Two days after becoming the first U.S. space fliers splash down in the sea in more than 45 years, astronauts Doug Hurley and Bob Behnken on Tuesday described their fiery ride back to Earth aboard SpaceX’s Crew Dragon capsule to cap a “flawless” test flight, setting the stage for operational flights beginning late this year.
Riding in their commercial Crew Dragon spacecraft, which they named Endeavour, the astronauts parachuted into the Gulf of Mexico Sunday after plunging through Earth’s atmosphere on a return trip from the International Space Station.
“I personally expected there to be certainly — not issues with the vehicle — but some challenges, some things that were maybe not quite what we expected,” said Hurley, the Crew Dragon’s spacecraft commander, and a veteran of two prior space shuttle flights. “I mean, even on our shuttle flights we had things that happened … something that you certainly wouldn’t have expected in a real flight.
“My credit once again is to the folks at SpaceX, the production folks, the people that put Endeavour together, and certainly our training folks,” Hurley said. “The mission went just like the simulators. Honestly, from start to finish, all the way, there were really no surprises.”
Hurley and Behnken launched May 30 on top of a Falcon 9 rocket from the Kennedy Space Center in Florida, becoming the first astronauts to launch into orbit from U.S. soil since the retirement of the space shuttle nearly a decade ago. The next day, the duo docked with the space station to join commander Chris Cassidy and Russian cosmonauts Anatoly Ivanishin and Ivan Vagner.
Behnken joined Cassidy on four spacewalks in June and July to finish a multi-year effort to upgrade batteries on the space station’s solar power truss. Hurley assisted with operating the station’s Canadian-built robotic arm, and both Dragon astronauts helped perform maintenance, scientific experiments and other tasks during their two-month stint on the orbiting research lab.
But the prime objective of Hurley and Behnken’s mission — designated Demo-2, or DM-2 — was to verify the performance and capabilities of the Crew Dragon spacecraft. They were the first astronauts to fly into space on a Crew Dragon, following the unpiloted Demo-1 test flight to the space station in March 2019.
The final major task for the Crew Dragon Endeavour spaceship was the return to Earth.
Hurley and Behnken floated into the capsule Saturday, and the ship autonomously detached from the space station. A series of maneuvers using the Dragon’s Draco thrusters steered the capsule a safe distance from the station and lined up with the targeted recovery zone in the Gulf of Mexico roughly 34 miles (54 kilometers) off the coast near Pensacola, Florida.
A final 11-minute deorbit burn allowed the Crew Dragon to drop back into the atmosphere. A thermal shield protected the capsule and the astronauts inside from the scorching heat of re-entry, and temperatures outside the spacecraft were expected to reach up to 3,500 degrees Fahrenheit (1,900 degrees Celsius).
As expected, a sheath of plasma around the spacecraft blocked communications for several minutes between the astronauts and SpaceX mission control in Hawthorne, California. Mission control regained contact with the crew moments before the capsule deployed two drogue parachutes to stabilize its descent through the atmosphere, then unfurled four large orange and white main chutes to slow the capsule to about 15 mph (24 kilometers per hour) for splashdown.
The Crew Dragon’s return to Earth “was more than what Doug and I expected,” said Behnken, who served as the spacecraft’s pilot.
“As we kind of descended through the atmosphere, I personally was surprised at just how quickly the events all transpired,” Behnken told reporters Tuesday. “It seemed just like a couple minutes later after the (deorbit) burn was complete, we could look out the windows and see the clouds rushing by at a much accelerated rate.”
“Once we descended a little bit into the atmosphere, Dragon really came alive,” Behnken said. “It started to fire thrusters and keep us pointed in the appropriate direction. The atmosphere starts to make noise. You can hear that rumble outside the vehicle, and as the vehicle tries to control, you feel that little bit of shimmy in your body. And our bodies were much better attuned to the environment, so we could feel those small rolls, pitches, and yaws. All those little motions were things we could pick up on inside the vehicle.”
It took just 12 minutes from the time that the Crew Dragon encountered the uppermost reaches of the discernible atmosphere until splashdown. NASA’s winged space shuttles made a more gradual descent, taking roughly 30 minutes from the start of re-entry until touchdown on a runway.
“As we descended, through the atmosphere, the thrusters were firing almost continuously” Behnken said. “I did record some audio of it, but it doesn’t sound like a machine, it sounds like an animal coming through the atmosphere with all the puffs that are happening from the thrusters and the atmospheric noise. It just continues to gain magnitude as you descend down through the atmosphere. I think we both really, really noticed that aspect of things.”
Behnken, a 50-year-old veteran of two space shuttle missions, also described what the crew felt when the Crew Dragon’s trunk section jettisoned just before the deorbit burn, along with the sensations inside the spaceship when mortars fired to deploy the parachutes.
