- After launching two NASA astronauts into orbit in May, SpaceX is now ready to bring them back from the International Space Station on August 2 in the same spacecraft.
- Elon Musk has said that this stage of the mission worries him the most.
- SpaceX’s Crew Dragon spacecraft will have to undock from the space station, survive a fiery fall through Earth’s atmosphere, and deploy parachutes to land safely in the Atlantic Ocean.
- Visit the Business Insider home page for more stories.
Two astronauts aboard the International Space Station are in the middle of a historic mission: the first human commercial space flight.
The high-risk test of SpaceX’s human-grade spacecraft, the Crew Dragon, sent NASA’s Bob Behnken and Doug Hurley to the station on the company’s Falcon 9 rocket on May 30. The spacecraft successfully docked the space station the following day.
But now comes the difficult part: bringing the crew back to Earth.
Behnken and Hurley must board the Crew Dragon again and return at full speed to the atmosphere, a journey that will require the spacecraft to withstand temperatures of up to 3,500 degrees Fahrenheit.
An illustration showing SpaceX’s Crew Dragon spacecraft returning from Earth from orbit and resisting intense heating from atmospheric reentry.
SpaceX / YouTube
SpaceX CEO Elon Musk said this is the part of the mission that worries him the most.
“Returning is more dangerous in some ways than promotion, so we don’t want to declare victory yet,” Musk told reporters after the launch.
The astronauts’ return schedule was initially unclear. The spacecraft, currently installed alongside the ISS, has up to 110 days from arrival until a corrosive form of oxygen high above Earth degrades its solar panels.
But NASA set a date for the return on Friday: Administrator Jim Bridenstine tweeted that the mission points to August 1 to undock Crew Dragon from the space station, and August 2 to land in the Atlantic Ocean.
“The weather will drive the actual date,” Bridenstine said.
If the mission, called Demo-2, ends as planned, it will set the stage for SpaceX to regularly transport astronauts to and from the ISS. Complete success from start to finish would restore human space flight in the United States for the first time since the Space Shuttle program ended in 2011.
This is what you can expect during the return of the astronauts.
The Crew Dragon must survive a fiery fall through Earth’s atmosphere.
SpaceX’s Crew Dragon spacecraft, called Endeavor, approaches the International Space Station to dock on May 31, 2020.
POT
Behnken and Hurley’s return from the space station to a safe landing point in the ocean could take six to 30 hours, NASA spokeswoman Stephanie Schierholz told Business Insider. The duration of the trip depends on when NASA decides to start it.
When the time comes, Behnken and Hurley will board the Crew Dragon again, and the spacecraft will retract the hooks that hold it to the ISS.
An illustration of the docking of SpaceX’s Crew Dragon spacecraft with the International Space Station.
SpaceX
Crew Dragon will gently fire its thrusters to get away from the orbiting lab. Once you are far enough away from the ISS, the capsule will fire more aggressively to get itself on the right path to its splash location off Florida’s Atlantic coast.
From there, the spacecraft will drop its tube-shaped trunk, a lower section equipped with fuel tanks, solar panels, and other hardware that astronauts will no longer need. The log should fall into Earth’s atmosphere and burn.
An illustration of SpaceX’s Crew Dragon spacecraft tossing its trunk before returning to Earth.
SpaceX via YouTube
This will expose the heat shield of the capsule. After another six minutes of firing thrusters to push it into Earth’s atmosphere, the spacecraft will begin to fall. Its thermal shield will deflect and absorb energy from the superheated plasma, protecting hardware and astronauts as they traverse Earth’s atmosphere at 25 times the speed of sound.
“The part I would be most concerned about would be the reentry,” Musk told Irene Klotz of Aviation Week in May, a few days before launch.
An illustration of SpaceX’s Crew Dragon spacecraft returning to Earth with a plasma glow in front of its heat shield.
SpaceX via YouTube
Musk added that his “biggest concern” about the new spacecraft is the asymmetric design of the capsule. The shape was necessary for the emergency escape system, which can throw the capsule away from the launch rocket if it fails to hang. Although Musk said asymmetry is unlikely to cause a problem, he is concerned that it may complicate a return to Earth.
“If it spins too much, then it could trap the plasma in the super Draco exhaust thruster pods,” Musk said, adding that this could overheat parts of the craft or cause it to lose control due to the wobble. “We’ve looked at these six ways until Sunday, so it’s not like I think this is going to fail. It’s just that I’m a little concerned that it’s asymmetric at heart.”
Catching the spaceship crash is your own challenge
Assuming the crew Dragon survives the fall through Earth’s upper atmosphere, the capsule’s parachutes must deploy just a few minutes later to slow the ship down as it falls through thicker parts of the atmosphere. . The first slide must be released at 18,000 feet, while the Crew Dragon shoots down to the ground at 350 mph. You should delay dropping the capsule to about 119 mph by the time it reaches 6,000 feet, when more parachutes will be deployed.
SpaceX’s Crew Dragon is guided by four parachutes as it splashes into the Atlantic Ocean about 200 miles off the east coast of Florida on March 8, 2019, after returning from the International Space Station on mission Demo-1.
Cory Huston / NASA
“The parachutes are new. Will the parachutes deploy properly? And then the system will guide Dragon 2 to the correct location and splash safely?” Musk said in March 2019, after the company’s Demo-1 mission, an unmanned test flight from its spacecraft, took off. The parachutes worked well at the end of that mission, but they failed a test just a month later.
During a press conference before the May manned launch, Hans Koenigsmann, vice president of mission assurance for SpaceX, was asked what kept him awake at night regarding the mission. He also pointed out the parachutes, as their packaging cannot be tested until they are deployed.
However, if all goes well, the capsule should splash in the ocean 22 to 175 nautical miles off the Florida coast.
USAF personnel train to rescue astronauts from SpaceX’s Crew Drago spacecraft.
NASA Langley Research Center / Ron Beard
Behnken and Hurley will wait inside the capsule for 30 minutes to an hour, depending on the weather and the state of the spacecraft, as recovery teams approach in boats. The teams will retrieve the astronauts and give them a preliminary medical checkup.
NASA astronaut Doug Hurley, with NASA and SpaceX teams, tests his extraction from the Crew Dragon on August 13, 2019 in Cape Canaveral, Florida.
NASA / Bill Ingalls
A helicopter will take Behnken and Hurley to shore. From there they will take a plane to Houston.
At that point, the astronauts will have safely completed a mission with a 1 in 276 chance of killing them.
NASA and SpaceX teams practice emergency medical evacuation procedures aboard the GO Searcher ship August 15, 2019 in the Atlantic Ocean off Cape Canaveral, Florida.
Bill Ingalls / NASA
“I’m giving a sigh of relief,” Bridenstine said after the Dragon of the Crew reached orbit on May 30. “But I’ll also tell them that I won’t celebrate until Bob and Doug are home safely.”
Dave Mosher contributed reporting.
