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SpaceX and NASA target next astronaut launch for October 23 – SatelliteProME.com

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The mission will carry NASA astronauts along with JAXA mission specialist Soichi Noguchi for a six-month science mission aboard the orbiting laboratory.

NASA and SpaceX are targetting no earlier than October 23 for the first operational flight with astronauts of the Crew Dragon spacecraft and Falcon 9 rocket to the International Space Station as a part of the agency’s Commercial Crew Program.

NASA’s SpaceX Crew-1 mission will be the first of regular rotational missions to the space station following completion of NASA certification.

The mission will carry Crew Dragon commander Michael Hopkins, pilot Victor Glover, and mission specialist Shannon Walker, all of NASA, along with Japan Aerospace Exploration Agency (JAXA) mission specialist Soichi Noguchi for a six-month science mission aboard the orbiting laboratory following launch from Launch Complex 39A at NASA’s Kennedy Space Center in Florida.

Crew-1 will launch in late October to accommodate spacecraft traffic for the upcoming Soyuz crew rotation and best meet the needs of the International Space Station. The launch will follow the arrival of NASA astronaut Kate Rubins and cosmonauts Sergey Ryzhikov and Sergey Kud-Sverchkov of the Russian space agency Roscosmos aboard their Soyuz MS-17 spacecraft and the departure of NASA astronaut Chris Cassidy and cosmonauts Anatoly Ivanishin and Ivan Vagner from the space station. The launch timeframe also allows for a crew handover with NASA’s SpaceX Crew-2 mission next spring.

The Crew-1 mission is pending completion of data reviews and certification following NASA’s SpaceX Demo-2 test flight, which successfully launched NASA astronauts Robert Behnken and Douglas Hurley to the International Space Station on May 30 and returned them safely home with a splashdown off the Florida coast in the Gulf of Mexico on August 2.  Demo-2 was the first crewed flight test of a commercially-owned and operated human space system.

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Paradox-Free Time Travel Is Theoretically Possible, Researchers Say – WBFO

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“The past is obdurate,” Stephen King wrote in his book about a man who goes back in time to prevent the Kennedy assassination. “It doesn’t want to be changed.”

Turns out, King might have been onto something.

Countless science fiction tales have explored the paradox of what would happen if you do something in the past that endangers the future. Perhaps one of the most famous pop culture examples is Back to the Future, when Marty McFly went back in time and accidentally stopped his parents from meeting, putting his own existence in jeopardy.

But maybe McFly wasn’t in much danger after all. According a new paper from researchers at the University of Queensland, even if time travel were possible, the paradox couldn’t actually exist.

Researchers ran the numbers, and determined that even if you make a change in the past, the timeline would essentially self-correct, ensuring that whatever happened to send you back in time would still happen.

“Say you travelled in time, in an attempt to stop COVID-19’s patient zero from being exposed to the virus,” University of Queensland scientist Fabio Costa told the university’s news service.

“However if you stopped that individual from becoming infected — that would eliminate the motivation for you to go back and stop the pandemic in the first place,” said Costa, who co-authored the paper with honors undergraduate student Germain Tobar.

“This is a paradox — an inconsistency that often leads people to think that time travel cannot occur in our universe.”

A variation is known as the “grandfather paradox” — in which a time traveler kills their own grandfather, in the process preventing the time traveler’s birth.

The logical paradox has given researchers a headache, in part because according to Einstein’s theory of general relativity, “closed time-like curves” are possible, theoretically allowing an observer to travel back in time and interact with their past self — and potentially endangering their own existence.

But these researchers say that such a paradox wouldn’t necessarily exist, because events would adjust themselves.

Take the coronavirus patient zero example. “You might try and stop patient zero from becoming infected, but in doing so you would catch the virus and become patient zero, or someone else would,” Tobar told the university’s news service.

In other words, a time traveler could make changes — but the original outcome would still find a way to happen. Maybe not the same way it happened in the first timeline; but close enough so that the time traveler would still exist, and would still be motivated to go back in time.

“No matter what you did, the salient events would just recalibrate around you,” Tobar said.

The paper, “Reversible dynamics with closed time-like curves and freedom of choice,” was published last week in the peer-reviewed journal Classical and Quantum Gravity. The findings seem consistent with another time travel study published this summer in the peer-reviewed journal Physical Review Letters. That study found that changes made in the past won’t drastically alter the future.

Best-selling science fiction author Blake Crouch, who has written extensively about time travel, said the new study seems to support what certain time travel tropes have posited all along.

“The universe is deterministic and attempts to alter Past Event X are destined to be the forces which bring Past Event X into being,” Crouch told NPR via email. “So the future can affect the past. Or maybe time is just an illusion. But I guess it’s cool that the math checks out.”

Copyright 2020 NPR. To see more, visit https://www.npr.org.

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Starship SN8 prepares for test series – First sighting of Super Heavy – NASASpaceflight.com

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Starship SN8 prepares for test series – First sighting of Super Heavy – NASASpaceFlight.com

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Chang'e-4 lander finds radiation levels on the moon 2.6 times higher than at space station – Firstpost

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As the US prepares to return humans to the Moon this decade, one of the biggest dangers future astronauts will face is space radiation that can cause lasting health effects, from cataracts to cancer and neurodegenerative diseases.

Though the Apollo missions of the 1960s and 1970s proved it was safe for people to spend a few days on the lunar surface, NASA did not take daily radiation measurements that would help scientists quantify just how long crews could stay.

This question was resolved Friday after a Chinese-German team published in the journal Science Advances the results of an experiment carried out by China’s Chang’E 4 lander in 2019.

“The radiation of the Moon is between two and three times higher than what you have on the ISS (International Space Station),” co-author Robert Wimmer-Schweingruber, an astrophysicist at the University of Kiel told AFP.

“So that limits your stay to approximately two months on the surface of the Moon,” he added, once the radiation exposure from the roughly week-long journey there, and week back, is taken into account.

There are several sources of radiation exposure: galactic cosmic rays, sporadic solar particle events (for example from solar flares), and neutrons and gamma rays from interactions between space radiation and the lunar soil.

Scientist-astronaut Harrison Schmitt collecting lunar rake samples during the first Apollo 17. Schmitt was the lunar module pilot for the mission. The Lunar Rake is used to collect discrete samples of rocks and rock chips of different sizes. Image courtesy: NASA

Radiation is measured using the unit sievert, which quantifies the amount absorbed by human tissues.

The team found that the radiation exposure on the Moon is 1,369 microsieverts per day – about 2.6 times higher than the International Space Station crew’s daily dose.

The reason for this is that the ISS is still partly shielded by the Earth’s protective magnetic bubble, called the magnetosphere, which deflects most radiation from space.

Earth’s atmosphere provides additional protection for humans on the surface, but we are more exposed the higher up we go.

“The radiation levels we measured on the Moon are about 200 times higher than on the surface of the Earth and five to 10 times higher than on a flight from New York to Frankfurt,” added Wimmer-Schweingruber.

NASA is planning to bring humans to the Moon by 2024 under the Artemis mission and has said it has plans for a long term presence that would include astronauts working and living on the surface.

For Wimmer-Schweingruber there is one work-around if we want humans to spend more than two or three months: build habitats that are shielded from radiation by coating them with 80 centimeters (30 inches) of lunar soil.

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