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James Webb Space Telescope nails secondary mirror deployment – Space.com

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The James Webb Space Telescope achieved another major milestone today, successfully extending its secondary mirror as it continues to sail seamlessly through its never-before-conducted deployment sequence on the way to its destination. 

The 2.4-foot-wide (0.74 meters) secondary mirror sits attached to a tripod opposite the main mirror. Its task is to concentrate the light collected by the gold-coated main mirror into an opening at the main mirror’s center. Through this opening, the light reaches the third mirror, which reflects it to the telescope’s instruments.

The secondary mirror travelled to space stowed on top of the main mirror, attached to three 26-feet-long (8 m) legs that form its supporting tripod.

On Wednesday (Jan. 5), operators at Webb’s operations center at the Space Telescope Science Institute in Baltimore released latches that secured the legs in place during launch. After having first performed a very small move to ensure the motors worked well, they then commenced the deployment procedure, which saw the legs extend and fall into place over the course of 10 minutes. NASA streamed the maneuver live with commentary on its TV channel. 

Related: A James Webb Space Telescope astronomer explains how to send a giant telescope to space — and why

This animation of the James Webb Space Telescope shows how light is reflected from its mirrors onto its scientific instruments. (Image credit: NASA)

The confirmation that the mirror was in place arrived at about 11:30 a.m. EST (1630 GMT). The operators then took another 30 minutes to lock the tripod in place with several latches to ensure it will remain stable for the duration of Webb’s at least ten-year scientific mission. 

“This is unbelievable. We are now at a point where we’re about 600,000 miles [1 million kilometers] from Earth, and we actually have a telescope,” Bill Ochs, the James Webb Space Telescope project manager at NASA’s Goddard Space Flight Center in Greenbelt,  Maryland, said in the webstream. “So congratulations to everybody.”

“Once it’s latched, it’s complete and we do not ever come back and adjust this again,” added Webb’s deputy commissioning manager Julie van Campen, also of NASA Goddard.

The secondary mirror deployment comes only a day after the operators completed the most challenging part of Webb’s self-building sequence — the unfurling and tensioning of the telescope’s tennis-court-sized sunshield

On Thursday (Jan. 6), the operators will unpack a radiator on the back of the telescope, designed to remove heat from the scientific instruments. They will then move on to assembling the main 21-foot (6.4 m) mirror, which due to its size also had to be folded for launch.

“In the first 12 days after the launch, we focused on the spacecraft system deployments like the solar array, the communication system and the sunshield,” van Campen said. “Today, we have switched gears and moved to the optical elements of the telescope. And then, in the final part of the commissioning, we will switch gears again and focus on the science instruments.”

James Webb Space Telescope's operators can monitor its deployment via a visualization tool that receives telemetry data from the spacecraft.

James Webb Space Telescope’s operators can monitor the observatory’s deployment via a visualization tool that receives telemetry data from the spacecraft. (Image credit: NASA)

The telescope’s deployment sequence was a source of apprehension with some describing it as nerve-wracking. Webb’s scientific objective, to see the first stars and galaxies that formed in the universe in the first hundreds of millions of years after the Big Bang, required an observatory of an unprecedented size and complexity. For this reason, the telescope is so big that no existing rocket could launch it without having it folded up first. The mission stretched engineers and technologies to their limits, leading to a plethora of ingenious engineering solutions. Those solutions, which see the telescope self-assemble in space like a transformer, have never before been used in space. The extensive testing program that took years to complete is, however, paying off. 

“It has worked incredibly well over the past 12 days,” van Campen said. “We’ve had moments of excitement and lots of tension as we kind of wait to see how things work out. But it’s been going great and we are slightly ahead of schedule.”

The telescope won’t be ready for science until this summer. It will take more than 100 days for Webb to cool down to its operational temperature of minus 400 degrees Fahrenheit (minus 235 degrees Celsius). Only in such extreme cold will the telescope be able to detect the faintest infrared signals from the most distant stars and galaxies. 

Van Campen explained that operators can’t monitor the deployments visually as no existing camera technology would survive in the extreme cold behind the sunshield. Electronic interference from the cameras could also affect the scientific observations. Instead, operators use a computer-based visualization tool that receives telemetry data from the telescope. 

