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NASA-LLIS-0013
Lessons Learned - Fluid Sampling Techniques for Spacecraft Ground Support Equipment (Auxiliary Power Unit)
Year: 1991
Abstract: Description of Driving Event:
The gaseous nitrogen service coupling of the shuttle orbiter Auxiliary Power Unit (APU) #2 fuel tank was found to be leaking after servicing for shuttle mission STS-3. It was determined that this leakage was the result of contamination/corrosion at the ground/airborne Quick Disconnect (QD). The probable source of the contamination was believed to be a stainless steel filter in the Ground Support Equipment (GSE). Moisture being trapped and held between the filter and its support screens had corroded the filter elements thereby causing the filter to fail and allowing contamination to migrate to the QD's where it was deposited on the poppet seat. Sampling of the fluid had been conducted at the GSE cart upstream of the filter. Investigation has shown that there are many types of contamination and corrosion present in the QD's. Leaking of nitrogen from the APU fuel tank could potentially result in the inability to restart the APU for orbiter re-entry. The following actions were proposed to resolve this problem: (1) modification of the Ground Support Equipment (GSE) to provide for fluid sampling at the GSE/airborne interface, and (2) change the procedures to require filter inspection and replacement on a regular basis.
The gaseous nitrogen service coupling of the shuttle orbiter Auxiliary Power Unit (APU) #2 fuel tank was found to be leaking after servicing for shuttle mission STS-3. It was determined that this leakage was the result of contamination/corrosion at the ground/airborne Quick Disconnect (QD). The probable source of the contamination was believed to be a stainless steel filter in the Ground Support Equipment (GSE). Moisture being trapped and held between the filter and its support screens had corroded the filter elements thereby causing the filter to fail and allowing contamination to migrate to the QD's where it was deposited on the poppet seat. Sampling of the fluid had been conducted at the GSE cart upstream of the filter. Investigation has shown that there are many types of contamination and corrosion present in the QD's. Leaking of nitrogen from the APU fuel tank could potentially result in the inability to restart the APU for orbiter re-entry. The following actions were proposed to resolve this problem: (1) modification of the Ground Support Equipment (GSE) to provide for fluid sampling at the GSE/airborne interface, and (2) change the procedures to require filter inspection and replacement on a regular basis.
Subject: Configuration Management
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| contributor author | NASA - National Aeronautics and Space Administration (NASA) | |
| date accessioned | 2017-09-04T15:05:24Z | |
| date available | 2017-09-04T15:05:24Z | |
| date copyright | 07/16/1991 | |
| date issued | 1991 | |
| identifier other | LBYCQCAAAAAAAAAA.pdf | |
| identifier uri | https://yse.yabesh.ir/std/handle/yse/2860 | |
| description abstract | Description of Driving Event: The gaseous nitrogen service coupling of the shuttle orbiter Auxiliary Power Unit (APU) #2 fuel tank was found to be leaking after servicing for shuttle mission STS-3. It was determined that this leakage was the result of contamination/corrosion at the ground/airborne Quick Disconnect (QD). The probable source of the contamination was believed to be a stainless steel filter in the Ground Support Equipment (GSE). Moisture being trapped and held between the filter and its support screens had corroded the filter elements thereby causing the filter to fail and allowing contamination to migrate to the QD's where it was deposited on the poppet seat. Sampling of the fluid had been conducted at the GSE cart upstream of the filter. Investigation has shown that there are many types of contamination and corrosion present in the QD's. Leaking of nitrogen from the APU fuel tank could potentially result in the inability to restart the APU for orbiter re-entry. The following actions were proposed to resolve this problem: (1) modification of the Ground Support Equipment (GSE) to provide for fluid sampling at the GSE/airborne interface, and (2) change the procedures to require filter inspection and replacement on a regular basis. | |
| language | English | |
| title | NASA-LLIS-0013 | num |
| title | Lessons Learned - Fluid Sampling Techniques for Spacecraft Ground Support Equipment (Auxiliary Power Unit) | en |
| type | standard | |
| page | 2 | |
| status | Active | |
| tree | NASA - National Aeronautics and Space Administration (NASA):;1991 | |
| contenttype | fulltext | |
| subject keywords | Configuration Management | |
| subject keywords | Energetic Materials - Explosive/Propellant/Pyrotechnic | |
| subject keywords | Ground Equipment | |
| subject keywords | Ground Operations | |
| subject keywords | Hardware | |
| subject keywords | Launch Vehicle | |
| subject keywords | Parts Materials & Processes | |
| subject keywords | Spacecraft |