All the signs of stranded NASA astronauts' ill health as they fly home

Astronauts Sunita Williams , 59 , and Barry Wilmore , 61 , have spent more than nine months on the International Space Station (ISS) The pair will be placed on stretches and immediately taken for medical evaluations.

They will need up to six weeks of rehabilitation to regain their strength, which will include guided exercise and a nutritional plan.

Dr Vinay Gupta , a pulmonologist and Air Force veteran, said the astronauts could need six weeks' rehabilitation.

Williams and Wilmore were only supposed to spend eight days on the ISS when they blasted off on June 5 .

But a scourge of technical issues with their spacecraft, Boeing 's Starliner , ultimately drove NASA to delay their return until they could hitch.

At the start of the mission, six-foot -tall Wilmore weighed more than 210 pounds .

It's unclear how much weight he's lost since boarding the ISS .

NASA 's chief health and medical officer Dr JD Polk told DailyMail.com: 'All NASA astronauts aboard the International Space Station are in good health' Williams and Wilmore will need to stick to an intense rehabilitation program once they're back on Earth .

Williams and Wilmore may need to rehabilitate their minds, according to psychiatrist Dr Carole Lieberman .

She recently told DailyMail.com that the astronauts will need to process intense emotions they may have been feeling during their time on the ISS , such as fear of dying and frustration with having to stay in space longer than they planned.