The Critical Role of CubeSat Spacecraft in a Multi-Tier Mission for Mars Exploration JEREMY STRAUB DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF NORTH DAKOTA

Overview  What is a multi-tier architecture?  Why use a multi-tier architecture?  What role do CubeSats have in a multi-tier architecture?  Why are CubeSats important?  Conclusions & Future Work

What is a multi-tier architecture?  Fink [1] proposed a “tier-scalable” approach that combined orbital, aerial and ground craft (other types of craft have also been proposed).  This featured a central controller which provides the benefit of making decisions using the best computational hardware but creates a single point of failure and doesn’t allow local decision making which considers local conditions  Work on swarm and sensornet approaches (e.g., [2, 3] and federated satellite systems [4] has also provided insight  Prior work [5-7] has demonstrated the Multi-Tier approach, which makes command decisions as close to the implementing node as possible  Distributed architecture  Fault resilient Control Pathways of Tier-Scalable Architecture [8]. Control Pathways of Mult-Tier Architecture [8].

Multi-tier architecture (cont.)  Current work utilizes a Blackboard architecture with a ‘solver’ and supporting score determination routine for decision-making  The use of a combined Blackboard and Intelligent Water Drop approach has also been proposed [8]. Blackboard Architecture Approach [9]. Rule Score Determination [9].

Why use a multi-tier architecture?  Provides single-mission benefits:  Resilience  Multiple small craft mean acceptable loss levels can be defined  Allows local (limited human oversight control)  Localized command / control  Allows quick decision making (no round-trip for decisions)  Decomposes high-level goals into work packages  Allows use of management by exception technique  Greater exploration  Deploy small autonomous groups to multiple areas of a planet / body  Autonomous command means more exploration (not waiting)  Risk tolerance  Deploy to higher-risk areas  Limit pre-planning  Make deployment decisions based on what is detected by orbital / aerial craft, not beforehand  Multi-mission coordination benefits

What role do CubeSats have in a multi-tier architecture?  Part of the orbital tier  Sensing platforms  Communications relay platforms  Spatial positioning platforms  Could a larger CubeSat be designed to sense, decide and deploy?  Architecture features:  Only local (to planet) communications are needed, so antenna sizes / power / etc. can be reasonable  Facilitates effective use of sensed data with different spatial / temporal / etc. resolution levels

Why are CubeSats important?  Standardized platform  Low-cost components / designs (e.g., [10-11])  Potential for well-understood failure models  Repeated use of common components  Repeated use of common craft designs  Simple deployment  Potential to ‘add on’ mission (potentially multi-tier style) to larger craft (see, e.g., [12])  Growing capabilities  Ability to have collaboration between craft from multiple owners / investigators (see, e.g., [12])

Conclusions & Future Work  The multi-tier paradigm is poised to provide real benefits to future missions  Reduces risk / risk aversion through having multiple craft, with an expectation of some loss  Allows missions to be planned / modified based on what is sensed (particularly useful for first missions to a body / area)  CubeSats are an important part of this architecture: they extend the orbital tier  Multi-tier approach allows replication of Earth-orbit like mission without requiring advancements in communications / etc. capabilities, based on assumption of key services being available from primary craft

Thanks & Any Questions? Small satellite development work at the University of North Dakota (UND) is currently or has been supported by North Dakota EPSCoR (NSF Grant # EPS ), the North Dakota Space Grant Consortium, North Dakota NASA EPSCoR, the UND Faculty Research Seed Money committee and the National Aeronautics and Space Administration. Facilities and equipment used in this work have been supplied by the UND Department of Computer Science and the John D. Odegard School of Aerospace Sciences.EPS

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