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Full text of "NASA Technical Reports Server (NTRS) 19620001224: THE TIROS SATELLITES"

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By W. G. Stroud, Chief, Aeronomy and Meteorology Division, Goddard Space Flight Center, National 

Aeronautics and Space Administration 

This Workshop provides the opportunity to 
evaluate the performance of the Tiros meteoro- 
logical satellite system as part of the NASA 
studies of the atmosphere and its motions. In 
addition, the three satellites launched have 
varied in degree of success. The usual difficul- 
ties that an experimental physicist or meteorolo- 
gist may have in conducting atmospheric experi- 
ments have been encountered. However, these 
have been exaggerated by the unusual labora- 
tory (space) in which the experiments are being 

There has been no question for some time of 
the value of meteorological satellites. But the 
technology of the launch vehicles, the telemetry 
problem, that is, the problem of communicating 
the data from the satellite to the ground, and 
all the other practical considerations, including 
funds, have only recently permitted the reali- 
zation of the desires of meteorologists and geo- 
physicists iu bring (lie entire earth under 

The point of view taken by NASA is that 
Tiros represents a series of experiments rather 
than a purely operational tool or the final an- 
swer in the problem of making measurements 
from outside the atmosphere. A close analysis 
of the infrared and reflected solar radiation 
data obtained by the Tiros satellites reveals the 
experimental nature. Not only does it take 
time to receive the data from the satellite but it 

also takes time to interpret these data in terms 
of the atmospheric phenomena. 

The experimental Tiros system can really be 
broken down into four major elements: The 
launch vehicle; the spacecraft or satellite; the 
data acquisition, that is, the problems of acquir- 
ing the data from the satellite by the ground 
stations; and the data utilization, that is, the 
procedures by which the data are used. This 
paper is concerned with only the first three of 
these elements. 

The launch vehicle. — The Thor-Delta used to 
launch the satellite is a three-stage vehicle: 
liquid, liquid, and solid; that is, the first two 
stages are liquid and the third stage is solid. It 
has been used to launch Tiros I, II, and III. 
The Tiros I launch vehicle was slightly differ- 
ent in terms of guidance and sequencing, but it 
had the same propulsive units. These three 
vehicles have placed the satellites in nominally 

ods and roughly 48° inclination. This means 
that the satellite latitude excursion is between 
48° north and 48° south latitudes, correspond- 
ing roughly to the limits of the globe brought 
under observation. 

Figure 10-1 shows the Thor booster being 
inserted in the launch stand prior to the launch- 
ing of Tiros II. The first-stage Thor has a 
thrust of about 150,000 pounds. It is interest- 
ing that the Thor vehicle used to launch Tiros I 


Figure 10-1. Placement of the Thor booster on the 
launch stand for the Tiros II launch from Cape 

was extensively used as a training vehicle by 
the military services; finally, it was obtained 
by NASA and modified to the form used for the 
Tiros launches. This modified Thor success- 
fully performed in the launch of the Tiros I 
satellite itself. 

Figure 10-2 shows the vehicle on the launch 
stand. The launch vehicle stands about 90 feet 
high, it is about 8 feet in diameter, and at lift- 
off it weighs a little over 100,000 pounds. An 
impressive feature of the launch vehicle is the 
rate at which it consumes oxygen. It consumes 
oxygen during the boost phase at the same rate 
as about 6 million people. 

Table 10-1 summarizes the satellite orbital 

Figure 10-2. The Thor-Delta launch vehicle standing 
ready for launch in the early morning of November 
23, 1960. 

parameters resulting from the successful 
launch- vehicle performances : 

Table 10-1. — Orbit Information 

Tiros I 

Tiros II 

Tiros III 

Period, min _ . 

99. 24 

98. 26 
420 (676) 
451. 5 (726) 
387. 8 (624) 
0. 00727 
48. 530 

100. 4 
475 (760) 
509. 8 (820) 
457. 1 (736) 
0. 00593 
47. 898 

Average height, statute miles (km) 

Apogee, statute miles (km) _ 

450 (720) 
461. 3 (740) 
436. 0 (702) 
0. 00287 
48. 392 

Perigee, statute miles (km) _ 

Eccentricity. _ _ . 

Inclination, deg _ _ _ _ . 


The spacecraft. — Figure 10-3 shows a familiar weighs about 280 pounds and contains a vast 
view of the satellite which is 42 inches in diam- complex of optical, sensory, electronic, mag- 

eter and about 19 inches high. The satellite netic, and mechanical devices that serve the 

Figure 10-3. The Tiros satellite in the Tiros III configuration showing the base plate with cameras looking 

downward. The top is covered with solar cells. 

following functions : to detect, to store, and to 
transmit the data; to control the various func- 
tions; to provide memory (a clock) inside the 
satellite; to control the spin rate of the satel- 
lite because it is spin stabilized; to control the 
power; and to control the attitude to a certain 
extent. The attitude of the Tiros satellite is 
the most critical problem. 

Figure 10-4 shows a top view of the internal 
package. The main interest here is in the sen- 
sor systems. The tops of the television cameras 
can be seen in the figure: two wide-angle tele- 
vision systems (Nos. 5 and 30) and one of the 
big tape recorders (Nos. 3 and 19) on which 
the picture information is stored. The infra- 
red radiation system (No. 12) and instruments