Williams has logged 322 days during two space flights making her second on the list of most experienced US female astronauts. She also holds the record of longest spaceflight (195 days) for female space travellers.
Daughter of an Indian-American father from Gujarat and a Slovenian mother, Williams is the second woman of Indian origin to have been selected by NASA for a space mission after Kalpana Chawla and the second astronaut of Slovenian heritage after Ronald M. Sega.
Williams, Aki Hoshide of the Japanese Aerospace Exploration Agency and Russian cosmonaut Yuri Malenchenko spent 125 of their 127 days in space circling Earth onboard the ISS. The trio blasted off from the Baikonur Cosmodrome in Kazakhstan on July 15.
While on the outpost, they welcomed SpaceX's Dragon capsule making its first official cargo delivery, which included fresh apples and chocolate-vanilla swirl ice cream.
Williams and Hoshide also carried out two spacewalks.
Kevin Ford, the new ISS commander and his crewmates-Russian cosmonauts Oleg Novitskiy and Evgeny Tarelkin-will run the outpost as they await the arrival of three more crew members, including American Tom Marshburn, in December