# An Overview of CubeSat Missions and Applications
## 7 CubeSats as Deep-Space Exploration Platforms
### CubeSat Missions for Planetary Exploration  
So far, in the span of more than two and a half decades since the advent of CubeSats, only a single CubeSat mission to another planet has ever been undertaken. This mission was Mars Cube One (MarCO), which was coordinated by NASA and involved the launch of two 6U CubeSats, MarCO-A and MarCO-B, (which are presented in Figure 19(a)) into a Mars fly-by trajectory. The two CubeSats were launched on 5 May 2018 together with NASA's InSight Mars lander and their main mission was to serve as communications relay satellites, providing a real-time 8 kbps communication link between mission control and the InSight lander during the Mars atmospheric entry, descent, and eventual landing phases, when the InSight lander would not have a direct line of sight with the Earth. The two CubeSats were equipped with a large deployable UHF antenna via which they received signals from the InSight lander and a Xband antenna, through which they communicated with NASA's Deep Space Network (DSN). Furthermore, a powerful transponder capable of operating in both UHF (only receiving) and Xband (receiving and transmitting) spectra was present onboard, this transponder, named Iris, had been developed by NASA's JPL. The two spacecrafts also featured cold gas propulsion systems, used for the performance of trajectory correction maneuvers during their long journey to Mars. It must be noted that normally, only one CubeSat was required for the mission, however the existence of two instead of one offered redundancy. Both CubeSats were eventually successful in executing their mission, successfully demonstrating the viability of the carry-your-own-relay concept, which can now be utilized by a variety of future interplanetary missions, reducing or even eliminating the need for the placement of dedicated relay infrastructure before the execution of the main mission. Furthermore, the two MarCO CubeSats became the smallest spacecraft to successfully complete an interplanetary mission, to this day. Finally, the two spacecraft were also equipped with wide-angle cameras which were used to verify the successful deployment of deployable components (such as solar panels) and to capture various images. With this camera, MarCO-B managed to capture several pictures of Mars during its fly-by, one of which is presented in Figure 19(b)[272; 273; 274]. Several mission concepts which would utilize CubeSat platforms for the exploration of planets of our solar system are being studied as of 2025. One of these potential future planetary exploration missions involving CubeSats is CubeSat UV Experiment (CUVE), proposed by the University of Maryland College Park, which received funding for further development from NASA's Planetary Science Deep Space SmallSat Studies (PSDS3) program [13]. The CUVE mission concept proposes the use of a 12U CubeSat platform for the  
Figure 19: (**a**) An artistic illustration of the Mars Cube One A (MarCO-A) and Mars Cube One B (MarCO-B) CubeSats in their deployed configuration. (**b**) A picture of Mars that was captured by MarCO-B on 26 November 2018. Illustration and photo by NASA/JPL-Caltech [275]. study of the Venusian atmosphere's dynamics by measuring its ultraviolet absorption and nightglow emissions. More specifically, it will study the so-far unknown UV \"absorber\" that is present in the Venusian atmosphere, which produces the characteristic UV features observed in the Venusian disc, which are used to monitor the dynamics of the Venusian atmosphere's cloud motion. To perform this mission, the CUVE will be equipped with two scientific payloads. The first of these payloads is a low scattering Czerny-Turner image spectrometer operating in the spectrum between 190 nm and 380 nm with a spectral resolution of 0.2 nm, capable of resolving SO and SO\({}_{2}\) concentrations in the Venusian atmosphere.