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?
Spacecraft
1

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
UAV 1
SC 1
SC 2
Distributed architecture

Fault resilient
SC 3
SC 4
Control Pathways of Tier-Scalable
Architecture [8].
Spacecraft
1
Prior work [5-7] has demonstrated the Multi-Tier approach, which makes
command decisions as close to the implementing node as possible

UAV 2
UAV 1
SC 1
UAV 2
SC 2
SC 3
SC 4
Control Pathways of Mult-Tier
Architecture [8].
Multi-tier architecture (cont.)
Controller-Supplied
High-Level Goals
Legend
Data
Source
Identify ‘Final’
Conditions Required
for Goals
Data on
Blackboard
Decision
Are Rules
Triggered?
Task
No

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].
Difference
Current vs.
Previous
Results of
Previous Similar
Actions
Cost of Previous
Similar Actions
Difference
Current vs.
Previous
Value
Likelihood
Cost
Other Rules
That Can Use
Data
Yes
Determine What
Data is Needed for
‘Best’ Rule
Choose ‘Best’ Rule
Can This Data
Be Obtained?
Run Rule
No
Projected Value
Attributed Cost
No
Rule Identified
Yes
Choose Next Best
Rule
No More Rules
End
Task Data Collection
Is End Condition
Satisfied?
Summed Cost of All
Data Collection for
Rule
Yes
End
Blackboard Architecture Approach [9].
Value as Function of
Cost Units
Rule Score Determination [9].
For Each Data Element (Fact)
Required
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


Limit pre-planning


Deploy to higher-risk areas
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 # EPS814442), 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.
References
1.
W. Fink, J. M. Dohm, M. A. Tarbell, T. M. Hare, V. R. Baker, D. Schulze-Makuch, R. Furfaro, A. G. Fairén, T. Ferre and H. Miyamoto. 2007.
Tier-scalable reconnaissance missions for the autonomous exploration of planetary bodies. 2007 IEEE Aerospace Conference.
2.
K. Durga Prasad and S. Murty. 2011. Wireless sensor Networks–A potential tool to probe for water on moon. Advances in Space
Research 48(3).
3.
E. Vassev, M. Hinchey and J. Paquet. 2008. Towards an ASSL specification model for NASA swarm-based exploration missions.
Proceedings of the 2008 ACM Symposium on Applied Computing.
4.
A. Golkar. 2013. Architecting Federated Satellite Systems for Successful Commercial Implementation. Proceedings of the AIAA 2013
Space Conference and Exposition.
5.
J. Straub. 2014. Command of a Multi-Tier Robotic Network with Local Decision Making Capabilities. International Journal of Space
Science and Engineering, Vol. 2, No. 3.
6.
J. Straub. 2014. Building Space Operations Resiliency with a Multi-Tier Mission Architecture. Proceedings of the SPIE Defense + Security
Conference.
7.
J. Straub. 2013. A Data Collection Decision-Making Framework for a Multi-Tier Collaboration of Heterogeneous Orbital, Aerial and
Ground Craft. Proceedings of the SPIE Defense, Security + Sensing Conference.
8.
J. Straub. 2014. Using Swarm Intelligence, a Blackboard Architecture and Local Decision Making for Spacecraft Command. Accepted
for publication in the Proceedings of the 2015 IEEE Aerospace Conference.
9.
J. Straub. 2014. Comparing the Blackboard Architecture and Intelligent Water Drops for Spacecraft Cluster Control. Proceedings of the
AIAA Space 2014 Conference.
10.
J. Berk, J. Straub and D. Whalen. 2013. The Open Prototype for Educational NanoSats: Fixing the Other Side of the Small Satellite Cost
Equation. Proceedings of the 2013 IEEE Aerospace Conference.
11.
J. Straub, C. Korvald, A. Nervold, A. Mohammad, N. Root, N. Long, D. Torgerson. 2013. OpenOrbiter: A Low-Cost, Educational Prototype
CubeSat Mission Architecture. Machines, Vol. 1, No. 1.
12.
J. Straub, J. Berk, A. Nervold, C. Korvald. 2013. Application of Collaborative Autonomous Control and the Open Prototype for
Educational NanoSats Framework to Enable Orbital Capabilities for Developing Nations. Proceedings of the 64th International
Astronautical Congress.