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Stone tools suggest earlier human presence in North America – News 1130

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NEW YORK — Stone tools found in a Mexican cave suggest that people were living in North America as early as about 26,500 years ago, much earlier than most scientists accept, a new study says.

It’s a new step in the difficult and contentious process of establishing when people arrived in North America from Asia. Presently, the most widely accepted dates for the earliest known North American archaeological sites date to before 15,000 years ago and extend maybe to 17,000 years ago, says anthropology professor Tom Dillehay of Vanderbilt University in Nashville, Tennessee. He was not involved in the cave study.

In Wednesday’s issue of the journal Nature, scientists reported on artifacts found in a mountain cave in the state of Zacatecas in north-central Mexico. Ciprian Ardelean of the Autonomous University of Zacatecas and others say they found stone tools and debris from tool-making that they dated back as far as 26,500 years ago. There’s some indication that some artifacts go back beyond 30,000 years, but so far the evidence isn’t strong enough to make a firm claim, Ardelean said.

Ardelean said he believed people probably used the cave as a winter shelter for short periods of time. His team was unable to recover any human DNA from the cave.

Dillehay said the proposed date for the artifacts may be valid if it stands up to further scrutiny. But he suspects they aren’t more than 20,000 years old and most likely fall in the range of 15,000 to 18,000 years old. He doesn’t question that some of the artifacts are probably man-made, but said he’d like to see other evidence of human occupation of the cave, like hearths, butchered bones and burned edible plant remains.

In a Nature commentary, Ruth Gruhn, a professor emerita of anthropology at the University of Alberta in Edmonton, said the results should bring fresh consideration of six Brazilian sites proposed to be older than 20,000 years. Those age estimates are now “commonly disputed or simply ignored by most archaeologists as being much too old to be real,” she wrote.

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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.

Malcolm Ritter, The Associated Press

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NASA astronaut on SpaceX Crew Dragon return: ‘Sounded like an animal’ – The Verge

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As NASA astronauts Bob Behnken and Doug Hurley careened to Earth inside SpaceX’s Crew Dragon capsule on Sunday, the two said that the vehicle truly came “alive” when it plunged through Earth’s atmosphere. The capsule vibrated, jolted, and roared while the surrounding air heated up and scorched the outside of the vehicle — and the astronauts got it all on tape.

“I did record some audio of it, but it doesn’t sound like a machine. It sounds like an animal coming through the atmosphere with all the puffs that are happening from the thrusters and the atmospheric noise,” Behnken said during a press conference following the landing. “It just continues to gain magnitude as you descend down through the atmosphere.”

Both Behnken and Hurley made history in late May when they launched to the International Space Station inside SpaceX’s Crew Dragon, becoming the first two people to fly in the vehicle and the first crew to travel to orbit in a privately made space capsule. The two named their capsule Endeavour, after the Space Shuttle that Behnken and Hurley both previously flew in. After launch, Behnken said the ride was pretty lively, arguing that the Crew Dragon lived up to its namesake. “Dragon was huffing and puffing all the way into orbit, and we were definitely driving or riding a Dragon all the way up,” he said while on station.

Two months after arriving at the ISS, the duo returned to Earth in the Crew Drago over the weekend. The capsule undocked from the space station on Saturday evening and slowly distanced itself from the ISS, before taking a harrowing dive through the planet’s atmosphere and then splashing down in the Gulf of Mexico on Sunday afternoon.

Behnken noted that their trip was relatively smooth between undocking and the start of the dive, since he and Hurley were still in space, orbiting Earth. But the process of getting out of orbit became a vigorous one. Just an hour before landing, the Crew Dragon ejected its attached trunk — a large cylindrical piece of hardware that provided support during the mission. The capsule then fired its onboard thrusters, taking the vehicle out of orbit and setting it on course for Earth. Soon after, the Crew Dragon heated up immensely as it careened through the planet’s upper atmosphere, experiencing temperatures of up to 3,500 degrees Fahrenheit. Eventually, it deployed a series of parachutes to slow the capsule down so that it could touch down gently in the water off of Pensacola.

