ABSTRACT
Since the dawn of the space era, the space services market has been dominated by geostationary (GEO) communication satellites, delivering not only intercontinental and remote area communications, but also broadcast services such as pay TV. At the start of this century, the Iridium constellation was launched, providing competing services from Low Earth Orbit (LEO). Service provision from LEO differs from GEO by requiring many more satellites for continuous coverage, yet those satellites can be much cheaper, more technically advanced and updated more frequently than their GEO equivalents. In this update we survey the current and planned LEO constellations and contrast their characteristics with recent GEO launches. Special focus is given to characteristics applicable to military applications.
BIOGRAPHY
Craig is an executive director of Skykraft pty ltd, an Australian company that designs and builds small-satellite constellations. As the Chief Innovation Officer he is responsible for blending solutions to real-world problems with cutting edge space technology.
Craig is also a Visiting Fellow at UNSW Canberra (Australian Defence Force Academy) where he has taught subjects such as GPS, Electronic Warfare, Avionics, Surveillance Technology and Guided Weapons for the past 20 years. He began his career as an engineering officer in the Royal Australian Air Force, transferring to the reserve in early 2001.
Craig spent 5 years as author of the definition studies and then as engineering manager of the Australian Navigation Warfare acquisition project, being heavily involved in design and leading a large number of Navigation and Navigation Warfare (GPS jamming) trials.

BIOGRAPHY
Doug Griffin is an executive Director and Chief Engineer of Skykraft Pty. Ltd., an Australian company that designs and builds small-satellite constellations. Doug started his career in the European Space Industry before returning to Australia 5 years ago as Chief Engineer at UNSW Canberra Space, and now spin-out Skykraft.
An Australian mechanical engineer by training, over a 20-year period in Europe, Doug worked for an aerospace prime (Alenia Aerospazio now Thales Alenia Space), the University of Oxford and in National Research Laboratories in Italy and the UK (ENEA & the Rutherford Appleton Laboratory – RAL Space). He led the Space Systems Engineering group at RAL Space and developed spacecraft payloads for European Space Agency and NASA Earth Observation and Space Science missions.
Doug was instrumental in setting up the Australian National Concurrent Design Facility at UNSW Canberra, where space mission concepts can be matured to fundable stages.