Canadian astronaut Chris Hadfield finished out his five-month flurry of songs, snapshots and social media from outer space with a real doozy: a rendition of David Bowie’s “Space Oddity” that even Bowie is retweeting.

The music video was months in the making: With Bowie's approval, the song's lyrics were tweaked to reflect Hadfield's return from the International Space Station on Monday aboard a Russian Soyuz craft. "Lock your Soyuz hatch and put your helmet on," Hadfield sings in the video. After showing scenes of Hadfield strumming on his guitar and gazing soulfully out the station's windows, the video winds up with a Soyuz parachuting down to its landing.

Since "Space Oddity" went up on Sunday, it's been viewed on YouTube more than 2.7 million times.

The YouTube hit caps off an orbital tour of duty during which Hadfield sent down thousands of pictures via his Twitter account, performed the first original song recorded on the space station, mixed it up with "Star Trek" icon William Shatner and unveiled Canada's new $5 bill. For the past two months, he was doing all this while serving as the station's first Canadian commander.

"He's brought space back, not just for Canadians but for the world," fellow Canadian astronaut Jeremy Hansen told NBC News.

Dreams of space
Hadfield, 53, began his path to stardom during his childhood on a corn farm in southern Ontario. Watching Neil Armstrong's first steps on the moon in 1969 inspired him to dream of becoming an astronaut when he was 9 years old. He started flying airplanes in his teens, and went on to become a fighter pilot in the Canadian Armed Forces. He's been an astronaut since 1992, and he flew on space shuttle missions in 1995 and 2001.

Last December, he finally got his shot at a long-term stint in space — and he definitely made the most of the experience.

Slideshow: The antics and artistry of astronaut Chris Hadfield

Canadian spaceflier Chris Hadfield has posted incredible pictures of the world from space. He has also explained how to brush your teeth, shave and clip your nails while weightless.

Launch slideshow

Hadfield's 28-year-old son, Evan, told NBC News that his father put in several hours a day snapping pictures and sending tweets, in addition to his usual 10-hour work shift aboard the station. "When he wasn't working directly for space station maintenance, or on one of his science experiments, he was doing something with his time to benefit people down here," Evan Hadfield said.

Evan worked long hours, too, without pay. Over the past five months, he has been managing his father's social-media accounts and taking the lead in getting videos like "Space Oddity" produced. "I work about 16 hours a day, seven days a week," he said. "Last week I worked 19 hours a day. ... I read about 13,000 to 17,000 messages a day, and that's just in the morning."

"Space Oddity" was a special case, in part due to a tangle of international copyright issues. The Hadfields started working with Bowie and his team, as well as NASA and the Canadian Space Agency, even before the astronaut's launch in December. "It was definitely something we wanted to do," Evan said.

Why do it? Chris Hadfield hinted at the reasons in a different farewell-to-space video: "Who'd have thought that five months away from the planet would make you feel closer to people?" he asked. "Not closer because I miss them — just closer because seeing this [experience] this way and being able to share it through all the media that we've used has allowed me to get a direct reflection back immediately from so many people. ... It makes me feel like I'm actually with people more, that we're having a conversation. That this experience is not individual, but it's shared and it's worldwide."

Hansen said all of Hadfield's pictures, videos and tweets could be boiled down to a simple message: "We do live on a spaceship, a spaceship called Earth, and we need to work together to protect it."

The next chapter
So what's next? After Hadfield and his two Soyuz crewmates touch down in Kazakhstan, they'll be whisked away in separate directions: Russian cosmonaut Roman Romanenko will head toward Moscow, while Hadfield and NASA astronaut Tom Marshburn will be flown directly back to NASA's Johnson Space Center in Houston for medical checks, debriefings, rest and recuperation.

"We have a lot in store for these guys over a number of weeks," Hansen said. And that's not counting a single tweet.

It's hard to believe that Hadfield will be out of the social-media spotlight for long. "We've still got a lot of stuff," Evan Hadfield said. There are still lots of photos and videos from his father's spaceflight that have yet to be shared. But not even the Hadfields know how all those visions from outer space will come out, and on what timetable.

