After an incredible 286 consecutive days in space, the mental and physical toll on NASA’s stranded astronauts Sunita Williams and Butch Wilmore may have been much more serious than their smiles and thumbs-up indicated after splashdown.

The world rejoiced as the two fearless space scientists landed in waters off Florida on Tuesday, but the roller coaster of emotions after a 10-day mission turned into a marathon stay has taken its toll according to family members.

Williams’ mother, Bonnie Pandya, has spoken about the saga and explained her daughter was on the cusp of retiring before agreeing to take the ill-fated trip.

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

“You forget that in space you’re not holding hands, you’re not hugging people,” the message explained.

Ms Pandya also spoke of 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,” Ms Pandya said.

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.

“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 pressurised cabin, for extended periods,” medical experts told the Daily Mail.

“Her cheeks appear a bit sunken - and usually it happens when you’ve had sort of total body weight loss.”

In a bid to ward off the physical and mental strains on their astronauts, NASA adheres to a strict exercise program.

While in space, astronauts must exercise two hours per day, every day, as zero-gravity conditions can cause “bone and muscle deterioration” over time according to the NSA guidelines.

A regular morning for Williams would include working out first thing — waking up at 5.30am and “running, cycling, and weightlifting” until 7.30am.

Williams’ cousin, Falguni Pandya, was also “constantly in touch” with her.

“We are constantly meeting on Microsoft software, celebrating holidays together and we sent her gifts, cards and photographs,” Ms Falguni said two days before the return mission.

“She talks to her mother about every day.”

“People have seen her giving speeches people have seen her talk about intense topics and science and all that, but she really likes to laugh she finds joy in the smallest of things to the point where you know it’s very infectious,” Ms Pandya told Republic World.

“She is looking forward to seeing her two pet dogs again.”

and Wilmore blasted off on June 5 and docked on the ISS one day later.

While they were set to return home on June 13, a scourge of technical issues with their spacecraft, Boeing’s Starliner.

The problems ultimately drove NASA to delay their return until they could hitch a ride home on a safer ship.

Williams emerged from the SpaceX capsule on Tuesday smiling and waving as she was lifted onto a stretcher and taken for medical evaluations.