Two NASA astronauts say they expect it will be tough returning to such a drastically changed world next week, after more than half a year at the International Space Station.

Key points: Andrew Morgan and Jessica Meir have spent months on the International Space Station

Andrew Morgan and Jessica Meir have spent months on the International Space Station They will begin their return to Earth next Friday

They will begin their return to Earth next Friday Their departure will leave three astronauts, who arrived on Thursday, on board

Andrew Morgan said the crew had tried to keep across the pandemic news, but he said it was hard to comprehend what was really going on and what to expect when his nine-month mission ended next Friday.

"It is quite surreal for us to see this whole situation unfolding on the planet below," said Jessica Meir, who took part in the first all-female spacewalk last year.

"We can tell you that the Earth still looks just as stunning as always from up here, so it's difficult to believe all the changes that have taken place since both of us have been up here."

As an emergency doctor in the US Army, Dr Morgan said he felt a little guilty coming back midway through the medical crisis.

"It's very hard to fathom," Dr Morgan said.

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Ms Meir said it would be difficult not being able to hug family and friends, after seven months off the planet.

She anticipates feeling even more isolated on Earth than in space.

"We're so busy with so many other amazing pursuits and we have this incredible vantage point of the Earth below, that we don't really feel as much of that isolation," Ms Meir said.

"So we'll see how it goes and how I adjust," she said.

"But it will, of course, be wonderful to see some family and friends, at least virtually and from a distance for now."

Dr Morgan flew to the space station last July, and Ms Meir last September.

They will return in a Soyuz capsule with Russian Oleg Skripochka, landing in Kazakhstan.

Their departure will leave three astronauts, who arrived on Thursday, on board.

The three will return exactly 50 years after the Apollo 13 astronauts splashed down in the Pacific.

An oxygen tank explosion aborted the Apollo 13 moon-landing mission.

"Once again, now there's a crisis and the crisis is on Earth," Dr Morgan said.

AP