This weekend, two NASA astronauts are slated to return home to Earth inside SpaceX’s new passenger capsule, the Crew Dragon. It’ll be the first time that the Crew Dragon carries passengers back to the planet’s surface, ultimately proving if 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 at the end of May when they launched to the International Space Station inside the Crew Dragon, marking the first time a privately made vehicle carried people to orbit. The launch heralded the return of human spaceflight in the US. The last time people flew to 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 get astronauts to the ISS — but now the agency can use SpaceX’s vehicles instead.
“From the laws of physics standpoint, we’re only halfway done.”
While the launch received lots of fanfare, getting the astronauts home is an equally critical part of this mission. “From the laws of physics standpoint, we’re only halfway done,” Garrett Reisman, a former NASA astronaut and SpaceX consultant who used to work on the Crew Dragon, tells The Verge. “All that energy you put in [during launch], you have to take every bit of that energy out when you come home.” The Crew Dragon, with Behnken and Hurley inside, will have to undock from the station and plunge itself into Earth’s thick atmosphere. A heat shield should protect the crew from the intense heat created during the descent, which can reach up to 3,500 degrees Fahrenheit. Eventually, the Crew Dragon will deploy a suite of parachutes, slowing the vehicle down so that it can splash down relatively gently in the Atlantic Ocean.
SpaceX has brought multiple spacecraft back 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 asymmetrical than its predecessor, thanks to the inclusion of an emergency abort system. The company has brought the Crew Dragon back to Earth from space before — but only once, during an uncrewed test flight of the vehicle in March 2019.
“Bringing a spaceship home, that’s a really big deal,” Benji Reed, director of crew mission management at SpaceX, said during a press conference on the landing. “And it’s very important, as part of that sacred honor that we have, for ensuring that we bring Bob and Doug back home to their families, to their kids, and making sure that they’re safe.”
This landing is the last big test for SpaceX as part of NASA’s Commercial Crew Program, an initiative aimed at developing private spacecraft to ferry astronauts to and from low Earth orbit. But before those flights can get started in earnest, SpaceX has to prove to NASA that its Crew Dragon vehicles are safe. The company had to do an uncrewed test flight of the Crew Dragon — sending it to the station and then back home again — as part of a mission called Demo-1. Behnken and Hurley are part of SpaceX’s first crewed test flight, a mission dubbed Demo-2.
“Bringing a spaceship home, that’s a really big deal.”
The Crew Dragon has remained docked since arriving at the station on May 31st. The astronauts and NASA have done tons of analysis on the Crew Dragon to see how it’s held up in the space environment, and the vehicle seems to be doing just fine. “The systems on Dragon are doing very well,” Steve Stich, the manager of NASA’s Commercial Crew Program, said during the conference. “The spacecraft is very healthy.”
Right now, Behnken and Hurley are scheduled to undock from the space station at around 7:34PM ET on Saturday, August 1st. The capsule will then slowly distance itself from the ISS over the next several hours. Then on Sunday, August 2nd, the Crew Dragon is scheduled to fire up its thrusters at around 1:56PM ET, taking the vehicle out of orbit. The capsule should touch down in the Atlantic Ocean off the coast of Florida about an hour later at around 2:42PM ET. There are seven different landing sites where the Crew Dragon can potentially touch down.
This is all subject to change, as weather is a big limiting factor. The Crew Dragon is the first human-carrying spacecraft, since the Apollo missions, designed to land in water when it comes back to Earth, which means good weather at the landing site is key. NASA doesn’t want the astronauts landing in choppy water after pulling extra G forces on the way down to Earth. If things are too rough, the capsule could tip over, making it difficult for the astronauts to get out.
So for this landing, NASA wants calm waters and winds below 10 miles per hour at the landing site. The mission team doesn’t want rain or lightning in the area either. Originally, things weren’t looking good for a landing this weekend, as Hurricane Isaias was projected to track up the east coast of Florida on Saturday and Sunday. However, SpaceX has the option to land on the western coast of Florida if necessary, and NASA said it is moving forward with the schedule after a recent weather check.
“Once you separate from the space station, you’re committed to coming back.”
NASA and SpaceX will continue to evaluate if they need to move the undocking. But ultimately, undocking can be called off right at the last minute. “Literally, we have about an hour period where we can undock and if at the last minute we thought that the weather or something wasn’t okay, the SpaceX team could command the vehicle and Bob or Doug could stop and stop the whole undock sequence,” Reed said.
Once the Crew Dragon does undock from the station, that means the spacecraft is most likely going to splash down, according to Reisman. “Once you separate from the space station, you’re committed to coming back,” he says. “Because you are using up consumables on board the vehicle — like propellant, oxygen, and so forth.” SpaceX does have flexibility over when that splashdown occurs. Most of the landing opportunities occur about 15 or 17 hours after undocking, according to Reed. But SpaceX can delay the splashdown until 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.
Once in the water, Behnken and Hurley will wait inside the Crew Dragon until SpaceX’s two recovery boats arrive. The first vessel is designed to pull the Crew Dragon out of the water, while a crew of more than 40 people on board will help the astronauts out of the capsule. A second boat will recover the Crew Dragon’s parachutes, which will detach from the capsule after landing. If for some reason the astronauts are experiencing some kind of emergency, there is a helipad on board the main recovery boat, enabling a helicopter to evacuate Behnken and Hurley quickly from the splashdown 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
A successful landing should help pave the way for SpaceX to start doing routine missions to the ISS. A new Crew Dragon is already slated to fly in late September, carrying a crew of four to the space station for a longer mission. And then in spring of 2021, the Crew Dragon is scheduled for another flight with a crew of four. In fact, that mission next year will use the same Crew Dragon that Behnken and Hurley are coming home in. Just 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 have Dragon refurbished and ready to go in just a matter of a couple months — two months,” Reed said.
But before Crew Dragon can be fly again, it has to come home. All eyes are on Behnken and Hurley’s return, and anxiety is high as the two attempt a safe landing. “Until they’re on the boat or even until they’re on shore and I see them get out of the Gulfstream [jet] in Houston, waving to the crowd, I’m still going to be nervous,” Reisman says.