Precision Formation Flight: The CanX-4 and CanX-5 Dual Nanosatellite Mission

Autonomous formation flight has long been studied as a means to provide high resolution sensing from multiple satellites equipped with lower resolution sensors. The Space Flight Laboratory (SFL) at the University of Toronto Institute for Aerospace Studies (UTIAS) is developing enabling technologies in collaboration with the University of Calgary for future precise formation flying missions. These technologies will be validated on two nanosatellites under development as part of SFL’s Canadian Advanced Nanospace eXperiment (CanX) program. These nanosatellites, named CanX-4 and CanX-5, will be launched together to be among the first to demonstrate autonomous formation flight in orbit. With a mass of only 7kg and size of 20x20x20 cm, these identical satellites will achieve position determination to within a few centimeters, while controlling their relative position to an accuracy of less than one meter. The short development cycle and low cost of nanosatellites make them an ideal platform for demonstrating formation flight provided certain enabling technologies are made available. This paper describes the enabling nanosatellite technologies that have been developed at UTIAS/SFL for this mission, including formation flying control algorithms, a low power intersatellite communication system, a liquid-fuel cold-gas propulsion system, a three-axis attitude control system, and an intersatellite separation system. CanX-4&5 will fly four individual formations during the mission at separation distances ranging from 50m to 1000m. CanX-4&5 are currently targeting a 2009 launch