It’s time to come home

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SpaceX’s first Crew Dragon capsule to carry NASA astronauts will undock from the International Space Station tonight (Aug. 1), setting the stage for a historic weekend splashdown.

The SpaceX Crew Dragon capsule Endeavour is scheduled to undock from the station tonight at 7:34 p.m. EDT (2334 GMT) as its Demo-2 test flight enters its final stage. The spacecraft is expected to return to Earth with NASA astronauts Bob Behnken and Doug Hurley on Sunday (Aug. 2). 

Behnken and Hurley are flying on SpaceX’s first-ever crewed spaceflight. They launched to the station May 30 and are expected to spend just under a day in orbit before returning to Earth Sunday afternoon, NASA officials said.

You can watch the SpaceX undocking live here and on Space.com’s homepage, courtesy of NASA TV. You can also watch it directly from NASA here. NASA’s webcast will begin at 5:15 p.m. EDT (2115 GMT) tonight.

Full coverage: SpaceX’s historic Demo-2 Crew Dragon astronaut test flight

The astronauts got an early start on their departure with a farewell ceremony this morning to mark the upcoming undocking.

“It’s hard to put into words just what it was like to be a part of this Expedition 63,” Hurley said of the last two months working with the station’s crew. “It’ll be kind of a memory that will last a lifetime for me.”

Behnken said it’s been a great test flight with SpaceX’s Crew Dragon, the first commercial spacecraft every to carry astronauts in orbit, but there’s still a big trial ahead. 

Launching into space may have been the hardest part of this test flight, “but the most important part is bringing us home,” Behnken said.Loading video

Behnken and Hurley, or “Bob and Doug” as they’ve been affectionately dubbed by the public, launched to the space station May 30 as part of SpaceX’s historic first crewed mission to space. The launch, which is part of NASA’s Commercial Crew Program, also marks the first crewed commercial mission for NASA. 

SpaceX’s Demo-2 mission will conclude with the crew’s return to Earth, which will be the first U.S. splashdown in nearly 45 years. The pair of veteran astronauts are set to splash down in the Gulf of Mexico off the coast of Panama City, Florida, one of seven options available, at 2:42 p.m. EDT (1842 GMT) if weather conditions are favorable. 

This could prove tricky, as the National Oceanic and Atmospheric Administration’s (NOAA) National Hurricane Center is continuing to Hurricane Isais which is currently headed towards Florida. 

NASA officials have said they plan to make a final decision on whether to proceed with undocking about six hours before the event is scheduled to occur. That will come at about 1:30 p.m. EDT (1730 GMT). The target landing site could also change depending on weather conditions, they added.

Related: SpaceX’s historic Demo-2 crewed test flight in photosAdLoading video

A final landing site, and whether or not the splashdown will be delayed, will be decided upon based on a number of key factors including wind speed, the slope of the ocean waves, rain, lightning, availability of nearby recovery helicopters, the vessel’s pitch and roll, the visible ceiling and overall visibility. 

Visit Space.com today for complete coverage of the Crew Dragon landing. 

Email Chelsea Gohd at cgohd@space.com or follow her on Twitter @chelsea_gohd. Follow us on Twitter @Spacedotcom and on Facebook.

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NASA’s Mars 2020 rover Perseverance is ‘go’ for launch

Liftoff is scheduled for 7:50 a.m. EDT on Thursday (July 30). By Mike Wall @Space.com

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NASA’s next Mars rover has been cleared for liftoff.

This morning (July 27), the $2.7 billion Mars 2020 Perseverance rover passed its launch readiness review, the last big hurdle to clear before its planned liftoff Thursday (July 30) from Florida’s Cape Canaveral Air Force Station.

“The launch readiness review is complete, and we are indeed go for launch,” NASA Administrator Jim Bridenstine said during a news conference today.

Related: How to watch NASA’s Mars 2020 Perseverance rover launch live online

Perseverance is scheduled to lift off atop a United Launch Alliance Atlas V rocket Thursday during a two-hour window that opens at 7:50 a.m. EDT (1150 GMT). You can watch all the action live here at Space.com, courtesy of NASA.

Mother Nature looks likely to cooperate with that plan. There’s just a 20% chance that bad weather will scuttle Thursday’s attempt, launch weather officer Jessica Williams, of the 45th Space Force, said during today’s news conference.

The launch will send Perseverance on a nearly 7-month cruise to Mars, which will end with a dramatic, sky-crane landing within the Red Planet’s Jezero Crater on Feb. 18, 2021. 

Related: NASA’s Mars Perseverance rover mission to the Red Planet (photos)Loading video

The nuclear-powered rover will then spend at least one Mars year (nearly two Earth years) exploring the 28-mile-wide (45 kilometers) Jezero, which harbored a lake and a river delta in the ancient past. Perseverance will hunt for signs of ancient Mars life, study the crater’s geology and collect and cache several dozen samples, among other tasks.