The astronauts could really feel each of those important steps, according to Behnken, who described them in vivid detail. “All the separation events — from the trunk separation through the parachute firings — were very much like getting hit in the back of a chair with a baseball bat, you know, just a crack,” he said. “And then you get some sort of a motion associated with that usually, pretty light for the trunk separation. But with the parachutes, it was a pretty significant jolt.”

The Crew Dragon splashed down at around 2:48PM ET on Sunday, and SpaceX recovery vessels quickly met up with the capsule to get Behnken and Hurley out of the water. Soon after, recreational boats swarmed the area, defying restrictions from the US Coast Guard in order to get a close view of the capsule. The astronauts said they weren’t really aware of them while inside the Crew Dragon. “[Atmospheric] reentry is a pretty demanding environment as you know with the different scorches on the vehicle, and the windows were not spared any of that,” Hurley said. “The look out the windows, you could basically tell that it was daylight but very little else. So we didn’t really see anything clearly out of the windows until the SpaceX recovery crews got near with the fast boats, and then we can see a head or two out there.”

Overall, the two said that there were really no big surprises with the landing, thanks to all of the training and simulations they had done leading up to the mission. “My credit once again is to the folks at SpaceX — the production folks, the people that put Endeavour together and then certainly our training folks,” Hurley said at the press conference. “The mission went just like the simulators…from start to finish all the way — there was really no surprises.”

Now that Behnken and Hurley’s trip is over, NASA will spend the upcoming weeks looking at all of the data from this mission in order to certify the Crew Dragon for regular trips to and from the station. In fact, SpaceX is already slated to fly its next Crew Dragon in mid- to late-September, carrying a crew of four NASA astronauts to the ISS. Behnken and Hurley believe that the Crew Dragon is more than ready for those flights once that analysis is done.

“From a crew perspective, I think we’re perfectly comfortable saying that [the next crew] is ready when they finish the engineering and analysis associated with certification,” Behnken said. Hurley noted that SpaceX and NASA plan to sync up video of Crew Dragon’s launch and landing along with the crew’s audio from inside the capsule. “That will be passed on for multiple crews for them to use,” he said.

Now that they’re back on solid ground, the two hope to spend time with their families, but they say they’re honored to have been part of SpaceX’s first crewed mission to orbit. “I think for both of us, it still feels pretty surreal and I know that’s a little bit overused but I don’t know how else to describe it,” Hurley said. “One minute, you’re bobbing in the Gulf of Mexico and, you know, less than two days later you’re in a news conference.”

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Happy anniversary, Curiosity! NASA rover marks 8 years on Mars – Space.com

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NASA would be thrilled if its newly launched Mars rover ended up matching its predecessor’s longevity.

The agency’s car-sized Curiosity rover celebrates eight (Earth) years on the Red Planet today (Aug. 5), less than a week after the Perseverance rover took flight toward Mars

The synergy in timing is appropriate; Perseverance shares Curiosity’s chassis and “sky crane” landing strategy, among other features. And the new rover will build upon the many discoveries that Curiosity has made over the years.

Related: Amazing Mars photos by NASA’s Curiosity rover (latest images) 

Curiosity launched in November 2011 and touched down inside the 96-mile-wide (154 kilometers) Gale Crater on the night of Aug. 5, 2012, kicking off a surface mission designed to last at least one Martian year (which is equivalent to 687 Earth days).

The main goal of Curiosity’s $2.5 billion mission, officially known as Mars Science Laboratory, involves assessing whether Gale could ever have supported Earth-like life. The nuclear-powered robot has returned exciting news on this front, finding that the crater hosted a potentially habitable lake-and-stream system for long stretches in the ancient past, perhaps millions of years at a time.

