In this study, we have developed a navigation scheme for a swarm of satellites
equipped with both
electrostatic and conventional actuators. The main features of two new concepts
for formation
flying control i.e. electrostatic actuation, used for active control of
spacecraft charging for
relative position control and equilibrium shaping, which is a behavior based
swarm navigation
technique are highlighted in this study. The work described in this report is
divided into two
main sections.
In the first section, the propulsion system is investigated. The GEO region is
selected for this
study since, the Debye length is sufficiently high in this region and a model
of the interaction
between plasma and a charged spacecraft is derived. On the basis of this result
the requirements
for the hybrid propulsion system are defined and a new charge control strategy
with two currents
i.e. charging and stabilizing current is proposed. The stabilizing current Ist
counteracts
the natural environmental currents and drive the spacecraft potential toward
zero and charging
current is emitted with the acceleration voltage of desired potential level and
drives the spacecraft
to desired potential level in certain range. The candidate propulsion system
consists of a
radio frequency ion thruster engine (RIT) and an electron gun for emission of
charges from the
spacecraft.
In the second phase of the study the applicability of the electrostatic
actuation for formation
keeping and reconfiguration of swarms of satellites is considered. The recently
developed equilibrium
shaping navigation technique has been selected to control the maneuvers of the
swarm.
There is a specified set of formations that can be acquired in an autonomous
way by means
of the ES technique and a specified set of formation can be maintained only
relying upon the
EA concept. The compatible formations are those that can be acquired
autonomously relying
upon the ES path planning scheme and maintained using only the EA. These
formations enjoy
both a high level of autonomy, ensured by the equilibrium shaping, and high
fuel efficiency,
provided by the electrostatic actuation. Exploiting the results on the
compatibility, the electrostatic
i...