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The telescope is on its way to the Earth-sun Lagrange Point 2 some 930,000 (1.5 million km) away from our planet. At L2, Webb will orbit the sun hidden behind Earth, held in a stable position by the delicate interplay of the gravitational forces of the two bodies. 

The telescope is expected to reach its destination by the end of January, fully deployed. The $10 billion mission, the most complex and expensive space observatory ever built, is expected to revolutionize astronomy, providing previously impossible insights into star and planet formation, the chemistry of exoplanets and the behaviour of comets and asteroids at the outer fringes of the solar system

Follow Tereza Pultarova on Twitter @TerezaPultarova. Follow us on Twitter @Spacedotcom and on Facebook

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Mars Was Likely A Cold, Wet World 3 Billion Years Ago – IFLScience

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Mars is puzzling. From rover and satellite observations we know that it once had plenty of water on its surface, which usually suggests warm and wet conditions. On the other hand, evidence suggests the planet was always pretty chilly, even in the distant past, but it’s not a cold, dry desert either. These two ideas are often at odds, but new research suggests that they could both be true: ancient Mars was likely a frigid world both cold and wet.

Researchers set out to create a model that can explain the perplexing features witnessed on the Red Planet. If the planet wasn’t warm and wet or cold and dry could there be a third option? Publishing their findings in Proceedings of the National Academy of Sciences, they believe that their cold and wet scenario can explain the existence of a vast liquid ocean in the Northern Hemisphere of Mars, extending to its polar region.

However, the model needed to explain both the presence of a liquid ocean and ice-capped regions, like the presence of glacial valleys and ice sheets in the southern highlands.

Planetary scientists studying Mars have found evidence of ancient tsunamis that rocked the Red Planet. If the ocean was frozen due to a very cold climate, these tsunamis would not have happened. But a milder climate would have meant transferring water from the ocean to the land through precipitation. Cold and wet conditions, however, could have existed.

The team used an advanced general circulation model to work out the necessary parameters for this world. They calculated it was possible for an ocean to be stable even if the mean temperature of Mars was below 0°C (32°F), the freezing point of water, 3 billion years ago. They envisioned ice-covered plateaus in the south with glaciers flowing across the plains and returning to the ocean. Rainfall would have been moderate around the shoreline. In this scenario, the ocean surface could be up to 4.5°C (40°F); not tropical but enough for water to stay liquid.

The key to these conditions is all in the air. The atmosphere of Mars today is about 1 percent in density compared to Earth’s own. But, if in the past it was roughly the same and was made of about 10 percent hydrogen and the rest carbon dioxide, this scenario would actually work. Previous analyses have found strong evidence for a thicker atmosphere before it was ripped from the planet by the steady stream of particles from the Sun.

The model is certainly compelling in explaining the peculiarities of Mars, but of course, much more evidence is needed to understand what the Red Planet was really like billions of years ago.

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Explainer-Scientists struggle to monitor Tonga volcano after massive eruption

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Scientists are struggling to monitor an active volcano that erupted off the South Pacific island of Tonga at the weekend, after the explosion destroyed its sea-level crater and drowned its mass, obscuring it from satellites.

The eruption of Hunga-Tonga-Hunga-Ha’apai volcano, which sits on the seismically active Pacific Ring of Fire, sent tsunami waves across the Pacific Ocean and was heard some 2,300 kms (1,430 miles) away in New Zealand.

“The concern at the moment is how little information we have and that’s scary,” said Janine Krippner, a New Zealand-based volcanologist with the Smithsonian Global Volcanism Program.

“When the vent is below water, nothing can tell us what will happen next.”

Krippner said on-site instruments were likely destroyed in the eruption and the volcanology community was pooling together the best available data and expertise to review the explosion and predict anticipated future activity.

Saturday’s eruption was so powerful that space satellites captured not only huge clouds of ash but also an atmospheric shockwave that radiated out from the volcano at close to the speed of sound.

Photographs and videos showed grey ash clouds billowing over the South Pacific and metre-high waves surging onto the coast of Tonga.

