Standards Development

Scope

This standard provides technical methods to calculate the precipitation efficiency and liability of a flight hardware by measuring the screen effectiveness of thermal cycles. This standard can be applied, but not be limited to those recurring production, such as higher volume production or hardware of constellation programs, with a constant block of design, manufacture, as an option for those who wishes to modify or reduce the numbers of cycles with own database as a supplement standard of ISO 15864.

In case that the number of thermal cycles is agreed with the customer’s specified standard or determined by other means, this standard may be used as a supplement technical informative reference.

Purpose

Thermal vacuum test is one of most importance and most expensive environment tests of space systems. Thermal vacuum test is required to demonstrates the ability of the test item to meet the design requirements under vacuum conditions and temperature extremes, and to screen out initial failure such as workmanship error, integration error and latent material (ISO 15864). Number of cycles, which is one of the thermal vacuum test conditions, is essential to determine the ability to screen out initial failures. Therefore, number of cycles should be determined based on careful general technical considerations by taking into account various factors such as complexity, heritage and maturity of manufacturing, etc., as well as reliability required to the test article. This standard provides the general technical method to calculate the precipitation efficiency and reliability as one of the factors to determine number of cycles of thermal vacuum test for the recurring production flight hardware, such as higher volume production or hardware of constellation programs, as a supplement standard of ISO15864.