DEPARTMENT OF THE AIR FORCE SMC REGULATION 800-27

Headquarters Space and Missile Systems Center (AFMC)

Los Angeles Air Force Base, California 90009-2960

Acquisition Management

Use of Tin on Electrical

Components for Space Vehicles

This regulation establishes policies, procedures and assigns responsibilities for SMC program office acquisitions that contain electrical components in SMC launch and space vehicle programs.

1. Policy

Use of pure tin or tin alloy (>98% Sn) plating on electrical devices and hardware for SMC launch and space vehicles is prohibited.

2. Background

The use of pure tin plating on electrical devices and hardware for space applications can result in growth of tin whiskers. Growth of tin whiskers on such plating is well documented. These whiskers can produce permanent shorts in some electrical systems and temporary shorts or vacuum arcs in others, causing space system degradation or failure. The guiding document for this prohibition is MIL-STD-1547B, "Electronic Parts, Materials, and Processes for Space and Launch Vehicles."

3. Responsibilities and Procedures

a. For SMC launch and space vehicle programs each program office shall ensure that no electrical component or hardware has a surface finish consisting of pure tin or tin alloy (>98% Sn).

b. For SMC launch and space vehicle programs each program office shall require contractor compliance with paragraph 3.a.

c. Instructions for applying and executing this regulation are provided by SMC Regulation 540-15 (Systems Engineering Policy). Any program director who does not apply and execute this regulation, as required by SMCR 540-15, shall immediately request a waiver from the Commander.

Edward P. Barry, Jr.

Lieutenant General, USAF

Commander