Flight 90: Released from Alamogordo, New Mexico, 1502 MST, August 27, 1948
Recovered at Roswell, New Mexico
The .001", 20-foot polyethylene balloon used on this flight was released
in mid-afternoon to provide a test of the sunset effect on a balloon supported
by the automatic ballast valve.
From the height-time curve, Figure 40, it may be seen that the balloon
had attained a floating altitude shortly before the sunset and that the
action of the automatic ballast valve was sufficient to restore the buoyancy
[figure]
Figure 40
and cause the balloon to again reach a floating condition. The difference be-
tween the two floating levels may be explained by a consideration of the auto-
matic ballast valve and the minimum-pressure switch which was used to seal
off its aneroid capsule. Since the balloon had not fallen far enough to permit
the switch to seal off the valve before sunset, this action was accomplished
-48-