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LightSail 2 has Been Flying for 30 Months now, Paving the way for Future Solar Sail Missions – Universe Today

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Even after 30 months in space, The Planetary Society’s LightSail 2 mission continues to successfully “sail on sunbeams” demonstrating solar sail technology in Earth orbit. The mission is providing hard data for future missions that hope to employ solar sails to explore the cosmos.

LightSail 2, a small cubesat, launched in June 2019 on a SpaceX Falcon Heavy, as a demonstration mission to test how well a solar sail could change the orbit of a spacecraft.  A month after launch, when LightSail 2 unfurled its ultra-thin 32-square-meter Mylar sail, the mission was declared a success because the sail raised the orbit of the small, loaf-of-bread-sized spacecraft.

“We’re going to a higher orbital altitude without rocket fuel, just with the push of sunlight,” The Planetary Society’s (TPS) CEO Bill Nye said at a press conference following the deployment.  “This idea that you could fly a spacecraft and could get propulsion in space form nothing but photons, it’s surprising, and for me, it’s very romantic that you’d be sailing on sunbeams.”

TPS, whose members funded the $7 million mission, said it shares mission data with NASA to assist three upcoming solar sail missions:  NEA ScoutSolar Cruiser and ACS3. . NEA Scout is scheduled to hitch a ride to lunar space as early as February 2022 on NASA’s Space Launch System rocket during the Artemis I test flight. The mission will use its solar sail to leave the vicinity of the Moon and visit an asteroid.

Solar sails use the power of photons from the Sun to propel spacecraft. While photons have no mass, they can still transfer a small amount of momentum. So, when photons hit the solar sail, the craft is pushed very slightly away from the Sun. Over time, if a spacecraft is out in space without any atmosphere to encumber it, it could potentially accelerate to incredibly high speeds.

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A spacecraft with a solar sail wouldn’t need to carry fuel and so could theoretically travel for longer periods of time, as it wouldn’t need to refuel.

But LightSail 2 is in in orbit around the Earth. As the spacecraft swings its sails into the sunlight, it raises its orbit by as much as few hundred meters a day. But the small spacecraft doesn’t have the means to tilt the sails precisely enough to prevent lowering its orbit on the other side of the planet. Eventually,  LightSail 2 will dip far into the Earth’s atmosphere to succumb to atmospheric drag. It will deorbit and burn up.

This image taken by The Planetary Society’s LightSail 2 spacecraft on Aug. 7, 2021 shows tropical storm Mirinae off the coast of Japan during the Tokyo Olympics. North is approximately at top left. This image has been color-adjusted and some distortion from the camera’s 180-degree fisheye lens has been removed. Credit: The Planetary Society

A recent update from TPS says that LightSail 2’s altitude above Earth is currently about 687 kilometers.

“Thanks to optimized sail pointing over time, altitude decay rates during recent months have been the best of the entire mission,” wrote TPS’s Jason Davis. “Thrust even occasionally overcame atmospheric drag, slightly raising the spacecraft’s orbit. Additionally, below-average Sun activity has kept Earth’s upper atmosphere thin for much of the mission, creating less drag on the sail.”

But the Sun has recently become more active, emitting significant solar flares. The LightSail 2 team believes that this activity is likely now causing higher orbital decay rates than those seen earlier in the mission. However, mission engineers estimate the spacecraft could stay in orbit at least another year.

And in the meantime, while the spacecraft keeps sending back incredible pictures from orbit, engineers continue to glean insights that can be passed along to future missions.  

Note: If you are planning to visit the Smithsonian in Washington D.C., models of LightSail 2 will be part of a new display at the Smithsonian’s FUTURES exhibition, a collection of art and technology that showcases the future of humanity. The new exhibition begins November 20, 2021 at the Arts and Industries Building on the National Mall in Washington, D.C. and will continue until July of 2022. More info from TPS here.

Lead image caption:  This image taken by The Planetary Society’s LightSail 2 spacecraft on May 31, 2021 shows Afghanistan, Pakistan, and the Arabian Sea. The Caspian Sea is at lower left. The shadows of the spacecraft’s solar panels can be seen on the sail. North is approximately at the top left. This image has been color-adjusted and some distortion from the camera’s 180-degree fisheye lens has been removed. Credit: The Planetary Society

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Here's what the only total solar eclipse of 2021 was like from a cruise ship near Antarctica – Space.com

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Editor’s note: The only total solar eclipse of 2021 occurred Saturday, Dec. 4, over Antarctica, where few people could see it. Some intrepid explorers, like our columnist Joe Rao, attempted to see the eclipse from cruise ships near Antarctica. Here’s what Joe and his ship saw.

