A thud, dirt in the window of his capsule and the fresh smell of spring on the Kazakh steppe: Canadian astronaut Chris Hadfield recalled Thursday his safe return from a five-month mission to space.

"We hit the Earth just like a car crash," Hadfield told a webcast news conference from NASA headquarters in Houston, Texas, where he has been undergoing tests and readapting to gravity since Tuesday's landing.

"One person is on the bottom (in the Soyuz-TMA capsule), one is on the wall and one is hanging from the ceiling. I was the guy hanging from the ceiling."

Fellow astronaut American Tom Marshburn looked out of the window and saw "dirt and grass, where space had been just moments before," Hadfield said.

And when the hatch was opened, "we could smell the prairie. We could smell the steppe, the Kazakhstan steppe."

"One by one they plucked us out of the capsule and the first true sense of being home was a window full of the dirt of the Earth and the smell of spring and the growing grasses in Kazakhstan."

Hadfield returned to Earth with Marshburn and Russian cosmonaut Roman Romanenko, after a mission to the International Space Station saw him shoot to global stardom, captivating people worldwide with his Twitter microblog.

Russian state television pictures had shown the giant white parachute of the Soyuz capsule unfurling successfully after re-entry followed by the capsule touching down and sending a plume of dust into the sky.

The Soyuz capsule landed on its side, but this is a relatively common occurrence. Its outer shell was charred from the heat of more than 3,000 degrees Celsius (5,432 Fahrenheit) as it shot through the atmosphere.

Right after landing, Hadfield said: "I could feel the weight of my lips and tongue and I had to change how I was talking. I hadn't realized I'd learned to talk with a weightless tongue.

"So the subtle things and the big things are taking some getting used to. They're coming back one by one. I'm just trying to learn how to walk... I'm not ready to run."

"Weightlessness is just a superpower. You can fly, effortlessly. And it's a wonderful, liberating feeling," he said.

"But the reality of life for everyone is here on Earth. And this is where all the people that I love are. And so I'm readapting to it physically and mentally and we'll get there soon."

Hadfield likened his symptoms to aging.

"My blood vessels have hardened. My cardiovascular system has changed. How my blood regulates blood pressure, all those things have changed rapidly and now they're readapting."

Over the coming weeks, he said NASA scientists will be "poking and prodding" him for insights on astronauts' physical trauma.

"I'm a full-sized human lab rat," he said.

From space, Hadfield captured the public imagination with regular updates on Twitter that gave an unprecedented insight into daily life in space and access to spectacular images taken from the ISS.

Tweeting under the Star Trek-like name @Cmdr_Hadfield, the astronaut posted spectacular pictures of the Earth seen from the sky and also insights on the mundane aspects of eating and washing in space.

He and his team held the first live news conference from space, recorded the first music video in space -- a cover of David Bowie's classic "Space Oddity" -- conducted a record number of scientific experiments on the ISS and more.

Hadfield, who was commander of the station, also oversaw a dramatic spacewalk at the weekend performed by Marshburn and Chris Cassidy to halt an ammonia leak.

Using the power of social networks more effectively than anyone in the history of manned space flight, Hadfield has arguably become the world's most prominent astronaut since the days of Neil Armstrong and Buzz Aldrin.

He inspired the public at a time when some scientists question the need for manned space flight to the ISS amid constant budget pressures.

Hadfield said he delights in the world being able to see and maybe better understand the work and collaboration on board the ISS, "by seeing our star in the sky."

"I was a Cold Warrior, intercepting Soviet bombers in the 80s, and now look where we are. This space station is a wonderful example of how people do things right," he said.

"The experience of leaving Earth is still very new for humanity and the ability to explain it and to share it is growing leaps and bounds due to the technology that's available."

The experience of flying in space is something that should be shared with everyone, he added.

"It is just too good an experience to keep to yourself and the more people that see it and understand... the more the benefits of space exploration will roll back into daily life for all of us."