Environmental Engineering Reference
In-Depth Information
9
Autonomy in Spacecraft Constellations
In this chapter, we discuss the application of the autonomy technologies con-
sidered in previous chapters to spacecraft constellations. The needs of constel-
lations that can be supported by onboard autonomy are described along with
the enhancements attainable by constellation missions through the applica-
tion of onboard autonomy. A list of hypothetical constellation mission types
is also posed and a list of governance concepts is then presented in relation to
the degree of central control being exercised on the constellation. Finally, the
chapter discusses mobile agent concepts to support autonomic constellations.
9.1 Introduction
As described in Chap.
7
, spacecraft constellations are organized into virtual
platforms that appear as a single entity to the ground. They are often flown
in formation so that different spacecraft can view science phenomena from
a different perspective, or view contiguous areas at the same time. Simple
constellations are groups of identical spacecraft that coordinate their data
collection and merge the collected data to create a more complete view of the
science. Complex constellations are heterogeneous mixes of unlike spacecraft.
They share the characteristics of simple constellations, but may comprise dif-
ferent types of spacecraft and/or have different instruments. These differences
in spacecraft and instruments make the resulting data fusion more dicult,
but allows richer sets of science data to be collected. This configuration also
allows older, preexisting spacecraft to be used in new ways not thought of by
the original designers of the spacecraft [
26
].
An example of a NASA constellation is the ST5 mission. The ST5 mission
[
171
], launched in March 2006, has three identical spacecraft that fly in a
“string of pearls” formation (Fig.
1.1
), utilizing a single uplink/downlink to
the ground station.
