The men are aboard the International Space Station two months after launching from the Kennedy Space Center in Florida in a SpaceX Crew Dragon capsule.
Their journey began with a historic May launch that marked the first crew mission to fly out of the United States in nearly a decade, and it could be the first of many if the capsule splashed safely off the coast of Florida this weekend.
As of Thursday evening, NASA said it still planned to move forward with a splash, but “teams will continue to monitor the weather before unlocking Saturday night,”; the space agency said in a tweet.
Safe return home is crucial. Although SpaceX previously launched Crew Dragon during an unfinished demonstration mission, Hurley and Benken’s mission is still considered a test. Both men are veterans of NASA astronauts and test pilots, specially trained to respond to any technical problems that may arise on the new vehicle, and NASA does not officially certify Crew Dragon as a manned spacecraft until it makes a safe return.
And a trip in the opposite direction is in some respects an even more risky journey than the start. The Dragon crew will need to seep through the Earth’s atmosphere at 17,500 miles per hour. Fast air compression and friction between air and spacecraft will heat the outside of the spacecraft to about 3,500 degrees Fahrenheit, according to NASA.
Banken shared his experience of atmospheric transfer in previous NASA missions last year: “You actually see light from the atmosphere when it heats the outer parts of a spacecraft. You see orange lights flicker in the plasma as it passes through windows,” he said. “The vehicle is going through something pretty severe – and we’ll hope it takes care of us as it takes us through the entrance.”
Then, as the Dragon Crew approaches Earth, it will deploy a small set of parachutes called “drug parachutes” to begin slowing its descent in front of a large set of four parachute fans to slow the vehicle even further. If all goes well, the Crew Dragon will travel less than 20 miles per hour when it hits the water.
The astronauts will experience much higher G forces on the Dragon’s crew, Hurley said. And this will be the first time astronauts have landed in the water since 1975.
Even after splashing, the trip can be unpleasant. Water can overwhelm a spacecraft, making it inconvenient for astronauts as they await the arrival of ships to recover.
“It doesn’t take long, so … we’ll both have the right equipment if we start to feel a little sick,” Benken told a news conference on Friday. The hardware, the astronauts said, would be a paper bag, similar to airlines stuffing into the back seat pockets for nauseating passengers.
Banken and Hurley will also need to land in a calm place so that strong winds and high waves do not interfere with the outbreak or recovery process. This means that the weather impregnation criteria are even stricter than it was for the launch.
NASA and SpaceX officials will continue to monitor the forecasts until Crew Dragon returns to the atmosphere.
Confrontations with Mother Nature have already been a recurring theme of Harley and Banken’s travels. Their first attempt to launch in May was threatened by thunderstorms. And during their second (successful) launch on May 31, the clock returned to zero just as another batch of storm clouds cleared the sky.
If the weather prevents Crew Dragon from shutting down this weekend, NASA and SpaceX will try again next Wednesday, August 5th.