Those samples will be brought back to Earth, perhaps as early as 2031, by a joint NASA/European Space Agency campaign. Once the Mars material is here, scientists around the world will scour it for signs of life and clues about the planet’s mysterious history.

“That’ll be the first time in history that we’ve done a Mars return mission,” Bridenstine said. “In fact, it’s the first time in history we’ve done a return mission from any planet.” 

(Humanity has pulled off other types of sample-return missions, however. NASA’s Apollo astronauts brought hundreds of pounds of rocks back from the moon, and robotic probes have returned to Earth with asteroid material and specks of comet dust.)Loading video

Perseverance will also demonstrate several new technologies on the Martian surface. For example, one of the rover’s 10 instruments, called MOXIE, will generate oxygen from the Red Planet’s thin, carbon dioxide-dominated atmosphere. Such gear, once scaled up, could help future astronauts explore the Red Planet, a goal NASA wants to achieve in the 2030s.

In addition, a 4-lb. (1.8 kilograms) helicopter called Ingenuity will travel to Mars on Perseverance’s belly. Once the rover finds a good spot, the little chopper will detach and perform a few test flights — the first ever performed by a rotorcraft on an alien world. 

If Ingenuity is successful, future Mars missions may routinely employ helicopters as scouts for rovers or astronauts, NASA officials have said. Rotorcraft could also do substantial science work of their own, exploring hard-to-reach places such as caves and cliff faces. Loading video

Ingenuity won’t collect data in this manner; it carries no science instruments. But the little chopper does have a camera system, which should provide some amazing and unprecedented Red Planet views.

“Imagine looking from Perseverance out at a helicopter that is flying around Perseverance, and the helicopter is looking back at Perseverance, giving us images of Perseverance — what Perseverance is doing,” Bridenstine said. “We’re going to be able to see with our own eyes, with motion pictures, these kinds of activities happening on another world.”

Perseverance’s launch window extends through Aug. 15. If the rover is unable to get off the ground by then, it will have to be put into storage until the next opportunity in 2022. (Earth and Mars align properly for interplanetary missions for a few weeks every 26 months.)

The NASA rover’s launch will be the third Mars liftoff in less than two weeks. The United Arab Emirates’ Hope orbiter launched on July 19, and China’s Tianwen-1 orbiter-lander-rover mission followed suit on July 23.

Comet NEOWISE: 10 big questions (and answers) about the icy wanderer

Comet NEOWISE: 10 big questions (and answers) about the icy wanderer By Chelsea Gohd @ Space.com

(Image credit: NASA/Johns Hopkins APL/Naval Research Lab/Parker Solar Probe/Brendan Gallagher)

Comet NEOWISE has is delighting skywatchers around the Northern Hemisphere. But what makes this comet so special? Advertisement

The comet made its closest approach to the sun on July 3 but, until now, was only visible in the sky before dawn. Now, for keen observers in the Northern Hemisphere, the comet has been getting higher in the evening sky, sparkling northwest below the Big Dipper constellation, according to Joe Masiero, deputy principal investigator of NEOWISE (NASA’s Near-Earth Object Wide-field Infrared Survey Explorer, the NASA space telescope that first spotted the comet).

One of the most fascinating details about Comet NEOWISE is that it won’t return to our skies for another 6,800 years. But that’s not the only thing that makes this icy space rock special. So let’s take a dive into what makes Comet NEOWISE unique — and a little weird.

Related: How to see Comet NEOWISE in the evening sky now

What is Comet NEOWISE?

Comet NEOWISE, as photographed by Joy Ng, a multimedia producer at NASA’s Goddard Space Flight Center.  (Image credit: Joy Ng)

Officially known as C/2020 F3, Comet NEOWISE is a comet that was discovered on March 27, 2020, by NEOWISE, the asteroid-hunting afterlife of the Wide-field Infrared Survey Explorer (WISE) mission. 

Comets, often nicknamed “cosmic snowballs,” are icy, rocky objects made up of ice, rock and dust. These objects orbit the sun, and as they slip closer to the sun most comets heat up and start streaming two tails, one made of dust and gas and an “ion tail” made of electrically-charged gas molecules, or ions.

Can I see it?

This NASA sky map shows the location of Comet NEOWISE in the evening sky for viewers in the Northern Hemisphere in July 2020. (Image credit: NASA)

Yes! Because it is especially bright, the comet is visible in the night sky with the naked eye. Skywatchers in the Northern Hemisphere can spot the object just after sunset, to the northwest just under the Big Dipper constellation

In fact, the comet is so bright that scientists are “able to get a lot more and better data than we typically do for most comets,” Kramer said. “We’re able to study it with a wide variety of different telescopes, and that’ll allow us to do really interesting studies.”

Do I need a telescope? 

No! Because Comet NEOWISE is an especially bright object, it is relatively easy for astronomy enthusiasts to spot it in the night sky with just the naked eye, although binoculars or a small telescope will give you a better view.