Curiosity has also detected complex organic chemicals, the building blocks of life as know it, in Gale Crater rocks. In addition, the rover has rolled through several plumes of methane and discovered a seasonal pattern in the concentration of this gas, which here on Earth is primarily produced by living organisms. (Abiotic processes can generate methane as well, however, and the source of the stuff within Gale is unclear.)

In September 2014, Curiosity reached the base of Mount Sharp, which rises 3.4 miles (5.5 kilometers) into the sky from Gale’s center. For the past six years, the rover has been climbing through the mountain’s foothills, reading the rocks for clues about Gale’s past habitable environments and how Mars transitioned into the cold, dry desert planet we know today.

During its eight years on Mars, Curiosity has drilled 27 rock samples, scooped up six soil samples and put more than 14 miles (23 km) on its odometer, NASA officials said. (The Mars surface-distance record is held by another NASA rover, Opportunity, which covered 28.06 miles, or 45.16 km, between 2004 and 2018.)

Perseverance’s $2.7 billion mission, called Mars 2020, aims to extend Curiosity’s findings. The new rover will hunt for signs of ancient life in Mars’ 28-mile-wide (45 km) Jezero Crater, which was home to a lake and a river delta long ago. 

Perseverance will also collect and cache samples for future return to Earth and test out several new exploration technologies, including a tiny helicopter named Ingenuity and an instrument that generates oxygen from the thin, carbon dioxide-dominated Martian atmosphere.

Mars 2020 is scheduled to touch down on Feb. 18, 2021. Maybe Curiosity will take a short break from its work in Gale Crater that day, look up at the Martian sky, and send well wishes to the new arrival.

Mike Wall is the author of “Out There” (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook. 

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SpaceX Crew Dragon astronauts describe thrilling return to Earth – CBS News

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Plunging back to Earth in a SpaceX Crew Dragon capsule Sunday amounted to a high-speed thrill ride, astronauts Douglas Hurley and Robert Behnken reported Tuesday. The fiery, flawlessly-controlled descent to splashdown went off without a hitch — a major step toward certifying the vehicle for operational flights.

“What a ride!” Behnken tweeted, sharing long-range tracking camera footage of the Crew Dragon’s dramatic descent.

The Crew Dragon splashed down south of Pensacola, Florida, amid dozens of boaters, some motoring close to the gently rocking capsule despite earlier Coast Guard warnings to stay clear. The spacecraft, with Hurley and Behnken still strapped in their seats, was hauled aboard a SpaceX recovery ship without incident.

It was the first water landing for astronauts or cosmonauts returning from orbit since the final Apollo capsule closed out a joint flight with a Russian Soyuz spacecraft 45 years ago.

Behnken and Hurley, veterans of two space shuttle flights each, said the ride down was possibly more exciting than either expected. Behnken provided a blow-by-blow description Tuesday during a virtual news conference at the Johnson Space Center.

Robert Behnken, left, and Douglas Hurley answer phoned-in questions from reporters during a news conference two days after their historic return to Earth aboard a SpaceX Crew Dragon capsule.

NASA


“Once we descended a little bit into the atmosphere, Dragon really came alive. It started to fire thrusters and keep us pointed in the appropriate direction. The atmosphere starts to make noise. You can hear that rumble outside the vehicle,” he said.

“And as the vehicle tries to control (its orientation), you feel a little bit of that shimmy in your body, and our bodies were much better attuned to the environment (after two month in weightlessness) so we could feel those small rolls and pitches and yaws,” he added.

“As we descended through the atmosphere, the thrusters were firing almost continuously … But it doesn’t sound like a machine,” Behnken explained. “It sounds like an animal coming through the atmosphere with all the puffs that are happening from the thrusters and the atmospheric noise. It just continues to gain magnitude.”

When the capsule’s stabilizing drogue parachutes deployed, followed by four large main chutes inflating, it felt “very much like getting hit in the back of the chair with a baseball bat,” Behnken said. “It was a pretty significant jolt.”