FROM THE LE COMMANDANT CHARCOT IN THE SOUTHERN OCEAN OFF OF ANTARCTICA — Approximately 200 passengers on board this exploration cruise ship, owned by the French cruise line, Ponant, sadly suffered a complete cloud out of this total solar eclipse, which swept across a part of the frozen Antarctic continent on Saturday.

Late Friday evening, Captain Etienne Garcia, Master of the Le Commandant Charcot, reversed the course of the ship. It had been previously heading on a southeast trajectory just to the east of the center-line of the eclipse track, but based on a check of satellite imagery, Captain Garcia decided to turn and head on a northwest trajectory and maneuver the ship closer to the eclipse center line. The satellite images had shown a more-or-less general cloud cover, but the search was on for some thin spots which might have provided some partial visibility.

Photos: Amazing 2021 total solar eclipse views from Antarctica

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A view from the stern of Le Commandant Charcot looking up toward the ship’s bridge under overcast skies prior to the start of the total solar eclipse of 2021. (Image credit: Joe Rao)

Solar Eclipse Photography Guide

Unfortunately, during the overnight hours as the temperatures cooled the overcast only became thicker. And the passengers and crew who gathered at the stern of the ship after 3 a.m. (“Chilean Summer Time”) only saw gray skies.

At the time it encountered the moon’s dark umbral shadow, the 30,000-ton exploration vessel was located near 57.72 degrees south and 44.02 degrees west, to the northeast of the South Orkney Islands. About 20 minutes before second contact, the start of the total phase of the eclipse, passengers began to notice a subtle diminution of the light levels and it really began accelerating toward darkening in the final couple of minutes before totality as the moon’s shadow raced toward us from the northeast at 3,100 mph.

Related: The 8 most famous solar eclipses in history

The moment of totality of the total solar eclipse of 2021 from the deck of the  Le Commandant Charcot in the sea near the coast of Antarctica on Dec. 4, 2021. The sky was clouded out, but is considerably darker and lights can be seen shining on the ship’s bridge. (Image credit: Joe Rao)

A number of petrels — tube-nosed seabirds indiginous to this part of the world —were flying and swooping around the ship as the darkness was coming on and we also caught sight of two whales that breached the sea surface alongside our ship. Whether they were all reacting to the darkening sky is debatable, but certainly a possibility.

Totality lasted 97 seconds. No distinct shadow or cone of darkness was noted. Rather, just an amorphous darkening of the sky — like someone turning down a rheostat or dimmer switch. No colors were seen and the end of totality seemed more pronounced as the light seemed to come back quicker than it when it faded away.

During totality, it actually began to drizzle very lightly and a few minutes after third contact it actually started to snow lightly. The air temperature hovered at around 0C (32F), but factoring in the winds made it feel noticeably colder.

Related: The stages of the 2021 total solar eclipse explained

Captain Etienne Garcia, Master of the Le Commandant Charcot, making last-minute course corrections in an attempt to locate a break in the clouds for a view of the total eclipse. (Image credit: Joe Rao)

Well … we gave it our best shot, but unfortunately came up empty. Those who had never experienced a total solar eclipse, were impressed by the dramatic darkening of the sky, but for those like myself, who knew what was hidden from our view behind the cloud deck, it was quite disappointing.

I knew when I accepted this assignment to work with Captain Garcia and his staff, that the weather odds were long for success based on long-term climate records for this part of the world. It is nonetheless hard to take, considering how brilliantly sunny our skies were in the two days prior to the eclipse.

This was eclipse number 13 for me . . . the very first dating back to July 1972; only my second cloud-out (the first was 44 years ago in Colombia, October 1977). My batting average for eclipse success is 84.7%, so I really have little to complain about — but a bitter defeat nonetheless.

On a bright note, with today’s 97 seconds, I have now spent over 30 minutes “basking” in the shadow of the moon. 

Back in 1973, I was at a gathering of eclipse chasers at the Hayden Planetarium where Dr. Charles Hugh Smiley of Brown University was attending. The Director at Hayden, Mark Chartrand said that Dr. Smiley had spent more than 30 minutes in the Moon’s umbra, “An unprecedented total!” gushed Dr. Chartrand. I thought to myself at that time that I would never come remotely close to Dr. Smiley’s record, but with today’s eclipse I have. 

Dr. Smiley (who passed away in 1977), ended his career having observed 14 eclipses. Today, many veteran eclipse chasers have seen more than 20 total eclipses and a few individuals, such as solar physicist, Dr. Jay Pasachoff of Williams College in Massachusetts and Dr. Glenn Schneider of the University of Arizona’s Steward Observatory, have seen more than 30!