“The fact that we can see it is really what makes it unique,” Kramer said. “It’s quite rare for a comet to be bright enough that we can see it with a naked eye or even with just binoculars.”

What does it look like in the sky?

Astrophotographer Bill Dunford, a NASA social media specialist at the Jet Propulsion Laboratory in Pasadena, California, captured this view of Comet NEOWISE when it was visible in the predawn sky in early July 2020. (Image credit: NASA/Bill Dunford)

To those spotting the comet with the naked eye, without any tools or instruments like a telescope, it looks like a fuzzy star with a little bit of a tail. You do need to be away from city lights, though.

With binoculars or a small telescope, the comet will be more clear and the tail will be easier to spot. 

How much water is in the comet? 

An unprocessed image from the WISPR instrument on NASA’s Parker Solar Probe shows Comet NEOWISE on July 5, 2020, shortly after its closest approach to the sun. The sun is out of frame to the left. The small black structure near the lower left of the image is caused by a grain of dust resting on the imager’s lens. (Image credit: NASA/Johns Hopkins APL/Naval Research Lab/Parker Solar Probe/Brendan Gallagher)

There is “about 13 million Olympic swimming pools of water,” in Comet NEOWISE, Emily Kramer, a science team co-investigator forNASA’s NEOWISE at NASA’s Jet Propulsion Laboratory, said during a news conference July 15. “So that’s a lot of water.” 

“Most comets are about half water and half dust,” she added.

Does it have a tail?

Comet NEOWISE has two tails that typically accompany every comet.

As a comet nears the sun, it warms up and material pulls away from the surface into a tail. Often, dust is pulled away along with gases from sublimating (going directly from solid to a gas) ice. This dust tail is the sweeping trail seen in most comet images. Comets also have an ion tail made up of ionized gas blown back by the solar wind. 

Researchers studying Comet NEOWISE might actually also have a sodium tail. By observing what they believe to be atomic sodium in the comet’s tail, researchers can glean keen insight into the object’s makeup.

How big is Comet NEOWISE?

An unprocessed image from the WISPR instrument on NASA’s Parker Solar Probe shows Comet NEOWISE on July 5, 2020, shortly after its closest approach to the sun. The sun is out of frame to the left. The small black structure near the lower left of the image is caused by a grain of dust resting on the imager’s lens. (Image credit: NASA/Johns Hopkins APL/Naval Research Lab/Parker Solar Probe/Brendan Gallagher)

Comet NEOWISE is about 3 miles (5 kilometers) in diameter, “which is a reasonably large but roughly average-size comet,” Kramer said.

“It’s rare to see something that’s this bright,” she added. “There are comets that are of this size that we see regularly, but most of them are so from Earth that they don’t get this bright. They’re too far from the sun and the Earth to be able to see them in the way that we’re seeing this Comet NEOWISE.”

How fast is Comet NEOWISE?

Astrophotographer Chris Schur captured this view of Comet NEOWISE F3  from Payson, Arizona before dawn on July 5, 2020. (Image credit: Chris Schur/Chris Schur Astrophotography)

The comet is traveling at about 40 miles per second (that’s about 144,000 mph, or 231,000 km/h). 

Joe Masiero, deputy principal investigator of the NEOWISE mission, said the the comet is moving about twice as fast as the Earth’s speed around the sun. But don’t expect that rapid clip to last.  

Because of the comet’s extremely elliptical orbit, it will slow down as it reaches its farthest point from the sun, then fall back toward the inner solar system and accelerate again when it heads back round the sun. That trip around the sun is over for Comet NEOWISE’s current orbit and it’s moving back to the outer solar system.

“And so as it goes farther from the sun, [it] will be slowing down as it climbs back up that gravity well,” Masiero said.

Will it hit Earth?

Have no fear, Comet NEOWISE will not hit Earth. 

“This particular comet has no possibility of impacting the Earth. It crosses the plane of Earth orbit well inside of recovery orbit and almost near the orbit of Mercury, so there’s absolutely no hazard from this comet,” Lindley Johnson, the planetary defense officer and program executive of NASA’s Planetary Defense Coordination Office at NASA Headquarters, said during the news conference. 

The comet orbits the sun every 600 to 700 years, Johnson said. The comet is currently about 70 million miles (111 million kilometers) away from Earth.

Is it from interstellar space?

No, Comet NEOWISE originates in our own solar system. To date, only two interstellar objects have been discovered: ‘Oumuamua and Comet Borisov

“This one we know it’s not Interstellar object. By watching its motion, we can see that it’s bound to the sun’s gravity,” Kramer said. “So it’s coming in very rapidly and then it’s going to go far back out again and then but then should come back in again in about 6,800 years.”

Email Chelsea Gohd at cgohd@space.com or follow her on Twitter @chelsea_gohd. Follow us on Twitter @Spacedotcom and on Facebook.

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