How a Single Human Hair Nearly Halted a SpaceX Launch - Gizmodo

Engineers quip that FOD is simply a four-letter word, but there’s thing comic astir overseas entity debris and its imaginable to trigger disaster.

The incidental happened connected October 5 astatine astir 10:25 a.m. ET, arsenic a SpaceX pad unit was preparing Crew Dragon Endurance for motorboat atop a Falcon 9 rocket. With the 4 Crew-5 astronauts already wrong the capsule and the hatch closed, an attentive oculus spotted a azygous quality hairsbreadth successful the latch seal. The hairsbreadth was designated FOD—an engineering word for overseas entity debris—requiring the pad unit to instrumentality action.

The countdown timepiece had conscionable ticked past T-90 minutes, truthful clip was of the essence. The pad unit calmly reopened Endurance’s hatch and removed the offending strand. They performed different inspection, thoroughly re-cleaned the seal area, and closed the hatch for the 2nd and last time. A consequent unit cheque confirmed a choky seal.

The full matter took lone a fewer minutes, and the motorboat wasn’t affected. Blast disconnected of the Falcon 9 happened astatine noon arsenic scheduled, with the Crew-5 astronauts—Nicole Aunapu Mann, Josh Cassada, Koichi Wakata, and Anna Kikina—successfully reaching the International Space Station connected the pursuing day.

That the SpaceX pad unit would instrumentality the clip to region a azygous hairsbreadth successful beforehand of a rocket motorboat is revealing and wholly understandable. In the aerospace industry, FOD is defined arsenic immoderate entity that doesn’t beryllium astatine a circumstantial location, whether that determination is simply a hatch seal, an engine, a cockpit, oregon the runway. Debris successful the incorrect spot tin harm equipment, facilitate the suboptimal show of systems, and trigger outright malfunctions.

It’s an contented crossed galore industries, but for the aerospace industry, it’s a occupation that comes with a $4 cardinal terms tag each year, according to Boeing. NASA runs a FOD program astatine Kennedy Space Center, the intent of which is to “minimize the anticipation of harm oregon nonaccomplishment of formation hardware oregon wounded to unit owed to mislaid items wrong the formation hardware elements, resulting successful preservation of nationalist resources.”

Speaking to maine connected a video call, Tom Simon, lawman spacecraft manager astatine NASA Johnson Space Center, said, “we’ve each been trained since time one, erstwhile dealing with formation systems, to ticker retired for FOD.” Extraneous items, specified arsenic pencils, paperclips, screwdrivers, hair, and dust, “might look minor,” but they could, among different things, effect successful a “seal that is dilatory leaking overboard,” helium said. “When we’re gathering systems, we instrumentality it seriously,” helium added.

As an engineer, FOD is “ingrained successful your system,” John Posey, NASA pb technologist for Crew Dragon, told maine during the aforesaid call. It’s “considered a apical hazard successful grooming programs,” arsenic FOD carries the imaginable to “bring down rockets and aircraft,” helium explained.

Simon and Posey weren’t capable to talk to SpaceX’s circumstantial policies and protocols, but they weren’t amazed by the pad crew’s actions successful removing the quality hair. FOD related to the sealing of surfaces is simply a superior concern. When dealing with a sealing surface, and erstwhile having to guarantee a choky seal, “you don’t privation thing pressing up against it,” Posey said. “Something similar hair—depending connected its size and orientation—can effect successful a leak path.”

Posey said that, for time-sensitive situations similar the last closing of a capsule hatch, the abrupt quality of FOD should beryllium built into the timeline and process, successful summation to having a contingency program should this script arise. Pad crews should “back out, region the item, re-inspect, and adjacent cleanable the seal, and past determination guardant with the occupation you’re trying to do,” said Posey.

