Formation Flying and Position Determination for a Space-Based Interferometer in GEO Graveyard Orbit

Spacecraft formations enable a variety of mission concepts,
from gravity reconstruction to extrasolar planet detection
to heliophysics observatories. In particular, space-based radio
interferometers can detect signals in frequency ranges that are
absorbed by Earth’s ionosphere or atmosphere. Furthermore,
such formation missions are now feasible under constrained cost
caps due to the growing availability of SmallSat components
with spaceflight heritage that are compatible the CubeSat formfactor.
Accordingly, we analyze a mission concept operating
multiple SmallSats in a passive cluster to establish a space-based
interferometer. The goal of this array is to reconstruct radio
emissions associated with Coronal Mass Ejections (CMEs) from
the Sun, giving us insight into the particle acceleration occurring
during these events. This low-cost mission concept presents
a number of unique challenges in regards to mission design
and navigation, particularly the configuration of the spacecraft
to optimize science return and the reconstruction of precise
spacecraft-spacecraft separation values. After providing a brief
overview of the mission concept, this paper presents several key
features of the mission design and orbit determination strategy
that enable this potential heliophysics mission.