NASA Astronomy Picture of the Day

September 12, 2024

Young Star Cluster NGC 1333

This spectacular mosaic of images from the James Webb Space Telescope peers into the heart of young star cluster NGC 1333. A mere 1,000 light-years distant toward the heroic constellation Perseus, the nearby star cluster lies at the edge of the large Perseus molecular cloud. Part of Webb's deep exploration of the region to identify low mass brown dwarf stars and free floating planets, the space telescope's combined field of view spans nearly 2 light-years across the dusty cluster's turbulent stellar nursery. In fact, NGC 1333 is known to harbor stars less than a million years old, though most are hidden from optical telescopes by the pervasive stardust. The chaotic environment may be similar to one in which our own Sun formed over 4.5 billion years ago.

https://apod.nasa.gov/apod/astropix.html

https://science.nasa.gov/solar-system/skywatching/the-next-full-moon-is-a-partial-lunar-eclipse-a-supermoon-the-corn-moon-and-the-harvest-moon/

The Next Full Moon is a Partial Lunar Eclipse; a Supermoon; the Corn Moon; and the Harvest Moon

Sep 11, 2024

The Next Full Moon is a Partial Lunar Eclipse; a SuperMoon; the Corn Moon; the Harvest Moon; the Fruit or Barley Moon; the end of Ganesh Chaturthi and the start of Pitru Paksha; Madhu Purnima; the Mid-Autumn, Mooncake, or Reunion Festival Moon; Chuseok; and Imomeigetsu or the Potato Harvest Moon.

The full Moon will be Tuesday night, September 17, 2024, at 10:35 PM EDT.

This will be on Wednesday from Newfoundland and Greenland Time eastward across Eurasia, Africa, and Australia to the International Date Line.

Most commercial calendars will show this full Moon on Wednesday based on Greenwich or Universal Time.

The Moon will appear full for about three days, from Monday evening through Thursday morning.

This will be a partial lunar eclipse. The Moon will start entering the Earth's partial shadow at 8:41 PM EDT.

The slight dimming of the Moon will be difficult to notice until the top edge of the Moon starts entering the full shadow at 10:13 PM.

The peak of the eclipse will be at 10:44 PM with only the top 8 percent of the Moon in full shadow.

The Moon will finish exiting the full shadow at 11:16 PM and the partial shadow on Wednesday morning at 12:47 AM.

This will be a supermoon. The term "supermoon" was coined by astrologer Richard Nolle in 1979 as either a new or full Moon that occurs when the Moon is within 90% of its closest to Earth.

Since we can't see new Moons, what has the public's attention are full supermoons, the biggest and brightest Moons of the year.

Although different publications use different thresholds for deciding which full Moons qualify, most agree this will be the second of four consecutive supermoons (effectively tied with the full Moon in October for the closest of the year).

The Maine Farmer's Almanac first published "Indian" names for the full Moons in the 1930s and these names have become widely known and used.

According to this almanac, as the full Moon in September the Algonquin tribes in what is now the northeastern USA called this the Corn Moon, as this was the time for gathering their main staple crops of corn, pumpkins, squash, beans, and wild rice.

As the full Moon closest to the autumnal equinox, this is the Harvest Moon.

The first known written use of this name in the English language (per the Oxford English Dictionary) was in 1706.

During the fall harvest season farmers sometimes need to work late into the night by moonlight. On average moonrise is about 50 minutes later each night.

Around the Harvest Moon this time is shorter, about 25 minutes for the latitude of Washington, DC, and only 10 to 20 minutes farther north in Canada and Europe.

Other European names for this full Moon are the Fruit Moon, as a number of fruits ripen as the end of summer approaches, and the Barley Moon, from the harvesting and threshing of barley.

For Hindus, this full Moon marks the end of Ganesh Chaturthi and the start of Pitru Paksha. Ganesh Chaturthi (also called Vinayaka Chaturthi or Vinayaka Chavithi) is a 10 or 11 day festival honoring the god Ganesha that ends with this full Moon.

Ganesha is easily recognized by his elephant head and is worshiped as the god of beginnings, wisdom, arts and sciences, and as the remover of obstacles. Throughout the festival celebrants offer food, sweets, and prayers to clay statues of Ganesha at home and on public stages.

