Saturday , July 31 2021

New Horizons ready for the takeover of Ultima Tule

LAUREL, MD – NASA's New Horizons flight is ready to perform the furthest flight of an object from the solar system, an event that was largely not affected by the current closure of the government.

The new horizons will make their closest approach to the Kuiper Belt 2014 MU69 object, nicknamed Ultima Thule, at 12:33 am Eastern Yan 1. The spacecraft will pass 3,500 kilometers from the small body, 6.6 billion kilometers from Earth, with a speed of 14 kilometers per second.

The controllers carried New Horizons' knowledge update at the beginning of December 30, changing the timing of transitions in two seconds to reflect the improved knowledge of Ultima Thule's position with regard to the spacecraft. This is likely to be the latest update before the flight, said mission director Alice Bowman, mission manager at New Horizons, during a briefing at the University of Applied Physics at Johns Hopkins University (APL).

New Horizon itself is in good condition, with no signs of any problems that could hinder flight. "The craft is healthy," she said. When the spacecraft sent a confirmation that the update has been successfully applied, "we will probably breathe a huge sigh." Bowman on December 30 announced Twitter that the update was actually successfully installed on the spacecraft.

Scientists involved in the mission were excited about the science that New Horizons expect to return, but not nervous about the flight itself. "Much of my calmness reflects the fact that the mission works just as we expect. There are no indications of anything anomalous," said Geoff Moore, NASA's research scientist for planets, who runs a part of the New Horizons team dedicated to geology and geophysical research. "The latest update of knowledge puts us in a very good position to get some really gorgeous pictures."

The biggest challenge in the days leading up to flight was not technical but bureaucratic. The partial shutdown of the government, which began on December 22, when funding for some government agencies, including NASA, cast a key in plans developed several months earlier to announce the event. The NASA disconnection plan says the agency's website and social media will not be updated during shutdown and that NASA will also be present.

However, NASA Administrator Jim Bridgestone said December 27th that NASA and social network accounts will continue to operate during the flight, as the support contract for that job was "pre-funded" before shutdown. APL also made plans to broadcast briefings about flipping its own social media accounts and the website.

Alan Stern, chief researcher for New Horizons, said that on December 30 due to the closure of NASA officials who had previously planned to attend the flight, it could not do it in official capacity, including appearing at media events or giving statements. "Besides, we do not essentially influence," he said, adding that those officials are welcome to attend events like flights like private citizens.

Several members of the scientific team, who are NSA's civil servants, had to get exemptions from the workplace of the agency, because it is a critical operation, "said Stern.

Among them was Moore, who said that he and another scientist from Ames, Dale Cruise, had to "deal with bureaucracy" to get rid of the permitted and allowed to travel to the NFL for flight. "We both spent one day filling out the documents and handling the system," he said.

Stern Ultima Tule flybridge
Alan Stern, chief researcher at New Horizons, spoke about the forthcoming overflow of a briefing in the APL on December 30. Credit: SpaceNews / Jeff Fust

Scientific miracles

Moore and other scientists hope for the expected seven gigabytes of data that will collect New Horizons during the flight, including images, spectra and particulate data for Ultima Thule. While several images and other data will be returned on the days after the flight, the spacecraft will take about 20 months to transmit all the data it has collected due to the extreme distance from the Earth.

New horizons will be out of touch with the Earth during the flight. It will transmit some data collected before approaching access by December 31. After a close approach, it will transmit 15 minutes of telemetry that Bauman described as a "data outbreak for health and safety", including the amount of collected data. It is expected to arrive at Earth at 10:29 am Eastern Yan 1. The spacecraft will begin to return data collected during the flight later on January 1.

Ultima Thule is considered part of the family facilities of the Kuiper Belt called "Cold Classics". "Cold" in the name does not refer to their temperature, but also the fact that they orbit with low propensity and eccentricity, said Hal Viver, a project for new horizons scientist, indicating that they were not disturbed or modified by the formation of the solar system before 4 , 6 billion years ago.

"This is probably the most primitive object ever encountered by the spacecraft," he told Ultima Thule. "It is the best possible relic of the formation of the solar system at those distances."

"Kuiper's quasi is the only science wonderland. That's where we have the best preserved samples since the formation of the era of our solar system," said Stern. "From a scientific point of view there is nothing like this."

Scientists are also excited about the flight because it is so little known for Ultima Thule, discovered only in 2014, when looking for potential targets for an expanded mission for New Horizons, after its flight to Pluto in July 2015. The object, which does not exceed 30 kilometers, is visible only from the Hubble Space Telescope and the New Horizons.

"We do not know anything about MU69," said Stern. "We are never in the history of the spacecraft, went to the goal we knew less about."

Among these uncertainties is the rotational period of the object. Scientists hoped to determine how quickly Ultima Thule revolves around its axis, looking for a pattern in variations in the brightness of the object over time, known as light brown. However, observations of the object have so far revealed a flat light, making it difficult to recognize the period of rotation.

Weaver said there are "some hints" in the light-flower data they have, that the spacecraft returns quickly after a few hours. "The little that we can catch, suggests it can rotate pretty quickly, but we've been up and down in the team as to whether or not we believe it," he said.

Weaver says the most likely explanation for the lack of light is that New Horizons look directly at the rotary axis of Ultima Thule, so that all the time it sees the same part of the object.

However, there are alternative explanations. Mark Bui, who led the team that watched the stellar occultations in July 2017 and August 2018, when Ultima Thule passed away in front of a star, said the unusual shape of the building could explain the flat light. While these indications indicate that an object can have two lobes, an object with three lobes can also create a flat light shade.

Given enough time for developing models, Bui said he could probably come up with a Ultima Thule form explaining the light. But the spacecraft will soon give its own answers, he added. "Why do not you wait until we get pictures?"

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