There are about 750,000 objects larger than 1cm originated by human activities in outer space. Out of all these “space bullets”, only 17,000 are traceable and catalogued, and just about 1,250 are controllable active satellites. All other objects are uncontrolled with high risk to collide with other operational satellite, making space activities unsustainable and risky: if the satellites launched in orbit are not disposed quickly at the end of their mission, the possibility of chain collisions could become real. For example, one Iridium satellite was destroyed by a defunct Russian Cosmos satellite in 2009, causing shutdown of Motorola telecommunication network and costing millions of dollars to the Company. Over the next years the probability of the satellites failure due to collision with fragments has been predicted to grow incrementally, jeopardizing the space activities and their profitability.
The success rate of current disposal practices is only around 50%, making them insufficient and inefficient solutions. It has been recognized through many different studies that a minimum viable removal efficiency has to be at least 90% to keep the debris population at a steady value and to guarantee the conduction of space activities under an acceptable risk.
There are a number of different collision scenarios in orbit: for instance, a satellite that has reached end-of-life can collide with another operational satellite; or a satellite that has become uncontrollable by a major malfunction can jeopardize the functioning of a constellation of satellites; or a large number of smaller debris can threat satellites operating in the space.
Beyond the direct damage caused by the loss of a satellite or the interruption of a service, there are also indirect damage such as political frictions between the States where the colliding satellites were certificated or launched from.
Furthermore, collisions with people or assets on ground – although the probability is still fairly low - can occur as a consequence of the uncontrolled re-entry of defunct satellite from low-Earth orbits. If the satellite is larger than 500kg, some of the components (e.g. propellant tanks, reaction wheels, lens, etc.) can survive the tremendous heat and fall into the Earth, posing at risk people and assets. For instance, a large metal object (4.5m long and 1.2m wide) fallen from the sky into a jade mining area in north Myanmar in November 2016, disturbing people lives. The events of space debris on the Earth could also present a political risk, particularly in case when a satellite includes sensitive or strategic payloads.
The overall objectives are to complete and launch the down-scaled version of the D3 (D-SAT mission) demonstrating the feasibility of a safe, quick and direct decommissioning of a satellite in space through a dedicated device; update the decommissioning system requirements and design according to customers’ feedback; develop and CMMI certify the Control & Command software; and implement Manufacturing, Assembly, Integration and Test (MAIT) process.
