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NASA Astronauts prepare for 19-hour journey back to Earth

Posted Aug 1, 2020 by Karen Graham
NASA astronauts Robert Behnken and Douglas Hurley are preparing to leave the International Space Station (ISS) this evening and begin their 19-hour journey home, capping off their historic mission aboard SpaceX's Crew Dragon spacecraft.
The SpaceX Crew Dragon astronauts (front row  from left) Bob Behnken and Doug Hurley joined their Ex...
The SpaceX Crew Dragon astronauts (front row, from left) Bob Behnken and Doug Hurley joined their Expedition 63 crewmates (rear, from left) Ivan Vagner, Chris Cassidy and Anatoly Ivanishin for a crew farewell ceremony Saturday morning.
NASA TV
The SpaceX Crew Dragon capsule Endeavor is scheduled to undock from the ISS tonight at 7:34 p.m. EDT (2334 GMT) as its Demo-2 test flight enters its final stage. Splashdown will be one of four sites in the Gulf of Mexico on Sunday around 2:42 pm ET Sunday, reports CTV News Canada.
The two returning astronauts got an early start on their departure from the space station this morning with a farewell ceremony. "It's hard to put into words just what it was like to be a part of this Expedition 63," Hurley said of the last two months working with the station's crew, according to Space.com. "It'll be kind of a memory that will last a lifetime for me."
NASA and SpaceX are keeping a very close eye on the weather. The return to Earth will be a go only if the weather forecast looks acceptable this evening. Hurricane Isaias is forecast to approach the Florida coast this evening.
This is why several splashdown sites in the Gulf of Mexico were chosen. Forecasters are expecting the Gulf's waters to be a lot calmer than the Atlantic coast waters. A NASA spokesperson said Friday that officials are currently aiming to land the capsule near Panama City, Florida, reports CNN.
The departure from the space station
If everything is a go for the departure, after completing the undocking sequence at 7:34 pm ET, Dragon Endeavor's engines will fire up twice in quick succession to move the capsule away from the space station.
Endeavor will then slowly descend from the ISS using short engine burns to lower its altitude. Crew Dragon's maneuvers will all be executed by on-board computers. The astronauts will have plenty of food to eat during this time and will be able to sleep before splashdown.
By Sunday afternoon, the capsule will be orbiting just above the thick halo of the atmosphere encircling the Earth. This will be where the most dangerous part of the mission comes into play.
Endeavor will ignite its engine once again as it slices back into the air, traveling at 17,500 miles per hour. Rapid compression and the friction between the air and the capsule will heat the outside of the spacecraft to about 3,500 degrees Fahrenheit. However, the capsule's heat shield will keep Behnken and Hurley safe inside.
At the proper time, the capsule will then deploy a series of parachutes to slow its descent. By the time it hits the water, it should be traveling less than 20 miles per hour, according to a NASA spokesperson.
"I don't think we're nervous," Hurley said from the space station during an interview with CNN Business' Rachel Crane last month. "We have full confidence that the vehicle will perform just like it's supposed to. That being said, it's a completely different entry profile than what we are used to or had been used to in the Space Shuttle."
NASA is also hosting continuous webcast coverage of their return beginning at 5:15 pm ET Saturday.