Orbital Constellations for Multimedia Satellite Communications Systems Serving Europe
- Paper number
IAC-07-B2.6.02
- Author
Mr. John Draim, United States
- Coauthor
Dr. Paul J. Cefola, Massachussets Institute of Technology (MIT), United States
- Coauthor
Dr. Erick Lansard, Thales Alenia Space, France
- Coauthor
Mr. Jean-Didier Gayrard, Thales Alenia Space, France
- Year
2007
- Abstract
This paper compares a variety of satellite constellation types for possible future multimedia communications systems serving European customers. Included in the systems studied are several Walker type constellations (both circular and elliptical), sun-synchronous arrays capable of matching day-night usage patterns, and a four-satellite 4.8-hour prograde elliptical system. The altitude ranges of these systems include the Low-Earth Orbit (LEO) arrays, LEO Elliptical arrays (LEO E), High Elliptical Orbit (HEO) arrays, Medium Earth Orbit (MEO) arrays, Geostationary (GEO single and dual satellite) arrays, and several geosynchronous elliptical (Tundra) arrays with varying degrees of eccentricity. A minimum elevation angle limit of 10 degrees has been used to ensure satellite visibility from the European region. The latitude range for European coverage has been set from 35 degrees North latitude through 70 degrees North latitude. Zonal coverage of this latitude band can be effectively achieved using elliptical orbit constellations. A major advantage of using elliptical arrays over circular arrays is that extra Northern Hemisphere coverage can be provided by placing the perigees in the Southern Hemisphere. Essentially, coverage is being ‘stolen’ from the SH to benefit the coverage in the NH region. Another type of orbit; the elliptical sun-synchronous retrograde orbit; is shown to be useful as a building block for constellations having a desirable day vs night coverage bias. That is, there is a higher degree of coverage provided during daylight and early evening hours, than later at night when businesses are closed and people are sleeping. A recent 2003 study on establishing an orbital figure of merit (FOM) for coverage of a geographic point is described, and its extension to a regional FOM is discussed. This non-dimensional FOM includes the Delta V necessary to reach the orbit in question and the total daily time of coverage of a point or region on the earth’s surface. Advantages and disadvantages for the various types of constellations are discussed. A preliminary set of conclusions is presented, for the purpose of identifying those constellation types that appear to be most promising, and worthy of further study and development.
- Abstract document
- Manuscript document
IAC-07-B2.6.02.pdf (🔒 authorized access only).
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