Traditions include chanting of Vedic hymns and Hindu texts, prayers, and fasting. On the last day (near the full Moon), people carry the statues to a nearby river or ocean and immerse them.

As the clay dissolves, Ganesha is believed to return to his parents, the god Shiva and goddess Parvati, on Mount Kailash.

Pitru Paksha (fortnight of the ancestors) is a 15 days long festival that ends with the new Moon. During this time, Hindus honor their ancestors (pitrs) with rituals, food offerings, and scripture reading.

Pitru Paksha is also known by a number of other names. For some Buddhists in Bangladesh and Thailand this full Moon is Madhu Purnima, the Honey Full Moon Festival or the Honey-offering Festival.

The legend is that when the Buddha was trying to bring peace between two factions in a forest, an elephant and a monkey fed him, with the elephant offering fruit and the monkey offering a honeycomb.

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In China, Vietnam, and some other Asian countries, this full Moon corresponds with the Mid-Autumn Festival, a traditional harvest festival. In China, other names for this festival include the Moon Festival, the Mooncake Festival, and the Reunion Festival (with wives visiting their parents then returning to celebrate with their husbands and his parents).

Part of the festival includes offerings to the Moon Goddess Chang'e (the name the China National Space Agency gives their lunar missions).

In Korea, this full Moon corresponds with the harvest festival Chuseok, during which Koreans return to their traditional hometowns to pay respect to the spirits of their ancestors.

This full Moon corresponds with the first of two Japanese Tsukimi or "Moon-Viewing" festivals, also called Imomeigetsu (which translates as "potato harvest Moon") because of the tradition of offering sweet potatoes to the Moon.

These festivities have become so popular that they are often extended for several days after the full Moon.

In many traditional Moon-based calendars the full Moons fall on or near the middle of each month.

This full Moon is near the middle of the eighth month of the Chinese year of the Dragon and Rabi' al-Awwal in the Islamic calendar, the month in which many Muslims celebrate Mawlid, the birth of the Prophet Muhammad.

This full Moon is near the middle of Elul in the Hebrew calendar. Elul is a time of preparation for the High Holy Days of Rosh Hashanah and Yom Kippur.

Customs include granting and asking others for forgiveness as well as beginning or ending all letters with the wish that the recipient will have a good year.

As usual, the wearing of suitably celebratory celestial attire is encouraged in honor of the full Moon.

Go out and observe the Moon, enjoy this harvest season (including corn, fruit, and sweet potatoes, and honey), remember your ancestors, stay in touch with your parents, and forgive and ask forgiveness.

Here's wishing you a good year!

Pay attention to the news about Comet C/2023 A3 (Tsuchinshan-ATLAS)! There are a number of "ifs" so we don't like to raise expectations.

Similar visitors from the Oort Cloud have broken apart and fizzled out as they passed close to the Sun.

If this comet survives its passage by the Sun (closest approach on September 27, 2024) and if the amount of gas and dust it gives off does not decrease significantly, this might be one of the best comets in a long time.

If it strongly scatters sunlight towards the Earth it might even be visible in the glow of dusk just after its closest approach to Earth on October 12.

From the Washington, DC area and similar latitudes, this comet will be above the horizon before morning twilight begins from September 22 through October 4, with the current brightness curve predicting a steady increase in brightness from about visual magnitude 4 to near 3 (the smaller the number, the brighter the object).

As it brightens it may be visible under dark sky conditions and even more impressive through binoculars or a telescope, although towards the start and end of this period it may be too low on the horizon to see when the sky is completely dark.

Between about October 4 and October 11 the Sun’s glare will mask visibility from the Northern Hemisphere.

Check your local news or web sites for viewing information for your latitude. For example, Sky and Telescope reports that Southern Hemisphere skywatchers should fare better.

Comet C/2023 A3 (Tsuchinshan-ATLAS) will be at its closest to Earth on October 12 at 11:10 AM EDT. Around closest approach the comet's brightness is predicted to peak at about visual magnitude 3 (similar to many stars).

Forward scattering might increase the brightness significantly, possibly as high as -1 (brighter than every star except Sirius).

How bright the comet actually appears will depend upon how much gas and dust it is giving off, which can change quickly.

Also, brightness comparisons between comets and stars can be misleading as the light of the comet is spread out making it less distinct than a star with the same brightness.

