Design considerations in rapid-revisit small satellite constellations

Paper number

IAC-17,B4,4,6,x40353

Author

Mrs. Rachel Bird, Surrey Satellite Technology Ltd (SSTL), United Kingdom

Coauthor

Mr. Christopher Saunders, SSTL, United Kingdom

Coauthor

Mr. Alex da Silva Curiel, Surrey Satellite Technology Ltd (SSTL), United Kingdom

Coauthor

Prof. Martin Sweeting, Surrey Satellite Technology Ltd (SSTL), United Kingdom

Coauthor

Mr. Luis Gomes, Surrey Satellite Technology Ltd (SSTL), United Kingdom

Year

2017

Abstract

Earth observation satellites provide an invaluable supply of imagery for a range of applications. However most current systems consist of a single satellite, or a small constellation, which imposes a number of limitations including restricted coverage and limited revisit. The common use of sun-synchronous orbits for optical imaging satellites also means that passes are highly predictable and limited to a narrow time band each day.

A moderately sized constellation of small, low cost optical satellites, providing high resolution imagery and operating in a low inclination orbit in multiple planes, can provide frequent imaging to key areas of interest throughout the day allowing information updates with timeliness of the order of minutes. Coupled with a supporting ground and communications architecture which maximises the responsiveness of the system (minimising the total latency from image tasking to product delivery) enables applications including tracking and monitoring, change detection, pattern of life assessments and support to humanitarian or disaster operations.

Even a modest constellation (i.e. less than 50 satellites) requires the satellite design to be optimised such that manufacturing and testing processes can be highly automated allowing each satellite to be produced within days or weeks. This opens up the possibility of more ambitiously sized systems akin to the Megaconstellations currently under development for communications applications. Such constellations for Earth observation offer the possibilities of multiple sensor types or novel imaging techniques, such as multistatic RF imaging, and autonomous operations such as self-tasking via inter-satellite links.

The use of small, low cost satellites and the near term availability of low cost launch vehicles, also provides the possibility of responsive launches to target coverage over a specific area of interest (e.g. in the event of a disaster or humanitarian crisis). An alternative concept envisages a modest sized constellation which has the capability to be reconfigured on orbit, through re-positioning of the individual satellites in the constellation, requiring the use of efficient propulsion systems and manoeuvre regimes.

This paper presents the benefits and issues associated with deploying and operating a constellation of imaging satellites and describes several viable design concepts, including a Rapid Revisit Constellation, consisting of high resolution optical imaging satellites providing a GSD of around 1 m, designed to be quickly manufactured at a low cost, and able to provide extremely high revisit rates over key target areas. The paper also discusses the potential exciting applications and utility of constellations of the future.

Abstract document

IAC-17,B4,4,6,x40353.brief.pdf

Manuscript document

IAC-17,B4,4,6,x40353.pdf (🔒 authorized access only).

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