CanX-4&5 Formation Flying Mission Accomplished
In only four months following launch, the CanX-4 and CanX-5 dual satellite formation flying mission has been accomplished ahead of schedule.
During the month of October, the CanX-4&5 nanosatellites used on-board propulsion, GPS-based relative navigation, and intersatellite radios to execute a series of precise, controlled, autonomous formations, ranging from 1 km range down to 50 m separation. In each case, more than 10 orbits were accomplished with sub-meter formation control and centimeter-level relative navigation, feats which (to SFL’s knowledge) have never before been accomplished at the nanosatellite scale.
“CanX-4 and CanX-5 were designed to demonstrate formation flying in two along-track orbits, and two projected circular orbits,”, said Grant Bonin, the CanX-4&5 project manager. “We’re pleased to report that we’ve now completed all of the intended formations, and indications are that have out-performed our control performance requirements in every case. We are very pleased with the results.”
Launched on 30 June 2014 from Sriharikota, India onboard the Polar Satellite Launch Vehicle (PSLV) which also carried the SPOT-7 satellite and two other spacecraft from Germany and Singapore, the CanX-4 and CanX-5 nanosatellites were deployed separately following launch, after which a series of orbit acquisition and phasing maneuvers were used to bring the satellites within communication range of each other.
Using carrier-phase differential GPS techniques for extremely high-precision relative navigation, the mission first undertook along-track orbit (ATO) formations at 1000m and 500m, after which the two spacecraft were reconfigured to perform projected-circular orbit (PCO) formations (in which one satellite appears to circle the other from a ground observer’s standpoint) at 100m and then 50m range. All guidance, navigation and control algorithms were developed in-house and executed autonomously on-orbit, with no ground intervention required during formation flight.
“CanX-4 and CanX-5 have pushed the boundary of what can be achieved with miniature spacecraft”, said Dr. Robert Zee, director of the Space Flight Laboratory. “These two satellites have allowed us to demonstrate high-performance formation flying algorithms and hardware that can enable a wide variety of small and large missions.”
The technologies and algorithms demonstrated on CanX-4&5 have several applications for a wide range of missions, such as on-orbit inspection and repair, sparse aperture sensing, interferometry, and ground moving target indication.
“Both satellites continue to perform exceptionally well, and we still have a very large fraction of our propellant remaining in CanX-5, and close to a full tank in CanX-4”, said Bonin.
SFL intends to begin publishing the detailed results of the CanX-4 and CanX-5 experiments over the next several months. The two spacecraft were designed, built, tested, and are being operated from SFL’s Microsatellite Science and Technology Center (MSTC) in Toronto, Canada.