August 18, 2022

SpaceX, NASA investigating parachute ‘lag’ during latest Dragon recovery

SpaceX, NASA investigating parachute ‘lag’ during latest Dragon recovery
SpaceX, NASA investigating parachute ‘lag’ during latest Dragon recoverySpaceX, NASA investigating parachute ‘lag’ during latest Dragon recovery

On February 2nd, NASA officials reported that a SpaceX Cargo Dragon spacecraft suffered a minor parachute anomaly during its most recent reentry, descent, and splashdown.

On January 23rd, SpaceX’s CRS-24 Cargo Dragon 2 vehicle departed the International Space Station for the second time in less than six months with about 2.2 tons (~5000 lb) of science experiments, equipment, and refuse in tow. On January 24th, the Dragon successfully deorbited, reentered Earth’s atmosphere, deployed parachutes, and splashed down off of Florida’s Gulf Coast, where a SpaceX team quickly recovered the spacecraft and loaded time-sensitive cargo onto a waiting helicopter. Oddly, in an attempt to save perhaps a quarter of a percent of the total cost of the mission, NASA offered zero live coverage and didn’t even publish photos or videos of the Dragon recovery taken after the fact.

That left little more than social media posts for taxpayers who paid for the mission to experience it live. Ultimately, while those posts simply stated that the CRS-24 Dragon recovery was a success, they weren’t entirely accurate.

Mirroring behavior seen on Crew Dragon’s Crew-2 recovery in November 2021, NASA and SpaceX waited more than a week after the fact to report that one of Cargo Dragon’s four main parachutes also failed to fully inflate exactly when expected. However, while NASA and SpaceX withholding information is unsavory at best, the issue was once again minor.

Crew-2’s partially uninflated main chute is visible in the middle photo. (NASA)

Just like Crew-2, the ‘lagging’ CRS-24 chute took about a minute longer than its siblings to fully inflate but did so well before splashdown. More importantly, CRS-24’s chute lag also failed to register in telemetry or recovered data, meaning that it had no significant impact on capsule descent rate or the force of impact upon splashdown. According to senior SpaceX flight reliability engineer Bill Gerstenmaier, “if you [only] look at the…data, you wouldn’t even detect the fact that the chutes [lagged on Crew-2 or CRS-24].”

In other words, the lagging chute inflation has been entirely harmless and completely inconsequential. Further, because Crew Dragon and Cargo Dragon 2 use four main chutes, they can safely return to Earth even if one of those chutes fails entirely. The fact that the actual telemetry shows nothing amiss with three – instead of – four chutes fully deployed effectively confirms as much, though SpaceX also completed more than a hundred different parachute drop tests verifying as much before Dragon 2’s first flight.

However, in human spaceflight, the saying “sometimes a cigar is just a cigar” could not be further from reality. Any deviation from expected behavior – no matter how harmless – must be carefully investigated because a lack of full understanding in one area may be a symptom of a larger organizational error or a sign of other unknown issues. Even if that’s rarely the case, NASA – where Gerstenmaier was an executive for 17 years – knows the cost of systemic complacency better than any other company or space agency on Earth. There is no room for it.

As such, even if the communication of the event was lacking, it’s abundantly clear that NASA and SpaceX are doing what needs to be done to remain vigilant and ensure the safety of Dragon and its parachutes.

SpaceX, NASA investigating parachute ‘lag’ during latest Dragon recovery

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