Astronaut who tried to smuggle gorilla costume onto ISS is now a 'top contender' to replace Joe Biden

With Joe Biden taking himself out of the race, the Democratic party are looking for a new presidential candidate ahead of the election later this year.

While current VP Kamala Harris is the frontrunner, one of the other popular choices for the job is a pretty cool guy.

Mark Kelly has been a US senator for Arizona since 2020, following a special election held after the death of Senator John McCain.

He's currently tipped as one of the most popular non-Harris choices to become leader of the Democratic party, but even if he doesn't clinch it, he's also a favorite to be her running mate.

But, before he entered the world of politics, Mark - alongside his identical twin brother Scott - was an astronaut.

Before Mark Kelly was a US senator, he was a NASA astronaut (Roberto Gonzalez/Getty Images)

Kelly flew combat missions as a naval aviator during the Gulf War before being selected as a NASA Space Shuttle pilot in 1996. He flew his first space mission in 2001 and also commanded two flights, including the final mission of Space Shuttle Endeavour.

Beyond his impressive resume, Kelly is known as quite a bold character amongst the spaceflight community for his outspoken remarks and crazy stunts.

One particularly memorable instance is the time he tried to send a full-body gorilla suit to Scott, who was stationed on board the International Space Station (ISS) at the time.

However, the prank didn't quite go according to plan.

In fact, the suit exploded when the SpaceX Falcon 9 rocket it was travelling on was lost in a massive fireball.

But the Kelly brothers refused to give up.

"The next time I was on the phone with my brother, he goes, 'I'm sending you another gorilla suit,'" Scott told People.

In 2015, he smuggled a gorilla suit onto the International Space Station as a prank (X/Scott Kelly)

And, that's exactly what Mark did, leading to a viral video in which Scott zooms around the ISS wearing the gorilla suit, even chasing British astronaut Tim Peake around the station.

"Of course people liked it. How can you not like space gorilla?" Scott said of the viral clip.

He later admitted that Peake was in on the video and it was 'all staged.' But that didn't make the whole thing less funny.

"I floated down to the Russian segment," Scott added. "When they saw it, they were just laughing like you wouldn't believe.

"It was the end of my year in space so you need a little humor."

We'll have to hope Mark's pranking days are over if he's to take a position at the helm of running the country.