TEMPERATURES AND PRESSURES IN THE UPPER ATMOSPHERE 
where J is the average molecular weight of the air, R 
is the universal gas constant, g the acceleration of 
gravity, 7 the absolute temperature of the air, h the 
altitude, and p the measured pressure. Temperatures 
can also be calculated from the stagnation pressure at 
the nose, using the following simplification of Rayleigh’s 
formula for supersonic speeds: 
stagnation pressure 
ambient pressure 
= coo dl AG ae ToD) ae of ey 
speed of sound 
and using the known speed of the rocket to obtain the 
local speed of sound. Once the speed of sound is known, 
the temperature is quickly deduced. 
1.0 
0.8 
0.6 
(CVs 
Nae 
(6)° 
PRESSURE (MM HG) 
9 
©) © 
() = 
0.06 
0,04 
0.03 
0.02 
45 50 55 60 
65 10 
ALTITUDE (KM) 
75 
Fic. 6.—Pressures obtained from rocket flights above White 
Sands Proving Ground, New Mexico. Except for the point at 
61.3 km which is 0.17 + 0.03 mm of Hg, the data are probably 
correct to within 10 per cent of ambient. The flights are: 
(1) 10 October 1946, 1102 MST; (2) 7 March 1947, 1123 MST; 
(3) 22 January 1948, 1313 MST; (4) 5 August 1948, 1837 MST: 
(5) 28 January 1949, 1020 MST; (6) 3 May 1949, 0914 MST 
(taken from [10]). 
Three types of gages were employed in making 
rocket pressure measurements. For pressures down to 
50 mm of Hg, bellows gages were used. Pirani-type 
gages measured pressures in the interval from 2 mm 
to7 X 10-* mm of Hg. Philips gages were employed for 
the range from 10-? down to 10° mm of Hg. Un- 
fortunately there is a gap between the ranges covered 
by the bellows and Pirani gages, and this gap exists 
in the data obtained so far. Moreover, the Philips gage 
measurements were not too accurate in their range, 
partly because of peculiarities of the gage, and partly 
307 
because of the behavior of the rocket. At altitudes 
above 80 km the rocket pressure measurements were 
influenced to varying extents by motions of the missile 
and by emission of gas from the interior and surface of 
the rocket. Because of differences in missile behavior, it 
was necessary to make separate estimates for each 
rocket of the errors introduced by pitching and yawing. 
In many cases emission of gas placed an upper limit on 
the altitude to which pressures could be measured. 
Recently a new type gage invented by R. J. Havens 
[11] has been introduced into the rocket work. With 
this gage it should be possible in the future to cover 
the entire pressure range up to 150 km or more. 
Pressure and temperature data accumulated by R. 
J. Havens and his colleagues at White Sands during 
the past several years are shown in Figs. 6, 7, and 8. 
PRESSURE (MM HG) 
10) 20 
40 60 80 100 
ALTITUDE (KM) 
Fre. 7.—Pressures obtained from rocket flights above White 
Sands Proving Ground, New Mexico. The point at 82.4 km is 
0.007 + 0.002 mm of Hg and that at 61.3 kmis 0.17 + 0.03 mm of 
Hg. These were taken at the top of the rocket flight and 
pressure was therefore ambient within the error of the measure- 
ment. All other data up to 80 km are probably within 10 per 
cent of ambient. Data obtained above 90 km are not ambient 
due to the yaw of the rocket and the location of the gages. 
It is estimated that they are within a factor of two from am- 
bient. (1) 7 March 1947, 1123 MST; (2) 22 January 1948, 1313 
MST; (3) 3 May 1949, 0914 MST; (4) 28 January 1949, 1020 
MST (taken from [10]). 
120 140 
The temperatures are based on the assumption of sea- 
level composition throughout. 
Some of the differences in the pressure curves of Fig. 
6 could be due to seasonal and diurnal changes, and 
possibly to variations in solar conditions. The same is 
true of the temperature curves of Fig. 8. In the latter 
case, however, the differences are harder to pin down 
