Daily Image
14-10-2009
DARIS 5-Star satellite configuration : Relative Orbits
| Submitter: | Raj Thilak Rajan, Albert Jan Boonstra on behalf of the DARIS Team |
| Description: | DARIS is Distributed Aperture array for Radio Astronomy In Space, an ESA study project in which ASTRON, EADS ASTRIUM, Radbound University Nijmegen, and ALTRAN participate. The primary aim of DARIS is to investigate the feasibility of positioning a cluster of satellites in space for low frequency radio observations below 30 MHz. The team is doing preliminary studies on configurations, architectures, signal processing, communication and space expedient aspects; all of which is driven by the science cases proposed at these wavelengths. The deployment location of the cluster could either be the back-side of the Moon or in-orbit around Sun, Moon or Earth. For an orbiting cluster, the relative positions of the cluster elements (uvw coverage) change over time. It is therefore necessary to model the orbital path of the (un-tethered) cluster around Moon, Earth or Sun. We have chosen independent Keplerain orbits for each of the satellites, all having the same orbital period. The Keplerian parameters for each of the satellites are tuned such that the relative satellite distances remain within the maximally allowed value of 100 km. This number is related to the desired spatial resolution of the array. The image shows the relative orbits of a cluster of 5 satellites orbiting the Sun at an average distance of 150 Million km. The initial configuration of the satellites is chosen such that no two satellite comes closer than 5 km to each other. Due to the symmetry of the configuration within the cube, the positions of the satellite tend to repeat after every half cycle. The next question is how the baselines (uvw coverage) for such a configuration will evolve over time. |
| Copyright: | ASTRON |
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