The best time to look should be the evenings on and shortly after October 12 with the comet above the western horizon after sunset.

The evening of October 12 the comet will be 4 degrees above the western horizon as evening twilight ends, similar in altitude and to the right of Venus.

The comet is expected to dim as it moves away from the Earth, but will appear higher in a darker sky and set later each evening, which could make it easier to see.

As evening twilight ends on October 13 it will be 10 degrees above the western horizon, 12 degrees on October 14, 16 degrees on October 15, etc. The brightness will decrease to about magnitude 6 by the end of October.

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NASA Astronaut Don Pettit, Crewmates Arrive at Space Station

Sep 11, 2024

NASA astronaut Don Pettit, accompanied by Roscosmos cosmonauts Alexey Ovchinin and Ivan Vagner, arrived at the International Space Station Wednesday, bringing its number of residents to 12 for the 13-day handover period.

After a two-orbit, three-hour journey to the station, the Roscosmos Soyuz MS-26 spacecraft automatically docked to the orbiting laboratory’s Rassvet module at 3:32 p.m. EDT.

The spacecraft launched at 12:23 p.m. EDT (9:23 p.m. Baikonur time) from the Baikonur Cosmodrome in Kazakhstan.

NASA’s coverage of hatch opening will stream at 5:30 p.m. on NASA+, the NASA app, YouTube, and the agency’s website.

Hatch opening is scheduled to begin at 5:50 p.m. Learn how to stream NASA content through a variety of platforms, including social media.

Once aboard, the trio will join Expedition 71 crew members, including NASA astronauts Tracy C. Dyson, Mike Barratt, Matthew Dominick, Jeanette Epps, Butch Wilmore, and Suni Williams, as well as Roscosmos cosmonauts Nikolai Chub, Alexander Grebenkin, and Oleg Kononenko.

Expedition 72 will begin Monday, Sept. 23, upon the departure of Dyson, Chub, and off-going station commander Kononenko, completing a six-month stay for Dyson and a year-long expedition for Chub and Kononenko.

Pettit, Ovchinin, and Vagner will spend approximately six months aboard the orbital outpost advancing scientific research as Expedition 71/72 crew members before returning to Earth in the spring of 2025.

This is Pettit and Ovchinin’s fourth spaceflight and Vagner’s second.

During Expedition 72, two new crews will arrive aboard the space station, including NASA’s SpaceX Crew-9 launching in September, followed by Crew-10, scheduled for launch in February 2025.

https://www.nasa.gov/news-release/nasa-astronaut-don-pettit-crewmates-arrive-at-space-station/

https://plus.nasa.gov/video/nasa-astronaut-don-pettit-soyuz-ms-26-launch-docking-hatch-opening

9 Phenomena NASA Astronauts Will Encounter at Moon’s South Pole

Sep 11, 2024

NASA’s Artemis campaign will send the first woman and the first person of color to the Moon’s south polar region, marking humanity’s first return to the lunar surface in more than 50 years.

Here are some out-of-this-world phenomena Artemis astronauts will experience:

1. A Hovering Sun and Giant Shadows

Near the Moon’s South Pole, astronauts will see dramatic shadows that are 25 to 50 times longer than the objects casting them.

Why? Because the Sun strikes the surface there at a low angle, hanging just a few degrees above the horizon. As a result, astronauts won’t see the Sun rise and set.

Instead, they’ll watch it hover near the horizon as it moves horizontally across the sky.

1. Sticky, Razor-Sharp Dust …

The lunar dust, called regolith, that coats the Moon’s surface looks fine and soft like baking powder.

But looks can be deceiving. Lunar regolith is formed when meteoroids hit the Moon’s surface, melting and shattering rocks into tiny, sharp pieces.

The Moon doesn’t have moving water or wind to smooth out the regolith grains, so they stay sharp and scratchy, posing a risk to astronauts and their equipment.

1. … That’s Charged with Static Electricity

Because the Moon has no atmosphere to speak of, its surface is exposed to plasma and radiation from the Sun. As a result, static electricity builds up on the surface, as it does when you shuffle your feet against a carpeted floor.

When you then touch something, you transfer that charge via a small shock. On the Moon, this transfer can short-circuit electronics.

