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Articles 1 - 17 of 17
Full-Text Articles in Astrodynamics
Light Curve Generation For Satellites In Geostationary Orbits, Kimberly Andersen
Light Curve Generation For Satellites In Geostationary Orbits, Kimberly Andersen
Aerospace Engineering
This research were conducted at California Polytechnic State University San Luis Obispo throughout the Winter, Spring, and Fall quarters of 2013. The data presented in this paper was taken on the night of October 20, 2013 at the Cal Poly San Luis Obispo Astronomical Observatory and was reduced using IRAF software available on campus. This report describes the results of an observation of two bright XM geostationary satellites and the steps taken to get to those results. The average magnitude values of the XM-1 and XM-2 satellites were 13.753±0.007 and 14.015±0.007 respectively. The magnitude varied an average of 0.1 magnitudes …
Feasibility Of Cubesat Formation Flight Using Rotation To Achieve Differential Drag, Skyler M. Shuford
Feasibility Of Cubesat Formation Flight Using Rotation To Achieve Differential Drag, Skyler M. Shuford
Aerospace Engineering
This paper presents the results of a study conducted to understand the feasibility of CubeSat formation flight. The mechanism for separation and formation studied was differential drag, achieved by rotating the CubeSats to give them different cross-sectional areas. Intuitively, lower altitude orbits provide much higher separation effects. Although the most influential orbital effects occur with maximum and minimum cross-sectional areas, an attitude-controlled and a tumbling CubeSat may provide enough differential drag to meet separation requirements of a mission. Formation flight is possible, but due to the non-linearity of the system, gain scheduling may be the most effective method of long …
Three-Axis Stabilized Earth Orbiting Spacecraft Simulator, Alan F. Ma, Nikola N. Dominikovic
Three-Axis Stabilized Earth Orbiting Spacecraft Simulator, Alan F. Ma, Nikola N. Dominikovic
Aerospace Engineering
This report details the method and results of the program created for simulating an Earth orbiting spacecraft with control actuators and orbital perturbations. The control actuators modeled are reaction thrusters, reaction/momentum wheels, and control moment gyros (CMG). The perturbations modeled were gravity gradient, electromagnetic torques, solar radiation pressure, gravity gradients, third-body effects, Earth oblateness and atmospheric drag. This simulation allows for satellite control in all 6 degrees of freedom for any Earth orbiting spacecraft. Assumptions include rigid body dynamics, no sensor noise, constant spacecraft cross-sectional area, constant coefficient of drag and reflectivity, ignoring the effects due to the moon, moment …
High-Fidelity Low-Thrust Trajectory Determination Research And Analysis, Tyler Hill
High-Fidelity Low-Thrust Trajectory Determination Research And Analysis, Tyler Hill
Aerospace Engineering
This document discusses a numerical analysis method for low thrust trajectory propagation known as the proximity quotient or Q-Law. The process uses a Lyapunov feedback control law developed by Petropoulos[1] to propagate trajectories of spacecraft by minimizing the user defined function at the target orbit. A simplified propagator is created from the core mechanics of this method in MATLAB and tested in several user defined cases to demonstrate its capabilities. Several anomalies arose in test cases where variations in eccentricity, inclination, right ascension of the ascending node, and argument of perigee were specified. Solutions to these anomalies are discussed …
Computation Time Comparison Between Matlab And C++ Using Launch Windows, Tyler Andrews
Computation Time Comparison Between Matlab And C++ Using Launch Windows, Tyler Andrews
Aerospace Engineering
Processing speed between Matlab and C++ was compared by examining launch windows and handling large amounts of data found in pork chop plots. A compilation of code was generated in Matlab to produce the plots and an identical file was created in C++ that was then compiled and run in Matlab to plot the data. This file is known as a MEX-file. This report outlines some of the basics when working with MEX-files and the problems that face users. For Lambert’s solver, multi revolution cases were considered and some pork chop plots of single revolution trajectories were plotted. Three different …
Accelerating Lambert's Problem On The Gpu In Matlab, Nathan Parrish
Accelerating Lambert's Problem On The Gpu In Matlab, Nathan Parrish
Aerospace Engineering
