Riccardo Bevilacqua | Search NASA

NASA NTRS2018

Drag De-Orbit Device (D3): A Retractable Device for CubeSat Attitude and Orbit Control using Aerodynamic Forces

The increasing number of CubeSats being launched has raised concerns about orbital debris since most of these satellites have no means of active orbit control. Some technologies exist to increase the surface area of a CubeSat and expedite de-orbit due to aerodynamic drag in low Earth orbit, but most of these devices cannot be retracted and hence cannot be used for orbital maneuvering. This paper discusses the De-Orbit Drag Device (D3) module that is capable of de-orbiting a 12U, 15kg CubeSat from a 700 km circular orbit in under 25 years and can be deployed and retracted to modulate the aerodynamic drag force experienced by the satellite. This facilitates orbital maneuvering using aerodynamic drag and the active targeting of a de-orbit location. In addition, the geometry of this drag device provides 3-axis attitude stabilization of the host CubeSat using aerodynamic and gravity gradient torques which is useful for many missions and provides a predictable aerodynamic profile for use in orbital maneuvering algorithms.

algorithm↗

NASA NTRSDate not supplied

Measuring and Utilizing Gravity-Gradient Induced Torques on Future Gravity Recovery Missions

This research is a novel investigation into the use of newly-available relative angular acceleration measurements between a spacecraft utilized for gravity recovery missions and an internally located test mass. The gravity-gradient torque equation for zonal spherical harmonic order n is formulated for a known gravitational potential field, and through simulations it is proven that the Simplified-Gravitational Reference Sensor will be sensitive to the gravity-gradient induced torques acting on its test mass. The full conference paper will demonstrate how the presented gravity-gradient torque equation and the measured relative angular acceleration between the spacecraft and test mass will improve the accuracy of the gravity field models acquired by future gravity recovery missions by directly measuring the drag acting on the spacecraft with a single accelerometer.

gravity recovery↗