Attitude Control Optimization of a Two-CubeSat Virtual Telescope in a Highly Elliptical Orbit

Designing Monte Carlo Simulation and an Optimal Machine Learning to Optimize and Model Space Missions

“…Formation flying provides advantages over a single spacecraft including robustness, redundancy, reconfiguration, and broader coverage. Formation flying, as a key factor in virtual spacecraft formation [2], and rendezvous [3], is investigated in missions including virtual telescope for X-ray observation (VTXO) [4], Proba 3 [5], MASSIM X-ray virtual telescope [6], PRISMA [7], and SIMBOL-X [8]. Making a formation of spacecraft for astrophysics observation and optimizing the science mission lifetime of VTXO by 50% is studied in [9]- [12].…”

“…VTXO uses a lightweight Phased Fresnel Lens (PFL) to obtain near diffraction-limited angular resolution in the X-ray band [4], [10], [12], [15]- [18]. PFL provides the VTXO mission with nearly 55 milli-arcsecond (mas) (FWHM) imaging resolution of astrophysical sources in the X-ray band for a 1 km focal length.…”

“…Trajectory optimization is used to determine the optimal phases, the optimal orbits, and the optimal controllers for the GNC [6], [10]- [12]. For the VTXO, 3 phases are assigned to the ACS, and each phase is designed to optimize the performance of the VTXO mission by increasing the accuracy and reducing the energy consumption [4], [15]- [18], [22]. The benefits of assigning phases to the mission are…”

“…In VTXO, the speed of controller convergence is important as it defines T for the transient phase, and the dynamics of the nonlinear system is known. Multiplicative extended Kalman filter (MEKF) [1], [3], [4], [16], [30] can provide the state estimation with noisy sensor measurements and having disturbances and uncertainties in the system. Extended state observer (ESO) [23] have shown promising solutions to the disturbance and uncertainty estimation and rejection while providing asymptotic stability.…”

“…Quaternions exist in attitude dynamics of spacecraft, fluid mechanics, and quantum mechanics [35]. Highly accurate space missions including VTXO [4], Hubble telescope and James Webb telescope are usually long missions, and the quaternion solution accuracy in the simulation decreases while the quaternion norm decreases during the long intervals of time. Classical approaches like third and fourth order Runge-Kutta can solve ordinary differential equations (ODE) including quaternion ODE of motion.…”