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Spacecraft Constellations and Formations

Flower Constellations

King Defence Formation

The Flower Constellation Set is an infinite set of possible constellation designs based upon a particular formulation. This set of constellations was originally conceived as a constellation of satellites that all have the same repeating ground track. However, what we discovered is that these constellations can be arbitrarily oriented.

For More Information Visit flower constellation homepage >>

Faculty Investigator : Dr. Daniele Mortari

Formation Flight

Our faculty are internationally renowned for their contributions to the area of spacecraft formation flight, Modeling and Control of Distributed Space Systems (DSS) useful for interferometric applications is one of the projects currently being pursued in this area. Control laws have been developed by our faculty, for translation/attitude maneuvers of DSS. Simulations of the DSS, placed in a halo orbit about the L2 libration point of the Sun-Earth/Moon elliptic restricted three-body problem are presented in the following videos. The control laws not only orient individual satellites towards a master satellite, but move the entire DSS as a rigid body (slewing maneuvers). In the first case, the control laws are suitable for pointing to a target fixed in inertial space, consequently, it rotates in the LVLH frame attached to the Sun-Earth/Moon line. In the second case, the control law is suitable for pointing in the local frame

 

Video1 of Spacecraft Formation Simulations (Inertial Frame) >>

Video2 of Spacecraft Formation Simulations (LVLH Frame) >>

 

Graphic1
This image shows a configuration space projection of the stable invariant manifold for a halo orbit, associated with the circular restricted three-body problem (in this case, the Sun-Earth/Moon system). This manifold may be used to design trajectories that transfer a spacecraft from regions near the smaller primary (for example, the Earth) to a halo orbit around the libration points (in this case, the L2 point). Research on this project was funded by NASA GSFC
Cost Plot
This image shows the variation of fuel cost for optimal rendezvous using power-limited propulsion devices, near orbits around a single gravitational body, such as the Earth. Our Faculty team lead by Dr. Vadali, has developed analytical solutions to the rendezvous problem near orbits with arbitrary eccentricity, which allow one to obtain figures such as these, without computationally intensive numerical integration and solutions to two-point boundary value problems. Literature has already established the existence of various locations where rendezvous can be minimized, and that cost for rendezvous shows a tendency to decrease as time elapsed (f_T-f_0) increases, but for circular orbits (e=0). New results show the existence of newer minima, as a result of pitchfork bifurcation.
Faculty Investigators: Dr. Srinivas R. Vadali, Dr. Kyle T. Alfriend.

 

 



 


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