Moon dust also can make its way into astronaut living quarters, as the static electricity causes it to easily stick to spacesuits.

NASA has developed methods to keep the dust at bay using resistant textiles, filters, and a shield that employs an electric field to remove dust from surfaces.

1. A New Sense of Lightness

Artemis moonwalkers will have a bounce to their step as they traverse the lunar surface. This is because gravity won’t pull them down as forcefully as it does on Earth.

The Moon is only a quarter of Earth’s size, with six times less gravity. Simple activities, like swinging a rock hammer to chip off samples, will feel different.

While a hammer will feel lighter to hold, its inertia won’t change, leading to a strange sensation for astronauts.

Lower gravity has perks, too. Astronauts won’t be weighed down by their hefty spacesuits as much as they would be on Earth. Plus, bouncing on the Moon is just plain fun.

1. A Waxing Crescent … Earth?

When Artemis astronauts look at the sky from the Moon, they’ll see their home planet shining back at them.

Just like Earthlings see different phases of the Moon throughout a month, astronauts will see an ever-shifting Earth.

Earth phases occur opposite to Moon phases: When Earth experiences a new Moon, a full Earth is visible from the Moon.

1. An Itty-Bitty Horizon

Because the Moon is smaller than Earth, its horizon will look shorter and closer.

To someone standing on a level Earth surface, the horizon is 3 miles away, but to astronauts on the Moon, it’ll be only 1.5 miles away, making their surroundings seem confined.

1. Out-of-This-World Temperatures

Because sunlight at the Moon’s South Pole skims the surface horizontally, it brushes crater rims, but doesn’t always reach their floors.

Some deep craters haven’t seen the light of day for billions of years, so temperatures there can dip to minus 334 F.

That’s nearly three times colder than the lowest temperature recorded in Antarctica. At the other extreme, areas in direct sunlight, such as crater rims, can reach temperatures of 130 F.

1. An Inky-Black Sky

The Moon, unlike Earth, doesn’t have a thick atmosphere to scatter blue light, so the daytime sky is black.

Astronauts will see a stark contrast between the dark sky and the bright ground.

1. A Rugged Terrain

Artemis moonwalkers will find a rugged landscape that takes skill to traverse.

The Moon has mountains, valleys, and canyons, but its most notable feature for astronauts on the surface may be its millions of craters.

Near the South Pole, gaping craters and long shadows will make it difficult for astronauts to navigate. But, with training and special gear, astronauts will be prepared to meet the challenge.

https://science.nasa.gov/solar-system/moon/phenomena-nasa-astronauts-will-encounter-at-moons-south-pole/

https://www.nasa.gov/solar-system/planets/mars/nasa-scientists-re-create-mars-spiders-in-a-lab-for-first-time/

https://iopscience.iop.org/article/10.3847/PSJ/ad67c8

NASA Scientists Re-Create Mars ‘Spiders’ in a Lab for First Time

Sep 11, 2024

Since discovering them in 2003 via images from orbiters, scientists have marveled at spider-like shapes sprawled across the southern hemisphere of Mars.

No one is entirely sure how these geologic features are created. Each branched formation can stretch more than a half-mile (1 kilometer) from end to end and include hundreds of spindly “legs.”

Called araneiform terrain, these features are often found in clusters, giving the surface a wrinkled appearance.

The leading theory is that the spiders are created by processes involving carbon dioxide ice, which doesn’t occur naturally on Earth.

Thanks to experiments detailed in a new paper published in The Planetary Science Journal, scientists have, for the first time, re-created those formation processes in simulated Martian temperatures and air pressure.

“The spiders are strange, beautiful geologic features in their own right,” said Lauren Mc Keown of NASA’s Jet Propulsion Laboratory in Southern California. “These experiments will help tune our models for how they form.”

The study confirms several formation processes described by what’s called the Kieffer model: Sunlight heats the soil when it shines through transparent slabs of carbon dioxide ice that built up on the Martian surface each winter.

Being darker than the ice above it, the soil absorbs the heat and causes the ice closest to it to turn directly into carbon dioxide gas — without turning to liquid first — in a process called sublimation (the same process that sends clouds of “smoke” billowing up from dry ice).

As the gas builds in pressure, the Martian ice cracks, allowing the gas to escape. As it seeps upward, the gas takes with it a stream of dark dust and sand from the soil that lands on the surface of the ice.