There are no official reports of injuries or deaths in Tonga https://www.reuters.com/business/environment/impact-assessment-aid-efforts-underway-world-responds-tonga-tsunami-2022-01-16 yet but internet and telephone communications are extremely limited and outlying coastal areas remain cut off.

Experts said the volcano, which last erupted in 2014, had been puffing away for about a month before rising magma, superheated to around 1,000 degrees Celsius, met with 20-degree seawater on Saturday, causing an instantaneous and massive explosion.

The unusual “astounding” speed and force of the eruption indicated a greater force at play than simply magma meeting water, scientists said.

As the superheated magma rose quickly and met the cool seawater, so did a huge volume of volcanic gases, intensifying the explosion, said Raymond Cas, a professor of volcanology at Australia’s Monash University.

Some volcanologists are likening the eruption to the 1991 Pinatubo eruption in the Philippines, the second-largest volcanic eruption of the 20th century, which killed around 800 people.

The Tonga Geological Services agency, which was monitoring the volcano, was unreachable on Monday. Most communications to Tonga have been cut after the main undersea communications cable lost power.

LIGHTNING STRIKES

American meteorologist, Chris Vagasky, studied lightning around the volcano and found it increasing to about 30,000 strikes in the days leading up to the eruption. On the day of the eruption, he detected 400,000 lightning events in just three hours, which comes down to 100 lightning events per second.

That compared with 8,000 strikes per hour during the Anak Krakatau eruption in 2018, caused part of the crater to collapse into the Sunda Strait and send a tsunami crashing into western Java, which killed hundreds of people.

Cas said it is difficult to predict follow-up activity and that the volcano’s vents could continue to release gases and other material for weeks or months.

“It wouldn’t be unusual to get a few more eruptions, though maybe not as big as Saturday,” he said. “Once the volcano is de-gassed, it will settle down.”

 

(Reporting by Kanupriya Kapoor; Editing by Jane Wardell and Michael Perry)

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Astronauts at Risk of 'Space Anemia' | Health | thesuburban.com – The Suburban Newspaper

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MONDAY, Jan. 17, 2022 (HealthDay News) — Astronauts can develop a condition called space anemia because their bodies destroy more red blood cells than normal when in space, a groundbreaking study shows.

Assessments of 14 astronauts over six months between space missions found that 54% more blood cells were destroyed while they were in space than when they were on Earth, according to findings published Jan. 14 in Nature Medicine.

“Space anemia has consistently been reported when astronauts returned to Earth since the first space missions, but we didn’t know why,” said lead author Dr. Guy Trudel of the Ottawa Hospital Research Institute in Canada. “Our study shows that upon arriving in space, more red blood cells are destroyed, and this continues for the entire duration of the astronauts’ mission.”

Before this study, it was believed that space anemia was due to fluid shifting into an astronaut’s upper body upon arrival in space.

Astronauts lose 10% of the liquid in their blood vessels this way. It was thought that their bodies rapidly destroyed 10% of their red blood cells to restore the balance, and that red blood cell control returned to normal after 10 days in space.

But this study found that red blood cell destruction is a primary effect of being in space, not just the result of fluid shifts.

On Earth, our bodies create and destroy 2 million red blood cells every second. But the astronauts in this study — both male and female — destroyed 3 million every second while in space.

Five of 13 astronauts in the study were clinically anemic when they returned to Earth. One of the 14 did not have blood drawn on landing.

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The researchers also found that space anemia is reversible, with red blood cells levels progressively returning to normal three to four months after astronauts returned from space.

“Thankfully, having fewer red blood cells in space isn’t a problem when your body is weightless,” Trudel said in a hospital news release. “But when landing on Earth and potentially on other planets or moons, anemia affecting your energy, endurance and strength can threaten mission objectives. The effects of anemia are only felt once you land, and must deal with gravity again.”

The findings could be prove useful for patients who develop anemia after long illnesses that require bed rest. Bed rest has been shown to cause anemia, but how it does so is unknown.

The mechanism may be like what occurs in space anemia, according to Trudel, who plans to investigate this theory in future research.

More information

The American Academy of Family Physicians has more on anemia.

SOURCE: The Ottawa Hospital, news release, Jan. 14, 2022

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