SpaceX’s Crew Dragon is slated to bring NASA astronauts home for the first time this weekend.

This weekend, two NASA astronauts are slated to return to their Earth home inside SpaceX’s new passenger pod, the Crew Dragon. It will be the first time that Crew Dragon has taken passengers back to the planet’s surface, ultimately demonstrating whether the vehicle can safely transport people to space and back.

Veteran astronauts Bob Behnken and Doug Hurley will be aboard the spacecraft. The duo made history in late May when they launched to the International Space Station inside the Crew Dragon, marking the first time that a private vehicle brought people into orbit. The launch announced the return of human space flight in the United States. The last time people flew into orbit from the United States was in 2011, with the last flight of the space shuttle. For nine years, NASA relied on Russian rockets to bring astronauts to the ISS, but now the agency can use SpaceX vehicles.

While the launch received a lot of fanfare, bringing the astronauts home is an equally critical part of this mission. “From the point of view of the laws of physics, we are halfway there,” says Garrett Reisman, a former NASA astronaut and SpaceX consultant who used to work on Crew Dragon. The edge. “All that energy that you put into [during launch], you have to get all that energy out when you get home. “The Crew Dragon, with Behnken and Hurley inside, will have to decouple from the station and dive into Earth’s thick atmosphere. A heat shield must protect the crew from the intense heat. created during the descent, which can reach up to 3,500 degrees Fahrenheit, the Crew Dragon will eventually deploy a series of parachutes, slowing the vehicle down so it can splash relatively smoothly in the Atlantic Ocean.

SpaceX has brought several spaceships from space before, but all of those vehicles were cargo versions of the Crew Dragon, which are different in shape and overall function. The Crew Dragon is more asymmetric than its predecessor, thanks to the inclusion of an emergency abort system. The company have It brought the Crew Dragon back to Earth from space before, but only once, during an unmanned test flight of the vehicle in March 2019.

Image: NASA

“Bringing a spacecraft home is a big problem,” Benji Reed, director of crew mission management at SpaceX, said during a press conference on the landing. “And it is very important, as part of that sacred honor that we have, to make sure that we bring Bob and Doug back to their families, to their children, and to make sure that they are safe.”

This landing is the last major test for SpaceX as part of NASA’s Commercial Crew Program, an initiative aimed at developing private spacecraft to transport astronauts to and from low Earth orbit. But before those flights can begin in earnest, SpaceX has to prove to NASA that its Crew Dragon vehicles are safe. The company had to make an unmanned test flight of the Crew Dragon, sending it to the station and then back home, as part of a mission called Demo-1. Behnken and Hurley are part of the first SpaceX manned test flight, a mission called Demo-2.

The Crew Dragon has remained docked since arriving at the station on May 31. Astronauts and NASA have done tons of analysis on the Crew Dragon to see how it stays in the space environment, and the vehicle appears to be working well. “The systems in Dragon are working very well,” Steve Stich, manager of NASA’s Commercial Crew Program, said during the conference. “The spacecraft is very healthy.”

At this time, Behnken and Hurley are scheduled to undock from the space station around 7:34 PM ET on Saturday, August 1. The capsule will slowly drift away from the ISS over the next few hours. Then on Sunday, August 2, the Crew Dragon is slated to fire its thrusters around 1:56 PM ET, taking the vehicle out of orbit. The capsule should land in the Atlantic Ocean off the Florida coast approximately an hour later around 2:42 PM ET. There are seven different landing sites where the Dragon of the crew can potentially land.

Image: NASA

All of this is subject to change, as the weather is a major limiting factor. The Crew Dragon is the first spacecraft to transport humans, since the Apollo missions, designed to land in the water when it returns to Earth, which means that good weather at the landing site is key. NASA does not want astronauts to land in choppy waters after pulling additional G-forces on the way to Earth. If things are too difficult, the capsule could tip over, making it difficult for the astronauts to exit.

So for this landing, NASA wants calm water and winds of less than 10 miles per hour at the landing site. The mission team also doesn’t want rain or lightning in the area. Originally, things were not looking good for a landing this weekend, as Hurricane Isaias was projected to track the east coast of Florida on Saturday and Sunday. However, SpaceX does have the option of landing on the west coast of Florida if necessary, and NASA said it is moving forward with the schedule after a recent weather check.

NASA and SpaceX will continue to evaluate whether they need to move the decoupling. But ultimately, the decoupling can be canceled at the last minute. “We literally have a period of about an hour where we can undock and if at the last minute we think the weather or something is not right the SpaceX team could control the vehicle and Bob or Doug could stop and stop the entire sequence decoupling, “Reed said.

Once the Crew Dragon does According to Reisman, decoupling from the station, that means the spacecraft is likely to be splashed. “Once he is separated from the space station, he agrees to return,” he says. “Because you are using consumables on board the vehicle, such as thrusters, oxygen, etc.” SpaceX has flexibility over when that splash occurs. Most landing opportunities occur approximately 15 or 17 hours after the decoupling, according to Reed. But SpaceX can delay the splash for up to two days later if necessary. The Crew Dragon also has enough resources on board, such as food, oxygen, and more, to last up to three days.

Image: SpaceX

Once in the water, Behnken and Hurley will wait inside the Crew Dragon until the two SpaceX recovery boats arrive. The first ship is designed to lift the Crew Dragon out of the water, while a crew of more than 40 people on board will help astronauts get out of the capsule. A second boat will retrieve the Dragon’s parachutes from the crew, which will detach from the capsule after landing. If for some reason astronauts are experiencing some sort of emergency, there is a helipad aboard the main recovery boat, allowing a helicopter to quickly evacuate Behnken and Hurley from the dive site. But if that’s not necessary, the boat will take everyone to shore.

A successful landing should help pave the way for SpaceX to start doing routine missions to the ISS. A new Dragon crew is already slated to fly in late September, taking a crew of four to the space station for a longer mission. And then, in the spring of 2021, the Crew Dragon is slated for another flight with a crew of four. In fact, that mission next year will use the same Crew Dragon in which Behnken and Hurley will return home. Right after SpaceX launched this Crew Dragon, NASA approved the company to reuse the capsules on future flights. And SpaceX says it won’t take long to turn them around. “We should be able to restore Dragon and be ready to go in just a couple of months, two months,” Reed said.

But before Crew Dragon can fly again, he has to go home. All eyes are on the return of Behnken and Hurley, and anxiety is high when the two attempt a safe landing. “Until they are in the boat or even until they are on shore and I see them leave the Gulfstream [jet] in Houston, waving to the crowd, I’m still going to be nervous, “says Reisman.