National Aeronautics and Space Administration (NASA) astronauts Sunita Williams and Butch Wilmore are not the only astronauts who are spending a longer-than-scheduled time in space. They have now joined a long list of astronauts who spent more time on the International Space Station (ISS) than initially scheduled.

NASA extended Sunita Williams’ and her colleague Butch Wilmore’s stay at the ISS after the space agency decided to return the Starliner spacecraft back to Earth uncrewed due to technical problems.

While Boeing’s Starliner will begin its return journey on 6 September, its two-member crew will ride back home on the SpaceX Dragon Crew-9 mission in February 2025. NASA’s Boeing Crew Flight Test mission, which was to return by mid-June 2024, has now been delayed by eight months.

NOT ‘stuck’ and NOT a ‘mishap’

However, NASA has maintained that the two Starliner astronauts – Sunita Williams and Butch Wilmore – are not “stuck” in space as they “are safe aboard the space station working alongside the Expedition 71 crew conducting research and performing station maintenance”.

The astronauts are said to be enjoying their extended mission at the International Space Station. In an interaction with media in July, Wilmore had said, “It’s a great place to be, a great place to live and a great place to work.”

NASA also denied calling the change in return plans as a “mishap”. Officials said earlier said that if NASA makes the call to change the mission – that the crew would ride home on something other than the Starliner – “…we don’t necessarily need to consider that a NASA mishap.”

Sunita Williams’ not the only extended mission in history

Human spaceflights are “risky”, and “test flight, by nature, is neither safe, nor routine,” NASA Administrator Bill Nelson said earlier. Astronauts are trained and prepared for such missions.

NASA argues that extended missions provide researchers the opportunity to better observe the effects of long-duration spaceflight on astronauts.

In several scenarios, astronauts have spent more time in space than initially scheduled. Here are a few cases to look at:

1. Sergei Krikalev’s case

There’s one famous case of Russian cosmonaut Sergei Krikalev, who had logged over 800 days aboard the International Space Station, Mir space station, Soyuz spacecraft, and the space shuttle, as per NASA.

Krikalev had launched on Soyuz TM-12 in May 1991. He returned to Earth in March 1992, the European Space Agency said.

Krikalev was in space when the Soviet Union was dissolved in December 1991. According to the International Astronautical Federation, his return was delayed and he stayed on the MIR space station board for 311 consecutive days, twice as long as the mission had originally called for.

“During that time, the Soviet Union collapsed and a new Russia was born. For this, Krikalev is sometimes called ‘the last Soviet citizen’,” The New Mexico Museum of Space History said on its website.

As per the European Space Agency, in July 1991, Krikalev had agreed to stay on Mir as flight engineer for the next crew, scheduled to arrive in October because the next two planned flights had been reduced to one.

Read here the story behind the incredible journey of Apollo 13 mission crew

2. Frank Rubio’s case

Heard about the curious case of lost tomatoes in space? NASA astronaut Frank Rubio was at the centre of the controversy over the “lost space tomatoes”.

NASA said Rubio’s mission is the longest single spaceflight by a US astronaut in history. He spent 371 days in space aboard the International Space Station in a “record-breaking mission”.

He had launched aboard Roscosmos Soyuz MS-22 on September 21, 2022 alongside Roscosmos cosmonauts Sergey Prokopyev and Dmitri Petelin. He was scheduled to take the same spacecraft back to Earth in March 2023. However, had to catch a ride on a different Soyuz in September 2023.

Rubio’s mission was delayed because of a coolant leak in his Soyuz spacecraft. According to the New York Times, the leak could have created potentially fatally hot temperatures for the crew on their return to Earth, so a different spacecraft was sent to the space station.

This forced Rubio and his two Russian crewmates to extend his stay aboard the International Space Station (ISS) by an extra six months, Space.com reported.

During his stay at the International Space Station, Frank Rubio was accused of eating the first tomatoes he had harvested aboard the space station in 2022. However, the case was not what it was suspected to be. Read more here about the ‘saucy’ story of lost tomatoes here.

3. Columbia space shuttle disaster fallout

The crew of Expedition 6 to the International Space Station – US astronauts Kenneth Bowersox and Donald Pettit, and Russian cosmonaut Nikolai Budarin – returned to Earth on May 4, 2003 after spending 162 days on board.

The European Space Agency said that initially, “the Expedition 6 crew was to have been relieved in March by a new crew arriving on Space Shuttle flight STS 114”.

“After the Columbia accident, the European Space Agency agreed to a six-month postponement of Pedro Duque’s mission to the Station, initially scheduled for April, making the Soyuz flight available for relieving the Expedition 6 crew,” the European Space Agency had said.

The two American astronauts and a Russian cosmonaut had spent an extra three months on the ISS after the Columbia space shuttle disintegrated into thousands of pieces during its reentry to the atmosphere in February 2003. Indian-American Kalpana Chawla was among the seven astronauts killed in the disaster.