# Methodology for CubeSat Debris Collision Avoidance Based on Its Active ADCS System
###### Abstract  
This research assesses the feasibility of a collision avoidance methodology for CubeSats lacking propulsion. The approach involves altering the satellite's orientation to modify its cross-sectional area and, subsequently, the drag force. Examining altitudes within low Earth orbit (LEO) across 2U, 3U, and 6U CubeSat formats, maneuvers are considered two days before the Time to Closest Approach (TCA). Evaluation against the Conjunction Data Messages (CDMs) threshold miss distances reveals a minimum 7% and maximum 106% deviation in Vertical Distance Difference (VDD), and 68% to 1045% in Horizontal Distance Difference (HDD) concerning the notification threshold. These findings strongly endorse the practicality of the proposed collision avoidance methodology, utilizing CubeSat Attitude Determination and Control Systems (ADCS). Ongoing research focuses on assessing ADCS maneuver execution rates and implementation times, advancing our understanding and applicability of this innovative CubeSat collision avoidance approach. CubeSat; debris; collision avoidance; ADCS +
Footnote †: journal: Applied Sciences  
1
Footnote 1: [[https://doi.org/10.3390/app132212388](https://doi.org/10.3390/app132212388)]([https://doi.org/10.3390/app132212388](https://doi.org/10.3390/app132212388))  
Footnote †: journal: Applied Sciences  
CubeSats, a type of nanosatellite that use a standard size and form factor for education and space exploration, have become more prevalent in recent years. Over 1600 CubeSats have been launched into LEO, with a projected launch of over 2500 nanosats in the next 6 years. Although the risk of collision from these small satellites is low due to their low mass and small collision areas, a collision could still have significant economic consequences for the institutions behind these satellites. Most CubeSat missions can be completed without propulsion. Propulsion systems for small satellites provide the necessary capabilities for orbital maneuvering, maintaining their position, avoiding collisions, and implementing safe de-orbiting strategies. This enables these satellites to carry out longer, more functional missions beyond Earth's orbit. There are some reviews of different types of electric propulsion systems for small satellites based on current research and knowledge, which present metrics to evaluate these propulsion systems and highlight the limitations and challenges of current electric propulsion technologies. They further suggest potential areas for future research to improve electric propulsion for small satellites [2]. As mentioned before, CubeSats can incorporate CubeSat Attitude Determination and Control Systems (ADCS), normally based on magnetorquers actuators, effective in their low altitude orbits. The objective of this research is the development of a methodology to avoid predicted high-probability collisions with space debris, in the context of CubeSats in LEO, through the reaction wheel of their ADCS system. The idea is to modify the ballistic coefficient to result in a change in the drag coefficient, resulting in a slight change of height in orbit. This article presents a study to reduce the probability of a collision involving a CubeSat without a propulsion system, just using its active ADCS. Changing the orientation of the satellite, when the alert is received, will modify its cross section, increasing or reducing the drag force. This avoiding action will have a direct effect on the position of the satellite after a period of time. To analyze the effectiveness of this methodology, CubeSats of different sizes (2U, 3U and 6U) are simulated in circular orbits with three different altitudes within the typical range of operation of CubeSats. Simulations will be performed in System Tool Kit (STK) to predict how the coefficient change will impact the drag and the slight change in orbit height.