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|  MIL-F -l4252 ( AR )
the ambient temperature maintained at plus 51C (}125F) , and
the equipment subjected to this radiation for a period of 4 hours.
The equipment shall then be placed in operation and shall be
capable of meeting the specified requirements of the detail speci-
fication e
4.3.2.3 Procedure III - Transient effect, solar radiation.-
The purpose or this test is to determine t he transient th ermal
effects due to solar radiationo The equipment is subjected to
a controlled ambient temperature conforming to condition E or G
of Table XVI as specified. 360 Btu\sq-ft\hr of solar radiation 11
is introduced at the top surface of the equipment until tempera-
ture distribution In the equipment is stabilized 2/. The tests
shall be wade at periodic intervals after subjection to solar
radiaticn as specified in the detail specification.
4.3.3 Temperature cycling
4.3.3.1 Procedure I - Operational test.- The equipment shall be
0
conditioned in an air tem erature of minus 62C (-80 F) for a
period of 3 days. The air temperature shall then be raised 3/
tc a value conforming to the specified condition of Table XVI
until thermal stabilization 2 of the equipment Is reached at
which time the equipment shal4 1 be visually examined in accordance
with 4.2.3, operated at specified conditions, and the results
compared with data obtained in 4.2.2. The temperature of the
0
0
air shall then be raised to plus 71 C (\160 F) until thermal
stabilization is reached by the equipment and allowed to remain
at that temperature for a period of 4 hours. The air temperature
shall then be reduced to plus ~lC (\125F) until thermal stabili-
zation of the equipment is reached. Solar radiation 1/ of in-
tensity of 360 Btu/sq-ft /hr shall then be introduced at the top
surface of 0the equipment with the ambient temperature maintained
at plus 51 C (/l25W), and the equipment subjected to this radia-
tion for a period of 4 hours. The equipment shall then be placed
in operaticn and shall be capable of meeting the performance re-
quiarments of the detail specification. This cycle shall be re -
o
peated 5 times or as specified in the detail specification.
1 / .o1 ar radiation shall ccnsist of 5O-60 percent of the total
S
energy in wavelengths above
7 6O O A and 45.6.o percent. in
wavelengths below 3800 A and the balance in visible light.
2/ Thermal stabilizaticm has been reached when the temperature
of the largest internal mass centrally located of the equip-
0
ment does not vary more than l from the ambient temperature.
3/ Start of cycle.
.
51
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