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Prolonged microgravity exposure doesn’t cause loss of brain tissue, study says



Sept. 4 (UPI) — Long-term space travel can have a variety of effects on the physiology of astronauts. New research suggests prolonged exposure to microgravity does cause parts of the brain to reorganize itself, but does not trigger neurodegeneration, the loss of brain tissue.

For the new study, published Friday in the journal Science Advances, researchers imaged the brains of 11 male cosmonauts from Russia who spent an average of roughly six months in space. Seven months later, the team followed up with a second round of imaging.

“This specific type of MRI we used, diffusion MRI, operates by acquiring 153 brain scans for each session, rather than just one brain scan,” lead researcher Steven Jillings, doctoral student at the University of Antwerp, told UPI in an email. “Each of these 153 scans have slightly different parameters.”

By tweaking one parameter called the b value, scientists can effectively lower the signal on the MRI. This signal decay, can help scientists identify different types of brain tissue, including gray matter, white matter and cerebrospinal fluid.

This novel imaging technique allowed researchers to assess the effects of spaceflight on tissue microstructures in the brain. Researchers calculated relative amounts of each of the three main brain tissue types in each voxel of the brain scans.

“A voxel for MRI is like the pixel for a picture,” Jillings said.

The analysis showed that while prolonged exposure to microgravity can alter the positioning of the brain and the distribution of tissue, brain tissue is not lost or destroyed.

The images confirmed what other studies have demonstrated — that the brain reorganizes itself in response to microgravity.

“We started this study to investigate whether neuroplasticity occurs as a result of spaceflight,” Jillings said. “Neuroplasticity is the ability of the brain to adapt to new situations and environments. This is also exactly what we found, namely neuroplasticity in motor regions of the brain.”

Scientists suspect the slight changes in the ratios of white and gray matter in different parts of the motor cortex are the result of astronauts learning to move around in a weightless environment.

Researchers also measure changes in the amounts of cerebrospinal fluid surrounding the brain.

“We saw a decrease over the top half of the brain and an increase along the base or lower half of the brain,” Jillings said. “This is something that has been shown in previous studies as well and points toward a redistribution of the fluid within the skull as a result of weightlessness. None of our findings are associated with cognitive function.”

Researchers found that some, but not all, of the shifts in brain tissue ratios and cerebrospinal fluid distribution had returned to normal after seven months back on Earth.

In followup studies, scientists plan to investigate whether age, mission duration and previous experience in space influence structural changes in an astronaut’s brain.

“Many open questions remain, because there have been so few studies looking at the effects of spaceflight on the brain,” Jillings said. “Some of the most important ones are whether accumulative time in space — either longer mission durations or multiple missions to space — also causes accumulative effects.”

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NASA’s OSIRIS-REx touches down on asteroid Bennu to nab sample



Oct. 20 (UPI) — NASA’s OSIRIS-REx touched down on asteroid Bennu on Tuesday evening in a mission to scoop a sample of rocks and dirt.

The spacecraft — the Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer — made soft contact with the asteroid at 6:12 p.m. EDT.

The historic “touch and go” event featured animation displaying OSIRIS-REx’s sample collection activities in real time. It takes time for real images of the touchdown to travel back to the Earth, so they won’t be released to the public until Wednesday.

The craft executed a series of maneuvers over the course of several hours before making soft contact with the surface of the asteroid to collect regolith, or rocks and dirt.

“It will be four and a half hours of anxiousness,” Beth Buck, OSIRIS-REx mission operations manager at Lockheed Martin Space, said in a news conference ahead of the event.

Buck made a comparison to the descent of a spacecraft on Mars, when there is typically “seven minutes of terror.”

The goal is to learn more about the solar system’s history and help “planetary defense” engineers with missions to protect earth from rogue asteroids. Bennu is believed to be a window into the solar system’s past since it’s a pristine, carbon-rich body carrying building blocks of both planets and life.

At around 1:50 p.m. EDT, the spacecraft left orbit around the asteroid before executing a series of burns to position itself over a sampling area nicknamed Nightingale.

Once in position, the craft began its approach to the asteroid at 5:50 p.m. EDT. It then spent about 15 seconds attempting to collect the regolith sample before backing away again.

