How much NASA astronauts Butch Wilmore and Sunita Williams are paid following nine months of overtime in space

Here is how much NASA could be paying astronauts Butch Wilmore and Suni Williams for their nine months of overtime in space.

Yesterday (18 March) saw Barry 'Butch' Wilmore and Sunita 'Suni' Williams land safely off the coast of Florida alongside fellow astronauts Nick Hague and Alexander Gorbunov, therefore bringing an end to one of the biggest space stories of the year.

They left Earth last June as test pilots for Boeing's Starliner mission, however a series of technical issues meant that Butch and Suni had an unexpected lengthy stay on the International Space Station.

The pair were expected to spend around eight days in orbit for the mission but ended up staying in space for a whopping 286 days.

This would mean the pair spent an additional 278 (roughly nine months) in space.

Butch Wilmore after exiting the Dragon capsule (Keegan Barber/NASA via Getty Images)

So you'd imagine the pair have racked up a pretty hefty overtime bill.

How much will Butch and Suni be paid for their extra time in space?

NASA has not commented on how much the two astronauts will be paid for spending an additional nine months in space, which means we don't know exactly how much extra Butch and Suni will be paid, however it may not be as much as you'd think.

According to former NASA employee Cady Coleman, astronauts receive 'no overtime' on top of their regular salary.

"There is some small amount of money per day for incidentals that they end up being legally obligated to pay you," Coleman explained to the Washingtonian back in February, adding that for her incidental pay was about $4 (£3) a day.

Should Coleman's figure still be accurate, then Butch and Suni would receive an additional $1,144 (£882) for their time in space alongside their regular salaries, reportedly around $125,133 (£96,513) and $162,672 (£125,466) a year.

These figures are, of course, not confirmed, but if true, it's not quite the mega-payout many were expecting.

Butch and Suni, alongside fellow NASA astronaut Nick Hague and Russian cosmonaut Alexander Gorbunov (Keegan Barber/NASA via Getty Images)

The suggested lack of a payout may also have to do with the fact that neither Butch or Suni were 'stranded' or 'trapped' on the ISS, which initially appeared to be the case.

NASA has repeatedly insisted that the pair weren't abandoned but had instead joined the existing ISS crew mission. Astrophysicist Jonathan McDowell also explained to the outlet that two astronauts were pulled from a scheduled ISS mission in September, allowing Butch and Suni to replace the pair.

This also meant the pair wouldn't be returning home any earlier than this month, as the station needs a certain amount of astronauts to function properly.

This is also backed up by retired Canadian astronaut Chris Hadfield, who recently explained to LADbible: "They were where they wanted to be, and they could come home if they needed to, every single day that they were there. Nobody's stranded."