Military Space Mission Design and Analysis in a Multi-Body Environment: An Investigation of High-Altitude Orbits as Alternative Transfer Paths, Parking Orbits for Reconstitution, and Unconventional Mission Orbits

High-altitude satellite trajectories are analyzed in the Earth-Moon circular restricted three-body problem. The equations of motion for this dynamical model possess no known closed-form analytical solution; therefore, numerical methods are employed. To gain insight into the dynamics of high-altitude trajectories in this multi-body dynamical environment, periapsis Poincare\u27 maps are generated at particular values of the Jacobi Constant. These maps are employed as visual aids to generate initial guesses for orbital transfers and to determine the predictability of the long term behavior of a spacecraft\u27s trajectory. Results of the current investigation demonstrate that high-altitude transfers may be performed for comparable, and in some cases less, V than conventional transfers. Additionally, transfers are found that are more timely than a launch-on-demand capability that requires 30 days lead time. The ability of satellites in such orbits to provide remote sensing coverage of the surface of the Earth is also assessed and found to be low relative to that of a satellite at geostationary altitude (35,786 km); however, intervals of high performance exist. The current investigation demonstrates not only the potential utility of high-altitude satellite trajectories for military applications but also an effective implementation of methods from dynamical systems theory

Constrained Optimal Orbit Design for Earth Observation

The purpose of this dissertation is to demonstrate use requirements for a satellite observation mission can be used to determine a constrained optimal orbit based on observation site requirements, observation condition restraints, and sensor characteristics. The typical Earth observation satellite is first designed according to an appropriate orbit; then the observation requirements are used to develop a target schedule. The new design process outlines the development of the appropriate orbit by incorporating user requirements at the forefront of mission planning, not after an orbit has been selected. This research shows how to map the user requirements into constraints for the cost function and optimization process. A global case study with variations demonstrates the effectiveness of the design process. Additionally, a case study is performed for a regional or clustered set of targets. Finally, a lifecycle analysis tests the orbit in a full perturbation environment to evaluate the changes in the ideal orbital elements over time without orbit maintenance or corrections

Stable orbits in the proximity of an asteroid: solutions for the Hayabusa 2 mission

This thesis studies the dynamics that arise in the surroundings of a small asteroid with the objective of identifying feasible trajectories for use in the Japanese mission Hayabusa 2. Hayabusa 2, which is expected to be launched at the end of year 2014, will travel to near earth asteroid 1999 JU3 and rendezvous with it. The main purpose of the mission is to collect a sample of the asteroid’s rock and carry it back to the earth for a detailed analysis. The spacecraft, however, will remain close to the asteroid for approximately 1.5 years, and it will perform several other types of scientific observations. All of the operations will be carried out from a controlled hovering position, that is, a fixed point between the earth the asteroid, close to the latter. This study aims at finding orbital strategies, different from hovering, that can enhance the scientific returns of this phase. In particular, orbits passing repeatedly close to the asteroid would provide a wealth of information on the gravitational field, and thus the internal structure, that would not be available through simple hovering. A first part of this work is focused on the circular augmented Hill’s 3–body problem, a formulation similar to the restricted 3-body problem that well describes the asteroidal environment, including solar radiation pressure. In this system we perform a grid search that results in a collection of several periodic orbits. We study a group of these orbits in detail, constructing their whole families with numerical continuation and analyzing their stability properties. The orbit families are also subject to a comparison on the basis of the characteristics most appropriate to Hayabusa 2. The result of this part is the identification of a type of orbit that is most feasible for the Japanese mission. Not treated in the above part are the two other important properties of the dynamical system, that is, the inhomogeneity of the asteroid’s mass and the ellipticity of its orbit around the sun. These are considered in the second part as perturbations, and a linear quadratic regulator (LQR) is set up in order to actively eliminate them. We show that the LQR is capable of stabilizing the periodic orbits against these and other effects, using thrusts attainable, in theory, with electric propulsion. The final part of this thesis addresses the need for trajectories that are stable in the elliptic Hill’s problem without any control. Rather then looking for periodic orbits in this more complex system, we use the results from the circular case to identify non-periodic repetitive trajectories that are nonetheless stable. The result in a map of the space of initial conditions containing a wide group of trajectories that neither impact nor escape from the asteroids for long periods of time. Among these trajectories, some are especially suitable for the purposes and instrument requirements of Hayabusa 2

NEUTROSOPHIC LOGIC, WAVE MECHANICS, AND OTHER STORIES

There is beginning for anything; we used to hear that phrase. The same wisdom word applies to the authors too. What began in 2005 as a short email on some ideas related to interpretation of the Wave Mechanics results in a number of papers and books up to now. Some of these papers can be found in Progress in Physics or elsewhere. It is often recognized that when a mathematician meets a physics-inclined mind then the result is either a series of endless debates or publication. In this story, authors preferred to publish rather than perish. Therefore, the purpose with this book is to present a selection of published papers in a compilation which enable the readers to find some coherent ideas which appear in those articles. For this reason, the ordering of the papers here is based on categories of ideas