“All the separation events, from the trunk separation through the parachute firings were very much like getting hit in the back of the chair with a baseball bat — just a crack, and then you get some sort of a motion associated with that,” Behnken said.
He said that feeling was “pretty light for the trunk separation, but with the parachutes it was a pretty significant jolt, and a couple of jolts as you go through dis-reefing (expansion) of the parachutes as well.”
Behnken said he quoted to Hurley during the re-entry a humorous scene from the 1985 comedy film Spies Like Us, where Chevy Chase asks Dan Aykroyd if he wants some coffee after training in a spinning centrifuge.
“I took a line from an old movie that Doug and I were both familiar with at one point,” he said. “Under the G-load of about 4.2 Gs, I said, ‘Want to get some coffee,’ much like we’d seen in an old movie that we had watched because that was really the feeling that we had. That’s the best way to describe if you’ve seen an old movie that happened to have some guys who’d been in a centrifuge. That’s what we felt like.”
The Crew Dragon capsule is equipped with an altimeter to estimate the ship’s altitude using GPS navigation data, and the astronauts were watching the display during the final descent under the parachutes.
“It’s not super-accurate everywhere that you’re located, so we got below zero for our altitude on that indicator, which was a little bit surprising, and then we felt the splash and we saw it splash up over the windows. It was just a great relief, I think, for both of us at that point,” Behnken said.
SpaceX provided audio recordings from the Crew Dragon’s first orbital test flight to help prepare Hurley and Behnken for the ride during launch and re-entry. Behnken said that helped the astronauts know what to expect as the rode the Crew Dragon for the first time.
“We were really comfortable coming through the atmosphere even though it felt like we were inside of an animal,” Behnken said.
He said it was difficult to see out the windows, which are located near the astronauts’ feet, during the period of entry with the highest G-loads. Instead, the astronauts focused on their touchscreen displays.
The thermal control system inside the capsule was designed to keep the temperature below 85 degrees Fahrenheit, or 29 degrees Celsius, as temperatures reached their hottest outside the spacecraft during entry.
“I do feel like I felt some warming of the capsule on the inside,” Behnken said.
By the time the capsule was through the hottest part of re-entry and the G-forces subsided, the capsule’s windows were blackened from the ordeal. Scorch marks were also visible on the outer skin of the crew capsule, and those were anticipated by SpaceX and NASA.
“You can see from just an overall view of the capsule that re-entry is a pretty demanding environment, with the different scorches on the vehicle, and the windows were not spared any of that,” Hurley said. “To look out the windows, you could basically tell that it was daylight but very little else.”
Hurley said the Crew Dragon Endeavour spacecraft was “rock solid” during the descent back to Earth.
“Personally, I expected the entry to diverge somewhat from what we saw in the simulation,” Hurley said. “What I mean by that is as the capsule gets into the thicker atmosphere … just prior to the drogues (parachutes) with Dragon, I expected there to be some divergence in attitude control because it’s a real tough problem for the ship as it gets into thicker air to maintain perfect attitude control.”
He expected the vehicle might command the drogue parachutes to deploy a bit early to help stabilize its attitude, or orientation. That wasn’t required Sunday.
“The vehicle was rock solid right up until the nominal drogue deploy altitude,” Hurley said. “You could feel it, you felt the decel (deceleration), you knew the drogues both worked, and then it was the same of the mains. We felt the different stages of dis-reef, and then right to the impact in the water … We kind of had a feeling that it would not be as much (of an impact) as a (Russian) Soyuz landing as it was described to us, but it was going to be a pretty firm splashdown, and then even how we bobbed in the water, and how the vehicle sat in the water.”
By all accounts, the Crew Dragon aced the test flight. NASA expects to convene a review in late August or early September to formally certify the Crew Dragon for operational crew rotation flights to and from the space station.
Three NASA astronauts and a Japanese astronaut are training for the first operational Crew Dragon mission, known as Crew-1, for launch on a six-month expedition to the space station as soon as late September. Sources said the late September launch schedule is somewhat optimistic, and there’s a chance SpaceX’s Crew-1 launch might be delayed until after the launch of the next Russian Soyuz crew capsule, which is set for Oct. 14.
“So my compliments to SpaceX and the commercial crew program. The vehicle performed exactly how it was supposed to, and you feel really good about Crew-1, and what they should expect and what they should see when they fly their mission,” Hurley said.
For now, NASA and SpaceX officials say they remain hopeful for a Crew-1 launch before the end of next month.
