The Distributed Spacecraft Attitude Control System Simulator is a testbed comprised of two independent spherical air-bearing platforms, useful for formation-flying attitude control simulation. The DSACSS is intended to support a wide range of functions. As such, requiring that all controllers be robust to approximations of the system parameters is impractical. We document the development of bat...

In this paper, the consensus problem for multi-agent systems with general linear dynamics is studied. A novel event-triggered control scheme with some desirable features, including distributed, asynchronous and independent, is proposed. It is shown that consensus of the controlled multi-agent system can be reached asymptotically. The feasibility of the eventtriggered strategy is further verifie...

I . ABSTRACT JPL is developing novel RF tracking sensors for both of NASA’s New Millennium Program constellation missions, ST-3LStarLight and ST-5. ST-3/StarLight9 the Separated Spacecraft Inlerferometer, is a two-satellite formation in heliocentric orbit designed to demonstrate various technologies required for space interferometry. Scheduled for a 2006 launch. ST-3 will fly JPL’s Autonomous F...

New Worlds Observer is an external starshade mission designed to observe Earth-like planets around nearby stars. A telescope spacecraft operates in the “shadow” cast by a starshade spacecraft, located tens of thousands of kilometers away. We explore the requirements that these two free-flying spacecraft place on the orbital, propulsion, control, and communication systems and some baseline solut...

Orbit determination of spacecraft in orbit has been mostly dependent on either GNSS satellite signals or ground station telemetry. Both methods present their limitations, however: can only be used effectively earth orbit, and ground-based presents an inherent latency that increases with the Earth–spacecraft distance. For flying formations, alternative method determination, independent external ...

Abstract Ionospheric irregularities can adversely affect the performance of Global Navigation Satellite System (GNSS). However, this opens possibility using GNSS as an effective ionospheric remote sensing tool. Despite monitoring has been undertaken for decades, these in multiple spatial and temporal scales are still not fully understood. This paper reviews Virginia Tech’s recent studies on mul...

The problem of determining minimum-fuel maneuver sequences for a four-spacecraft formation is considered. The objective of this paper is to determine fuel-optimal configuration trajectories that transfer a four spacecraft formation from an initial parking orbit to a desired terminal reference orbit while satisfying particular formation constraints. In this paper, the configuration problem is so...

Prior space missions have not routinely used onboard decision-making. The Autonomous Sciencecraft (ASE), flying onboard the Earth Observing One spacecraft, has been flying autonomous agent software for the last decade that enables it to analyze acquired imagery on board and use that analysis to determine future imaging. However ASE takes approximately one hour to analyze and respond. This paper...