DDA2001, April2001
Session 8. Unnatrual Things
Tuesday, 3:20-4:50pm

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[8.02] Celestial Mechanics Aspects of Formation Flying Satellites

K.T. Alfriend, S.R. Vadali (Texas A&M University), H. Schaub (Sandia National Laboratory)

A swarm of small satellites flying in formation is a concept currently being pursued by NASA and the USAF. Most of the studies for identifying potential relative motion orbits for these formations have assumed a spherical Earth. The relative motion orbits identified from this assumption result primarily from small changes in the eccentricity, e, and the inclination, i. This is satisfactory for identifying the potential relative motion orbits, but unsatisfactory for determining long term motion, fuel budgets and the best formations. Assuming all satellites in the formation are nearly identical the primary perturbation is the differential gravitational perturbation due to the Earth’s oblateness, J2. Since the differential gravity perturbations are a function of (a,e,i) the small changes in these elements result in different drift rates for each satellite and the negation of these drifts result in different fuel requirements for each satellite. Since some satellites running out of fuel before others will degrade the system performance it would be advantageous to have the satellites have equal fuel consumption.

Two subjects are discussed in this paper, a) Determination of the initial conditions that prevent relative drift of the satellites in the presence of gravitational perturbations, and b) A concept for controlling the constellation that minimizes total fuel consumption and also results in equal fuel consumption by each satellite.

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