MIL-STD-202.

MIL-STD-202 is the United States military standard that defines test methods for electronic and electrical component parts. It establishes the laboratory procedures used to qualify components — resistors, capacitors, inductors, connectors, switches, relays, transformers and similar devices — against the environmental and mechanical stresses they encounter in defense applications. The standard is the component-level companion to MIL-STD-810 (system-level environmental engineering) and remains widely referenced even outside defense by industries that demand high-reliability component qualification.

MIL-STD-202 governs component-level testing. MIL-STD-810 governs system-level environmental engineering. Many MIL-STD-810 test plans rely on components that have already been qualified to relevant MIL-STD-202 methods, and many commercial high-reliability programmes (avionics, automotive, industrial) use MIL-STD-202 methods even when the end product is qualified to a non-military standard.

Scope

MIL-STD-202 is structured as a method library. Each method specifies a single test (or related family of tests) applied to electronic component parts, with defined test conditions, severity options, equipment requirements and acceptance procedures. The standard does not specify which methods apply to which component — that selection comes from the component specification, the procurement document or the qualification programme.

The method numbering scheme groups tests by category:

• 100 series — Environmental tests
• 200 series — Physical characteristics tests
• 300 series — Electrical characteristics tests

This page focuses on the methods most frequently encountered in environmental and mechanical qualification — the 100 and 200 series.

Test methods

100 series — environmental tests

Method 101 — Salt atmosphere (corrosion)

• Purpose: Determine the resistance of component finishes, terminals and structural elements to corrosion in salt-laden atmospheres
• Procedure: Component exposed to continuous salt fog under controlled temperature and concentration for the specified duration
• Test conditions: 5% NaCl solution by mass, 35 °C ± 1.4 °C chamber, atomized fog at pH 6.5 to 7.2; typical exposure 24 / 48 / 96 / 240 / 504 h per severity (MIL-STD-202 Method 101).
• Application: Connectors, terminals, exposed metal surfaces in marine or coastal applications

Method 103 — Humidity (steady state)

• Purpose: Evaluate the ability of components to maintain electrical and mechanical properties under prolonged exposure to high humidity
• Procedure: Steady high temperature and high relative humidity exposure for the specified duration
• Application: All electronic components for which moisture absorption, surface leakage or galvanic corrosion is a concern

Method 105 — Barometric pressure (reduced)

• Purpose: Verify component performance under reduced atmospheric pressure encountered at altitude
• Procedure: Pressure chamber with controlled reduction to specified low pressure; functional verification during and after exposure
• Application: Components in unpressurised aerospace bays, high-altitude vehicles, missile systems

Method 106 — Moisture resistance

• Purpose: Combined thermal-humidity cycling stress for accelerated revelation of moisture-related failure modes
• Procedure: Cyclic exposure alternating high humidity at high temperature with low-temperature phases over multiple days

Method 107 — Thermal shock

• Purpose: Test the ability of components to withstand rapid transitions between hot and cold extremes
• Procedure: Two-chamber transfer test (or liquid-to-liquid) with specified high and low temperatures, transfer time and number of cycles
• Application: Components subjected to rapid thermal transients in operation or environmental qualification

Method 108 — Life (at elevated ambient temperature)

• Purpose: Accelerated life testing under elevated temperature to evaluate long-term reliability
• Procedure: Sustained operation at elevated temperature for the specified test duration
• Application: Lifetime qualification, screening for early failures

200 series — physical and mechanical tests

Method 201 — Vibration (sinusoidal)

• Purpose: Determine component response to single-frequency vibration along defined axes
• Procedure: Sweep or dwell at specified frequencies and amplitudes; three orthogonal axes
• Application: Components mounted on vibrating platforms; airborne, vehicle and shipborne applications

Method 204 — Vibration (high frequency)

• Purpose: Higher-frequency sinusoidal vibration than Method 201; covers ranges relevant to specific platform classes

Method 207 — Random drop

• Purpose: Simulate the rough handling that components experience during shipping and field service

Method 213 — Shock (specified pulse)

• Purpose: Test resistance to single mechanical shock pulses
• Procedure: Specified pulse shape (half-sine, sawtooth or trapezoidal), peak acceleration and pulse duration along orthogonal axes
• Application: Drop shock, impact events, transport shock

Method 215 — Random vibration

• Purpose: Power spectral density vibration profile applied to components, more representative of operational environments than sinusoidal sweep

300 series — electrical characteristics

The 300 series covers tests such as dielectric withstanding voltage (Method 301), insulation resistance (Method 302), thermal resistance (Method 312) and similar component-level electrical evaluations. These are referenced from component specifications and qualification documents rather than environmental test plans.

Applicability

• Defense components (connectors, relays, capacitors): 101, 103, 105, 107, 108, 201, 213
• Defense / aerospace lifetime qualification: 108, 215
• Marine / shipborne electronics: 101, 103, 106
• Industrial high-reliability components: 103, 107, 108, 201, 213
• Automotive (selective use): 107, 213 in addition to AEC-Q standards
• Aerospace components (commercial): 107, 215 alongside DO-160 system-level

Component-level qualification under MIL-STD-202 is often a precondition for system-level acceptance under MIL-STD-810 or RTCA DO-160 — the system test programme relies on the assumption that internal components have already demonstrated baseline robustness.

Related standards

• MIL-STD-810 — System-level environmental engineering; references MIL-STD-202 for component-level qualification of internal parts
• MIL-STD-883 — Test methods for microelectronic devices (the equivalent of MIL-STD-202 for ICs)
• MIL-STD-750 — Test methods for discrete semiconductor devices
• MIL-STD-1344 — Test methods for electrical connectors (overlaps with several MIL-STD-202 methods)
• EIA-364 — Electrical connector and socket test procedures (commercial counterpart, often referenced alongside or instead of MIL-STD-202)
• JEDEC standards — IC reliability test methods that adapt MIL-STD-202 concepts for commercial semiconductor industry
• IEC 60068-2 — International equivalent for many environmental test methods; less prescriptive for component-level qualification

Engineering implications

MIL-STD-202 compliance for components is typically a programme-level requirement: the prime contractor specifies the methods and severity levels in the component qualification document, and component suppliers demonstrate compliance through dedicated test campaigns. Three programme-level decisions drive test scope:

• Method selection — which subset of the 100/200/300 series applies to the component class; many programmes use a tailored subset rather than full battery
• Severity selection — within each method, severity levels are chosen to match the platform environment (e.g. avionics altitude vs ground-vehicle dust)
• Sample size and acceptance — number of samples tested, allowed failure rate, treatment of marginal results

For component manufacturers, maintaining a current MIL-STD-202 qualification on key part numbers significantly shortens the certification cycle for defense and high-reliability programmes that reference those qualifications.