“If you’ve seen an old movie that happened to have some guys who’d been in a centrifuge, that’s what we felt like,” he said. “When the time came to splash down … we felt the splash and we saw it splash up over the windows. It was just a great relief.”

They did not say whether they felt any nausea before the gently bobbing spacecraft was recovered and pulled onto the recovery ship Go Navigator, something they mentioned before launch as a possibility.

Behnken and Hurley had nothing but praise for SpaceX and NASA’s Commercial Crew Program, thanking SpaceX for the extensive training they received and for audio recordings and video from an unpiloted Crew Dragon test flight last year that let them know what to expect during the trip back to Earth.

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The Crew Dragon descending under parachutes Sunday, moments before splashdown in the Gulf of Mexico south of Pensacola, Florida.

NASA/Bill Ingalls


“When it performed as expected, and we could check off those events, we were really, really comfortable coming through the atmosphere, even though, you know, it felt like we were inside of an animal,” Behnken said.

Hurley and Behnken were launched atop a SpaceX Falcon 9 rocket on May 30. The spacecraft carried out an automated rendezvous to catch up with the International Space Station and, after the astronauts tested its manual control system, docked with the lab complex using the same forward port that once accommodated visiting space shuttles.

The Crew Dragon astronauts were welcomed aboard by Expedition 63 commander Chris Cassidy and two Russian cosmonauts, Anatoly Ivanishin and Ivan Vagner.

Over the next two months, Hurley and Behnken assisted Cassidy with a full slate of U.S. and partner agency research, logging 114 hours carrying out experiments that would not otherwise have gotten done with a single U.S. astronaut aboard.

Behnken also participated in four spacewalks with Cassidy to wrap up installation of replacement batteries in the station’s solar power system. Including six excursions during two previous shuttle missions, Behnken now ranks fourth on the list of most experienced spacewalkers, with 61 hours and 10 minutes spent outside the station.

Hurley, who piloted two shuttle missions, including the winged orbiter’s final flight to the space station in 2011, said he expected some surprises during the Crew Dragon’s reentry.

“I expected there to be some divergence and attitude control, because it’s a real tough problem for the ship as it gets into the thicker air to maintain perfect attitude and control,” he said. “And … the vehicle was rock solid.”

The Crew Dragon is the first American spacecraft to launch astronauts into orbit from U.S. soil since the space shuttle’s final flight in 2011. For the past nine years, NASA has relied on Russia’s Soyuz spacecraft to ferry U.S. and partner agency astronauts to and from the station, paying more than $80 million per seat under recent contracts.

The Crew Dragon and, eventually, Boeing’s Starliner CST-100 capsules are intended to end that sole reliance on Russia while opening up low-Earth orbit to private-sector development.

080420-astros.jpg
Robert Behnken, left, and spacecraft commander Douglas Hurley, greet recovery crews moments after the hatch of their Crew Dragon capsule was opened.

NASA/Bill Ingalls


SpaceX launched and recovered an unpiloted Crew Dragon capsule last year and carried out a dramatic in-flight abort, again unpiloted, earlier this year. That cleared the way for Hurley and Behnken to blast off on the program’s first piloted mission, a test flight known as Demo 2.

The spacecraft performed in near-flawless fashion throughout its first piloted mission and, if a detailed post-flight review confirms that, NASA managers hope to certify the spacecraft for operational crew rotation missions to and from the space station starting this fall.

“They do need to look at the data from our entry,” Behnken said. “They will do a very thorough review, both on the SpaceX side and the NASA side, to make sure that they’re comfortable. But from a crew perspective, I think that it’s definitely ready to go.”

That will be good news for Behnken’s wife, astronaut Megan McArthur. She’s one of four astronauts scheduled to blast off next year aboard the same Crew Dragon capsule that carried Behnken and Hurley back to Earth.

“My wife is assigned to a SpaceX mission, and we have a young son,” Behnken said. “So I’ll definitely be focused on making sure that her mission’s as successful as possible and supporting her just as she did for me over the last five years.”


SpaceX splashdown marks a milestone

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