The men were on board for two months after being released from the Kennedy Space Center in Florida into the Crew Dragon capsule.
Their voyage began with the historic start of May, marking the first mission of crew members to take off from U.S. land in nearly a decade, and it could be the first of many if the capsule spills safely off the coast of Florida this weekend.
On Thursday night, NASA said it was still planning to move forward with the splashdown, but “teams will continue to monitor the weather before shutting down on Saturday night,”; the space agency said on Twitter.
A safe return home is very important. Although SpaceX previously launched Crew Dragon on an unsupervised demonstration mission, the Hurley and Behnken mission is still considered a test. Both men are NASA astronaut veterans and test pilots, specially trained to respond to any technical issues that may arise in a new vehicle. NASA will not officially certify the Crew Dragon as a human-rated spacecraft until it returns safely.
A trip back is in some ways an even riskier trip than a start. The crew dragon will need to fly back through the Earth’s atmosphere at a speed of 17,500 miles per hour. Fast air compression and friction between the air and the spacecraft It will heat the exterior of the spacecraft to about 3,500 degrees Fahrenheit, NASA reports.
Behnken described his experience of restoring the atmosphere in previous NASA missions last year: “You actually see atmospheric light as it warms the exterior of the spacecraft. You see some orange bulbs flashing in the plasma as they pass through the windows,” he said. “The vehicle is going through something pretty heavy – and we’ll hope it takes care of us as it enters us.”
As the crew dragon approaches Earth, it will deploy a small set of parachutes called “drug parachutes” to begin slowing its descent before a large stream of four parachute fans displace the vehicle to further slow it down. If all goes well, the Crew Dragon will travel less than 20 miles per hour on the water.
Crew dragon astronauts will experience much higher G forces, Hurley said. This will mark the first landing of astronauts since 1975.
Even after a splash, the journey can be unbearable. Water can shock the spacecraft, making it uncomfortable for astronauts as they wait for emergency ships to arrive.
“It’s taking a while, so … we’ll both have the right hardware if we start to get a little nauseous,” Behnken said at a news conference on Friday. The “equipment,” explained to the astronauts, will be a paper bag, much like the airlines’ pockets in the backrest pockets to make passengers sick.
Behnken and Hurley will also have to descend in a place where there is calm air so that strong winds and strong waves do not interfere with the spraying or recovery process. This means that the air pressure falls are even more severe than it was at the start.
NASA and SpaceX officials will continue to monitor the predictions until Crew Dragon repeats the atmosphere.
The stand-off with Mother Nature was already a recurring theme in Hurley and Behnken’s travels. Their first attempt to launch in May was frightened by a thunderstorm. During the second (successful) attempt to launch them on 31 May. The countdown clock reached zero as soon as one batch of storm clouds cleared the sky.
If the weather doesn’t allow Crew Dragon to open this weekend, NASA and SpaceX will try again next Wednesday, August 5th.