"I don't know, and I don't even want to speculate, because what if I'm wrong?" Evan said. "I hope, I really hope that people take Dad's message to heart and continue it past his return."

Update for 12:25 p.m. ET May 14: The "Space Oddity" video viewership is up to nearly the 7 million mark, and Hadfield commented on the YouTube phenomenon shortly after his landing in Kazakhstan. "I'm very happy that ... 7 million are interested. It is very interesting and historic to be in space," Reuters quoted Hadfield as saying.

"It's part of humanity to be in space," Hadfield said in Russian. "What we were feeling, what we were doing there, the music we played, this is a big part of our lives." 

More about Chris Hadfield:

• Astronaut's artistry hits warp speed
• How Canada's top astronaut sees the world
• Cosmic Log archive on Chris Hadfield

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

This story was originally published on Mon May 13, 2013 7:49 PM EDT

Canada's new printed-polymer $5 bill has received the country's highest sendoff, altitude-wise, from International Space Station commander Chris Hadfield. Tuesday's currency-unveiling ceremony in space was just the latest in a series of achievements that have drawn attention to Canada's best-known spaceflier.

Hadfield already has made his mark as a photographer, a musician and composer, and an explainer of outer-space phenomena ranging from crying to vomiting in zero-G. There's a reason why the Bank of Canada turned to him to introduce one of the last currency notes to be converted to counterfeit-resistant polymer: One side of the $5 bill celebrates Canada's contributions to space exploration, including the space station's Canadarm2 and DEXTRE robot.

"I just want to tell you how proud I am to be able to see Canada's achievements in space highlighted on our money," Hadfield told Canadian officials via a space-to-Earth video link. Hadfield said the pictures played to Canada's strength in space robotics.

As Hadfield spoke, he plucked a bill from the wall of the station's Destiny laboratory and set it spinning in zero gravity in front of the camera. The other side of the bill has a less spacey theme: It features a portrait of Sir Wilfrid Laurier, who was Canada's prime minister from 1896 to 1911.

Bank of Canada spokeswoman Julie Girard said the outer-space ceremony was "quite a few months in the making." The polymer note was flown up to the space station with Hadfield back in December, and held in reserve for Tuesday's ceremony. "We wanted to be the first to unveil a bank note in space," she told NBC News.

Bank of Canada

This rendition of the Canadian $5 bill shows Canadarm2 and DEXTRE in more detail. The bank note is to be issued in November.

Canada's new $10 note, which commemorates the country's rail system, was unveiled at the same time in Ottawa. The $5 and $10 bills will complete Canada's conversion to polymer-based currency, tricked up with transparent areas and hologram markings to make them harder to counterfeit. The Bank of Canada says these notes should last two to three times longer than the country's cotton-based paper bank notes — and when they wear out, they can be traded in and recycled.

The new notes won't be rolled out to the Canadian public until November. That'll provide enough lead time for training clerks and law enforcement officials to get familiar with the bills. Hadfield will be back on Earth long before November: He's due to get on board the next Soyuz capsule leaving the station on May 14, alongside NASA's Tom Marshburn and Russia's Roman Romanenko.

So what happens to Hadfield's $5 bill? Girard said the astronaut will bring the note down with him, and it will eventually be put on exhibit at the Bank of Canada's currency museum.

Several of Hadfield's priceless photographs of Earth from space are already on exhibit in our latest Month in Space Pictures slideshow. Check out the pictures, plus this bonus 3-D picture of Mars from NASA's Curiosity rover. The 3-D photo was featured in our "Where in the Cosmos" contest on Facebook. Cosmic Log fan Ryan Meader was the first to report that the mountain featured in the picture is referred to as Mount Sharp (by Curiosity's science team) and Aeolis Mons (by the International Astronomical Union).

Meader says he's a long-time reader: "I think it's fair to say that I'm on the hard-core passionate end of the spectrum — so it was to my great delight that I got the jump on this little contest," he wrote.

