Crew Dragon Demo-2

• 1. Introduction

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  Crew Dragon Demo-2 was set to launch on the 27th of May 2020. With just under seventeen minutes left on the clock, thunderstorms and light rain from Tropical Storm Bertha forced a scrub. President Donald Trump and Vice President Mike Pence had traveled to Kennedy Space Center to watch. Three days later, on the 30th of May, they came back. This time the countdown held. A Falcon 9 rocket carried NASA astronauts Doug Hurley and Bob Behnken off the pad at 19:22:45 UTC. They were sealed inside a Crew Dragon capsule they would soon name Endeavour. NASA's own stream drew 3 million live viewers, and SpaceX's feed peaked at 4.1 million. The agency estimated roughly 10 million people watched across every platform combined. Why had NASA gone nearly a decade without launching its own astronauts? And why was this flight, run by a private company, the one that would finally end that wait? What would Hurley and Behnken find waiting for them aboard the International Space Station, and how would they get home?

• 2. A Decade Without American Launches

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  The Space Shuttle program came to an end in 2011, leaving NASA without a spacecraft that could carry its astronauts to orbit. From then on, NASA had to buy seats on Russian Soyuz vehicles to reach the International Space Station. Each seat cost up to 80 million US dollars.

  Commercial Crew Program contracts with private companies including SpaceX were meant to cut that cost by half once the system reached regular operation. By the time of Demo-2, NASA had already committed 3.1 billion US dollars to developing the Dragon 2 capsule. Demo-2 was SpaceX's last major test before NASA would certify the vehicle for regular crewed missions. The company had already flown twenty cargo missions to the station, but never one carrying a crew. Boeing was pursuing its own crewed spacecraft under the same NASA program, working toward the same goal by a different path.

• 3. The Crew And Their Insignia

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  NASA announced Doug Hurley and Bob Behnken as the Demo-2 crew on the 3rd of August 2018. Both men had already flown to space twice on the Space Shuttle, making Demo-2 their third mission each. Zebulon Scoville served as lead flight director for the mission. Kjell Lindgren was named sole backup, standing in for both Hurley and Behnken.

  Andrew Nyberg, an artist from Brainerd, Minnesota, designed the Demo-2 mission insignia. He was also Hurley's nephew. The patch combines the logos of the Commercial Crew Program, Falcon 9, and Crew Dragon alongside the red chevron from NASA's meatball insignia. An American flag and a graphic of the International Space Station appear within it. Around the border are the words NASA, SPACEX, FIRST CREWED FLIGHT, and DM-2, along with both astronauts' surnames. The whole insignia is outlined in the shape of the Crew Dragon capsule.

  The Falcon 9 rocket that launched Endeavour carried NASA's worm insignia, a logo retired since 1992 and never used officially again until this flight. NASA branded its television and media coverage of the launch as Launch America, complete with its own logo. SpaceX's own patch shows the top of a spacesuit. The ISS and North America are pictured on the helmet shield, and a white star marks the launch site at Cape Canaveral. An American flag sits behind the suit. The words SPACEX DRAGON and NASA DEMO-2 run around the black border in white. The astronauts' names sit at the bottom, with a cloverleaf between them.

• 4. The Road To Launch

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  NASA calculated the odds of a fatal loss of crew for Demo-2 at 1-in-276, safely better than the program's required threshold of 1-in-270. That figure included plans to inspect the docked Crew Dragon for micrometeoroid damage while it sat at the station. A separate measure, the loss of mission risk, stood at 1-in-60. That covered scenarios where the capsule never reached the station but the crew still returned safely. Demo-2 was first planned for July 2019, envisioning a 14-day mission for a two-person crew. Those plans stalled on the 20th of April 2019, when the Demo-1 capsule was destroyed during a static fire test of its SuperDraco thrusters. SpaceX traced the failure to leaking oxidizer that solidified inside the high-pressure helium lines and damaged a valve. Engineers replaced the valves with burst discs to prevent a repeat. The redesigned system passed an in-flight abort test on the 19th of January 2020.

  NASA Administrator Jim Bridenstine spoke on the 9th of April 2020. He said he was "fairly confident" that astronauts could fly to the station by the end of May or early June. He noted the schedule still depended on final parachute tests, data reviews, and training kept clear of the COVID-19 pandemic. NASA and SpaceX confirmed the 27th of May 2020 as the launch date on the 17th of April. Arrival of the Crew Dragon would raise the station's population from three to five. Hurley and Behnken were expected to remain aboard for two or three months. They would then splash down in the Atlantic Ocean near Cape Canaveral. Bridenstine also asked space enthusiasts to watch from home rather than travel to Kennedy Space Center. He explained that maintenance crews were working in separate shifts to limit exposure to the virus. On the 1st of May 2020, SpaceX successfully demonstrated its Mark 3 parachute system, a milestone NASA required before approving the mission.

  Crew Dragon Demo-2 also became the first crewed US spaceflight without public access to the Kennedy Space Center Visitor Complex. The pandemic forced that change. The Visitor Complex reopened with limited capacity on the 28th of May 2020, after the mission's earlier delay. Its tickets sold out almost immediately. NASA and SpaceX invited members of the Class of 2020, whose graduations had been canceled by the pandemic. Students and graduates could send photos that would fly aboard the capsule. Hurley and Behnken arrived at Kennedy Space Center on the 20th of May 2020 to begin final preparations. The Falcon 9 rocket rolled out to the launch pad the following day. A static fire test on the 22nd of May marked a major milestone before liftoff. On launch day, a Tesla Model X carried the two astronauts to Launch Complex 39A.

