As the number of objects in Earth orbit grows, the international satellite industry faces a growing problem associated with orbital debris and space collision avoidance. In September 2007, the Inter-Agency Space Debris Coordination Committee (IADC) issued a report entitled "Space Debris Mitigation Guidelines" where it was recommended that satellites deorbit within 25 years after the completion of their mission or within 30 years of launch if they cannot be parked in less dense orbits. Governments around the world are introducing procedures to implement the recommendations of the IADC. This new requirement poses a significant programmatic risk for space missions, especially those missions requiring rapid, responsive, short missions in low Earth orbit.
"Deorbit" means a reduction in altitude of the satellite such that the satellite will burn up in the atmosphere or make its way back to the surface of Earth in a very short period of time, typically days or weeks. Deorbiting a satellite may be accomplished through passive or active means. In some cases, the characteristics of the satellite (e.g. its ballistic coefficient) and its altitude are such that the satellite will naturally deorbit within 25 years of mission end. In many cases, however, because of an unfavorable ballistic coefficient or relatively high altitude, the deorbiting of the satellite must be accomplished through a dedicated means that is not considered to be part of the main mission. In other words, a dedicated device is used to deorbit the satellite at the end of its mission. This could be a propulsion system, a solar sail, an electrodynamic tether, or a drag sail of some kind.
Unfortunately, for satellites under 100 kg, the so-called "microsatellites" (and "nanosatellites" under 10 kg), that are ideal for responsive and short space missions, none of the active deorbiting approaches have sufficient technological maturity to be used consistently and reliably for this class of mission. Indeed, none of the technologies have successfully flown and served as a deorbiting device. Due to the energies and/or time required for deorbiting, there is a strong preference for passive deorbiting devices, i.e. devices that do not require that the satellite remain operational for deorbiting. Passive approaches include tethers and drag sails.
CanX-7 is a demonstration mission involving a nanosatellite that will incorporate a lightweight, compact, deployable drag sail under development at SFL. The mission is funded by Defence R&D Canada (Ottawa), NSERC and COM DEV Ltd. The mission will demonstrate the drag sail's customizability, modularity, stowability and effectiveness at achieving the deorbiting requirements of the IADC. The results will then be used to create a low cost, modular, and customizable deorbiting device for nanosatellites and microsatellites in low Earth orbit, thus alleviating the programmatic and technical risk to space missions when using satellites of this class.