We're delighted to send Meader a free pair of red-blue 3-D glasses, compliments of Microsoft Research's WorldWide Telescope project — and we'll have a few more spectacles to give away in the weeks to come. So click on the "like" button for the Cosmic Log Facebook page and get ready for the next "Where in the Cosmos" contest.

Slideshow: Month in Space: April 2013

Chris Hadfield / CSA

Feast your eyes on an alligator-like mountain range and other curiosities seen from outer space in April 2013.

Launch slideshow

NASA / JPL-Caltech

A stereo image from NASA's Mars Curiosity rover shows the terrain between the robot and Mount Sharp (a.k.a. Aeolis Mons) inside Gale Crater. Wear red-blue glasses to get the 3-D effect, and don't dwell too much on the hardware in the foreground. Trying to focus in on that part of the picture can make you go cross-eyed.

More about Canada's best-known spaceflier:

• Chris Hadfield's tribute to Boston bomb victims
• What happens to a washcloth in space?
• NBC News archive on Chris Hadfield

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with NBCNews.com's stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Chris Hadfield via Google+

Australian wildfire: Look closely, you can see the flames from orbit ...

Astronaut Chris Hadfield is making a name for himself as the International Space Station's first Canadian commander, the "Singing Spaceman" and Star Trek skipper William Shatner's Twitter buddy — but he's also one heck of a photographer.

Since his arrival at the station on Dec. 21, Hadfield has posted more than 100 pictures to Twitter and Google+, most of them showing amazing views of Earth below. Between his official duties and his unofficial Earth-watching sessions, how does he find time to sleep?

"Yes, I should sleep more on station," he told one follower, "but the view from the window is like a perpetual magnet, too wondrous to ignore."

The space station's six residents all take turns behind the lens, but some astronauts take the job way more seriously than others: Notable shooters from past orbital stints include NASA's Scott Kelly, Douglas Wheelock, Ron Garan and Don Pettit, as well as Japan's Soichi Noguchi and Dutch astronaut Andre Kuipers. Hadfield is sure to take his place among them.

His favorite hangout is the seven-windowed Cupola observation deck, which provides an unparalleled view of Earth. His favorite camera? "We use primarily Nikon F2s and F3s, with a variety of lenses," he said on Twitter. "We even take them out on spacewalks, into the hard vacuum."

To get those awesome pictures of Earth landscapes, he brings out the Big Lens. "The big lens is Nikkor 600 mm, used with a 2-fold converter = 1200 mm," he tweeted. "Available for just US$10,300."

When you consider that the space station's crew is delivering pictures that no one on Earth can, that seems like a small price to pay. Check out a few of the recent masterpieces from outer space:

Chris Hadfield via Twitter

Chris Hadfield photographing Earth from the International Space Station's Cupola, using the big lens. http://pic.twitter.com/kL9iQdAN

Chris Hadfield via Twitter

Australia: The dryness creates colors and textures that make the Outback immediately recognizable from space. http://pic.twitter.com/0D4lvgJt

Chris Hadfield via Twitter

It's hard to believe the colours of the Bahamas from space. http://pic.twitter.com/0DhYXmel

Chris Hadfield via Twitter

Humans need straight lines, nature doesn't. Indecisive river and orderly farmers, central Asia. http://pic.twitter.com/BIL8Syqw

Chris Hadfield via Twitter

Seattle, WA: Look carefully, you can see Pike Place Market. http://pic.twitter.com/0OFm0iO0

Chris Hadfield via Twitter

Glacier tongues in the Himalayas. http://pic.twitter.com/A9xe7AfG

Correction for 8 p.m. ET Jan. 8: The original headline for this item called Hadfield the space station's skipper, but it's a little too early to call him that. NASA astronaut Kevin Ford is currently the station commander, and Hadfield is a flight engineer. Hadfield will take on the title of commander when Ford heads back down to Earth in March.

Update for 1 p.m. ET Jan. 9: I've added a link to Hadfield's Google+ page as well as a couple of fresh images, showing the Australian wildfires and a Central Asian landscape.

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Chad Blakley

The green glow of the aurora seems to stretch from horizon to horizon in Chad Blakley's photo from Sweden's Abisko National Park.

