After 144 days, 2,336 orbits of the Earth, and hundreds upon hundreds of posts to Twitter, Facebook and Youtube, Commander Chris Hadfield has returned from the International Space Station a household name – arguably space travel's first since the Apollo Moon landings. Gizmag takes a look back at Hadfield's 5-month mission to see how and why Hadfield inspired millions.

Within hours of returning to Earth today, Hadfield's Twitter bio had been updated to indicate his location "in a field in Kazakhstan." This followed a 3.5-hour descent with NASA's Tom Marshburn and the Russian Federal Space Agency's Roman Romanenko aboard Soyuz TMA-07M, touching down safely at 10:31 p.m. EDT to the southeast of Dzhezkazgan in Kazakhstan.

In his five months in orbit, Hadfield has educated and delighted a band of followers that has grown from five figures in December to more than 900,000 today. At the time of writing, his account is gaining several followers every second.

Many discovered Hadfield's Twitter presence following a memorable exchange in January with actor William Shatner, who played James T. Kirk in the original Star Trek television and film series:

Hadfield's response was firmly in the Trekker spirit, but also typical of his human approach to talking to his Earth-locked fellow Homo sapiens about his time in space: a humanity in contrast to the straight-lacedness of space's heroes of yesteryear that he says inspired him.

Yet Hadfield is cut from similar cloth. He joined the Canadian Armed Forces in 1978 (having been raised on an Ontario farm), and was top pilot among his compatriot trainees at Portage la Prairie airbase in 1980 and at Moose Jaw in 1984 and 1985, before flying CF-18s for NORAD. He would go on to train as a test pilot at Edwards Air Force Base and subsequently fly more than 70 kinds of aircraft.

His career as an astronaut began in 1992 when he and three others were picked out from a field of over 5,000 applicants by the Canadian Space Agency. At NASA, he worked on the development of the space shuttle's glass cockpit, and was CapCom – the voice of mission control – for 25 Shuttle missions. He left Earth's atmosphere in 1995 on Space Shuttle Atlantis mission STS-74, only the second docking of a shuttle to the Mir space station. The year 2001 saw his return to space, when Space Shuttle Endeavour took the robot arm Canadarm2 to the ISS for installation. Hadfield performed two space walks, spending almost 15 hours outside the space station, during that mission.

With his high-flying past, Hadfield would be forgiven for having a gruff, no-nonsense exterior, and yet the Hadfield we have come to know couldn't be further removed from this archetype. Every evening (GMT time, the ISS's timezone of choice), Hadfield would post pictures of the Earth from orbit. The photographs were not only beautiful reminders of our scale and place on the Earth, but also eye-opening and sometimes abstract illustrations of the planet's human and natural geography.

Hadfield: "I have no idea what this Brazilian outcrop looks like on the ground, but from orbit, it's a brain" (Photo: Chris Hadfield/NASA)

It's easy to forget that public engagement was not Hadfield's sole role aboard the ISS for Expeditions 34 and 35. During any one stint aboard the ISS, crew will be involved in some 200 experiments, some brief, and some inherited and passed on to other crews.

On March 15, Hadfield took over as ISS Commander for Expedition 35, becoming the first Canadian to do so. Experiments conducted on Hadfield's watch include InSPACE-3, which is gathering data on the behavior of fluids of ellipsoid particles, the physical properties of which alter according to changes in magnetic fields. The experiment will build our knowledge of so-called smart materials better able to withstand earthquakes.

The astronauts of Expedition 35 also underwent ultrasound scans while aboard the ISS which, combined with MRI and high-fidelity ultrasound scans following their return to Earth, will help asses health risks in microgravity environments.

And during his tenure aboard the ISS, Hadfield had the opportunity to test the Canadian Space Agency's tricorder-like Microflow device, a miniaturized flow cytometer which uses a laser to analyze cells in a fluid sample.

And then there's the wonderful SPHERES-Zero-Robotics experiment, which invites school children to develop algorithms to control the small SPHERES experimental satellites, which can fly free and perform tasks within the cabin of the ISS.

Perhaps more memorable to those of us on the ground will be the informal experiments Hadfield performed on video at the behest of the gravitationally challenged. April 16, 2013 will live long in the memories of Nova Scotia students Kendra Lemke and Meredith Faulkner, who wanted to know the effects of weightlessness on a wrung-out washcloth. The results are mesmerizing:

More often, Hadfield's videos for the Canadian Space Agency gave bite-sized but irresistible insights into life aboard the ISS, from how and where to sleep and shave to how to make a peanut butter sandwich and what to do if you feel sick.

Hadfield's final days aboard the ISS were a little more eventful than planned. On Thursday evening, he spotted ammonia particles leaking from the ISS. Though NASA has said the crew were never in danger, a spacewalk to replace a pump was given the go-ahead on Friday. Chris Cassidy and Tom Marshburn completed repairs over the weekend, with the 48-hour turnaround hailed as the shortest ever for a spacewalk from the ISS.

With Hadfield, Marshburn and Romanenko safely back on terra firma, the ISS has been left in the hands of Commander Pavel Vinogradov, Aleksandr Misurkin and Chris Cassidy. They will be joined on May 28 by Karen Nyberg, Fyodor Yurchikhin and Luca Parmitano, restoring the ISS to its full complement of six crew. Nyberg is already an active Twitter user, and perhaps she will continue the tradition and return to Earth with many more followers after her 6-month stay.

After his months of perpetual free-fall about Earth at a speed of 7.71 km/s, Hadfield is due some well-earned rest. Hopefully he will have some time to reflect on his new status as an educator and inspirer of millions. Hadfield drew his time in space to a close with a special recording of David Bowie's Space Oddity. We may be well used to seeing images of humans in space; Hadfield, though, has given us our first glimpses of humanity. Really made the grade, indeed:

You can see a selection of some of our favorite photos of Earth taken by Hadfield aboard the ISS in recent weeks in this article's gallery.

View gallery - 17 images