Title: Integrated Communication and Controls for Swarms of Small Satellites
Authors: Jonathan Diller, Qi Han, Chris Dreyer, Federico Rossi, Saptarshi Bandopadhyay, Jean-Pierre de la Croix, Amir Rahmani, Pamela Clark
Keywords: swarm of small satellites; orbit optimization; integrated communication and control

Abstract: Small space body exploration and monitoring missions traditionally involve a single spacecraft with several instruments for collecting data. The utility of these spacecraft has been limited due to the need to find a balance between optimal orbits for different sensor types while also needing to send the collected data to the ground station on the earth over the deep space network. The NEAR-Shoemaker mission to 433 Eros is an example of such a mission. Swarms of small spacecraft are a promising solution to better utilize resources and more efficiently gather scientific data while exploring and mapping small bodies. However, a few of the main constraining factors in multi-robot systems are communication limitations and data capacity.

In this work we optimize orbits for a swarm of small satellites to increase data capacity and integrate that with Ad hoc On-Demand Distance Vector (AODV), a Mobile Ad hoc Network (MANET) routing protocol. AODV provides a robust solution for moving data across a dynamic network of small satellites with potentially multiple hops and helps overcome intermittent connectivity problems and limited onboard storage constraints. We apply our integrated solution to a case study of 433 Eros, where six small spacecraft follow data-optimized orbits and use AODV routing to forward data back to a single carrier satellite for long-term storage and relay back to Earth.  Our simulation studies show that this integrated approach allows us to gather significantly more data than using a single spacecraft or using multiple non-collaborative small satellites. 

This work provides a basis to further optimize the orbits of the small satellite swarm. The simulation could be used as feedback to optimization algorithms used to help find the optimal combinations of orbits that further maximize the amount of data that can be collected from an asteroid or other small body object in space. This work also can be further developed to evaluate other emerging networking technologies. The simulation results provides promising results that can be further evaluated and validated with a physical testbed.