2019.B.2.1. Alternative communications approach to deep-space missions

Author(s)

Janis Dalbins (1)
Pekka Janhunen (2)
Mart Noorma (1)
Andris Slavinskis (1)

University of Tartu, Estonia
Finnish Meteorological Institute, Finland

Session

B.1

Keywords

Communications, Asteroids, Asteroid belt, Deep-space, Interplanetary, Nanosatellite, Nanospacecraft, CubeSat, Monte Carlo, Simulations

Abstract

This paper presents simulation results of communication for interplanetary missions without the use of a deep-space network. We analyse the data downlink during a returning Earth flyby. Such a communication approach was proposed for the Multi-Asteroid Touring mission concept where the propellantless electric solar wind sail is used. It enables a fleet of nanospacecraft to flyby a range of asteroids in the main asteroid belt but, given the size and the number of spacecraft, the use of the current deep-space communication solutions is infeasible. A range of values for spacecrafts’ initial distance in two dimensions from Earth and initial speed are derived as of result of Monte Carlo simulations of Earth flybys and large-volume data downlink sessions. Typical link budget equation was used to calculate possible data-rate as a function of distance and downlinked data amount during the flyby session. Results have been validated in General Mission Analysis Tool (GMAT) where range of values for B-plane coordinates were obtained. By using existing communications system solutions for CubeSats, it is possible to downlink up to 40 GB of data during optimal Earth flyby of the spacecraft. The result is applicable to other interplanetary missions given that the spacecraft can perform an Earth flyby after taking scientific measurements. Without the use of alternative deep-space communication solutions, numerous interplanetary mission concepts of small satellites fleets, swarms and constellations might be rendered infeasible due to the limited capacity of deep-space networks.