The challenges and benefits of using the GPU to compute solutions to Lambert’s Problem are discussed. Three algorithms (Universal Variables, Gooding’s algorithm, and Izzo’s algorithm) were adapted for GPU computation directly within MATLAB. The robustness of each algorithm was considered, along with the speed at which it could be computed on each of three computers. All algorithms used were found to be completely robust. Computation time was measured for computation within a for-loop, a parfor-loop, and a call to the MATLAB command ‘arrayfun’ with gpuArray-type inputs. Then, a Universal Variables Lambert’s solver was written in CUDA and compiled for use …
The Numerical Open-Source Many-Body Simulator (Noms), Jason Lloyd Daniel, Javen Kyle Foster-O'Neal
The Numerical Open-Source Many-Body Simulator (Noms), Jason Lloyd Daniel, Javen Kyle Foster-O'Neal
Aerospace Engineering
This paper outlines the setup and creation of an object-oriented N-body simulator as part of a continued project to explore physical phenomenon and human-computer natural interaction technologies. The tools and processes required to build an N-body simulator are also included. Several integrators were evaluated based on their ability to maintain system energy The 2nd order integrator Verlet and 3rd order integrator Hermite algorithms had the greatest accuracy to model large-scale N-body dynamics for their given computation time. Other algorithms required significantly shorter time steps to achieve similar short-term accuracy. At present, NOMS can reasonably simulate 10,000 particles at less than …
Comprehensive Matlab Gui For Determining Barycentric Orbital Trajectories, Steve Katzman
Comprehensive Matlab Gui For Determining Barycentric Orbital Trajectories, Steve Katzman
Aerospace Engineering
When a 3-body gravitational system is modeled using a rotating coordinate frame, interesting applications become apparent. This frame, otherwise known as a barycentric coordinate system, rotates about the system’s center of mass. Five unique points known as Lagrange points rotate with the system and have numerous applications for spacecraft operations. The goal of the Matlab GUI was to allow easy manipulation of trajectories in a barycentric coordinate system to achieve one of two end goals: a free-return trajectory or a Lagrange point rendezvous. Through graphical user input and an iterative solver, the GUI is capable of calculating and optimizing both …
De-Orbiting Upper Stage Rocket Bodies Using A Deployable High Altitude Drag Sail, Robert A. Hawkins Jr., Joseph A. Palomares
De-Orbiting Upper Stage Rocket Bodies Using A Deployable High Altitude Drag Sail, Robert A. Hawkins Jr., Joseph A. Palomares
Aerospace Engineering
This report examines the effectiveness of a drag sail to de-orbit upper stage rocket bodies. Many other perturbations contribute to the de-orbiting of these rocket bodies, and these perturbations will also be discussed briefly. This paper will show the length of time needed to force the altitudes of various launch vehicle stages with varying drag area sizes to less than 100 km. The upper stage of the Delta IV launch vehicle in an orbit with an altitude of 500 km will naturally de-orbit in 720 days but when equipped with a 20 m2 drag sail, it will de-orbit in …
Investigating Various Propulsion Systems For An External Attachment For A Controlled-Manual De-Orbit Of The Hubble Space Telescope, Nelson De Guia
Investigating Various Propulsion Systems For An External Attachment For A Controlled-Manual De-Orbit Of The Hubble Space Telescope, Nelson De Guia
Aerospace Engineering
This reports explains the results for a proposed senior project. This project concerns the Hubble Space Telescope, and exploring the possibility of having an external propulsion attachment for a manual de-orbit. The Hubble Space Telescope was proposed to return to Earth via the Space Shuttle. Although, through the current U.S. Space Administration, the Space Shuttle has been retired before the Hubble Space Telescope was retrieved. By completing this project, the results could provide insight to what type of propulsion would best de-orbit the Hubble upon its retirement. Different propulsion systems were considered to attempt to determine an optimal attachment, varying …
An Analysis Of Stabilizing 3u Cubesats Using Gravity Gradient Techniques And A Low Power Reaction Wheel, Erich Bender
An Analysis Of Stabilizing 3u Cubesats Using Gravity Gradient Techniques And A Low Power Reaction Wheel, Erich Bender
Aerospace Engineering
The purpose of this paper is to determine the feasibility of gravity gradient stabilizing a 3U CubeSat and then using a miniature reaction wheel to further increase stability characteristics. This paper also serves as a guide to understanding and utilizing quaternions in attitude control analysis. The analytical results show that using 33 centimeter booms and 400 gram tip masses, a 3U CubeSat will experience a maximum of 6 degrees of angular displacement in yaw and pitch, and less than .5 degrees of angular displacement in the nadir axis. A .120 kilogram miniature reaction wheel developed by Sinclair Interplanetary was introduced …
An Analysis Of N-Body Trajectory Propagation, Emerson Frees Ii
