# An Overview of CubeSat Missions and Applications
## 3 CubeSats as Earth Observation and Earth Science Platforms
### The Role of CubeSats in Earth Science Missions
This way, the date collected by EZIE are expected to enable the proposition of more accurate models regarding auroras and geomagnetic storms from the scientific community. To perform their mission, the three CubeSats are equipped with the Microwave Electrojet Magnetogram (MEM) instrument. The core components of the MEM payload are four integrated 118 GHz heterodyne spectropolarimeters that will be used to detect the microwave radiation that is emitted by oxygen molecules during Zeeman splitting, which has a frequency of 118 GHz. The three EZIE CubeSats were successfully launched on 15 March 2025 onboard SpaceX's Transporter-13 mission and are reported to operate nominally. In Figure 9, an artistic illustration of the operation of the three EZIE CubeSats is presented [123; 124; 125; 126]. Figure 9: An illustration of the three CubeSats of the Electrojet Zeeman Imaging Explorer (EZIE) mission during their operation. Illustration by NASA/Johns Hopkins Applied Physics Laboratory (APL)/Steve Gribben [127]. In general, it is widely accepted that Earth observation and science CubeSats, in order to perform their mission, must be orbiting the Earth and in most cases find themselves in LEO. This is reasonable, as the close proximity to the Earth correlates with greater data acquisition prospects, especially for imaging instruments, as well as with higher data transfer rates towards mission control. However, as shown by the EQUilibriUm Lunar-Earth point 6U Spacecraft (EQUULEUS), this may not always be the case, as important Earth science missions can also be performed from beyond Earth orbit. EQUULEUS was a 6U CubeSat jointly developed by the university of Tokyo and JAXA; it was launched on 16 November 2022 as a secondary payload of the Artemis I mission. The satellite demonstrated a series of trajectory control techniques, low-thrust maneuvers, orbit changes, and eventually placed itself in an orbit around the Earth-Moon L2 Lagrange point. From there, the CubeSat began the observation and mapping of the plasmasphere that surrounds the Earth by using its PHOENIX (Plasmospheric Helium ion Observation by Enhanced New Imager in eXtreme ultraviolet) UV imager. The data collected by PHOENIX will further the scientific community's understanding of the radiation environment around our planet and help us better prepare for future deep-space exploration missions. It should be noted that, apart from its main Earth science mission, EQUULEUS also took advantage of its position in the cislunar space to also perform lunar and asteroid exploration tasks. One of these tasks was the observation of lunar surface meteoroid impact flashes and near-Earth asteroids using the DEtection camera for Lunar impact PHenomena IN 6U Spacecraft (DELPHINUS), which was also part of its payload. Furthermore, EQUULEUS was also equipped with Cis-Lunar Object detector within THermal insulation (CLOTH), by which it would measure the size and spatial distribution of dust and solid objects such as micro-meteoroids in the cislunar space around the Earth-Moon L2 point, data that can form the basis for risk assessments for future lunar missions [128; 129].