DISCUS - The Deep Interior Scanning CubeSat mission to a rubble pile near-Earth asteroid

TL;DR

DISCUS is a proposed 6U CubeSat mission employing bistatic radar to probe the internal structure of rubble pile near-Earth asteroids, aiming to improve understanding of their composition and support future deflection strategies.

Contribution

This study presents the initial conceptual design of DISCUS, a novel CubeSat mission integrating radar tomography for asteroid interior analysis.

Findings

Design of a low-frequency radar with stepped-frequency modulation

Feasibility of using CRT for asteroid interior imaging

Integration of optical and laser sensors for navigation

Abstract

We have performed an initial stage conceptual design study for the Deep Interior Scanning CubeSat (DISCUS), a tandem 6U CubeSat carrying a bistatic radar as main payload. DISCUS will be operated either as an independent mission or accompanying a larger one. It is designed to determine the internal macroporosity of a 260-600 m diameter Near Earth Asteroid (NEA) from a few kilometers distance. The main goal will be to achieve a global penetration with a low-frequency signal as well as to analyze the scattering strength for various different penetration depths and measurement positions. Moreover, the measurements will be inverted through a computed radar tomography (CRT) approach. The scientific data provided by DISCUS would bring more knowledge of the internal configuration of rubble pile asteroids and their collisional evolution in the Solar System. It would also advance the design of future asteroid deflection concepts. We aim at a single-unit (1U) radar design equipped with a half-wavelength dipole antenna. The radar will utilize a stepped-frequency modulation technique the baseline of which was developed for ESA's technology projects GINGER and PIRA. The radar measurements will be used for CRT and shape reconstruction. The CubeSat will also be equipped with an optical camera system and laser altimeter to sup- port navigation and shape reconstruction. We provide the details of the measurement methods to be applied along with the requirements derived of the known characteristics of rubble pile asteroids.