How a Single Human Hair Almost Held a SpaceX Launch

Crew Dragon Endurance atop a SpaceX Falcon 9 rocket on October 1, 2022.

Crew Dragon Endurance atop a SpaceX Falcon 9 rocket on October 1, 2022.
photograph: SpaceX

Engineers quip that FOD is a four-letter phrase, however there’s nothing humorous about international object particles and its potential to set off catastrophe.

The incident occurred on October 5 at round 10:25 am ET, as a SpaceX pad crew was making ready Crew Dragon endurance for launch atop a Falcon 9 rocket. With the 4 Crew-5 astronauts already contained in the capsule and the hatch closed, an attentive eye noticed a single human hair within the latch seal. The hair was designated FOD—an engineering time period for international object particles—requiring the pad crew to take motion.

The countdown clock had simply ticked previous T-90 minutes, so time was of the essence. The pad crew calmly reopened endurance‘s hatch and eliminated the offending strand. They carried out one other inspection, completely re-cleaned the seal space, and closed the hatch for the second and closing time. A subsequent strain examine confirmed a good seal.

The SpaceX pad crew re-inspecting the seal shortly after having to reopen the hatch upon discovering FOD in the form of a human hair.

The SpaceX pad crew re-inspecting the seal shortly after having to reopen the hatch upon discovering FOD within the type of a human hair.
Screenshot: SpaceX

The whole affair took just a few minutes, and the launch wasn’t affected. Blast off of the Falcon 9 occurred at midday as scheduled, with the Crew-5 astronauts—Nicole Aunapu Mann, Josh Cassada, Koichi Wakata, and Anna Kikina—efficiently reaching the Worldwide House Station on the next day.

That the SpaceX pad crew would take the time to take away a single hair prematurely of a rocket launch is revealing and completely comprehensible. Within the aerospace business, FOD is outlined as any object that does not belong at a particular location, whether or not that location is a hatch seal, an engine, a cockpit, or the runway. Particles within the flawed place can harm tools, facilitate the suboptimal efficiency of programs, and set off outright malfunctions.

It is a difficulty throughout many industries, however for the aerospace business, it is an issue that comes with a $4 billion price ticket every year, in accordance to Boeing. NASA runs a FOD program at Kennedy House Middle, the aim of which is to “decrease the potential for harm or lack of flight {hardware} or damage to personnel as a consequence of misplaced objects inside the flight {hardware} components, leading to preservation of nationwide assets.”

Chatting with me on a video name, Tom Simon, deputy spacecraft supervisor at NASA Johnson House Middle, mentioned, “we have all been educated since day one, when coping with flight programs, to be careful for FOD.” Extraneous objects, akin to pencils, paperclips, screwdrivers, hair, and dirt, “may appear minor,” however they may, amongst different issues, end in a “seal that’s slowly leaking overboard,” he mentioned. “After we’re constructing programs, we take it severely,” he added.

As an engineer, FOD is “ingrained in your system,” John Posey, NASA lead engineer for Crew Dragon, instructed me throughout the identical name. It is “thought-about a prime threat in coaching applications,” as FOD carries the potential to “convey down rockets and plane,” he defined.

Simon and Posey weren’t in a position to converse to SpaceX’s particular insurance policies and protocols, however they weren’t stunned by the pad crew’s actions in eradicating the human hair. FOD associated to the sealing of surfaces is a severe concern. When coping with a sealing floor, and when having to make sure a good seal, “you don’t need one thing urgent up towards it,” Posey mentioned. “One thing like hair—relying on its measurement and orientation—can lead to a leak path.”

Posey mentioned that, for time-sensitive conditions like the ultimate closing of a capsule hatch, the sudden look of FOD must be constructed into the timeline and course of, along with having a contingency plan ought to this state of affairs come up. Pad crews ought to “again out, take away the merchandise, re-inspect, and even clear the seal, after which transfer ahead with the job you are making an attempt to do,” mentioned Posey.

