He floated forward in a Superman-like pose, stretched out his arm, and lunged towards Andrey Borisenko (Commander of the ISS) with a spinning airborne embrace.
He then embraced Ron Garan, Alexander Samokutyaev, Sergei Volkov, Satoshi Furukawa, and lastly Mike Fossum.
Ferguson's entry to the ISS was followed by the rest of his crew, which comprised of Doug Hurley, Rex Walheim, and Sandy Magnus.
The Atlantis crew is docking at the ISS mainly to deliver crucial supplies and spare parts. It's expected to return to earth on July 20.
The ISS, residing in space, has much less gravity than earth, so floating hugs are possible. However, that's not the only cool thing astronauts have done in that environment.
Below is the video of the space hug plus a montage of pictures from low gravity space environments.