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Burn-In

Scope and Description

This topic pages covers burn-in testing of electronics. Burn-in is a screening process where acceptance units (i.e., hardware intended for flight) is operated for an extended period to detect workmanship errors. Burn-in is typically done at elevated temperature. The goal of burn-in is to precipitate failures due to workmanship defects, correct them, and demonstrate a sufficient period of failure-free operation after any corrections are made. Any time spent operating at elevated temperature (e.g., in thermal cycling or thermal vacuum testing) typically counts towards the total required time in burn-in. Because smallsat projects often do not follow traditional manufacturing processes and utilize COTS components, burn-in testing can be a relatively simple - albeit time consuming - way to significantly improve reliability by screening for workmanship defects.

Resources in this topic area are primarily standards that provide burn-in requirements and books that present procedures, context, and guidance regarding burn-in testing.

Best Practices and Lessons Learned

  • Elevated temperature (usually at least the hot acceptance temperature) is important to effective burn-in screening. Ambient temperature burn-in testing is very unlikely to detect defects and is probably not worth the cost and schedule impact.
  • The configuration of the unit under test is one of the most important factors in effective burn-in. This configuration should sufficiently exercise and involve all components. Your goal is to accumulate stress in these components now, so that you see failure on the ground where you can correct it and not after 200 hours on-orbit. Careful configuration of the unit under test (e.g., loading conditions on power supplies, switch states, and data flows) will ensure that the impact of any workmanship flaws are accumulated during this test and therefore unlikely to lead to failure on-orbit.
  • Because this is a time consuming process that often requires 200+ hours under test, planning and management of labor and equipment is extremely important. If you are serious about completing burn-in, schedule for it and allocate substantial margin to account for the impact of rework to correct at least one failure. This margin should include the time to remove the unit from the test assembly, correct the flaw, re-install the unit, and complete the required failure-free burn-in time (typically 50 hours).
  • Burn-in is an excellent "entry-level" candidate for automated testing. The return on investment will be positive after fewer tests than more complex, dynamic tasks like electronics functional testing. Make sure to thoroughly qualify your automated test equipment and, if possible, build in fail-safe behavior to identify failures in the unit under test, safely shut down equipment, log the time of this event, and notify appropriate individuals (e.g., via automated email).
  • Always be aware of datasheet limits for parts and/or components prior to burn-in-testing. Extended periods of time significantly over datasheet levels may reduce lifetime or cause unnecessary failure. Recognize the risk trade involved when designing burn-in (or other screening) testing levels.

Resources

Book
David Gilmore

This chapter titled "Thermal Testing" is a comprehensive reference regarding thermal testing of space ... flight hardware. The tests covered are thermal cycling (ambient pressure), thermal vacuum, thermal balance, and burn-in. It includes a description of the elements and stages of the traditional approach, environments, margins, requirements, and required equipment/facilitates.

White Paper
US Department of Defense

This handbook provides in-depth guidance on testing of space vehicles. The testing covered includes structural ... loading, thermal vacuum, thermal cycling, thermal balance, pressure testing, burn-in, random vibration, acoustic, and pyroshock - among others. This is a dated but comprehensive source of space hardware test environments and processes.

Article
S. Agarwal

This workshop slide presentation details the importance of and recommendations for burn-in procedures ... of microcircuits based on NASA standards. The backup slides include additional resources such as MIL standards for burn-in temperatures and performance specifications for screening tests performed on hermetic microcircuits.

Standard
US Department of Defense

This resource is the first part of MIL-STD-883L, last updated in March of 2020, for test method standard ... microcircuits. While there are six parts to MIL-STD-883L, this document covers the basic test method standard for testing microelectronic devices used in military and aerospace applications.

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