  Earth's magnetosphere is vital for today's technologically dependent society.
To date, numerous design studies have been conducted and over a dozen science
missions have own to study the magnetosphere. However, a majority of these
solutions relied on large monolithic satellites, which limited the spatial
resolution of these investigations, as did the technological limitations of the
past. To counter these limitations, we propose the use of a satellite swarm
carrying numerous and distributed payloads for magnetospheric measurements. Our
mission is named APIS (Applications and Potentials of Intelligent Swarms),
which aims to characterize fundamental plasma processes in the Earth's
magnetosphere and measure the effect of the solar wind on our magnetosphere. We
propose a swarm of 40 CubeSats in two highly-elliptical orbits around the
Earth, which perform radio tomography in the magnetotail at 8-12 Earth Radii
(RE) downstream, and the subsolar magnetosphere at 8-12RE upstream. In
addition, in-situ measurements of the magnetic and electric fields, plasma
density will be performed by on-board instruments.
  In this article, we present an outline of previous missions and designs for
magnetospheric studies, along with the science drivers and motivation for the
APIS mission. Furthermore, preliminary design results are included to show the
feasibility of such a mission. The science requirements drive the APIS mission
design, the mission operation and the system requirements. In addition to the
various science payloads, critical subsystems of the satellites are
investigated e.g., navigation, communication, processing and power systems. We
summarize our findings, along with the potential next steps to strengthen our
design study.
