The Why of Robotic On-Orbit Servicing

Abstract

The field of Robotic On-Orbit Servicing covers a diverse set of space mission types like lifetime extension and active debris removal. In general, a robotic spacecraft - frequently called servicer - capable of a certain degree of autonomy, approaches an object that needs to be serviced. In the case of lifetime extension, the servicer may dock with a customer's satellite and take over its orbit and attitude control system, or even refuel or repair it. In the case of active debris removal, the procedure is more drastic: A debris object (e.g. rocket upper stage or non-operational satellite) that represents a substantial collision risk for other operational spacecraft is captured and removed from orbit. Recently, the field finally gains the traction it deserves. Northrop Grumman serviced two Intelsat satellites with their Mission Extension Vehicles (MEV) 1 and 2, thereby prolonging the operational life of those satellites. Other companies like ClearSpace and Astroscale try to establish a market for active debris removal with first technology demonstration missions. And yet some doubt prevails: Can lifetime extension and in-orbit repair ever be done economically? Will there ever be a large enough market to sustain a solid business case? Who will pay for removal of non-operational satellites? Is there even a customer? While these kinds of frequently asked questions are legitimate, they indicate short-term thinking and a rather narrow perspective. In contrast, it is worth trying to shift the focus to the bigger picture and to the long-term perspective. For that purpose, the meaning of spaceflight itself for our lives today has to be considered. Research, navigation, Earth observation, communication - hardly any domain that does not depend on space infrastructure in one way or another. And with the numerous global challenges we have to face today and certainly in the future, this space infrastructure will have to advance considerably in capability and capacity. This talk intends to give some insights about the possible nature of these advancements and how Earth orbit may look like as a result. Regardless of its exact nature, it won't be possible to realize this infrastructure by traditional means. Ultimately, Robotic On-Orbit Servicing, advanced to its logical conclusion, will be one of the essential tools to create, maintain and protect the space infrastructure of the future, for the benefit of life on Earth and as a gate into the solar system. We have to push forward with the development of this highly complex tool to be prepared for the long-term challenges that lie ahead.