The area, which is 52 feet in diameter, will make for a more demanding landing than expected, Kenneth Getzandanner, OSIRIS-REx flight dynamics manager at the NASA Goddard Space Flight Center in Maryland, said in the news conference.

The original mission called for a landing “zone” about 150% larger than Nightingale, at 82 feet, but that changed because Bennu was more rocky than expected.

The goal was to collect at least 1.7 ounces of fine-grained material, but the spacecraft can carry up to 4.4 pounds, Heather Enos, OSIRIS-REx deputy principal investigator at the University of Arizona said.

“I would love for that capsule to be completely full,” Enos said.

Though early images from the asteroid should hint at whether the mission succeeded, it will take engineers roughly 10 days to compare and analyze the mass before and after the maneuver to actually know how much dirt is inside the OSIRIS-REx.

If it failed, the spacecraft has enough fuel to attempt two more touch downs to collect material.

The spacecraft is expected to return to Earth, with the regolith sample from Bennu, in 2023.

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SpaceX scrubs Starlink launch until Thursday, if weather cooperates



Oct. 21 (UPI) — Just three days after sending 60 more Starlink satellites into orbit, SpaceX is aiming to launch another batch of broadband satellites into space from Florida.

If the weather cooperates, Thursday’s launch will be SpaceX’s 15th Starlink mission.

Liftoff had been scheduled for 12:29 p.m. EDT Wednesday aboard a Falcon 9 rocket at Launch Complex 40 at Cape Canaveral Air Force Station, but controllers scrubbed the launch due to weather and rescheduled for 12:14 p.m. on Thursday.

With a launch Sunday, SpaceX increased the size of their Starlink constellation to nearly 800 satellites. The 15th mission will see another 60-odd satellites join the network.

“The goal of Starlink is to create a network that will help provide Internet services to those who are not yet connected, and to provide reliable and affordable Internet across the globe,” according to the Kennedy Space Center.

Weather for Wednesday’s planned launch had looked so-so and the Space Force’s 45th Weather Squadron predicted a 60 percent chance of favorable conditions.

“A mid-level inverted trough and associated easterly wave currently across the Bahamas will meander into the state over the next few days, bringing enhanced moisture, cloud cover, and instability with a higher coverage of showers and storms,” Space Force forecasters wrote.

They said Thursday’s forecast looks quite similar to Wednesday’s.

Earlier this month, SpaceX founder and CEO Elon Musk tweeted that Starlink’s constellation was big enough to begin beta-testing the Internet service system in both the United States and southern Canada.

SpaceX has already offered Starlink Internet services to emergency responders in wildfire-stricken areas of Washington State.

Washington’s Hoh tribe is also using the Internet service to provide their members online education and telehealth services.

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Chernobyl-level radiation harms bumblebee reproduction



Oct. 21 (UPI) — Bees are more sensitive to radiation than scientists thought. Scientists found the reproduction rates of bumblebees declined significantly when exposed to Chernobyl-level radiation.

The research, published Wednesday in the journal Proceedings of the Royal Society B: Biological Sciences, suggests radiation in Ukraine’s Chernobyl Exclusion Zone could impair pollination services, triggering wider ecological consequences than previously estimated.

Humans are not allowed to live in the Chernobyl Exclusion Zone, the disaster area more directly impacted by the 1986 nuclear accident, the worst in history. However, the destroyed nuclear reactors are surrounded by forests that are populated by robust populations of birds, bears, bison, lynx, moose, wolves and more.

Efforts to gauge the effects of radiation contamination on insects have yielded mixed results in the past. While some studies have suggested insects are relatively radiation-resistant, others have demonstrated significant impairment.

When researchers exposed bumblebees in the lab to radiation dose of 100 µGyh-1, an amount approximating exposure inside the Chernobyl Exclusion Zone, reproduction rates among the bees dropped between 30 and 45 percent.

Researchers found a direct correlation between the size of the radiation dose and reproduction rate declines. Lower levels of radiation had a smaller effect, while larger doses yielded greater declines.

Scientists were surprised to find they were able to detect reproductive rate declines at very small levels of radiation exposure.

“Our research provides much needed understanding as to the effects of radiation in highly contaminated areas and this is the first research to underpin the international recommendation for the effects of radiation on bees,” lead study author Katherine Raines, environmental scientist at the University of Stirling in Scotland, said in a news release.

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