REG NASA-LLIS-5011-2011 Lessons Learned Spacecraft Surface Cleanliness Challenges During Ogive Assembly Operations in the VAB.pdf

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1、Public Lessons Learned Entry: 5011 Lesson Info: Lesson Number: 5011 Submitting Organization: KSC Submitted by: Jenni Palmer Subject: Spacecraft Surface Cleanliness Challenges During Ogive Assembly Operations in the VAB Abstract: Spacecraft assembly and integration operations in the Vehicle Assembly

2、Building (VAB) may require a higher level of cleanliness (lower particle count) than the ambient air in the VAB environment. Considering spacecraft ground processing needs early in the design process will ensure that the required cleanliness levels are more easily obtainable. Description of Driving

3、Event: This problem arose while the Orion Contamination Control Plan was being developed for the Constellation Program. An appendix to the plan contained cleanliness requirements for Orion processing following the turnover of the spacecraft to the Government. The requirements for cleanliness of spac

4、ecraft surfaces that would be exposed during Launch Abort System (LAS) fairing assembly operations in the VAB caused concern. In particular, the Command Module (CM) backshell had a surface cleanliness requirement to meet the visibly clean (VC) standard under an incident light level of less than 50 f

5、t-candles at an inspection distance of 5 to 10 ft. Based on the Orion concept of operations, this surface would have been exposed to the VAB ambient air for at least two shiftsfrom the time the CM cover was removed until the time the LAS fairing assembly was installed. Several experts on this topic

6、agreed that it would be risky to expose the backshell surface to the ambient air in the VAB for that length of time and still maintain the VC standard of cleanliness. When the cleanliness requirement was imposed on ground operations, we looked at mitigating this challenge with a full-up cleanroom. T

7、he life-cycle cost estimate for this approach was over $20M. Because this estimate was so high, the Orion project investigated another solution to this problem that involved using spacecraft covers. This cover solution was credible, but its life-cycle cost estimate was also high. Lesson(s) Learned:

8、A modular open-top cleanroom could be used in conjunction with a facility crane during LAS fairing assembly operations, which was a solution that was much more cost-effective. Figure 1: Temporary Enclosure Figure 2: Example of a Temporary Enclosure Recommendation(s): Communicate effectively with the

9、 spacecraft designers to inform them of KSC facility environments and limitations so that they can develop a more robust spacecraft design that will not be so susceptible to particle contamination. Study all potential capabilities to ensure that spacecraft cleanliness requirements can be met by the

10、ground systems (i.e., through such means as a clean work area in the VAB, spacecraft covers, offline operations in an environmentally controlled facility, or spacecraft design modifications). Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Evidence o

11、f Recurrence Control Effectiveness: N/A Documents Related to Lesson: Orion Cleanliness KBR 3204 Mission Directorate(s): Exploration Systems Additional Key Phrase(s): Program Management. Program Management.Communications between different offices and contractor personnel Additional Info: Project: Constellation Approval Info: Approval Date: 2011-10-28 Approval Name: mbell Approval Organization: HQ Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-