It isn’t simply hatches which might be liable to FOD threat. Launch operators implement processes to mitigate FOD threat, akin to utilizing covers or shields when work like chopping or sawing must be achieved close to spacecraft. And naturally, the operators themselves must be clear. Propulsion programs, by which fuels and oxidizers are pumped by way of high-pressure programs, may be affected by FOD, mentioned Posey, who labored on the House Shuttle throughout its closing days and “spent hundreds of hours on propulsion programs, engaged on the ground with technicians, to verify it is all good.”

As Simon defined, the required diploma of cleanliness typically is dependent upon the character of the challenge or mission itself. Posey mentioned each system wants its personal management plan, with engineers defining acceptable limits and deciding what must be screened.

Clear room protocols for uncrewed satellite tv for pc launches are usually minimal, “to the purpose of washing palms and placing on gloves,” he mentioned. Missions involving a crew are a distinct story, nonetheless. “With crews, not solely does the avionics system should work, you additionally do not need to have issues flying in all places,” along with preserving the seals clear, mentioned Simon. As soon as in orbit, microgravity can abruptly trigger unnoticed FOD to drift round, together with hair and dirt. Posey mentioned filtration programs are designed to take care of this form of stuff, “however you continue to need to stop hassles,” akin to requiring covers over hatch seals, amongst different measures. And “even covers should be cleaned and checked for leaks,” he added.

Posey provided some sage recommendation: “At all times be sure to’re opening a system in a clear room, carry out solely what it is advisable to do, and do an inspection previous to closing it up.” And “should you see one thing that does not look proper, go in and examine,” as it is a “mandatory burden,” he mentioned. A second set of eyes will not damage, he added. “FOD will discover a approach to get into your system,” mentioned Posey, therefore the time period “Good FOD.” He recounted an incident by which a bootie, or a shoe cowl, was abruptly found within the Shuttle compartment. “It simply slipped off somebody’s foot, and some of these issues may be humorous looking back,” mentioned Posey, however booties or tape or the rest that does not belong generally is a flammability concern.

The Webb Space Telescope inside a Northrop Grumman clean room in Redondo Beach, CA, in March 2018.

The Webb House Telescope inside a Northrop Grumman clear room in Redondo Seaside, CA, in March 2018.
photograph: NASA

Measures to forestall FOD from moving into elements or advanced programs begin within the clear room, and each clear room has its personal cleanliness necessities, relying on the challenge. Clear rooms “are specifically licensed and monitored to a sure cleanliness ranking relying on what’s in there,” and objects sometimes must be accepted earlier than they’re allowed right into a clear room, mentioned Posey.

Lockers can be found to carry unfastened objects; tape and sticky ground pads can safe objects that should be within the room; and tethers can catch something that is by chance dropped. Overalls, recognized to engineers as “bunny fits,” cowl legs and arms and normally characteristic a hood with a hair web. Beards get lined by beard nets, whereas sneakers get booties.

“When you’re prepared and all equipped, you step by way of a double door,” mentioned Posey, the primary of which “closes behind you and then you definately go into the clear room.” Within the medium chambers of some double doorways, “air blows throughout you, sucking up any mud or particles,” he defined. Workers will acquire any FOD discovered and examine the place it got here from and whether or not any extra controls are wanted. Clear rooms “are by no means clear sufficient,” Posey added.

These measures are an added however mandatory headache. The excellent news is that FOD detection is enhancing over time. Cameras at the moment are routinely used to look at just about each nook of a launch pad, whereas X-ray and CT scans can peer inside objects and create 3D photographs of a component’s inside. With these instruments, engineers can “see meeting points” and “detect FOD that would not have been discovered in any other case,” Posey mentioned. An enhanced potential to sniff-out FOD is of accelerating significance to the non-public sector, notably within the period of element reusability.

The human hair discovered contained in the hatch seal might or might not have induced an issue through the Crew-5 flight, however that does not matter. What issues is security and the elimination of something that might put human lives in danger. Engineers will proceed to hunt out FOD, whatever the inconvenience it might trigger.

Extra: remembering Enterprise: The Take a look at Shuttle That By no means Flew to House.


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