NASA astronaut Sunita Williams may have put a brave face while stuck in space, but her family have revealed how she was secretly hurting.

Williams' mother, Bonnie Pandya, said her daughter was considering retiring weeks before being deployed on the mission that was meant to last just 10 days.

During her nine uncertain months stranded on the International Space Station, Williams complained of missing her family and the warmth of their touch.

In an interview with local news station WCNC, Williams' sister Dina Annad shared the context of a private email between her and her sibling.

In it, Williams wrote: 'You forget that in space you're not holding hands you're not hugging people.'

Bonnie Pandya also shared a heartwarming message upon her daughter's return, saying her family and friends have been 'waiting and waiting.'

'We missed you a lot, but with you keeping in touch with everybody and all of us, the family, we didn't miss that much but just enough,' Pandya said.

Williams and her crewmate Butch Wilmore spent a total of 286 days on the ISS, which is second to Frank Rubio who was on the ISS for 371 consecutive days,

The pair finally returned to Earth Tuesday, splashing down off the coast of Florida at 5:57pm ET and reuniting with family hours after. 

Throughout William's stay, the public and medical experts raised concerns about her health as she appeared gaunt in photos taken of her on the ISS.

Dr Gupta told DailyMail.com: 'What you're seeing there in that picture is somebody that I think is experiencing the natural stresses of living at a very high altitude, even in a pressurized cabin, for extended periods.

'Her cheeks appear a bit sunken - and usually it happens when you've had sort of total body weight loss,' Dr Gupta added.

But through it all, Williams kept a stony face and even laughed about her extended stay during press conferences.  

During a press conference on March 4, Williams actually said she would miss being in space.

But behind the scenes, a different story was happening. 

Annad told WCNC that Williams' was missing her friends and family just as much, so much they sent funny stories and jokes to the ISS.

Williams' cousin, Falguni Pandya, was also 'constantly in touch' with her.