Page 15 - Intro to Space Sciences Spacecraft Applications

2 Introduction to Space Sciences and Spacecraft Applications

on interplanetary craft, allow a clearer look at the universe of which we
are such a small part, giving us a better understanding of where we have
been and what the future may hold.
The need for advanced global communication capabilities caused many
to look toward space as an alternative to earlier methods. As early as the
1940s, science writer Arthur C. Clarke hypothesized that a platform
placed at a particular location in space (where it would appear motionless
with respect to the ground) could be used as a communications relay sta-
tion. A multitude of such systems exist today, and the resulting real-time,
global availability of information has transformed the news, entertain-
ment, and communications industries and has had a major impact on polit-
ical and military operations as well.
When the first artificial satellite, the Soviet Union’s Sputnik I, began
circling the globe, U.S. scientists discovered a method for using the sig-
nals transmitted by the satellite to accurately determine one’s position
anywhere on the earth. Satellite navigation is now employed by military,
government, private, and commercial users for positioning and surveying
on land as well as for aircraft and ship navigation.
When man himself ventured into space, many benefits resulted as by-
products of the developments in technology required to support these mis-
sions. Astronauts conducted experiments that proved that the unique envi-
ronment of space offered many useful possibilities. In microgravity

Figure 1-1. Sputnik (left) and Explorer (rightethe first satellites launched by
the Soviet Union and the United States, respectively.