NASA, SpaceX Offer Reassurances on Dragon Parachutes

NASA, SpaceX Offer Reassurances on Dragon Parachutes

NASA and SpaceX officials told reporters today they are not overly concerned about the delayed opening of parachutes during the splashdowns of the two recent flights of the Dragon spacecraft. Each spacecraft has four parachutes and only three are needed for a safe landing, but why the fourth lagged behind is not understood yet. Nonetheless, they are confident enough to proceed with plans to launch the next NASA crew on April 15.

The anomaly was observed in two successive flights of Dragon: the return of Crew-2 in November and the return of the cargo version of Dragon on the Commercial Resupply Services-24 or CRS-24 mission last month.

Steve Stich, manager of NASA’s Commercial Crew Program, and Bill Gerstenmaier, Vice President of Build and Reliability for SpaceX, theorized that the delay in the opening of the fourth parachute could be a feature of the four-parachute system where the canopies of three shade the fourth and it “struggles” to inflate on time.

View of Crew-2’s parachutes during its nighttime splashdown in the Gulf of Mexico, November 8, 2021. Screengrab.

Their main message is that the anomaly is not totally understood and they will continue to investigate, but they see no reason to delay launches or change anything on the Crew Dragon spacecraft currently docked to the International Space Station.

Gerstenmaier said the effects of the lag are not noticeable in the data.

“If you look at the actual data, you wouldn’t even detect the fact that these chutes we saw on Crew-2 and CRS-24 were actually late. If you look at the descent data, it looks just like a regular four chute return.” — Bill Gerstenmaier, SpaceX

Crew-2’s flight was on Endeavour, one of the three SpaceX reusable Crew Dragon spacecraft that have flown so far. The others are Resilience and Endurance. Endurance is currently docked to ISS, having delivered Crew-3 in November. It will bring them home in April after Crew-4 arrives. Crew-4 gets a brand new spacecraft, whose name has not been revealed yet.

On March 30, before Crew-4 launches, SpaceX will send Resilience back to the ISS, but not with a NASA crew. Instead it is the first U.S. Private Astronaut Mission to the ISS with an experienced former NASA astronaut, Michael López-Alegria, in the commander’s seat and three wealthy men as passengers. The flight, Ax-1, was arranged by Axiom Space. Gerstenmaier doesn’t anticipate any changes to that flight either.

The next crew to fly on a SpaceX Crew Dragon will be the first U.S. private astronaut mission to ISS, Axiom-1 (Ax-1). Currently scheduled to launch on March 30, 2022 are (L-R): Larry Connor (U.S.), Michael López-Alegria (U.S.), Mark Pathy (Canada), and Eytan Stibbe (Israel). López-Alegria is a retired NASA astronaut who now works for Axiom Space, the company that arranged the mission. The other three passengers are wealthy entrepreneurs.

After the 1986 Space Shuttle Challenger and 2003 Space Shuttle Columbia tragedies, NASA was criticized for getting into a “normalization of deviance” mode where engineers did not pay enough attention to anomalies that happened repeatedly, but without causing failures.

Until they did. Like foam coming off the space shuttle’s External Tank and hitting the orbiter during ascent. It happened so often without serious damage that they did not fully investigate why it was happening or how to prevent it. During Columbia’s launch, a piece of foam struck the wing and created a hole, allowing superheated gas (plasma) to enter the wing when the shuttle was returning to Earth through the atmosphere. The wing deformed and the shuttle was torn apart by aerodynamic forces, killing all seven crew members aboard.

NASA just finished its “Day of Remembrance” that commemorates the deaths of the Apollo 1, Challenger and Columbia crews. Top NASA leadership — Administrator Bill Nelson, Deputy Administrator Pam Melroy, and Associate Administrator Bob Cabana — all of whom have flown in space, held a “safety standdown” on January 27, the 55th anniversary of the 1967 Apollo 1 fire, to stress that safety is NASA’s core value.

Paying tribute to NASA’s fallen astronauts at Arlington National Cemetery, January 27, 2022, the 55th anniversary of the Apollo 1 tragedy, L-R: NASA Deputy Administrator Pam Melroy, NASA Administrator Bill Nelson, and NASA Associate Administrator Bob Cabana. Credit: NASA/Bill Ingalls

Cabana bought up the lagging parachute issue that day.

“When something is anomalous or not going as it should but nothing bad happens, it’s easy to get into a mode that it’s OK. And that’s why we have to pay such close attention when something isn’t working exactly right. I would say we’ve seen a couple of parachute delays now of our chutes with cargo vehicles returning, and one crew vehicle, and we need to make sure that we understand the model that we have, that we’re OK as we go forward. That’s going to require a little looking into and not just accepting that well, it’s OK, nothing bad happened.”  — Bob Cabana, NASA

At today’s media briefing, the NASA and SpaceX officials were asked whether the decision to move forward without understanding the parachute anomaly is an example of the normalization of deviance.

Stich replied that Crew Dragon can safely land with three parachutes. One parachute could be completely missing and the spacecraft would “still be certified” to land. In this case, the lagging parachute still provides drag, almost as much as if it were fully deployed, so “we’re going to continue to dig into it, but it doesn’t really affect planning performance very much.”

Gerstenmaier, who spent most of his career at NASA and headed the human spaceflight program until 2019 before retiring and joining SpaceX, made it clear they will keep looking at the hardware and the data. Is this a feature of a four-parachute system, which hasn’t flown before, “or something else that we didn’t see? We want to understand, is there something else there. So we say we are being hungry and inquisitive and we’re trying to understand even though this isn’t a big problem to us in overall performance, is there something here that we should learn and understand and change the way we do operations moving forward?”

Kathy Lueders, who now heads human spaceflight at NASA and previously managed the commercial crew program, said what Stich and Gerstenmaier are doing demonstrates they are not accepting deviance.

“They’re still hungry and that’s what we’ve got to [do is] keep looking at the hardware to say — do we understand the hardware even when from a performance standpoint it may be operating within expected limits.”  Kathy Lueders, NASA

Former space shuttle program manager Wayne Hale, who chairs the NASA Advisory Council’s Human Exploration and Operations Committee and used to work for Gerstenmaier, tweeted his support for exactly that.

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