• 5. Liftoff, A Name, And Docking

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  Forecasters gave both the 27th of May and the 30th of May attempts just a 50 percent chance of favorable weather. The second attempt held anyway. Falcon 9's first stage booster, serial number B1058, landed itself on the floating droneship Of Course I Still Love You. It touched down on a barge prepositioned in the Atlantic. On the ground, roughly 150,000 people gathered along Florida's space coast to watch in person.

  Hurley and Behnken described Falcon 9 as a "very pure flying machine", smoother than the Space Shuttle's solid rocket boosters had been. Hurley said the Merlin Vacuum engine on the rocket's upper stage felt rougher. He compared it to "kind of like driving fast on a dirt road". Shortly after reaching orbit, the astronauts revealed their capsule's name: Endeavour, capsule number 206. The choice revived a tradition from the Mercury, Gemini, and Apollo programs, where crews named their own spacecraft. It was the third US spacecraft called Endeavour. An earlier one was a shuttle built in 1991 to replace one destroyed in 1986. Before that came an Apollo command module flown on Apollo 15 in 1971. Hurley said they chose the name because both of their first spaceflights had been aboard the Shuttle Endeavour.

  Each man had brought a toy from home for the ride: an Apatosaurus named Tremor and a Ty plush toy. Both were meant to visibly float once the capsule reached weightlessness. Behnken and Hurley called it "a super cool thing for us to get a chance to do for both of our sons." They hoped the boys would enjoy seeing their toys float in zero gravity. On their second day in flight, the crew was woken with Black Sabbath's "Planet Caravan". That continued a NASA tradition of astronaut wake-up songs begun during the Gemini program. The tradition was first used to rouse a crew during Apollo 15.

  Nineteen hours after launch, Hurley took manual control of Endeavour's touchscreen piloting system as the capsule closed on the station. He flew it to within 220 meters before handing control back to the autopilot. Endeavour then soft-docked to pressurized mating adapter PMA-2 on the station's Harmony module at 14:16 UTC on the 31st of May. Eleven minutes later, at 14:27 UTC, twelve hooks closed to complete a hard capture. About two hours after that, the last of three hatches swung open. At 17:22 UTC, Hurley and Behnken floated aboard the ISS. Waiting to greet them was the Expedition 63 crew: station commander Chris Cassidy and Russian cosmonauts Anatoly Ivanishin and Ivan Vagner.

• 6. Sixty-Two Days In Orbit

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  Behnken completed four spacewalks alongside fellow American astronaut Chris Cassidy, replacing batteries that had arrived earlier aboard a Japanese cargo vehicle. Across their stay, Hurley and Behnken logged more than 100 hours on science experiments. In that time, the station carried them through 1024 orbits of Earth, covering some 27 million miles.

• 7. The Return To Earth

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  Endeavour undocked from the station at 23:35 UTC on the 1st of August 2020, ending a stay of 62 days, 9 hours, and 8 minutes. At undocking, the capsule weighed roughly 12520 kilograms. Four departure burns carried it clear of the station. A phasing burn lasting more than six minutes then set up the return trajectory. The crew woke on their last day to prerecorded voice messages from their sons. A yaw maneuver at 17:51 UTC separated the capsule's "claw" umbilical mechanism from its trunk. The deorbit burn, lasting 11 minutes and 22 seconds, began shortly after 17:56 UTC. The nose cone closed just before reentry at 18:11 UTC. Drogue chutes opened at 18:44 UTC, followed roughly a minute later by the main parachutes. The crew experienced a maximum of 4 g during reentry.

  At 18:48:06 UTC on the 2nd of August 2020, Endeavour splashed down off the coast of Pensacola, Florida. It carried 150 kilograms of cargo, including 90 kilograms of frozen science samples. It was the first splashdown by NASA astronauts in 45 years, and the first ever crewed splashdown in the Gulf of Mexico. Recovery boats first checked the air around the capsule for toxic hypergolic propellant. A separate crew gathered the four detached parachutes. Despite Coast Guard warnings, private boats entered the restricted zone, with some passing close enough to endanger both the capsule and recovery crews. Radioed warnings eventually pushed them back into a wider ring. The Coast Guard later said its patrol boats lacked the resources to board interfering vessels. It added that it would review the incident with NASA and SpaceX. Future missions would use a 16-kilometer keep-out zone patrolled by more boats.

  Examination of the returned heat shield found unexpectedly heavy erosion at four points where tension ties bolt the capsule to its trunk. One tie showed especially deep wear. SpaceX attributed the damage to unexpected airflow around the ties, and redesigned the heat shield with more erosion-resistant material there. Hans Koenigsmann speculated that different mass and trajectory from the Demo-1 test flight might explain why the wear had not shown up before. Engineers also found that the parachutes had deployed slightly lower than expected, though still within safe limits. They replaced the barometric pressure instrument used to trigger deployment.

• 8. Endeavour Flies Again

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  SpaceX refurbished Endeavour and flew it again on the Crew-2 mission, which launched on the 23rd of April 2021. Behnken did not fly that mission; his seat instead went to his wife, astronaut K. Megan McArthur. Between Demo-2 and Crew-2 came Crew-1, SpaceX's first fully operational crewed flight. It lifted four Expedition 64 astronauts aboard a different capsule, Resilience, on the 16th of November 2020 at 00:27:17 UTC.