After almost 200 days in space, four astronauts are returning to Earth this week from the International Space Station (ISS). The only problem? The eight-or-so-hour mission will be toilet-less after the SpaceX Dragon capsule toilet was found to leak pee after use.

"Spaceflight is full of lots of little challenges," NASA astronaut Megan McArthur said during a news conference from orbit as reported by AP.

"This is just one more that we'll encounter and take care of in our mission. So we're not too worried about it."

Toilets on the ISS and other spacecraft are notoriously tricky, with a suction funnel for pee and a hole for aiming your poop into.

But even that sounds better than what the crew will be doing instead. NASA has said they'll be using absorbent 'undergarments' – also known as 'adult diapers' for the eight-hour trip home.

According to NASA, the Crew Dragon spacecraft, named Endeavour, is scheduled to undock from the ISS at 2:05 pm EST (1905 UTC) on Monday, with a splashdown scheduled for around 10:30 pm EST the same day (0330 UTC the next morning).

The four astronauts – NASA's McArthur and Shane Kimbrough, Akihiko Hoshide of Japan's JAXA, and ESA's Thomas Pesquet from France – will be leaving three astronauts behind on the station, one American and two Russian crew members.

The leaking toilet (which the team had to clean manually a couple of weeks back) hasn't been the only challenge to this crew changeover, there's also been some issues with getting the next crew into space.

Firstly there was bad weather, and secondly an undisclosed 'minor medical issue' with one of the next crew members pushed back the launch date.

This means that the team won't be able to do their handover in space, it'll have to happen remotely.

"A lot of that handover time is just showing little things on living in space — the things we don't get trained on, like eating and going to the bathroom and sleeping and those kinds of little tidbits that we would pass on to the next crew if they were here," Kimbrough told reporters.

"And if we're not here, then [remaining American astronaut] Mark Vande Hei is certainly capable to do that and get that next crew up to speed."

With the undocking beginning very soon (you can watch the live video below), the team will be getting ready to depart with 240 kilograms (530 pounds) worth of stuff – such as hardware and other things associated with their scientific experiments.

This might include some of the space-grown chili peppers that the crew harvested last week. The rest were eaten by the crew, including the 'best space tacos yet' according to McArthur.

"They have a nice spiciness to them, a little bit of a lingering burn," she said. "Some found that more troublesome than others."

Let's just hope the chilis have already passed through their system – because that sounds like a spicy trip back down in a diaper.