‘Stranded’ NASA astronauts have finally returned to Earth but conspiracy theorists are asking bizarre questions

The 'stranded' NASA astronauts touched down on Earth on Tuesday (18 March) after a whopping nine months on the International Space Station (ISS).

Back in June last year, Sunita 'Suni' Williams and Barry 'Butch' Wilmore thought they were off for an eight-day mission, but unfortunately, the days turned into months when their faulty Boeing Starliner capsule suffered helium leaks and a thruster malfunction, and had to return home without them.

Fast forward to Tuesday, and the pair were finally able to return, after a joint mission between NASA and Elon Musk's SpaceX saw the pair travel back to Earth along with two other astronauts - Nick Hague and Roscosmos cosmonaut Aleksandr Gorbunov.

Footage of the pair splashing down off the coast of Florida at around 5:57pm local time has been shared online, with the astronauts being carried out of the capsule via a stretcher.

This is because people sometimes experience dizziness and nausea when they travel home, similar to how some suffer motion sickness on a roller coaster or boat.

However, in one clip of Williams and Wilmore leaving the capsule, people have been discussing some rather wild conspiracy theories.

Most people were excited to see that the pair were back on Earth and set to be reunited with their families, while others bizarrely questioned if they had actually been to space at all.

Of course, there's nothing to suggest the astronauts have been anywhere but up on the ISS for the past nine months.

One person wrote: "But were they really there?"

While another added: "Plot twist : they never were in outer space."

And a third said: "Nice, clean shaved and all.....barbers up there are good."

And a fourth added: "Just open the studio door."

The pair are back on Earth (Keegan Barber/NASA via Getty Images)

While they've been away, concern has mounted up surrounding the astronauts' health - particularly when it comes to their lack of muscle used as a result of microgravity.

According to the BBC, the lack of use of back, neck, calf and quad muscles can mean they begin to atrophy, and can even plummet by as much as 20 percent in just two weeks, and by 30 percent between 3-6 months.

Williams herself has previously spoken about some of the changes she has experienced.

While up on the ISS, she explained she had lost the ability to carry out several basic tasks, and can’t even remember what it's like to walk.

The pair have returned home this week, thanks to a mission between NASA and SpaceX (Keegan Barber/NASA via Getty Images)

Speaking with Needham High School in Massachusetts earlier this year, she told the students: "I've been up here long enough, right now I've been trying to remember what it's like to walk. I haven't walked. I haven't sat down. I haven't laid down."

There have previously been concerns surrounding the health of the astronauts after they appeared to be noticeably thinner.

However, it's expected Williams and Wilmore will now undergo some health checks following their return to Earth.