REG NASA-LLIS-0203-1992 Lessons Learned - Corrosion of Base Materials by Reaction Products Resulted from the Expected Release of Small Quantities of a Hypergolic Propellant (Nitrogppli.pdf

1、Lessons Learned Entry: 0203Lesson Info:a71 Lesson Number: 0203a71 Lesson Date: 1992-11-10a71 Submitting Organization: JSCa71 Submitted by: John McGeeSubject: Corrosion of Base Materials by Reaction Products Resulted from the Expected Release of Small Quantities of a Hypergolic Propellant (Nitrogen T

2、etroxide, N204) Reacting with Externally Applied Tape on Nearby Component. Description of Driving Event: External corrosion of tubing material caused leakage in a shuttle orbiter Reaction Control System (RCS) helium Quick Disconnect (QD). Neoprene tape was applied to the tubing in the vicinity of th

3、e N2O4 source. The corrosion was due to chemical attack by the products of a chemical reaction between nitrogen tetroxide (N204), propellant oxidizer, and the neoprene tape material. The products formed were nitric acid and various chlorides. Due to the presence of the nearby QD, small quantities of

4、 N204 were routinely present in the external environment upon mating and demating of the QD. An integrated materials compatibility assessment would have identified this incompatibility issue.Lesson(s) Learned: Failure to consider expected releases of fluids into the external environment as part of a

5、n integrated materials compatibility assessment led to leakage from system tubing.Recommendation(s): Integrated compatibility assessments now performed for externally applied materials subjected to expected fluid releases to preclude any potential degradation and subsequent deleterious effects.Evide

6、nce of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Parts Materials & ProcessesAdditional Info: Approval Info: a71 Approval Date: 1993-09-13a71 Approval Name: Ron Montaguea71 Approval Organization: JSC/NS3a71 Approval Phone Number: 281-483-8576Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-