Responsive Satellites Through Ground Track Manipulation Using Existing Technology

Traditional space operations are characterized by large, highly-technical, long-standing satellite systems that cost billions of dollars and take decades to develop. Many branches of the US government have recognized the problem of sustaining current space operations and have responded by heavily supporting research and development in a field known as Operationally Responsive Space (ORS). This ORS research focuses on hardware, interfaces, rapid launch and deployment with the overall goal of reducing per-mission-cost down to $20 million. However, there are few studies on the feasibility of maneuvering satellites in lowEarth orbit (LEO) from a ground-track perspective once an asset is launched. We can achieve operational responsiveness by changing the ground track of a given satellite and thereby a geographical target location by applying existing thruster technology. Therefore it is not so much a new technology but a change in the Concept of Operations (CONOPS) of today’s space systems application. The existing paradigm on maneuvering is that it is costprohibitive, especially in performing orbital plane changes, thus orbit-changing maneuvers are only done at the beginning-of-life to establish the service orbit, end-of-life for disposal, and when absolutely necessary for the safety of the system (collision avoidance). This paradigm along with traditional space programs have to change and a transition to responsive and maneuverable systems must take place to meet the needs of space users in a timely manner. The analysis we present here shows that a satellite equipped with a standard chemical propulsion thruster in a 60-degree inclined, 500-km altitude orbit can move the ground over-flight target anywhere on the globe (within 60 degrees north and south latitudes) in as little as ten hours from the time of the maneuver with a fuel expenditure, measured in change in velocity (ΔV), of 100 meters-per-second. Similarly, a more efficient electric propulsion thruster can provide the same maneuverability in 27 hours from the start of the maneuver while expending the same amount of ΔV. This research demonstrates that existing technology can maneuver a satellite significantly to change its ground track to overfly a desired target on Earth in a relatively short period of time and well-within standard fuel budgets.