Earlier this month, SpaceX engineers completed the 27th and final test of the parachute system that will soon be responsible for carrying astronauts back to Earth. When the four parachute canopies successfully unfurled over the Mojave Desert, it indicated that the company was finally ready to start sending humans to space after nearly a decade of relentless testing and dramatic setbacks. Now SpaceX’s Crew Dragon capsule is on the cusp of becoming only the fifth American spacecraft to ever be certified by NASA for human spaceflight. But before that happens, the company has to pass a final high-stakes test: sending a pair of astronauts into orbit and bringing them safely back home.
On May 27, SpaceX is expected to launch NASA astronauts Bob Behnken and Doug Hurley to the International Space Station from Kennedy Space Center in Florida. The astronauts will be doing critical scientific work on the space station, but the upcoming Demo-2 mission is first and foremost about certifying Crew Dragon for human spaceflight. “Most of our human certification is being completed with this mission,” SpaceX president Gwynne Shotwell said during a press conference earlier this month. “We’re doing this to wring out the system. This is a test mission.” She estimated that the Demo-2 mission would account for about 95 percent of the human-rating certification process for the Crew Dragon capsule.
(Both SpaceX and NASA officials did not respond to WIRED’s request for additional comment.)
NASA routinely launches satellites worth billions of dollars into space. These launches are subject to strict engineering reviews to minimize the chance that something will go wrong and waste years of effort. It’s a rigorous process that can take months and has a lot of similarity with the certification process for a crewed mission, says Ed Mango, the former program manager for NASA’s commercial crew program. When NASA launches a satellite or a deep space probe, it’s entirely focused on mission success—making sure the spacecraft gets where it needs to go and does the job it was designed to do. “But with crew, it’s about mission success as well as crew safety,” says Mango. “You need to add that extra element to it.”
The last time NASA certified a new spacecraft for humans was in 1981, during the maiden flight of the space shuttle. The shuttle program came to an end in 2011, which was the last time American astronauts launched to space from US soil. For the past decade, all astronauts bound for the space station have hitched a ride on Russian rockets. NASA awarded SpaceX and Boeing contracts to certify their own crewed vehicles only a year after the last shuttle flight, but building a human-rated spacecraft has proven to be a long journey.
Before any hardware was built, SpaceX’s Crew Dragon capsule was subjected to a series of design reviews to ensure that it meets the fundamental requirements outlined by NASA. The agency provides the high-level specifications, but the details of the certification process are different for each vehicle. “The commercial crew concept was that NASA will define the safety and performance requirements at the highest level they can and let the partners innovate and design the system that can meet those requirements,” says Mango. For example, all human-rated spacecraft must be capable of being manually and remotely controlled, even if the spacecraft is usually almost entirely automated.
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NASA certifies a spacecraft based on the fundamental design of the vehicle as well as the missions it is designed to perform. A vehicle to take astronauts to the moon would have to meet a different set of requirements than one carrying them to low Earth orbit. Thus, the first part of the design process involves simply identifying needs of the mission and designing the spacecraft to meet them. For example, since Crew Dragon will be used to shuttle astronauts to and from the space station, it needs to be able to interface with its docking ports and survive in space for at least 210 days.
During the design process, NASA and its contractors also had to agree on a flight test program that would demonstrate that each spacecraft works as intended. For some tests, NASA let the companies decide how they would be conducted. For example, SpaceX and Boeing had to prove that, in the event of an emergency, their spacecraft could abort a mission and carry its crew to safety. Both companies successfully completed pad abort tests, which involve firing the escape thrusters on a crew capsule while it’s still on the launch pad. But only SpaceX conducted an in-flight abort test and jettisoned its capsule from a rocket during flight. Boeing opted to do simulations of an in-flight abort test based on its data.
Other aspects of the flight test program were non-negotiable. For example, NASA required both companies to conduct a non-crewed demo flight, followed by a crewed demo flight, to the ISS. SpaceX successfully completed its uncrewed Demo-1 mission to the space station last year. Boeing had to end its attempt early thanks to a timer malfunction on its Starliner spacecraft and will have to try again. Although SpaceX’s uncrewed mission demonstrated the core functionality of its capsule, the company still needs to put some humans on board to show that it can do everything it's meant to. That’s what the upcoming mission is all about.
“We got a great check-out of the whole spacecraft on Demo-1,” Steve Stich, the deputy manager of NASA’s commercial crew program, said during a press conference earlier this month. “But this time, we’re going to check on the life support systems, the spacesuits, the display system, and many other systems that Bob and Doug will need to live and work inside the Dragon on the way to the Space Station.”
The Crew Dragon will be on autopilot for most of its 19-hour journey to the space station. But just before it docks with the orbital laboratory, Behnken and Hurley will take manual control. The astronauts won’t really be “piloting” the capsule, since they aren’t changing its trajectory. Instead, they’ll use the spacecraft’s Draco thrusters to perform a few basic maneuvers that will change the capsule’s orientation. This will demonstrate that the crew can control it in the event of an emergency or if there’s an unexpected problem with the automated controls. It is one of the most important goals of the Demo-2 mission, and critical to certifying the capsule for human spaceflight.
SpaceX will continue to conduct tests while the spacecraft is docked to the station. Per NASA’s requirements, the capsule must be able to execute commands from mission control on Earth when there aren’t any crew members inside. During Behnken and Hurley’s stay on orbit, mission control operators on Earth will periodically wake Crew Dragon to run tests and make sure all its systems are in good shape.
Behnken and Hurley may spend up to three and a half months on the ISS, and once they splash down off the coast of Florida, NASA and SpaceX engineers will spend the next few months reviewing data from the mission to determine whether the capsule passed muster. If it passes this final review, SpaceX will be ready to begin operational missions carrying NASA astronauts and other paying customers to the ISS.
The extreme rigor of NASA‘s human-rating process is a product of the agency’s “failure is not an option” ethos. As detailed in the agency’s official certification documents, human rating is less of a process and more of “a mindset where each person feels personally responsible for their piece of the design and for the safety of the crew.” That’s a lot of responsibility for engineers to shoulder, but earlier this month NASA Administrator Jim Bridenstine expressed his confidence in the safety of SpaceX’s capsule during a press conference.
“This is a big day for NASA and a big day for SpaceX,” Bridenstine said. “But we should not lose sight of the fact that this is a test flight. We’re doing this to learn things.”