maximum depth. Conversely, range and endurance 
can be increased by changing to a glide angle 
of about 10 degrees which will result ina 
velocity of avout 5 knots. 
Variations in mission profile could be ob- 
tained in future vehicles by addition of a 
simple heading control system. Before launch, 
the desired mission profile could be programmed 
into the heading control system, allowing the 
vehicie to perform circular, zigzag, or other 
maneuvers while gathering oceanographic data. 
CONCLUSIONS 
It is believed that the Porpoise concept 
offers a unique and effective method of ob- 
taining oceanographic data. The vehicle size 
for most instrumentation payloads is small 
enough to be operated from existing oceanographic 
vessels. A vessel operating several Porpoise 
vehicles while also taking oceanographic data 
using the shipboard equipment would be able to 
collect data from large areas of the ocean 
simultaneously. In addition, utilizing a fuel 
such as ethylene oxide should make operating 
costs reasonable, and the simplicity of the 
vehicle inherently should provide high relia- 
bility and long life. 
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