Sadly ironic that on the day before the eclipse, the skies were brilliantly sunny.  Here is Renate Rao (my wife), enjoying the cold Antarctic sunshine.  Note the large iceberg in the Southern Ocean behind her.  (Image credit: Joe Rao)

At least one cruise ship did get a view of the totally eclipsed sun. Word reached us that National Geographic’s ship “Endurance” managed to sight the sun’s corona between clouds at a position near the beginning of today’s totality path. There were also chartered flights that took observers about 33,000-feet above the cloud cover for airborne views of this morning’s celestial spectacle.

In all, it is estimated that fewer than 3000 people attended observation of today’s total eclipse. 

Another member of the Ponant cruise ships, the Le Boreal, passed our ship on its way north to position itself along the totality path.  A wayward petral photobombed it in this view. (Image credit: Joe Rao)

Related stories:

The next total eclipse on April 20, 2023, will actually be an unusual annular-total, or “hybrid” eclipse, in which along part of the eclipse path an annular or ring eclipse is seen, while along other parts of the eclipse path the eclipse is total. Most eclipse watchers are likely to converge on Cape Range National Park in Western Australia, where totality will last for 62 seconds.

On April 8, 2024, a total eclipse will cross parts of Northern Mexico and the Southern and Eastern United States and Eastern Canada. About 35 million people live in the totality path of this eclipse with the total phase in some cases exceeding 4 minutes.

Editor’s Note: If you snap an amazing solar eclipse photo and would like to share it with Space.com’s readers, send your photo(s), comments, and your name and location to spacephotos@space.com.

Joe Rao serves as an instructor and guest lecturer at New York’s Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers’ Almanac and other publications. Follow us on Twitter @Spacedotcom and on Facebook

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Scientists observe total solar eclipse in Antarctica – Global Times

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Scientists from the Chilean Union Glacier Station observe a total solar eclipse in Antarctica, Dec. 4, 2021.Photo:Xinhua

 
Scientists from the Chilean Union Glacier Station observe a total solar eclipse in Antarctica, Dec. 4, 2021.Photo:Xinhua

Scientists from the Chilean Union Glacier Station observe a total solar eclipse in Antarctica, Dec. 4, 2021.Photo:Xinhua

 

Scientists from the Chilean Union Glacier Station observe a total solar eclipse in Antarctica, Dec. 4, 2021.Photo:Xinhua

Scientists from the Chilean Union Glacier Station observe a total solar eclipse in Antarctica, Dec. 4, 2021.Photo:Xinhua

 

Photo taken from Chilean Union Glacier Station in Antarctica on Dec. 4, 2021 shows a total solar eclipse.Photo:Xinhua

Photo taken from Chilean Union Glacier Station in Antarctica on Dec. 4, 2021 shows a total solar eclipse.Photo:Xinhua

 

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Dinosaur Tail Found In Chile Could Point To Discovery Of New Species – NDTV

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Paleontologists have discovered 80 percent of the dinosaur’s skeleton.

Santiago:

Chilean paleontologists on Wednesday presented their findings on a dinosaur discovered three years ago in Patagonia which they said had a highly unusual tail that has stumped researchers.

The remains of the Stegouros elengassen were discovered during excavations in 2018 at Cerro Guido, a site known to harbor numerous fossils, by a team who believed they were dealing with an already known species of dinosaur until they examined its tail.

“That was the main surprise,” said Alexander Vargas, one of the paleontologists. “This structure is absolutely amazing.”

“The tail was covered with seven pairs of osteoderms … producing a weapon absolutely different from anything we know in any dinosaur,” added the researcher during a presentation of the discovery at the University of Chile.

The osteoderms — structures of bony plaques located in the dermal layers of the skin – were aligned on either side of the tail, making it resemble a large fern.

Paleontologists have discovered 80 percent of the dinosaur’s skeleton and estimate that the animal lived in the area 71 to 74.9 million years ago. It was about two meters (almost seven feet) long, weighed 150 kilograms (330 pounds) and was a herbivore.

According to the scientists, who published their research in the journal Nature, the animal could represent a hitherto unknown lineage of armored dinosaur never seen in the southern hemisphere but already identified in the northern part of the continent.

“We don’t know why (the tail) evolved. We do know that within armored dinosaur groups there seems to be a tendency to independently develop different osteoderm-based defense mechanisms,” said Sergio Soto, another member of the team.

The Cerro Guido area, in the Las Chinas valley 3,000 km (1,800 miles) south of Santiago, stretches for 15 kilometers. Various rock outcrops contain numerous fossils.

The finds there allowed the scientists to surmise that present-day America and Antarctica were close to each other millions of years ago.

“There is strong evidence that there is a biogeographic link with other parts of the planet, in this case Antarctica and Australia, because we have two armored dinosaurs there closely related” to the Stegouros, said Soto.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

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