When winter turns to spring and the remaining ice sublimates, according to the theory, the spiderlike scars from those small eruptions are what’s left behind.

For Mc Keown and her co-authors, the hardest part of conducting these experiments was re-creating conditions found on the Martian polar surface: extremely low air pressure and temperatures as low as minus 301 degrees Fahrenheit (minus 185 degrees Celsius).

To do that, Mc Keown used a liquid-nitrogen-cooled test chamber at JPL, the Dirty Under-vacuum Simulation Testbed for Icy Environments, or DUSTIE.

“I love DUSTIE. It’s historic,” Mc Keown said, noting that the wine barrel-size chamber was used to test a prototype of a rasping tool designed for NASA’s Mars Phoenix lander.

The tool was used to break water ice, which the spacecraft scooped up and analyzed near the planet’s north pole.

For this experiment, the researchers chilled Martian soil simulant in a container submerged within a liquid nitrogen bath.

They placed it in the DUSTIE chamber, where the air pressure was reduced to be similar to that of Mars’ southern hemisphere.

Carbon dioxide gas then flowed into the chamber and condensed from gas to ice over the course of three to five hours.

It took many tries before Mc Keown found just the right conditions for the ice to become thick and translucent enough for the experiments to work.

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Once they got ice with the right properties, they placed a heater inside the chamber below the simulant to warm it up and crack the ice.

Mc Keown was ecstatic when she finally saw a plume of carbon dioxide gas erupting from within the powdery simulant.

“It was late on a Friday evening and the lab manager burst in after hearing me shrieking,” said Mc Keown, who had been working to make a plume like this for five years. “She thought there had been an accident.”

The dark plumes opened holes in the simulant as they streamed out, spewing simulant for as long as 10 minutes before all the pressurized gas was expelled.

The experiments included a surprise that wasn’t reflected in the Kieffer model: Ice formed between the grains of the simulant, then cracked it open.

This alternative process might explain why spiders have a more “cracked” appearance. Whether this happens or not seems dependent on the size of soil grains and how embedded water ice is underground.

“It’s one of those details that show that nature is a little messier than the textbook image,” said Serina Diniega of JPL, a co-author of the paper.

Now that the conditions have been found for plumes to form, the next step is to try the same experiments with simulated sunlight from above, rather than using a heater below.

That could help scientists narrow down the range of conditions under which the plumes and ejection of soil might occur.

There are still many questions about the spiders that can’t be answered in a lab. Why have they formed in some places on Mars but not others?

Since they appear to result from seasonal changes that are still occurring, why don’t they seem to be growing in number or size over time?

It’s possible that they’re left over from long ago, when the climate was different on Mars— and could therefore provide a unique window into the planet’s past.

For the time being, lab experiments will be as close to the spiders as scientists can get.

Both the Curiosity and Perseverance rovers are exploring the Red Planet far from the southern hemisphere, which is where these formations appear (and where no spacecraft has ever landed).

The Phoenix mission, which landed in the northern hemisphere, lasted only a few months before succumbing to the intense polar cold and limited sunlight.

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California Line Fire: NASA Snaps 'Fire Clouds' as People Told Stay Indoors

Updated Sep 11, 2024 at 8:53 PM EDT

Images taken from space show vast plumes of smoke billowing from the wildfires burning on the outskirts of Los Angeles, filling the air with particulate pollution.

The Line Fire in San Bernardino County threw out so much smoke and heat that it generated "fire clouds"—also known as pyrocumulus or flammagenitus—in the sky above it, which were snapped from space.

The smoke from this fire, as well as from the Bridge Fire and Airport Fire nearby, have wreaked havoc on the air quality between the eastern edge of L.A. and the Coachella Valley, sparking warnings for residents to stay indoors.

Pyrocumulus clouds are formed when extreme heat rises into the atmosphere, often from a wildfire or volcanic eruption.

The intense heat causes the air near the ground to rise rapidly, eventually cooling and condensing into water droplets, forming a towering cumulus cloud.

In the case of wildfires or volcanic eruptions, pyrocumulus clouds often contain large amounts of ash, soot, and other particles that are lofted into the air along with the water vapor, giving the cloud a dark, dirty appearance.

