There are many varied sources of satellite Earth Observation and Remote Sensing data currently in-orbit. However, in general there is a distinct lack of rapid-response data for timely application. This is particularly of value in disaster situations where the value of information rapidly falls as time progresses after the event. Micro-satellite constellations, with their low-cost and low launch costs provide a potential affordable solution to the issue of data timeliness. This researchp roject, supportedb y Surrey Satellite Technology Limited, addressesth e problem of data timeliness through the development of a solution for a micro-satellite constellation to give global daily imaging revisit opportunities at a Ground Sample Distance of 30-40m in Red, Green and Near Infra-Red bands. This thesis reviews existing Earth Observation capabilities to highlight the niche that exists for this mission. It then describes the development of the mission and spacecraft system solution as well as ground segment characteristics. The spacecraft and mission design is taken from a conceptual phase to launch and validation via in-orbit operations. This is the first micro-satellite constellation for Earth Observation, and the first microsatellite solution to addresst he rapid-responsep roblem. Research into potential applications for the image data is also presented, focussing in particular on disaster management applications. Wildfire management applications and flood monitoring are considered in most detail, whilst other potential application areas are addressed in brief. This research clearly indicates that there is much potential for the DMC imagery to add value, over and above the current available Earth Observation data sources, to a number of applications. It is noted that further work should be performed to validate the use of DMC data in any given application.

The papers contained in this Volume of Proceedings have been collected from an international Workshop entitled 'Mission Design and Implementation of Satellite Constellations' which was held in Toulouse, France, in November 1997. This Workshop represented the first international gathering of the specialists in this currently very active field of research activity. The initiative to organise a Workshop around this theme was conceived during the Congress of the International Astronautical Federation (IAF) in Beijing, China, in October 1996. On that occasion, the IAF explored concepts and possibilities for the conduct of small specialist Workshops and Symposia of current interest. Topical, interesting, and focused themes in the general field of space technology (both theories and applications) will be selected for these Symposia. They aim at offering a dedicated forum at international level for specialists and experts to exchange their views and experiences on recent and future developments within the selected theme. These specialist Workshops and Symposia supplement the comprehensive annual IAF Congresses which cover all aspects of space technology and draw a correspondingly diverse audience.

This book details key trends involving the recent formation of scores of companies that build and launch small satellites or provide key components for small satellite constellations. The applications and usage are quite diverse and include student experiments, serious scientific experimentation, and totally new types of commercial constellations, particularly in telecommunications and remote sensing. The explosive growth in the design, manufacturing, and launch of small satellites is one of the most dynamic aspects in the area of space exploration and exploitation today. New commercial space companies such as Planet Labs, Sky Box, OneWeb, and LeoSat are now building and launching thousands of small satellites and cubesats into orbit. Small companies and big aerospace companies alike are getting into this exciting and interesting new business. This is a practical guide that provides advice to students, researchers, LEO satellite companies, and regulators wrestling with some of the new challenges that small satellites present as more and more companies and countries around the world enter the new small satellite arena.

The biennial IAA Symposium on Small Satellites for Earth Observation provides a forum for scientists, engineers and managers to exchange information about planned and on-going programs and missions, and present new ideas, covering small satellite mission objectives as well as technology and management aspects for dedicated earth observation satellites. This volume presents selected contributions of the 5th IAA Symposium on Small Satellites for Earth Observation, April 4 - 8, 2005, organized by the International Academy of Astronautics (IAA), Paris, France, and hosted by the German Aerospace Center (DLR), Berlin, Germany.

Sparse military satellite constellations were designed using two methods: a traditional approach and a genetic algorithm. One of the traditional constellation designs was the Discoverer II space based radar. Discoverer II was an 8 plane, 24 satellite, Low Earth Orbit (LEO), Walker constellation designed to provide high-range resolution ground moving target indication (HRR-GMTI), synthetic aperture radar (SAR) imaging and high resolution digital terrain mapping. The traditional method designed 9-ball, 12-ball, 18-ball, and 24-ball Walker constellations. The genetic algorithm created constellations by deriving a phenotype from a triploid genotype encoding of orbital elements. The performance of both design methods were compared using a computer simulation. The fitness of each constellation was calculated using maximum gap time, maximum revisit time, and percent coverage. The goal was to determine if one design method would consistently outperform the other. The genetic algorithm offered a fitness improvement over traditional constellation design methods in all cases except the 24-ball constellation where it demonstrated comparable results. The genetic algorithm improvement over the traditional constellations increased as the number of satellites per constellation decreased. A derived equation related revisit time to the number of ship tracks maintained.

Earth observation (EO) satellites provide helpful imagery to a variety of applications ranging from weather monitoring to agricultural support. Disaster response imaging is an essential but difficult application for EO to support. Reconfigurable satellite constellations (ReCon) provide a flexible solution to the challenge of quickly providing imagery of unknown locations. ReCon leverages the natural shift of ground tracks due to the disparity between the Earth’s rotation and the period of an orbit to maneuver a constellation into repeating ground track (RGT) orbits. This maneuvering strategy relies on altitude changes to vary an orbit’s ascending node and mean anomaly, which both dictate the location of satellite’s ground track. Altitude changes require significantly less fuel than plane changes. Using ReCon allows for smaller constellations to provide high-performance imagery for disaster response for a lower cost. This work explores additional trades for consideration when developing ReCon designs. The following explores satellite image scheduling techniques to further the efficacy of an Earth observation constellation. The scheduler incorporates agile satellites to add imaging targets outside of the satellite’s nadir field of view. The ability for a satellite to slew to off-nadir targets is incredibly important when leveraging RGTs. Another design trade considered for ReCon is the propulsion system incorporated on the satellites. Performance and cost trades invoked when using electrical propulsion instead of chemical propulsion are presented within the ReCon framework. This work presents recommendations and future considerations to inform future designers. An investigation into the potential use of staged and responsive launch options further explores flexible options. Using alternative launch strategies allows a program to leverage dropping launch costs and adapt to uncertain imagery demand. The use of flexible options for EO satellite constellation design is vital in low Earth orbit as satellite technology improves, and space becomes a more crowded domain.