Assessment and development of de-orbiting technology for nanosatellites

Abstract

The accumulating space debris has been a developing problem for many years. Technological advances led to the creation of nanosatellites, which allows more affordable access to space. As a result, the number of satellite launches is rapidly increasing, which, translates into an increase in debris in the low earth orbit (LEO) and geostationary orbit (GEO). To comply with the Inter-Agency Space Debris Coordination Committee (IADC) requirement of a 25-year maximum orbital lifetime, nanosatellites must have an end of life strategy. Failure to meet these guidelines may not only cause catastrophic collisions but may make future space travel even more challenging. Consequently, orbital lifetime predictions must be completed for nanosatellites. Considering this, the aim of this thesis is to investigate the orbital lifetime predictions for the nanosatellite ZACube-2, and the effects on the orbital lifetime if ZACube-2 is fitted with deorbiting technology, specifically a drag argumentation device. An in-depth literature review regarding the current state of technology pertaining to nanosatellite de-orbiting was conducted. This was followed by studies regarding orbital dynamics and perturbation forces. Four case studies were simulated in NASA’s Debris assessment software (DAS 2.0) using orbital parameters extracted from the two-line element (TLE) file. General information such as launch date and final mass was provided by F’SATI. The Baseline case study presented the orbital lifetime of ZACube-2, without any drag enhancement device. This was followed by case study 1,2 and 3 which represented ZACube-2 when fitted with three different drag enhancement devices. A comparison study indicated a reduction in all three cases. A new inflatable cube de-orbiting device (ICDD) concept was also presented, and the effects it has on the orbital lifetime predictions are showcased in case study three. Two deployment concepts were considered and evaluated against design requirements. Solidworks software was used to model the most suitable concept as well as perform finite element analysis on the structure. Static analysis was followed by natural frequency analysis in which the natural frequencies of the components and assembled structure were extracted. The Soyuz launch vehicle’s sinusoidal testing requirements were used to evaluate the structures survivability under dynamic loading. Based on the finite element , and harmonic analysis it was concluded that the structures will survive the launch conditions of the Soyuz launch vehicle. Furthermore, individual parameters affecting orbital lifetime predictions are also identified, in the form of a mass and cross-sectional sensitivity study and a ballistic coefficient versus orbital time study.