Advanced Onboard Spacecraft Guidance and Navigation Console

This proposal defines an advanced onboard navigation interface and trajectory design tool for future astronauts. As the space industry expands and becomes more commercialized, future spaceflight will include long-duration exploration to more distant destinations. Mission tasks, such as rendezvous, docking, descent, landing, and in-space trajectory planning will become commonplace. Presently, many of these tasks are performed with the assistance of ground-based mission control. The onboard crew typically has limited control of vehicle guidance and navigation. This is in stark contrast with the more mature commercial and private aircraft industry, for which guidance, navigation and control are operated primarily by the crew. As the space industry continues to expand with more and more space vehicles, it will become necessary and desirable for the crew to have independent onboard guidance, navigation and control capability. It will not be possible nor efficient to have ground-control operations of every space vehicle, particularly those that are distant from Earth. Just as the pilot operates a suite of instruments and controls on a conventional aircraft, new concepts for spacecraft crew interfaces will be needed for future space pilots. As such, this research proposes the conception and design of an onboard spacecraft pilot interface called the “Spaceflight Console.” The purpose is to provide the crew full autonomy for spacecraft navigation and guidance via touch-controls and holographic visual displays. The objective is to design an intuitive interface for onboard trajectory planning and a wide range of mission tasks that will become more commonplace in the future, such as interplanetary departure, trajectory corrections, orbital insertion, rendezvous, station keeping, landing site selection and targeting, and so on. The proposed Spaceflight Console will be built and demonstrated using a virtual-reality (VR) engineering-design platform designed by the ASTRO Lab at Texas A&M, called SpaceCRAFT. Using SpaceCRAFT crew interfaces can be designed, evaluated in the context of a mission environment in VR, and revised easily. Control panels for crew selections or data entry will be coupled with 3D visual displays that enable crew situational awareness in an orbital or interplanetary context. Similar to an aircraft cockpit and the usual suite of flight instruments, the Spaceflight Console presents intuitive information to the crew while internally performing complex computations to support the mission tasks. In effect, the Spaceflight Console aims to translate many complex ground-control capabilities into a fully onboard system with a simple and intuitive interface that operates from the pilot’s perspective

Optimal Relative Path Planning for Constrained Stochastic Space Systems

Rendezvous and proximity operations for automated spacecraft systems requires advanced path planning techniques that are capable of generating optimal paths. Real-world constraints, such as sensor noise and actuator errors, complicate the planning process. Operations also require flight safety considerations in order to prevent the spacecraft from potentially colliding with the associated companion spacecraft. This work proposes a new, ground-based trajectory planning approach that seeks an optimal trajectory while meeting all mission constraints and accounting for vehicle performance and safety requirements. This approach uses a closed-loop linear covariance simulation of the relative trajectory coupled with a genetic algorithm to determine fuel optimal trajectories. Spacecraft safety is addressed using statistical data from the linear covariance model to bound the probability of collision

Satellite swarms for auroral plasma science

With the growing accessibility of space, this thesis work sets out to explore space-based swarms to do multipoint magnetometer measurements of current systems embedded within the Aurora Borealis as an initial foray into concepts for space physics applications using swarms of small spacecraft. As a pathfinder, ANDESITE---a 6U CubeSat with eight deployable picosatellites---was built as part of this research. The mission will fly a local network of magnetometers above the Northern Lights. With the spacecraft due to launch on an upcoming ELaNa mission, here we discuss the details of the science motivation, the mathematical framework for current field reconstruction, the particular hardware implementation selected, the calibration procedures, and the pragmatic management needed to realize the spacecraft. After describing ANDESITE and defining its capability, we also propose a follow-on that uses propulsive nodes in a swarm, allowing measurements that can adaptively change to capture the physical phenomena of interest. To do this a flock of satellites needs to fall into the desired formation and maintain it for the duration of the science mission. A simple optimal controller is developed to model the deployment of the satellites. Using a Monte Carlo approach for the uncertain initial conditions, we bound the fuel cost of the mission and test the feasibility of the concept. To illustrate the system analysis needed to effectively design such swarms, this thesis also develops a framework that characterizes the spatial frequency response of the kilometer-scale filter created by the swarm as it flies through various current density structures in the ionospheric plasma. We then subjugate a nominal ANDESITE formation and the controlled swarm specified to the same analysis framework. The choice of sampling scheme and rigorous basic mathematical analysis are essential in the development of a multipoint-measurement mission. We then turn to a novel capability exploiting current trends in the commercial industry. Magnetometers deployed on the largest constellation to date are leveraged as a space-based magnetometer network. The constellation, operated by Planet Labs Inc., consists of nearly 200 satellites in two polar sun-synchronous orbits, with median spacecraft separations on the order of 375 km, and some occasions of opportunity providing much closer spacing. Each spacecraft contains a magneto-inductive magnetometer, able to sample the ambient magnetic field at 0.1 Hz to 10 Hz with <200 nT sensitivity. A feasibility study is presented wherein seven satellites from the Planet constellation were used to investigate space-time patterns in the current systems overlying an active auroral arc over a 10-minute interval. Throughout the this work advantages, limitations, and caveats in exploiting networks of lower quality magnetometers are discussed, pointing out the path forward to creating a global network that can monitor the space environment

