How a SpaceX launch was almost halted by a single human hair

Sunday, October 23, 2022 | Chimniii Desk

FOD is a three-letter word, but there is nothing funny about foreign object debris and its potential to cause disaster. The incident happened on October 5. 10:25 a.m, The crew was preparing the Crew Dragon for launch. With the four Crew-5 astronauts already inside the capsule and the hatch closed, an attentive eye spotted a single human hair in the latch seal. FOD is an engineering term for foreign object debris and it requires the pad crew to take action. The time was of the essence since the clock had just passed the 90 minute mark.

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The hatch was reopened and the strand was removed. They closed the hatch for the second and final time after thoroughly cleaning the seal area. A pressure check confirmed a tight seal. The launch was unaffected by the entire affair taking only a few minutes. The Crew-5 astronauts were able to reach the International Space Station on the day after the blast off of the Falcon 9. It's clear that the crew at the pad would have to remove a single hair in order to launch a rocket. FOD is defined as any object that doesn't belong at a specific location, whether that location is a hatch seal, an engine, a cockpit, or the runway. Equipment can be damaged by debris in the wrong place.

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It is a problem that comes with a $4 billion price tag each year, according to Boeing, so what would a Biden Climate Emergency Declaration actually do? NASA runs a FOD program at Kennedy Space Center, the purpose of which is tominimize the possibility of damage or loss of flight hardware or injury to personnel due to lost items within the flight hardware elements, resulting in preservation of national resources. ” Speaking to me on a video call, Tom Simon, deputy spacecraft manager at NASA Johnson Space Center, said, "we have all been trained since day one, when dealing with flight systems, to watch out for FOD." He said that extraneous items, such as pencils, paperclips, screwdrivers, hair, and dust, could result in a seal that is slowly leaking. He said that when building systems, they take it seriously. NASA's lead engineer for Crew Dragon told me during a call that FOD is in his system. FOD carries the potential to bring down rockets and aircraft, which is considered a top risk in training programs.

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They weren't able to speak to the policies and protocols of the company, but they weren't surprised by the actions of the pad crew. There is a serious concern about FOD related to the seal of surfaces. When dealing with a sealed surface and having to ensure a tight seal, you don't want something pressing up against it. A leak path can be caused by something like hair. For time-sensitive situations like the final closing of a capsule hatch, the sudden appearance of FOD should be built into the timelines and process in addition to having a contingency plan. Pad crews should back out, remove the item, re-inspect, and even clean the seal, and then move forward with the job they are trying to do.

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hatches are also prone to FOD risk. FOD risk is mitigated by the use of covers or shields when cutting or sawing near a vehicle. Operators need to be clean. When he worked on the Space Shuttle, he spent thousands of hours on the floor with technicians to make sure that the high-pressure systems that pumped fuels and oxidizers were not affected by FOD. Simon explained that the degree of cleanliness depends on the nature of the project. Every system needs its own control plan, with engineers defining acceptable limits and deciding what needs to be screened. Make sure you open a system in a clean room, perform only what you need to, and do an inspection before closing it up. Clean room protocols for uncrewed satellite launches tend to be minimal, to the point of washing hands and putting on gloves.

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Missions involving a crew are different. Simon said, "With crews, not only does the avionics system have to work, you also don't want to have things flying all over the place." Microgravity can cause hair and dust to float around. You still want to prevent hassles, such as requiring covers over hatch seals, even though the systems are designed to deal with this sort of stuff. Even the covers have to be checked for leaks. If you want to open a system in a clean room, perform only what you need to, and do an inspection prior to closing it up, you need to listen to Posey. He said that if you see something that doesn't look right, go in and investigate. He said a second set of eyes wouldn't hurt.

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The term "Smart FOD" refers to the fact that FOD will find a way to get into your system. There was an incident in which a bootie was discovered in the Shuttle compartment. "It slipped off someone's foot, and these types of things can be funny in retrospect, but booties or tape or anything else that doesn't belong can be a flammability concern." Measures to prevent FOD from getting into components or complex systems start in the clean room. Clean rooms are specially certified and monitored to a certain cleanliness rating depending on what is in there, and items typically need to be approved before they are allowed into a clean room.

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Tapes, sticky floor pads, and tethers can be used to catch items that are accidentally dropped. Engineers wear overalls that cover arms and legs and usually have a hood with a hair net. Beards and shoes are covered by nets. When you are ready, you step through a double door that closes behind you and then you go into the clean room. He explained that in the medium chambers of some double doors, the air blows all over you. Staff will collect any FOD and investigate where it came from. Clean rooms are never clean enough. These measures are needed. Over time, FOD detection is improving. X-ray andCT scans can peer inside objects and create 3D images of a part's interior, while cameras are used to observe virtually every corner of a launch pad.

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The tools allow engineers to see assembly issues and detect FOD that wouldn't have been found otherwise. In the era of component reusability, an enhanced ability to sniff-out FOD is of increasing importance to the private sector. The hatch seal may or may not have caused a problem during the Crew-5 flight, but that doesn't matter. The elimination of anything that could endanger human lives is what matters. Engineers will continue to look for FOD, even if it is inconvenient.

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