The Roswell Report: Fact vs. Fiction in the New Mexico Desert

temperature-compensate the diaphragm, the other to insulate and shield the valve from radiation.

Using the ceiling-control system, flights of less than 24 hours not passing through sunset, may be held at ceiling by use of a nonextensible balloon and a simple fixed rate of leak to over-compensate diffusion losses. The constancy of level will be better the lower the diffusion and the lower, therefore, the rate of rise of the ceiling. The automatic control is needed for flights lasting through a period in which day changes to night.

## 8. Preliminary trajectory analysis of two constant-level balloon flights, 7 July 1947 $ ^{7} $

The most striking feature of the constant-level balloon flight (Flight 11, fig. 9) originating at Alamogordo Army Air Base at $ 0 5^{h} 0 8^{m} $ MST $ ^{8} $ on 7 July 1947 is the disagreement between the actual trajectory and the trajectory that might have been estimated from routine upper-wind reports. In this connection the observations from the Weather Bureau stations at El Paso, Roswell, and Albuquerque have been examined, since the path of the balloon was contained within the triangle formed

by these stations. Over El Paso, the wind direction at 16,000 ft (the approximate average altitude of the balloon during the greater part of the flight) was approximately SW at $ 0 3^{\mathrm{h}} $ , ESE at $ 0 9^{\mathrm{h}} $ , and ESE at $ 1 5^{\mathrm{h}} $ . Over Roswell, the apparent average wind direction at 16,000 ft was S during this period. Over Albuquerque, which was considerably farther from the path of the balloon than the other two stations, the wind direction at 16,000 ft was variable between WSW and SSE during the interval from $ 0 3^{\mathrm{h}} $ to $ 1 5^{\mathrm{h}} $ . In contrast with these observations is the fact that the constant-level balloon floated in an essentially steady WSW current between $ 0 6^{\mathrm{h}} $ and $ 0 9^{\mathrm{h}} $ .

In fig. 8 the wind observations at 16,000 ft have been plotted for El Paso, Roswell, and Albuquerque for $ 0 3^{\mathrm{h}} $ $ 0 9^{\mathrm{h}} $ , and $ 1 5^{\mathrm{h}} $ . The wind directions at 14,000 ft, 16,000 ft, and 18,000 ft (only the intermediate level is shown in the figure) are all contained in the 150-degree sector between directions $ 9 0^{\circ} $ and $ 2 4 0^{\circ} $ ; yet the mean motion of the balloon (approximately $ 2 6 5^{\circ} $ ) between $ 0 5^{\mathrm{h}} 4 8^{\mathrm{m}} $ and $ 1 3^{\mathrm{h}} 1 1^{\mathrm{m}} $ falls entirely outside this sector.

An indication that this local WSW current was of small depth is given by a special upper-wind observation made at White Sands at about $ 13^{\mathrm{h}} $ . The observation in question recorded a wind direction of $ 250^{\circ} $ at 16,000 ft, which is in excellent agreement with the first

FIG. 9. Height-distance curve and planned trajectory of balloon Flight 11. Released at Alamogordo, New Mexico, 7 July 1947, at 0508 MST. (Numerals on curves indicate minutes after release.)