Tonight is prime time for the Geminid meteor shower, but there's another kind of spectacle that skywatchers are seeing up north: auroral displays in the Christmas colors of green and red.

The green glow you see above was captured on camera last week by Chad Blakley, the photographer behind Lights Over Lapland in Sweden. "It's aurora season in Abisko National Park," he writes. Blakley runs nightly photo tours in the park when the northern lights are active. To see more of his work, visit the Lights Over Lapland website or Facebook page.

National Geographic photographer Mike Theiss has also been getting some amazing auroral views, thanks to a photo assignment that took him to Whitehorse in Canada's Yukon Territory. Theiss rented a car and drove hundreds of miles farther north to the Arctic Circle. He's been using his Twitter account (@MikeTheiss) to share a series of pictures from his Arctic adventure — including an amazing shot that shows a meteor streak shooting through the auroral lights. You can see that picture below.

We're also including a Christmas bonus: Time-lapse videos from Vimeo and YouTube that incorporate Blakley's and Theiss' pictures. If you're able to, watch them full screen with HD resolution.

For more of Theiss' work, check out UltimateChase.com or Douglas Main's story at OurAmazingPlanet. And if you're a fan of the northern lights or meteor showers, you'll want to click through SpaceWeather.com's photo galleries as well.

Tonight's early reports suggest that this year's Geminid display is shaping up as a great show. If you snap a picture of the meteors  — or the northern lights, for that matter — please consider sharing it with us via NBC News' FirstPerson photo upload page for sky highlights. If I get enough pictures, I'll pass them along on Friday.

Mike Theiss / National Geographic

Mike Theiss' picture from Canada's Yukon Territory features ripples of the northern lights - plus a meteor streak that can be seen on the right side.

More auroral glories:

• Northern lights shine with the moon
• 'Tis the season for the northern lights
• Your guide to the northern lights
• Cosmic Log auroral archive

Today's pictures also provide a different twist on the Cosmic Log Space Advent Calendar, which usually features a daily view of Earth from space during the holiday season. Today, we're highlighting views of space from Earth. To catch up on past calendar entries, follow the links below:

• 2012 Cosmic Log Space Advent Calendar
• Day 1: A fantastic Chinese fan
• Day 2: Satellite shows a Grander Canyon
• Day 3: Typhoon stirs awe — and alarm
• Day 4: Glittering nighttime view of Riyadh
• Day 5: Night lights shine on 'Black Marble'
• Day 6: Holy sites seen at night
• Day 7: Blue Marble still leaves its mark
• Day 8: Satellites look into a volcano's hell
• Day 9: Jack Frost nipping at Alaska's nose
• Day 10: Cosmonaut looks down on peaks
• Day 11: Earth looms above moonwalker
• Day 12: Skytree casts shadow on Tokyo
• 2011 Cosmic Log Space Advent Calendar
• 2010 Cosmic Log Space Advent Calendar
• The Atlantic: Hubble Advent Calendar
• Zooniverse Advent Calendar

Colorful videos prove that the astronauts on the International Space Station had the best seats in the house during last month's flare-up of auroral activity.

NASA's Gateway to Astronaut Photography of Earth is offering a whole new batch of time-lapse videos from the Jan. 25-30 period, when an active region on the sun was blasting out a healthy dose of electrically charged particles and lighting up Earth's upper atmosphere.

These latest videos are notable because they're assembled from still pictures that were taken at a rate of one frame per second, rather than the usual frame every three seconds. As a result, the pace of the videos is more leisurely and a somewhat closer match to the true speed of the space station.

The video above documents a minute of flight heading east from the Pacific over the Canadian West Coast, heading toward southern Alberta near Calgary. I love watching the ripples and flashes of the green aurora over Canada — seasoned with a dash of red from the atomic oxygen that exists at higher altitudes. Why is there red as well as green in the aurora? We've addressed that question before, but this Aurora FAQ from the University of Alaska provides a quick explanation.

