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|  MIL-D-70789A (AR)
listed in Table 501.2-I of MIL-STD-810 (omit humidity cycle).
The operating test duration shall be a minimum of 72 hours and
simulated survey missions shall be performed whenever the chamber
temperature is +140F or lower (see 3.7.1.1 & 3.7.1.3).
4.8.5.5 LOW temperature. Low temperature tests shall be
performed on the DRU in accordance with MIL-STD-810, Method
502.2, Procedures I and II. Procedure I (storage) test duration
shall be a minimum of 72 hours at a stabilized temperature of
-60F. Procedure II (operational) shall include a 24 hour
nonoperational cold soak at -60F, followed by temperature
stabilization at -50F for a 6-hour simulated DRU survey mission
(See 3.7.1-1 & 3.7.1.3).
4.8.5.6 Tempurature shock. Temperature shock tests shall
be performed on the DRU in accordance with MIL-STD-810, Method
0
0
0
0
503.2, between the limits of -60 F (-51 C) and +160 F (+71 C).
The DRU shall meet the requirements of 3.7.1.2.
4.8.5.7 Solar radiation. Solar Radiation tests shall be
performed on the DRU in accordance with MIL-STD-810, Method
505.2, Procedure I and paragraph 3.7.6 using the HOT-DRY diurnal
cycle. Perform a 6 hour simulated survey mission at the peak
temperature for each of the three diurnal cycles.
4.8.5.8
Humidity.
Humidity tests shall be performed on the
DRU in accordance with MIL-STD-810, Method 507.2, Procedure III
and 3.7.3. In the last hour of the fifth and tenth cycles, while
maintaining current chamber conditions, perform a simulated
survey mission.
4.8.5.9
Snow. A snow test shall be performed using a
suitable environmental chamber or climatic test area to show that
the DRU operates in snow in accordance with 3.7.4. Perform a
simulated survey mission during the last hour of the test.
4.8.5.10
Icing.
An Icing/Freezing Rain test shall be
performed on the DRU in accordance with MIL-STD-810, Method 521.0
to prove that the DRU operates correctly when exposed to the
Icing Conditions specified in 3.7.5. Perform a simulated survey
mission during the last hour of the test.
4.8.5.11
Washdown. The DRU shall not be damaged nor leak
when exposed to a water stream from a 1-inch diameter nozzle fed
by a pressure of 50 + 5 pounds per square inch for a period of 30
minutes. The stream shall be directed onto each face, except the
DRU mounting surface, of the DRU from a distance of 3 feet, for
equal periods. At the start of the test the DRU temperature
shall be at least 10C (18F) higher than the water temperature.
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