JUANA SUMMERS, HOST:
A medical evacuation of an astronaut from the International Space Station is underway. A four-person crew departed the orbiting lab late today in a SpaceX Crew Dragon capsule. It was prompted by what NASA described as a serious but stable medical issue of one of the Crew-11 astronauts. It is the first time NASA has cut a mission short because of an astronaut's health. Central Florida Public Media's Brendan Byrne is following the story and is with us now. Hi.
BRENDAN BYRNE, BYLINE: Hey.
SUMMERS: Brendan, start by telling us what happens during this medical evacuation.
BYRNE: So this medical evacuation is much like a standard departure from the station. This time, it's just about a month earlier than anticipated. The medical issue has not been revealed publicly, and while the unnamed astronaut is stable, the agency still decided it's best to get them back on the ground for an evaluation with equipment they don't have at the station. So today, that crew of four donned their space suits, strapped into their seats, closed the hatch and began the nearly 10-hour trip back home.
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UNIDENTIFIED PERSON #1: Dragon copy.
UNIDENTIFIED PERSON #2: Undocking confirmed. Endeavor begins its journey home with the Crew-11 crew.
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BYRNE: Now, even though only one astronaut is affected by this medical issue, the entire crew had to come back. It's because they all only have this one ride to and from the station.
SUMMERS: Got it. OK. As we pointed out, this is a first for NASA. Was something like this ever expected?
BYRNE: Yeah, this really is a rare thing to happen in human spaceflight in general. In fact, a historian I spoke with can only recall one other mission ending early due to health, and that was a Soviet Union cosmonaut back in the mid-'80s. Astronauts go through rigorous physical and mental health screenings before they launch, and the space stations' equipped with some medical equipment and aid. Despite that, though, NASA actually thought that something like this would come more frequently over the life of the space station. Here's NASA's chief health and medical officer, Dr. J.D. Polk.
JD POLK: You know, in our 25-year history of the International Space Station, we've had many models that have said we should have had a medical evacuation approximately every three years in that 25-year history, and we've not had one to date.
SUMMERS: Brendan, what impact will this early departure have on the operation of the station?
BYRNE: It's going to leave the space station short-staffed. There are now only three people on board, two Russian cosmonauts and a U.S. astronaut. This limits the amount of science experiments that can happen and maintenance tasks can be done. The medical issue canceled an important spacewalk last week that was supposed to upgrade the station's solar power system. Still, NASA Administrator Jared Isaacman is calling the Crew-11 mission of - the departing crew - a success.
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JARED ISAACMAN: Over the last five months, Crew-11 contributed to the ongoing operations of the space station, conducted extensive scientific research, completed the majority of their mission objectives and upheld the standards of professionalism for which astronauts are known.
BYRNE: The crew that's set to replace them will launch from Florida's Space Coast in about a month. But, you know, this isn't too unusual. After the space shuttle retired back in 2011, the station operated with a smaller crew until SpaceX began launching astronauts to the station again starting in 2020.
SUMMERS: Got to say, 10 hours seems like quite a long time to get back down to Earth. Help me understand. Why does it take so long?
BYRNE: Well, it's rocket science. Well, actually, it's orbital mechanics. When their capsules dock to the station, it's traveling at more than 17,000 miles per hour. So to safely make the trip home, the capsule has to do a number of things to slow down and prepare to punch through the atmosphere unscathed. That includes tossing the spacecraft's trunk, which is a cylinder-like structure that's underneath the capsule that holds cargo and helps power the vehicle. The Dragon's engine fire a number of times to slow the spacecraft down, orient it in a way that it can punch through that atmosphere. It's going to get 3,000 degrees hot while it's falling through. But with all that done, they will pinpoint a target off the coast of San Diego at about 15 miles per hour.
SUMMERS: Central Florida Public Media's Brendan Byrne, thank you so much.
BYRNE: Anytime.
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