In this subsection, we mainly investigate the stability of satellite networks versus the main optimization variables (i.e., orbital height, inclination and the number of

orbital planes).

The thrust imposed on the base satellite always remains in the

orbital plane. In practical engineering, the value of thrust F is within the range of 100mN~10N and the specific impulse [I.sub.s] is in the range of 300s~400s.

The meaning and role of Keplerian elements Symbol Meaning Role [a.sub.s] Semimajor axis Define the size and shape of [e.sub.s] Eccentricity the trajectory [OMEGA] Longitude of the Define the orientation of the ascending node

orbital plane. i Inclination [[omega].sub.s] Argument of periapsis Define the angle between the ascending node and the periapsis.

In order that the control method of deployment could be conveyed conveniently with the generalized coordinates, the descriptive parameters of tether, that is, [l.sub.k] representing the length of kth tether, [[theta].sub.k] depicting the librational angle from local vertical in

orbital plane, and [[phi].sub.k] meaning the out-of-plane angle, are chosen to develop the dynamics model of the system.

The satellites used for IERS (International Earth Rotation and Reference Systems Service) applications are known as LAGEOS-1 and LAGEOS-2 which were launched in 1976 and 1992, respectively, with an altitude of 5900 km but in different

orbital planes. They both used fused silica glass cube-corner retroreflectors.

Many authors studied the motion of satellites that are close to the Earth with inclination near the critical value [26-29], which is a value for the inclination between the

orbital planes of the perturbing and the perturbed bodies, such that any near-circular orbit with inclination below this value remains near circular.

An asset without ORS hardware that continuously thrusts with an electric engine over a seven-day period can sufficiently change its velocity within the same

orbital plane to produce a 24-hour TOT change by modifying the ground track.

Objects in this region have highly eccentric orbits and are often wildly inclined to the

orbital plane of the major planets.

The pieces have remained in the

orbital plane of each satellite but are spreading out in altitude.

The

orbital plane, although fixed in space, can be arbitrarily oriented with respect to whatever reference plane is chosen (such as Earth's

orbital plane about the Sun, which is called the ecliptic, or the equator of the primary).

The right ascension of the ascending node [OMEGA], the inclination of the

orbital plane I, and the arguments of declination [u.sub.1] and [u.sub.2] from the equations

Venus'

orbital plane is inclined with respect to Earth's

orbital plane (which is called "the plane of the ecliptic").