Here are a couple more videos, tracking the space station's flight over the U.S. East Coast as well as central North America. But you don't have to stop here. Visit NASA's Gateway, which offers still photos from the space station in addition to the videos, and check out the YouTube channel for NASA Crew Earth Observations. My favorite places for space imagery also include the Fragile Oasis Facebook page, NASA astronaut Ron Garan's Google+ page and Jason Major's Lights in the Dark blog.

If auroras, atmospheric phenomena and solar activity are your thing, you can't do much better than SpaceWeather.com, which is keeping track of lovely aurora pictures like this one from Chad Blakley at Abisko National Park in Sweden. Be sure to check out Blakley's Lights Over Lapland website while you're at it.

Chad Blakley / Lights Over Lapland

Photographer Chad Blakley captured this view of the northern lights over Sweden's Abisko National Park on Feb. 6. "The lights started around 6:00 p.m. and continued into the very early hours of the morning," Blakley told SpaceWeather.com. Check out Blakley's gallery on SpaceWeather.com for still more stunning views.

AuroraMAX / CSA

The rippling northern lights share the skies with a nearly full moon over Yellowknife in Canada's Northern Territories early today, as seen by the Canadian Space Agency's AuroraMAX wide-angle camera. To keep on top of northern Canada's aurora extravaganza, check the AuroraMAX website and Twitpic account.

Update for 3:25 p.m. ET Feb. 8: I originally wrote that the pace of the latest videos from the space station was nearly a true match to the station's orbital speed, but after double-checking with the folks at Johnson Space Center, I'd say it's more accurate to call them a "truer" match than usual. The videos were assembled from still photographs that were captured by a digital camera at the rate of one frame per second, rather than the usual frame every three seconds. That makes for a slower-paced video, but not a real-time speed, because the Web video plays at a rate that's more than one frame per second.

M ore auroral glories:

• Planet looks back at northern lights
• Auroras spark awe across the north
• Northern lights go way, way south
• Speed through Lapland's lights
• Beautiful blasts from solar storms
• Get a video view of Canada's aurora
• Slideshow: The best of the northern lights
• Cosmic Log's auroral archive

It's very cool that two 17-year-old Canadians sent a flag-toting Lego figurine into the sky on a weather balloon, as part of a weekend project that cost less than $500. It's cooler still that they got back some fantastic video of the toy silhouetted against the backdrop of a curving Earth beneath a black sky. But let's not call it putting a "Lego man in space." Even though the balloon ascended to around 80,000 feet, that's only a quarter of the way to the boundary of outer space.

That distinction doesn't take anything away from the feat that Toronto teens Mathew Ho and Asad Muhammad pulled off this month: The high-school students worked during four months' worth of free Saturdays to put together their balloon-borne experimental package, including four cameras, a cell phone with a GPS app, a home-sewn parachute and a Lego "minifig" holding a Canadian flag.

When the wind conditions were right, as determined by a website that calculates balloon trajectories, the teens headed out to a soccer  field in Newmarket and sent their rig up on an $85 weather balloon. The data suggest that the balloon rose to somewhere around 80,000 feet over the course of 65 minutes, then blew apart. The Lego man and the cameras came back down to Earth, buoyed by the parachute and protected within a plastic-foam box during the half-hour descent. Eventually, the cell phone guided the kids to a field about 75 miles away from the launch point.

The cameras recorded two videos and 1,500 photos, documenting the Lego man's amazing trip up through the clouds. "We never knew it would be this good," Ho told the Toronto Star.

But it got even better: After the Star published the teens' story, they were swamped with media attention. Canon, the company that made the cameras used on the Lego man's trip, said it would give Ho and Muhammad top-of-the-line cameras so they could continue their "creativity and inspiration." Lego sent its congratulations. A Toronto couple offered to reimburse the kids for their costs. Reports about the feat filtered out to The Guardian, the Daily Mail, the Huffington Post and elsewhere. The YouTube video has been viewed more than 600,000 times, and there's even a Facebook fan page.

