Officials from NASA and SpaceX say that they are paying attention to a parachute issue with the Dragon spacecraft, but they do not believe significant actions will be needed to address it.

Upon returning to Earth from orbit, both the Crew and the latest Cargo versions of SpaceX's Dragon spacecraft use four main parachutes to slow the capsule before it impacts the water. If one parachute fails, the spacecraft can still land safely.

During the first two crewed flights of the Dragon spacecraft in 2020 and 2021, all four parachutes inflated nominally. However, when the Crew-2 mission carrying four astronauts returned to Earth in November 2021, one of the four parachutes was delayed by 75 seconds before it fully inflated. This had no effect on the spacecraft's planned descent rate because the extended parachute still offered some drag.

Following this night landing, NASA and SpaceX did a rapid but thorough examination of the issue and determined that it posed no serious threat to future spaceflights. Two days later, the Crew-3 mission launched in a different Crew Dragon spacecraft. This vehicle, nicknamed Endurance, is due to return to Earth in April 2022.

Happened again

On January 24, 2022, a Cargo Dragon spacecraft splashed down after a month-long supply trip to the International Space Station. NASA said that the un-televised landing was nominal, but two days ago Space News reported that one of four parachutes had failed to deploy at the scheduled time. This time the parachute was 63 seconds late to inflate. Again, the spacecraft landed with no harm.

On Friday, NASA's leader for human spaceflight operations, Kathy Lueders, its chief of commercial crew, Steve Stich, and a SpaceX senior engineer, Bill Gerstenmaier, all joined a teleconference with reporters to explain what had happened, what engineers were doing about it, and why NASA and SpaceX were confident in the safety of the Crew Dragon vehicle.

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Lueders emphasized that, in studying this issue, NASA had not convened any kind of formal mishap review. "This is just us assessing and doing our normal job of checking out the hardware," she said.

This analysis of the parachutes and flight data are ongoing as SpaceX and NASA continue to work toward an April 15 launch of the Crew-4 mission. The flight will use a new Dragon spacecraft, which is nearly completed at the company's factory in Hawthorne. A second stage for the mission is also in its final build. The Falcon 9 first stage for Crew-4, which has flown three times previously, is already in process at the company's launch facilities in Florida.

Stich noted that Crew Dragon is the first human spacecraft to use four main parachutes, instead of three, during its return trip. NASA has seen the delayed inflation of one parachute on some previous cargo flights and in tests, and this may simply be a feature of a four-parachute system. What NASA and SpaceX engineers think is happening is that three parachutes ingest air relatively quickly, but the fourth chute is "shaded" a little bit and starved for air. After the other chutes fully inflate, this fourth parachute does, too.

A learning opportunity

Gerstenmaier, a former NASA manager who now oversees safety at SpaceX, emphasized that this parachute analysis is not a safety concern for flight but more of a learning exercise.

"This is a super chance for us to learn," he said. "I consider this almost a gift that we got on CRS-24. We're going to get a chance to now have two sets of data that we can play against each other to improve our models and improve our knowledge and actually make a much safer system for everyone using these parachutes in the future."

Crew Dragon offers NASA the only US-based means of getting its astronauts into space. The space agency has been funding a second provider, Boeing, to develop the Starliner spacecraft for crewed flight. But Boeing has faced some technical challenges and probably won't carry humans on a test flight until at least next year. But even if Starliner were flying and proven today, there would be no cause to stand down flights of Dragon, the NASA officials said.