LEO Object’s Light-Curve Acquisition System and Their Inversion for Attitude Reconstruction

Abstract

In recent years, the increase in space activities has brought the space debris issue to the top of the list of all space agencies. The fact of there being uncontrolled objects is a problem both for the operational satellites in orbit (avoiding collisions) and for the safety of people on the ground (re-entry objects). Optical systems provide valuable assistance in identifying and monitoring such objects. The Sapienza Space System and Space Surveillance (S5Lab) has been working in this field for years, being able to take advantage of a network of telescopes spread over different continents. This article is focused on the re-entry phase of the object; indeed, the knowledge of the state of the object, in terms of position, velocity, and attitude during the descent, is crucial in order to predict as accurately as possible the impact point on the ground. A procedure to retrieve the light curves of orbiting objects by means of optical data will be shown and a method to obtain the attitude determination from their inversion based on a stochastic optimization (genetic algorithm) will be proposed.

Short-Arc Association and Orbit Determination for New GEO Objects with Space-Based Optical Surveillance

“…Ground-based optical telescopes have been primary facilities for detecting GEO objects, such as GEODSS [2], JAXA/IAT [3], AIUB ZIMLAT [4], Falcon [5], OWL-Net [6], FocusGEO [7], SSON [8,9], AGO70 [10], APOSOS [11], and so on. However, they are unable to detect and monitor GEO objects outside their effective FOV, and cataloguing the GEO objects over the full GEO region requires a global ground network, which may be unachievable for some countries.…”

Experimental Reflection Evaluation for Attitude Monitoring of Space Orbiting Systems with NRL Arch Method

“…In this frame, with several thousand objects orbiting around Earth, having a tool similar to a radar system that could help to track objects and determine their attitude and re-entry trajectory is therefore of primary importance. In order to envisage the trajectory of these objects, one has to know their attitude to evaluate the effects of the atmospheric drag on the trajectory itself, also associating radar measurements with other tracking systems such as the optical system, for example, LED (Light Emission Diodes) [4][5][6][7], or light-curve acquisition systems [8][9][10] or magnetometer data [11]. Knowing the attitude using radar systems, therefore, becomes one of the fundamental tasks for the detection of space debris, as demonstrated by the recent case of the Chinese Space Station Tiangong-1 [12].…”