Sparse Signal Recovery Based on Compressive Sensing and Exploration Using Multiple Mobile Sensors

The work in this dissertation is focused on two areas within the general discipline of statistical signal processing. First, several new algorithms are developed and exhaustively tested for solving the inverse problem of compressive sensing (CS). CS is a recently developed sub-sampling technique for signal acquisition and reconstruction which is more efficient than the traditional Nyquist sampling method. It provides the possibility of compressed data acquisition approaches to directly acquire just the important information of the signal of interest. Many natural signals are sparse or compressible in some domain such as pixel domain of images, time, frequency and so forth. The notion of compressibility or sparsity here means that many coefficients of the signal of interest are either zero or of low amplitude, in some domain, whereas some are dominating coefficients. Therefore, we may not need to take many direct or indirect samples from the signal or phenomenon to be able to capture the important information of the signal. As a simple example, one can think of a system of linear equations with N unknowns. Traditional methods suggest solving N linearly independent equations to solve for the unknowns. However, if many of the variables are known to be zero or of low amplitude, then intuitively speaking, there will be no need to have N equations. Unfortunately, in many real-world problems, the number of non-zero (effective) variables are unknown. In these cases, CS is capable of solving for the unknowns in an efficient way. In other words, it enables us to collect the important information of the sparse signal with low number of measurements. Then, considering the fact that the signal is sparse, extracting the important information of the signal is the challenge that needs to be addressed. Since most of the existing recovery algorithms in this area need some prior knowledge or parameter tuning, their application to real-world problems to achieve a good performance is difficult. In this dissertation, several new CS algorithms are proposed for the recovery of sparse signals. The proposed algorithms mostly do not require any prior knowledge on the signal or its structure. In fact, these algorithms can learn the underlying structure of the signal based on the collected measurements and successfully reconstruct the signal, with high probability. The other merit of the proposed algorithms is that they are generally flexible in incorporating any prior knowledge on the noise, sparisty level, and so on. The second part of this study is devoted to deployment of mobile sensors in circumstances that the number of sensors to sample the entire region is inadequate. Therefore, where to deploy the sensors, to both explore new regions while refining knowledge in aleady visited areas is of high importance. Here, a new framework is proposed to decide on the trajectories of sensors as they collect the measurements. The proposed framework has two main stages. The first stage performs interpolation/extrapolation to estimate the phenomenon of interest at unseen loactions, and the second stage decides on the informative trajectory based on the collected and estimated data. This framework can be applied to various problems such as tuning the constellation of sensor-bearing satellites, robotics, or any type of adaptive sensor placement/configuration problem. Depending on the problem, some modifications on the constraints in the framework may be needed. As an application side of this work, the proposed framework is applied to a surrogate problem related to the constellation adjustment of sensor-bearing satellites

Energetic particle injection events in the Kronian magnetosphere: applications and properties

The Kronian magnetosphere is highly dynamical. The inner part between 3 Rs and 13 Rs contains numerous injections of hot plasma with energies up to a few hundred keV. This thesis concentrates on electron measurements of the Magnetospheric Imaging Instrument (MIMI) onboard the Cassini spacecraft. It describes properties of the events themselves and uses them as a tool to characterize aspects of the global configuration of the magnetosphere. We show that the magnetospheric plasma subcorotates with about 80 % of full corotation at radial distances between 8 Rs and 13 Rs and explain the observations of inverted electron dispersion profiles with a differential velocity profile. The night and the morning sector of the magnetosphere are the preferred regions for the generation of hot plasma injections. The intensities of injection events show a clear dependency on local time. Injections originating in the noon to midnight sector are less intense than the ones injected on the midnight to noon sector. These facts help to infer the mechanisms that causes the injections. The low intensity injections can be associated with the interchange instability while the high intensity injections might be generated through dipolarization due to magnetic reconnection in the magnetotail of Saturn. Considering the intensity of injections with respect to their age, we infer a lifetime of about two planetary rotations for injections in the analysed energy range

AAS/GSFC 13th International Symposium on Space Flight Dynamics

This conference proceedings preprint includes papers and abstracts presented at the 13th International Symposium on Space Flight Dynamics. Cosponsored by American Astronautical Society and the Guidance, Navigation and Control Center of the Goddard Space Flight Center, this symposium featured technical papers on a wide range of issues related to orbit-attitude prediction, determination, and control; attitude sensor calibration; attitude dynamics; and mission design