In the context of Human Spaceflight exploration mission scenario, with the Lunar Orbital Platform-Gateway (LOP-G) orbiting about Earth-Moon Lagrangian Point (EML), Rendezvous and Docking (RVD) operational activities are mandatory and critical for the deployment and utilization of the LOP-G (station assembly, crew rotations, cargo delivery, lunar sample return). There is extensive experience with RVD in the two-body problem: in Low Earth Orbit (LEO) to various space stations, or around quasi-circular Low Lunar Orbits (LLO), the latter by Apollo by means of manual RVD. However, the RVD problem in non-Keplerian environments has rarely been addressed and no RVD has been performed to this date in the vicinity of Lagrangian points (LP) where Keplerian dynamics are no longer applicable. Dynamics in such regions are more complex, but multi-body dynamics also come with strong advantages that need to be further researched by the work proposed here. The aim of this paper is to present methods and results of investigations conducted to first set up strategies for far and close rendezvous between a target (the LOP-G, for example) and a chaser (cargo, crew vehicle, ascent and descent vehicle, station modules, etc.) depending on target and chaser orbit. Semi-analytical tools have been developed to compute and model families of orbits about the Lagrangian points in the Circular Restricted Three Body Problem (CR3BP) like NRHO, DRO, Lyapunov, Halo and Lissajous orbits. As far as close rendezvous is concerned, implementation of different linear and non-linear models used to describe cis-lunar relative motion will be discussed and compared, in particular for NRHO and DRO.
The parameterization method (pm) has been used to compute high-order parameterizations of invariant manifolds of vector fields at fixed points. This paper extends such approach to invariant manifolds of periodically-perturbed vector fields about a periodic orbit with the same frequency, with a direct application on the libration points of the Sun-Earth-Moon system. The Sun-Earth-Moon environment is modeled by the so-called Quasi-Bicircular Model (qbcp), which is a coherent restricted four-body model that describes the motion of a spacecraft under the simultaneous gravitational influences of the Earth, the Moon, and the Sun. The pm is adapted to account for the explicit time-dependency of the corresponding vector field. This new procedure yields high-order periodic semi-analytical approximations of the center manifolds about the libration points L 1,2 of the periodically-perturbed Sun-(Earth+Moon) and Earth-Moon systems. These approximations are then used to initialize the computation of Poincaré maps, which allow to get a qualitative description of the non-autonomous dynamics near the equilibrium points. It is shown that, with this new approach, the semi-analytical description of the center manifolds in a coherent four-body environment is valid in a neighborhood significant enough to be used in practice. In particular, the well-known Halo orbit bifurcation is recovered in all cases.
Although the eFFBD formalism dates back to the 1990s (or even, in a simplified form, the 1950s), it seems that it is still not as much used by the Systems Engineering community as it could. Indeed, eFFBD is a modeling language focusing on functional paradigm i.e. allowing functional and behavioral modeling and reasoning about a system. Currently, it is often confronted or compared to other languages such as SysML for activity modeling (activity diagrams) based on object paradigm. This paper aims to demonstrate the interest and the potential advantages for systems designers, like most of the discipline‐oriented designers to dispose of an enriched (conceptually and semantically) eFFBD modeling language called here xFFBD. This has to be a credible framework for modeling, communicating and reasoning about complex systems. After shortly recalling the history, the key concepts and capabilities of eFFBD, this paper compares eFFBD with other formalisms considered here as relevant for the study, Petri nets and SysML. Several leads are then identified and discussed in order to improve the eFFBD language and to provide a first draft version of xFFBD specification.
The rising production rate of space debris poses an increasingly severe threat of collision to satellites in the crowded Geostationary Orbit (GEO). It also presents a unique opportunity to make use of a growing supply of inspace resources for the benefit of the satellite community. "The Recycler" is a mission proposed to source replacements for failed components in GEO satellites by extracting functioning components from non-operational spacecraft in the GEO graveyard. This paper demonstrates a method of analyzing in-space re-purposing missions such as the Recycler, using real satellite data to provide a strong platform for accurate performance estimates. An inventory of 1107 satellites in the extended GEO region is presented, and a review into past GEO satellite anomalies is conducted to show that solar arrays would be in the greatest demand for re-purposing. This inventory is used as an input to a greedy selection algorithm and trajectory simulation to show that the Recycler spacecraft could harvest components for 67 client satellites with its allotted fuel budget. This capacity directly meets the levels of customer demand estimated from the GEO satellite anomaly data, placing the Recycler as a strong contender in a future second-hand satellite-component industry. Propellant mass is found to be a greater restriction on the Recycler mission than its 15-year lifetime -a problem which could be solved by on-orbit refueling.
The paper will showcase the design and development of the AIM experiment cube, the results of testing and the educational applications of the ICE Cubes Facility. The full data and results will be available after the completion of the mission which is expected to be between March and June 2020.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.