Flight 89: Released from Alamogordo, New Mexico, 1005 MST, August 26, 1948 Not recovered
On this flight a .001", 20-foot polyethylene balloon was used to carry a ballast meter to about 45,000 feet to determine the ballast requirements at that altitude, using an automatic ballast valve. No record of ballast flow was telemetered during this flight, but it is not known whether the ballast meter was inoperative or the ballast valve itself failed--possibly due to failure of a squib to detonate at the combined low pressure and cold temperatures aloft.
From the height-time curve, Figure 39, it will be noted that the balloon was in a near floating condition for about five hours after reaching its maximum altitude. The total weight available on this flight was 2 kg, so a loss of 400 grams per hour would have been required if the ballast was used during this period.
From Flights 70 and 71 we know that a balloon has remained for about four hours at slightly higher altitudes with no ballast flow to support it; Flight 89, therefore, is not necessarily an example of the action of the automatic ballast valve control.
Figure 39