FOD is a four-letter word, but there is nothing funny about foreign object debris and its ability to cause disaster. On October 5, there was an incident at 10:00 a.m. The Crew Dragon Endurance was being prepared for launch at the time. With the four Crew-5 astronauts already inside the capsule and the hatch closed, an attentive eye spotted a single human hair. FOD is an engineering term for foreign object debris and was used to designate the hair. Time was of the essence because the clock had just hit 90 minutes. The crew reopened the hatch and took out the strand. They closed the hatch for the second time after cleaning the seal area. The seal was confirmed by a pressure check.
The launch was unaffected by the 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.
It's clear that the crew of the rocket ship would take a long time to remove a single hair. FOD is defined by the industry as any object that doesn't belong at a specific location. Equipment can be damaged by debris in the wrong place.
It is an issue for many industries, but for theAerospace industry it is a problem that costs $4 billion a year. NASA runs a FOD program at Kennedy Space Center in order tominimize the chance of damage or loss of flight hardware or injury to personnel due to lost items within the flight hardware elements.
Speaking to me on a video call, Tom Simon, deputy spacecraft manager at NASA Johnson Space Center, said that they have all been trained to watch out for FOD. He said that extraneous items, such as pencils, paperclips, screwdrivers, hair, and dust, could result in a leak that is slowly leaking. He said that they take it seriously when they build systems.
NASA's lead engineer for Crew Dragon told me during a call that FOD is in his system. He explained that FOD carries the potential to bring down rockets and aircraft.
They weren't able to speak to the policies and protocols of the company, but they weren't surprised by the actions of the crew. There is FOD related to the seal of surfaces. When dealing with a sealed surface, you don't want something pressing up against it A leak path can be caused by things like hair and orientation.
The sudden appearance of FOD should be built into the process and timelines for situations like the final closing of a capsule hatch. Pad crews should back out, remove the item, re- inspect, and even clean the seal, and then move on with the job.
Hatches are prone to FOD risk. FOD risk is mitigated by the use of covers or shields when cutting or sawing near a space station. Operators must be clean. When he worked on the Space Shuttle, he spent thousands of hours on the floor with technicians to make sure it was safe.
The nature of the project or mission can affect the degree of clean up. Every system needs its own control plan with engineers defining acceptable limits and deciding what needs to be screened
“Always make sure you’re opening a system in a clean room, perform only what you need to do, and do an inspection prior to closing it up.”He said that clean room protocols for uncrewed satellite launches tend to be minimal. There are missions that involve a crew. Simon said that you don't want to have things flying all over the place with crews. Microgravity can cause undetected FOD to float around. You still want to prevent hassles, such as requiring covers over hatch seals, even though the filters are designed to deal with this sort of stuff. He said that even covers have to be cleaned.
If you want to open a system in a clean room, perform only what you need to, and do an inspection before closing it up, you need to listen to what Posey has to say. He said to investigate if you see something that isn't right. He said that a second set of eyes wouldn't hurt. The term "Smart FOD" is a reference to the fact thatFOD will find a way to get into your system. There was an incident in which a bootie was found in the shuttle compartment. "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."
The clean room is where measures to prevent FOD from getting into components or complex systems begin. Clean rooms are specially certified and monitored to a certain cleanliness rating depending on what is in there, and items need to be approved before they can enter.
Tapes, sticky floor pads, and tethers can be used to catch items that are accidentally dropped. Engineers typically wear overalls that cover their arms and legs and have a hood with a hair net. Beards are covered by nets and shoes are covered by boots.
When you are ready, you step through a double door, the first closing behind you, and then entering the clean room. Air blows all over you in the medium chambers of some double doors. staff will collect any FOD and investigate where it came from The rooms are not always clean enough.
These measures add to the headaches. FOD detection is getting better. X-ray andCT scans can peer inside objects and create 3D images of a part's interior, while cameras are often used to observe virtually every corner of a launch pad. Engineers can see assembly issues with the help of these tools. In the era of component reusability, an enhanced ability to sniff-out FOD is more important than ever.
It doesn't matter if the human hair found in the hatch seal caused a problem or not. The elimination of anything that could endanger humans is the most important thing. Engineers will continue to look for FOD no matter what happens.
The test shuttle that never flew to space was remembered.
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