Satellite formation flying

Satellite formation flying is the concept that multiple satellites can work together in a group to accomplish the objective of one larger, usually more expensive, satellite. [ [http://rst.gsfc.nasa.gov/Sect16/Sect16_11.html Remote Sensing tutorial] ] Coordinating smaller satellites has many benefits over single satellites including simpler designs, faster build times, cheaper replacement creating higher redundancy, unprecedented high resolution, and the ability to view research targets from multiple angles or at multiple times. These qualities make them ideal for astronomy, communications, meteorology, and environmental uses. [ [http://www.gsfc.nasa.gov/topstory/20010601eo1.html Spaceflight Now “Satellite formation flying concept becoming a reality”] ]

Types of formations

Depending on the application, there are three formations possible: trailing, cluster, and constellation. [ [http://rst.gsfc.nasa.gov/Sect16/Sect16_11.html Remote Sensing Tutorial] ]
* Trailing formations are formed by multiple satellites orbiting on the same path. They are displaced from each other at a specific distance to produce either varied viewing angles of one target or to view a target at different times. Trailing satellites are especially suited for meteorological and environmental applications such as viewing the progress of a fire, cloud formations, and making 3D views of hurricanes. Notable pairs are Landsat 7 with EO-1 (see [http://eo1.gsfc.nasa.gov/] ), CALIPSO with CloudSat, and Terra with Aqua.
* Cluster formations are formed by satellites in a dense (relatively tightly spaced) arrangement. These arrangements are best for high resolution interferometry and making maps of Earth. Example: TechSat-21.
* Constellation formations are satellites evenly dispersed to allow for simultaneous global coverage. A good example of this is the NAVSTAR program that supports GPS. NAVSTAR satellites are evenly spaced in orbit to allow communication for a GPS anywhere on Earth.

Usually, these formations are made up of numerous small satellites. A micro satellite weighs under 100kg and a nano satellite weighs under 10kg. Magnetosheric Constellation, for instance, would be composed of 100 micro satellites.(see [http://sec.gsfc.nasa.gov/roadmap_posters_mc.pdf] )

This technology has become more viable thanks to the development of autonomous flying. With an on board computer and this algorithm, satellites may autonomously position themselves into a formation. Previously, ground control would have to adjust each satellite to maintain formations. Now, satellites may arrive at and maintain formations with faster response time and have the ability to change the formation for varied resolution of observations. Also, satellites may be launched from different spacecrafts and rendezvous on a particular path. This advance was made possible by Dave Folta, John Bristow, and Dave Quinn at NASA’s Goddard Space Flight Center (GSFC). [ [http://rst.gsfc.nasa.gov/Sect16/Sect16_11.html Remote Sensing tutorial] ]

ee also

*Satellite constellation
*Fractionated Spacecraft

References

External links

* [http://wwwlegacy.cranfield.ac.uk/soe/space/flying.htm Cranfield School of Engineering - Space Research Center]
* [http://www.bnsc.gov.uk/content.aspx?nid=6068 BNSC "Formation Flying"]