# An Overview of CubeSat Missions and Applications
## 9 Review Conclusions and Discussion
### CDS Evolution and Regulatory Considerations  
Currently, the CubeSat concept has gained traction beyond its original educational intent, mainly due to the enabling factors discussed in Section 2. The CDS has evolved accordingly in order to accommodate more complex and sophisticated missions, with recent major updates occurring in July 2020 (Rev. 14) and February 2022 (Rev. 14.1) [324]. Except from form factors dictation, CDS has introduced a series of testing protocols and safety measures, actively transforming it to a stabilizing force in a rapidly diversifying ecosystem. Future revisions will likely focus on enhancing interoperability standards between subsystems, accommodating the unique requirements of deep space missions, orbital debris mitigation measures, and guidelines for advanced propulsion technologies. In this sense, CDS exemplifies a rare balance between prescriptive engineering control and adaptive capacity, supporting the cohesive and safe expansion of the CubeSat market. CDS's evolution will play a pivotal role in the upgrade of the CubeSats from standardized form to standardized function, which will ultimately lead to CubeSats serving as trusted platforms in the upcoming space economy. Furthermore, the rapid proliferation of CubeSats has prompted significant regulatory responses worldwide, creating both challenges and opportunities for mission planners. Spectrum allocation has emerged as a critical constraint, with the International Telecommunication Union (ITU) and national regulatory bodies implementing streamlined filing procedures specifically for small satellites, though the growing congestion in popular frequency bands continues to challenge new entrants [325; 326]. Orbital debris mitigation has similarly transformed from a secondary consideration to a primary design driver. For many years, a large number of space agencies and regulatory bodies required LEO CubeSats to demonstrate a 90% probability of atmospheric re-entry within 25 years of mission completion. However, with ever increasing satellite traffic in LEO, this 25-year period was not deemed adequate and on 29 September 2022, the US Federal Communications Commission (FCC) adopted a new rule for all the FCC-licensed satellites that are located in the LEO region that reduced the lifetime requirement to only 5 years after launch [327]. In a similar manner, ESA adopted the \"Zero Debris approach\" in 2025 in which it is stated that end-of-life time in LEO for all new ESA missions is reduced from the original 25 years to just 5 [328]. These strict regulations are driving innovations in deployable drag devices and propulsion systems for small satellites [329]. Several companies and institutions have already been implementing active and passive space debris removal systems. For instance, ClearSpace (Renens, Switzerland), a Swiss startup, is leading the ClearSpace-1 mission with the European Space Agency to actively remove space debris by capturing and deorbiting defunct satellites using a robotic arm system [330]. Another example is Astroscale (Tokyo, Japan), a Japanese company, who successfully demonstrated magnetic docking and deorbiting with its ELSA-d mission and is developing future missions like ADRAS-J2, which will use robotic arms for debris removal [331]. To further support these endeavors, passive systems for debris mitigation are developed, such as in the ESA-Dragliner project. Developed by the University of Luxembourg, in collaboration with the Finnish Meteorological Institute,it refers a passive deorbiting system employing a propellant-free plasma brake tether to safely deorbit satellites without using onboard resources [332]. Moreover, the Inter-Agency Space Debris Coordination Committee (IADC) guidelines [333] have been increasingly integrated into national licensing frameworks, while the United Nations Committee on the Peaceful Uses of Outer Space (UN COPUOS) has developed non-binding recommendations specifically addressing small satellite operations [334].