These images of the fire clouds rising above the Line Fire were captured from space by the OLI (Operational Land Imager) on Landsat 8.

On Tuesday, the smoke from this fire and the others burning nearby caused "Moderate to Unhealthy" Air Quality Index (AQI) levels in Palm Springs and Indio.

"Windblown dust will add to the current smoke pollution and is expected to cause Air Quality Index (AQI) values to reach Unhealthy for Sensitive Groups or worse in the Coachella Valley and Banning pass between Tuesday evening and Thursday morning," the South Coast AQMD said in a statement.

The South Coast AQMD warns residents to "limit your exposure by remaining indoors with windows and doors closed or seeking alternate shelter," avoid physical activity and use AC or air purifiers.

The AQI is calculated based on several key air pollutants regulated by health standards, including PM10 and PM2.5 particulate matter, ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide.

At "Unhealthy for Sensitive Groups" levels, members of sensitive groups —like children, the elderly, and people with respiratory or heart conditions—may experience health effects.

The Line Fire, which started near Highland on September 5, has now burned 34,659 acres as of about 7 a.m. local time on September 11 and is only about 14 percent contained.

Over 65,600 structures are at risk from the blaze, and several neighborhoods have Evacuation Orders and Evacuation Warnings in place.

The smoke from other nearby fires has actually helped slow the spread of the blaze.

"In the overnight hours of the Line Fire Wednesday, fire activity was moderated due to smoke shading and cooler weather.

However, the fire grew on the north and east sides due to slope and vegetation driven runs," Cal Fire said in a report this morning.

"Today elevated winds and continued dry conditions will allow the fire to grow. Smoke from fires across the region will help moderate fire activity unless the skies clear and the smoke thins.

That would allow for more slope and vegetation aligned runs. There are 3,179 personnel assigned to the fire. Limited resource availability continues to hamper control efforts."

To the west of the Line Fire, just north of Glendora, is the Bridge Fire. Burning across both Los Angeles and San Bernardino Counties, this blaze is 47,904 acres in area and 0 percent contained.

"Excessive heat and Red Flag Warning until Wednesday afternoon due to hot, dry, and unstable conditions with gusty onshore winds.

Winds will shift to the west and northwest on Wednesday, which may impact higher elevation areas. Temperatures will remain high, however humidity will improve and increase slightly.

Large vertical plume growth and visible smoke columns will be expected again for this fire," an Inciweb update said.

To the south of both of these fires, near Trabuco Canyon, the Airport Fire has grown from 5,432 acres on Tuesday to 22,376 acres as of Wednesday morning.

This fire is also 0 percent contained.

https://www.newsweek.com/california-line-fire-smoke-clouds-nasa-1952195

Polaris Dawn Completes First-Ever Spacewalk

On Thursday, September 12 at 7:58 a.m. ET, the Polaris Dawn crew completed the first-ever spacewalk – also known as an extravehicular activity (EVA) – from Dragon at 738 km above the Earth’s surface.

The crew began preparations for the spacewalk shortly after liftoff, through a two-day pre-breathe process designed to prevent decompression sickness by slowly acclimatizing the crew to lower pressures while slowly increasing oxygen levels within the spacecraft’s cabin.

Once complete, the crew began preparations for the spacewalk, which included donning their EVA suits, completing suit leak checks, and venting Dragon down to vacuum.

After opening the hatch, the Polaris Dawn crew became the first four astronauts to be exposed to the vacuum of space at the same time.

Over the next approximate 20 minutes, Commander Jared Isaacman and Mission Specialist Sarah Gillis each exited the vehicle, completed a series of tests designed to evaluate the suit’s mobility, thermal systems and the Dragon mobility aid “Skywalker” before returning to the cabin and closing the hatch.

Mission Pilot Scott “Kidd” Poteet and Mission Specialist and Medical Officer Anna Menon monitored vital support systems throughout the operation.

Once the hatch was closed, Dragon was re-pressurized, cabin oxygen and pressure levels confirmed, and the crew was able to remove their EVA suits, officially completing the suit testing alongside the first commercial spacewalk and the first EVA from a Dragon spacecraft.

https://www.space.com/polaris-dawn-first-commercial-spacewalk-stand-up-eva

https://www.spacex.com/launches/mission/?missionId=polarisdawn

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