the early 1990s. "

Scientists brought sleeping bags, pillows and even a tent to camp here at the Applied Physics Laboratory at Johns Hopkins University in Laurel, Maryland, where the New Horizons speeds are heading towards Ultima Thule – the next Pluto target.

Alice Bowman, operations manager for new horizons, said she was working on Sunday Sunday to get the latest navigation updates and help prepare "knowledge for updating" for a spacecraft connection.

The update has changed the timing of the image sequence and data to be collected during the flight in just 2 seconds, but that's enough to require some adjustment to ensure that cameras and sensors get the best information during a one-off meeting with Ultima Thule.

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

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

The new horizons are okay to meet Ultima Thule, and Bowman announced on Sunday evening that the "Certificate of Knowledge" was successfully accepted by the spacecraft for 6 hours and 8 minutes to travel the distance from the Earth to 186,000 km / h or 300,000 kilometers per second.

In fact, the latest navigation update from the Ultima Thule photos trapped by the LORRI camera on the spacecraft indicate that the New Horizons are about 30 kilometers from a target 2,200 miles (3,500 kilometers) from the object.

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

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

The 70m giant antenna, which is part of the Deep Space network near Madrid, will receive signals more than six hours later at 10:29 EST (1529 GMT). But the best images – with Ultima Thule that cover hundreds of pixels worldwide – will not arrive on Earth by the end of Tuesday, and are expected to be released to the public on Wednesday afternoon.

The LORRI Black and White camera is programmed to capture about 1,500 images during the flight. Other instruments on the new horizons will take color pictures, measure the composition of Ultima Thule and take infrared data.

The command line of flying that has already been carried out by the spacecraft. Due to the vast distance between the Earth and Ultima Thule, scientists and engineers rely on the meeting.

New Horizons has instructions already loaded on its computer to deal with any glitches at the last minute and continue with the data collection sequence.

"At this point, navigation efforts have been effectively completed," said Mark Bui, a member of the New Horizons team at the Southwest Research Institute. "From here out, it's party time."

The last grinder, which actually changes the trajectory of the New Horizons, was completed on December 18, and there are no more options to make course correction as quick approaches.

Bui led the team that monitored Ultima Thule during several stellar occultations when the object passed between two stars and the Earth in July 2017 and August 2018.

These observations gave scientists the idea of ​​the Ultima Thule's shape, which Buoy suggested, probably the shape of peanuts, at least according to the data of the occult. Some scientists believe Ultima Thule may be a binary pair of objects, but Bui says it ruled out the possibility, based on the latest measurements of August's circumcision.

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

E-mail to the author.

Follow Steven Clark on Twitter: @ StephenClark1.

Source link