Tracking footage of Crew Dragon’s descent, parachute deployments and splashdown pic.twitter.com/pzbm1iXCC6
— SpaceX (@SpaceX) August 4, 2020
After splashdown, the crew waited for SpaceX’s recovery team to arrive at the capsule and hoist it onto a recovery vessel. Once on-board the boat, the astronauts waited the SpaceX team to ensure there were no toxic vapors leaking from the capsule’s propulsion system, then technicians and medical personnel opened the hatch to help Hurley and Behnken out of the spacecraft.
Hurley said the astronauts took some time after splashdown to test out a satellite phone they had on-board. If they had landed off course well away from SpaceX’s recovery team, they could have used the phone to call rescue forces.
The astronauts first tried calling SpaceX mission control in California.
“When we called … they said standby,” Hurley said. “So we decided we would exercise our judgment and use our phone to call some other folks.”
Hurley joked Sunday night that the astronauts were “making prank satellite phone calls to whoever we could get ahold of, which was kind of fun.”
They called NASA’s flight director and their wives — both veteran astronauts — at the Johnson Space Center in Houston.
‘”Hi, this is Bob and Doug. We’re in the ocean.'”
“This was a great chance to reassure them that we were in the water, we were ok, we were feeling good,” Hurley said. “And at that point, we were still waiting on SpaceX, so we just decided to call a few other people that we knew their phone numbers.”
After getting out of the SpaceX capsule, getting out of their pressure suits and completing initial medical checks, the astronauts rode in a helicopter from SpaceX’s recovery vessel to Naval Air Station Pensacola, where they got on a NASA jet for the trip back to their home base in Houston to be reunited with their families.
Their first meal back on Earth? A pizza.
Amid an exercise protocol to help readapt to Earth’s gravity, the astronauts said they are looking forward to spending time with their families. The astronauts began training for the mission in 2015.
“There’s a lot of stuff to do in the next few weeks,” Hurley said. “We’re hoping at some point to take some time off and share some more time with our families since they were the ones that really had to sacrifice over the last five years.”
The astronauts said their experience flying the Crew Dragon gives them confidence the spacecraft is ready for regular crew rotation flights, pending analysis of all the data from the Demo-2 mission.
“They do need to look at the data from our entry,” Behnken said. “It’s not just the end users’ anecdotes of how well it performed. They will do a very thorough review, both on the SpaceX side and the NASA side, to make sure that they’re comfortable. But from a crew perspective, I think it’s definitely ready to go.
“There are things that could be improved … to make things a little bit more comfortable, or a little bit more efficient inside the vehicle for those crews. But from a crew perspective, I think we’re perfectly comfortable that Crew-1 is ready when they finish the engineering and analysis associated with certification,” Behnken said.
Hurley added that the extension of the Demo-2 mission’s duration from several days to two months also offered a chance of engineers to gather more data on the capsule’s performance, increasing confidence that the spacecraft will be ready for the roughly-six Crew-1 mission beginning later this year.
Behnken’s wife is astronaut Megan McArthur. NASA announced last week she will be the pilot on the Crew-2 mission, which is slated launch in the spring of 2021 and will use the same reusable Crew Dragon spaceship flown by Hurley and Behnken on the Demo-2 test flight.
“For me, I think in the short term I transition into a support role,” Behnken said Tuesday. “I’ll definitely be focused on making sure that her mission is as successful as possible and supporting her just as she did for me over the last five years with the uncertainty in our launch dates and the uncertainty in our return dates.
“It’s definitely her turn to focus on getting her mission, while I take care of the things that need to be taken care of for our home life,” said Behnken, an Air Force colonel and flight test engineer.
Throughout their flight, Hurley and Behnken shared images on Twitter of daily life on the International Space Station and spectacular snapshots of planet Earth, showing views of cities, mountain ranges, oceans and tropical cyclones.
Sun glint as we pass over Baja. pic.twitter.com/sec1JRIN8W
— Col. Doug Hurley (@Astro_Doug) July 27, 2020
Incredible colors as Namibia meets the Atlantic. pic.twitter.com/qWYZEBeCNI
— Col. Doug Hurley (@Astro_Doug) July 25, 2020
The Rocky Mountains and Denver. pic.twitter.com/uxg8CtSdj4
— Col. Doug Hurley (@Astro_Doug) July 26, 2020
— Bob Behnken (@AstroBehnken) July 19, 2020
“The perspective that you have from low Earth orbit of our planet is just one of just complete awe, said Hurley, a retired Marine Corps colonel and fighter pilot. “First of all, of how beautiful the planet is, that there are no borders that you can see from space that the atmosphere is so thin.
“The United States, and the world, has been dealing with so much chaos and drama, and the pandemic, and all the things that have been going on in the world,” Hurley said. If it were me, it would make me feel better to see these pictures form space, so we just felt like it was a way to have folks maybe have a distraction for awhile, and also to appreciate the planet that we’ve been given.”
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Follow Stephen Clark on Twitter: @StephenClark1.