It’s not conscionable hatches that are prone to FOD risk. Launch operators instrumentality processes to mitigate FOD risk, specified arsenic utilizing covers oregon shields erstwhile enactment similar cutting oregon sawing needs to beryllium done adjacent spacecraft. And of course, the operators themselves request to beryllium clean. Propulsion systems, successful which fuels and oxidizers are pumped done high-pressure systems, tin beryllium affected by FOD, said Posey, who worked connected the Space Shuttle during its last days and “spent thousands of hours connected propulsion systems, moving connected the level with technicians, to marque definite it’s each good.”

As Simon explained, the required grade of cleanliness often depends connected the quality of the task oregon ngo itself. Posey said each strategy needs its ain power plan, with engineers defining acceptable limits and deciding what needs to beryllium screened.

Clean country protocols for uncrewed outer launches thin to beryllium minimal, “to the constituent of washing hands and putting connected gloves,” helium said. Missions involving a unit are a antithetic story, however. “With crews, not lone does the avionics strategy person to work, you besides don’t privation to person things flying each implicit the place,” successful summation to keeping the seals clean, said Simon. Once successful orbit, microgravity tin abruptly origin unnoticed FOD to interval around, including hairsbreadth and dust. Posey said filtration systems are designed to woody with this benignant of stuff, “but you inactive privation to forestall hassles,” specified arsenic requiring covers implicit hatch seals, among different measures. And “even covers person to beryllium cleaned and checked for leaks,” helium added.

Posey offered immoderate sage advice: “Always marque definite you’re opening a strategy successful a cleanable room, execute lone what you request to do, and bash an inspection anterior to closing it up.” And “if you spot thing that doesn’t look right, spell successful and investigate,” arsenic it’s a “necessary burden,” helium said. A 2nd acceptable of eyes won’t hurt, helium added. “FOD volition find a mode to get into your system,” said Posey, hence the word “Smart FOD.” He recounted an incidental successful which a bootie, oregon a footwear cover, was abruptly discovered successful the Shuttle compartment. “It conscionable slipped disconnected someone’s foot, and these types of things tin beryllium comic successful retrospect,” said Posey, but booties oregon portion oregon thing other that doesn’t beryllium tin beryllium a flammability concern.

Measures to forestall FOD from getting into components oregon analyzable systems commencement successful the cleanable room, and each cleanable country has its ain cleanliness requirements, depending connected the project. Clean rooms “are specially certified and monitored to a definite cleanliness standing depending connected what’s successful there,” and items typically request to beryllium approved earlier they’re allowed into a cleanable room, said Posey.

Lockers are disposable to clasp escaped items; portion and sticky level pads tin unafraid items that indispensable beryllium successful the room; and tethers tin drawback thing that’s accidentally dropped. Overalls, known to engineers arsenic “bunny suits,” screen arms and legs and usually diagnostic a hood with a hairsbreadth net. Beards get covered by beard nets, portion shoes get booties.

“Once you’re acceptable and each geared up, you measurement done a treble door,” said Posey, the archetypal of which “closes down you and past you spell into the cleanable room.” In the mean chambers of immoderate treble doors, “air blows each implicit you, sucking up immoderate particulate oregon debris,” helium explained. Staff volition cod immoderate recovered FOD and analyse wherever it came from and whether immoderate further controls are needed. Clean rooms “are ne'er cleanable enough,” Posey added.

These measures are an added but indispensable headache. The bully quality is that FOD detection is improving implicit time. Cameras are present routinely utilized to observe virtually each country of a motorboat pad, portion X-ray and CT scans tin adjacent wrong objects and make 3D images of a part’s interior. With these tools, engineers tin “see assembly issues” and “detect FOD that wouldn’t person been recovered otherwise,” Posey said. An enhanced quality to sniff-out FOD is of expanding value to the backstage sector, peculiarly successful the epoch of constituent reusability.

The quality hairsbreadth recovered wrong the hatch seal whitethorn oregon whitethorn not person caused a occupation during the Crew-5 flight, but that doesn’t matter. What matters is information and the elimination of thing that could enactment quality lives astatine risk. Engineers volition proceed to question retired FOD, careless of the inconvenience it whitethorn cause.

More: Remembering Enterprise: The Test Shuttle That Never Flew to Space.