Engineering Issues for All Major Modes of In Situ Space Debris Capture

Artificial satellites and launch vehicles have created an ever growing number and variety of orbiting debris objects ranging in size from a few microns to several meters. The urgency of the situation has been exacerbated by the 2007 Chinese anti-satellite test and the 2009 collision of Iridium and Cosmos satellites. Sometime in the next one or two decades a space debris reduction program may be needed to assure continued access to, and use of, space for applications and exploration. Debris removal techniques and programs have been suggested, but none have been implemented. A recently completed investigation of engineering issues associated with the in situ capture of space debris objects spans the spectrum of options for all categories of these derelicts. This work concludes that not all debris can, or should, be removed. Technologies and systems for capturing very small debris do not exist. Only the largest of the objects can be effectively addressed with current technology. However, there remain several complications even for these derelicts. For example, every large debris piece may possess residual angular momentum with associated angular rates that could exceed 30 rpm. These objects are uncooperative and may have to be approached in such a way that angular momentum can be safely removed. Once stabilized, such objects may have to be grappled in order to control them. Then, a device may have to be attached in order to either apply proper removal forces or to store the object for later disposal. This paper attempts to identify and assess technologies and systems associated with in situ capture and control.