Most of the reports refer to the Lego man as being "in space" — which makes for a nice headline but is unfortunately wrong. The issue may not seem like a biggie, but over the past year there have been all sorts of things sent up on balloons to stratospheric heights — including a chair, an iPad (sans parachute), a vibrator and iPhones galore. Heck, a 7-year-old and his dad sent up an iPhone a couple of years ago, and the Toronto teens said they took their inspiration from the MIT students who kicked off the craze with a $150 balloon mission in 2009.

This is all great, but it could give folks the impression that sending things into space is so easy a kid can do it — so why are we spending millions or billions of dollars to put things into orbit?

Lofting payloads on suborbital trips beyond the internationally accepted boundary of outer space — 100 kilometers or 62 miles or more than 328,000 feet in altitude — is devilishly hard. Just ask Virgin Galactic. or XCOR Aerospace, or Blue Origin, or Armadillo Aerospace, or Masten Space Systems, or all the other ventures that are trying to open the suborbital frontier.

Putting payloads in orbit is much, much harder. Just ask SpaceX, which burned through three launches and millions of dollars before achieving its first success.

Ho and Muhammad haven't reached those heights ... yet. But someday, they may well be putting real men and women into space. The teens are off to a good start, and they deserve all the accolades they're receiving this week for their near-space adventure.

More about near space:

• Balloons built for future frontiers
• Twin-balloon airship hits high frontier
• Student experiments soar on NASA balloons
• Students reach high for amazing launch photos

Michael Ericsson Visuals

An auroral display dominates the sky over Tibbitt Lake in Canada's Northwest Territories on the night of Aug. 6.

Last week's solar storms sparked auroral displays as far south as Colorado and Nebraska over the weekend, but the best viewing was available way up north — for example, Canada's Northwest Territories, where photographer Michael Ericsson captured this amazing picture.

"It's one of the better spots in the world to see the aurora," Ericsson told me over the phone today from Yellowknife. He says you can see the northern lights on pretty much any clear night, "if you're out for enough hours."

Ericsson knew that the weekend would be prime time for aurora-viewing, thanks to a series of solar eruptions that started on Aug. 2. The outbursts didn't cause significant disruptions in satellite operations, communications or power grids, as some had feared, but they put on a heck of a show over Tibbitt Lake, where Ericsson set up his camera equipment. He put together a time-lapse series of the auroral display — shot at three-second intervals with a Nikon D3s at ISO 6400 — to produce this must-see video. (Make sure you're seeing this in PhotoBlog's wide-screen format.)

Ericsson says he's seen brighter auroral displays, particularly during the long northern winter, but this one was special nevertheless. "It's really neat getting a summer aurora, because in Yellowknife we're still not getting complete darkness," he told me, "and that's part of the reason why I didn't see it as the most intense aurora."

He and a couple of friends traveled to Canada's Nunavut territory in April to document the northern lights there and also gather some oral history from the local elders. Here's yet another must-see video that features the sights of the lights and the sounds of Alice Ayalik, telling tales of the aurora in her native tongue:

Check out Ericsson's Vimeo website as well as his blog and MichaelEricsson.com for much, much more from the Great White North.

Ericsson wasn't the only one to catch last weekend's show. Yuichi Takasaka's time-lapse video offers a subtler look at the aurora, punctuated by passing clouds and airplanes. Takasaka specializes in views of the night sky, focusing on the northern lights as well as noctilucent clouds and the International Space Station. This view of the Aug. 5 aurora was captured from Burton Campground in British Columbia:    

Check out Takasaka's Blue Moon Promotions website for more.

SpaceWeather.com offers a whole gallery of photos and videos featuring this month's auroral displays, and the show may not be over just yet: Just today, the most powerful flare in years blasted out from the sun. The flare was not directed toward Earth (which is a good thing), but it still might spark a fresh wave of auroras later this week. To learn more about how auroras arise, and how best to see them, check out this FAQ page from the University of Alaska's Geophysical Institute.

More about auroras:

• Southern lights look sweeter from space
• Weird glow from Earth's auroras explained
• A mystery glows on Saturn
• All about auroras on msnbc.com

Connect with the Cosmic Log community by "liking" the log's Facebook page or following @b0yle on Twitter. You can also add me to your Google+ circle, and check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.