Astrophysicist says he has ‘no sympathy’ for NASA astronauts as they land back on Earth after 9 months ‘stranded’ in space

Sunita Williams and Butch Wilmore have finally touched down to Earth, after their eight day mission turned into nine months in space.

The pair were only due to be on the International Space Station (ISS) for around a week, but after technical issues, they found themselves there for an extra 278 days.

Williams and Wilmore, who are seasoned professionals and used to space conditions, are no doubt happy to be back on Earth, but it turns out those who work in the space industry weren't worried for their safety.

Sunita Williams has now returned to Earth after her eight day mission turned into nine months in space. (NASA / Keegan Barber / Handout/Anadolu via Getty Images)

Astrophysicist Neil deGrasse Tyson has revealed he wasn't worried over their safety as he spoke in an interview to NDTV: "They are professional astronauts... they are selected not just because they are physically fit but also because they are emotionally fit, okay?

"And when you are emotionally fit, things like, 'okay, instead of eight days it's nine months'... you don't see them freaking out or reacting in some way that would jeopardise the safety of the crew. So that's why I was never worried... even if everybody else was. At no time did I have sympathy for them.

"I don't think they needed sympathy, personally."

Tyson continued: "There is no reason to think their muscles will not be able to hold them up... on the ISS they have many ways to exercise.

"The difference is... when you spend this much time being weightless, your ability to orient for what is 'up' and 'down' is compromised because you never had to use these tools of the inner ear to establish 'up' and 'down' in space. Now I haven't been in space... but I have spoken to astronauts, friends of mine, who have spent a lot of time there, and they say typically they will recover within a week..."

He added that they might have slightly weaker muscles initially now they're back on Earth as he joked: "If you hand them a glass they just let go (because their muscles are weaker) So, make sure the first few beverages are in a plastic cup."

Whilst the mission went on for a lot longer than additionally planned, Tyson did explain that he had rarely been worried for their safety whilst they were up in space.

He shared: "The fact is we had options...when Plan A failed, we brought in Plan B - another rocket, from a whole other private company. The fact we had options is a sign that the space frontier is becoming part of everyday understanding of where human beings can be."

The astronauts landed home earlier this week. (NASA)

The comments also come as it's thought Williams and Wilmore might not be financially compensated for their additional time stuck in space. While the exact figure has not been confirmed, we do know that in the past, the amount has been surprisingly small.

Former NASA astronaut Cady Coleman told the Washingtonian that astronauts are paid like any federal employee on a business trip – that is to say, they get their regular salary with no overtime, while NASA takes care of transportation, lodging, and food.

She explained: "There is some small amount of money per day for incidentals that they end up being legally obligated to pay you."

She added that she received around $4 a day when she went on a 159-day mission between 2010 and 2011 – a number that works out at around $636.

According to the Daily Mail, Williams and Wilmore’s salaries range between $125,133 and $162,672 per year, which – based on Coleman’s figures – means they could earn little more than $1,000 in 'incidental' cash on top of their basic salary.