An Analysis Of N-Body Trajectory Propagation, Emerson Frees Ii
Aerospace Engineering
Trajectories created with n-body orbit models were propagated in geocentric and interplanetary test cases. The n-body models were created in MATLAB® using numerical integration. In the geocentric test case, the n-body codes were compared to a two-body orbit model and to the default HPOP model used in Satellite Tool Kit®. The interplanetary test case compared the n-body model to the HORIZONS ephemeris data from JPL and an equation for ephemeris propagation. Both cases used the same initial positions and velocities and were propagated for the same duration. The results of the analysis showed that while n-body models …
Design, Fabrication, And Testing Of An Electromagnetic Rail Gun For The Repeated Testing And Simulation Of Orbital Debris Impacts, Jeff Maniglia, Jordan Smiroldo, Alex Westfall, Guy Zohar
Design, Fabrication, And Testing Of An Electromagnetic Rail Gun For The Repeated Testing And Simulation Of Orbital Debris Impacts, Jeff Maniglia, Jordan Smiroldo, Alex Westfall, Guy Zohar
Aerospace Engineering
An Electromagnetic Railgun (EMRG) was designed, built, and tested, capable of firing a projectile a 1 gram projectile at 650 m/s muzzle velocity. The EMRG utilizes an injector, a high voltage power supply, a capacitor bank, inductors and rails. The injector fires 2300 psig Nitrogen gas into the system to provide an initial velocity. The high voltage power supply charges the capacitor bank. The capacitor bank discharges the electric potential built up through the projectile while inside the rails in order to create the EMRG’s force. The inductors are used to pulse form the capacitor bank in order to get …
Mapping Galileo's Trajectory, Mark Woods
Mapping Galileo's Trajectory, Mark Woods
Aerospace Engineering
The NASA Galileo mission was mapped out using a patched conics approximation. Galileo launched from Earth, underwent a gravity assist from Venus back to Earth for another gravity assist. Galileo then came back to Earth for one more gravity assist to propel it to Jupiter. A simulation ignoring all perturbations (i.e. third body effects, zonal (harmonics, solar wind, drag) was carried out. The simulation was able to make it to the final Earth flyby before diverging from the actual trajectory. The simulated and actual flyby dates all differed by less than 5 hours, and the simulated and actual flyby altitudes …
Interplanetary Gravity Assisted Trajectory Optimizer (Igato), Jason Bryan
Interplanetary Gravity Assisted Trajectory Optimizer (Igato), Jason Bryan
Aerospace Engineering
Interplanetary space travel is an extremely complicated endeavor that is severely limited by our current technological advancements. The amount of energy required to transport a spacecraft from one planet to the next, or even further, is extraordinary and in some cases is even impossible given our current propulsive capabilities. Due to these complications, the search for other means of exchanging energy became imperative to future space exploration missions. One particularly powerful method that was discovered, and the most commonly used one, is referred to as planetary gravity assist. In order to plan out multiple gravity assist trajectories, complex and robust …
Senior Project: Global Position Determination From Observed Relative Position Of Celestial Bodies, Michael Holmes
Senior Project: Global Position Determination From Observed Relative Position Of Celestial Bodies, Michael Holmes
Aerospace Engineering
A method was developed to determine the latitude and longitude of an observer based on the observed position of the Moon and several other celestial bodies. The basic principal developed dealt with the proximity of the Moon. Its relative displacement from calculated values was measured using photography by comparison with stars near the Moon. Photographs were taken from a location in San Luis Obispo at Longitude 120°35.9' and Latitude 35°13.3'. The analysis method has determined the location of the observer to a Longitude of 117°43.8'. An additional method located the observer to 36°38.7'N Latitude and 114°47.6'W Longitude.
Matlab® Gui Visualization Of Classical Orbital Elements, Nancy Teresa Cabrera
Matlab® Gui Visualization Of Classical Orbital Elements, Nancy Teresa Cabrera
Aerospace Engineering
The classical orbital elements of an orbit are eccentricity, angular momentum, inclination, right ascension of ascending node, true anomaly, and argument of perigee. These six parameters define an orbit. Using MATLAB® to model a satellite orbiting Earth in three dimensions, a graphical user interface was created to allow a user to manipulate the orbital elements to desired quantities. In doing so, each parameter’s impact on the orbit is visually displayed. This furthers the understanding of how the parameters are linked to the orbit. When the interface is first opened, the default circular orbit has a range of 20,000 kilometers, an …