Environmental Engineering Reference
In-Depth Information
1
Introduction
To explore new worlds, undertake science, and observe new phenomena, NASA
must endeavor to develop increasingly sophisticated missions. Sensitive new
instruments are constantly being developed, with ever increasing capability
of collecting large quantities of data. The new science performed often re-
quires multiple coordinating spacecraft to make simultaneous observations of
phenomena. The new missions often require ground systems that are corre-
spondingly more sophisticated. Nevertheless, the pressures to keep mission
costs and logistics manageable increase as well.
The new paradigms in spacecraft design that support the new science bring
new kinds of mission operations concepts [
165
]. The ever-present competition
for national resources and the consequent greater focus on the cost of opera-
tions have led NASA to utilize adaptive operations and move toward almost
total onboard autonomy in certain mission classes [
176
,
195
]. In NASA's new
space exploration initiative, there is emphasis on both human and robotic
exploration. Even when humans are involved in the exploration, human tend-
ing of space assets must be evaluated carefully during mission definition and
design in terms of benefit, cost, risk, and feasibility.
Risk is a major factor supporting the use of unmanned craft: the loss of hu-
man life in two notable Shuttle disasters has delayed human exploration [
160
],
and has led to a greater focus on the use of automation and robotic technolo-
gies where possible. For the foreseeable future, it is infeasible to use humans
for certain kinds of exploration, e.g., exploring the asteroid belt, for which the
concept autonomous nano technology swarm (ANTS) mission was posed -
discussed in Chap.
10
- where uncrewed miniature spacecraft explore the as-
teroid belt. A manned mission for this kind of exploration would be pro-
hibitively expensive and would pose unacceptable risks to human explorers
due to the dangers of radiation among numerous other factors.
Additionally, there are many possible missions where humans simply can-
not be utilized for a variety of reasons such as the long mission timeline
reflecting the large distances involved. The Cassini mission taking 7 years to
reach Titan, the most important of Saturn's moons, is an example. Another
