Astronaut Scientific Debriefings, 1962-1963

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112
MAURICE DUBIN
Since the velocity distribution of meteors is over the range from 10 to 70
km/sec, for the purpose of computation an average velocity of 40 km/sec was used.
Pmax and nm.a.--.. were determined accordingly.
From equation (1) and WATSON'S (1941) estimate for the number and size
distribution of meteors entering the earth's atmosphere Table I was computed.
The computation has been made for three altitudes, 85 km, 100 km, and 115 km,
using the following rocket pressures:
Altitude (km)
I Pressure (mm.of Hg)
Number density of
air molecules (cm- •)
85
4 X l0- 3
1014
100
4 X l0- •
10l3
115
4 X 10- 5
1012
Thus equation (1) becomes
7 X 1023
9
(
1
p
)2
n = 4 X 4 X 10- 2pra}
1
3 4 X 10- 2r 00
2
= 1.6 x l021
2 ( 1 -
l
) •
n115
r 00
3 X 103
00
r
The number of electrons per cm of path becomes, from HERLOFSO
(1948),
n X 10- 2
n X 10- s
n. cm-1 = ---­ ­
v
4
From Table I it is evident that the number of electrons for a shell of 1 cm
thickness over the surface of the earth, resulting from meteors, is 1020 electrons
per day at 85 km produced mainly from meteors of visual magnitudes 1 to 4,
about 1020 electrons per day at 100 km with the major contribution for visual
magnitudes 6 to 15, and again about 1020 electrons per day at 115 km from mag.
7 to 20. The number of electrons produced per cm of path per cm2 per sec at these
three altitudes is thus 1020/ ( 4 . 4 x 1023 ) = 2 x 10- 4 electrons per cm 3 per
second.
Now according to HERLOFSON, the kinetic energy of a typical meteor is divided
in the ratio 104 : 102 : 1 for the production of heat, light, and ionization, respec­
tively. These values were used in the computation of Table I. However, from