Master's Projects

Series

Master's Projects

Permanent Link

https://hdl.handle.net/1853/71003

Series Type

Publication Series

Full item page

Publication Search Results

Now showing 1 - 10 of 43

Development of an Earth SmallSat Flight Test to Demonstrate Viability of Mars Aerocapture

(Georgia Institute of Technology, 2017-05-01) Werner, Michael S.

A smallsat mission concept is developed to demonstrate the feasibility of an aerocapture system at Earth. The proposed mission utilizes aerocapture to transfer from a GTO rideshare trajectory to a LEO. Single-event drag modulation is used as a simple means of achieving the control required during the maneuver. Low- and high-fidelity guidance algorithm choices are considered. Numeric trajectory simulations and Monte Carlo uncertainty analyses are performed to show the robustness of the system to day-of-flight environments and uncertainties. Similar investigations are performed at Mars to show the relevance of the proposed mission concept to potential future applications. The spacecraft design consists of a 24.9 kg vehicle with an attached rigid drag skirt, and features commercially-available hardware to enable flight system construction at a university scale. Results indicate that the proposed design is capable of targeting the desired final orbit, surviving the aerothermodynamic and deceleration environments produced during aerocapture, and downlinking relevant data following the maneuver
Trajectory Trade-space Design for Robotic Entry at Titan

(Georgia Institute of Technology, 2017-05-01) Roelke, Evan

In recent years, scientific focus has emphasized other ocean worlds such as Europa, Enceladus, and Titan, due to their potential for harboring life. The only spacecraft ever to land on these moons was the Huygens Probe in 2005; however, this probe’s main purpose was to study the atmosphere and surface of Titan, with no real landing target. Future missions to other ocean worlds would likely require a science target and thus add several constraints to the mission such as arrival time, entry state, and aeroshell geometry, among others. Of the three ocean worlds previously mentioned, Titan is an optimal target for initial mission concepts for several reasons. The atmospheric composition, winds, and surface features are well studied by Cassini and the Huygens Probe. Additionally, of the aforementioned moons, Titan does not have a thick ice sheet to penetrate in order to sample the surface and/or liquid seas, enabling such mission to double as a stepping stone for missions to other ocean worlds. Finally, Titan exhibits a myriad of interesting planetary features that, if studied, could further the understanding of both Titan’s and the solar system’s geologic history. In this paper we analyze the trade-spaces of various important parameters involved in Entry, Descent, and Landing (EDL) as it pertains to robotic missions for Titan in order to provide a guideline for optimizing a mission’s system parameters while minimizing both system complexity and the landing footprint. It is found that the ideal geometry is a ballistic spherecone body entering from orbit to allow flexibility in the entry state vector. The aerothermodynamic environment is most affected by the entry velocity and the vehicle bluntness ratio, while the peak deceleration is most influenced by the entry velocity and entry flight path angle. In addition, multiple parachutes decrease the landing footprint, impact speed, and descent time compared to single parachute systems, at the expense of being more complex. Larger ballistic coefficients decrease the landing footprint and descent time while increasing the impact speed. Finally, it is discovered that the uncertainty in the entry altitude and flight path angle have the most impact on the final state vector.
Mechanical Design of a Cubesat Aeroshell for an Earth Demonstration of Single-Stage Drag Modulated Aerocapture

(Georgia Institute of Technology, 2016-08-01) Woollard, Bryce A.

The following article documents the conceptual study of a smallsat entry vehicle to be implemented for demonstration of single-stage drag modulated aerocapture at Earth. The specific nature of the contents below focuses on the mechanical design and analysis of the aeroshell and drag device, as well as the mechanisms by which all parts are to be manufactured, assembled and actuated in order to perform the intended orbital maneuver. The results of this study show that accomplishing aerocapture with a cubesat entry vehicle appears to be feasible with a 2U payload and would require approximately 20 kg and 0.1 m3 of secondary payload mass and volume, respectively. First order stagnation point thermal protection sizing suggests that 4.2 cm of PICA would be required globally around the vehicle, although potential exists to optimize this value relative to geometric location. Static stability analysis indicates that the designed vehicle is nose-forward stable for a majority of the atmospheric interface with outstanding questions pertaining to atmospheric egress. Manufacturing costs for a full scale aeroshell would be approximately $15,000 and require roughly 2 months of lead time, dependent on presently available machine shop capabilities.
Supersonic Vehicle Configuration Transitions to Enable Supersonic Retropropulsion during Mars Entry, Descent, and Landing

(Georgia Institute of Technology, 2016-02-29) Blette, David J.

This paper investigates types of supersonic vehicle configuration transition events nec essary to initiation supersonic retropropulsion as part of human-class Mars entry, descent, and landing. This research assumes an entry vehicle with a 105 mT entry mass and an ellipsled aeroshell similar to the NASA EDL Design Reference Architecture 5.0. All entry architectures are assumed all-propulsive. Three transition architectures are considered: a pitch-around maneuver, an aeroshell front-exit, and an aeroshell hinged-exit. Propulsive subsystem thrust requirements are defined for the pitch-around maneuver. For transitions involving solid mass ejections, debris flight envelopes are determined and compared to a descent vehicle trajectory under a modified gravity turn. It is shown that far-field recon tact risks exist for the proposed architectures involving solid mass ejections and recontact mitigation schemes are required.
Entry Characteristics of a Half-Ogive Aeroshell at Earth

(Georgia Institute of Technology, 2016-02-05) Booher, Robert M.
Analytic Aerodynamic and Solar Radiation Pressure Modeling of Resident Space Objects

(Georgia Institute of Technology, 2015-02-05) Hart, Kennneth A., Jr.

Two significant non-gravitational perturbations on Earth-orbiting objects are aerody namics and solar radiation pressure. An analytic methodology is developed to characterize these perturbations for primitive geometries. These results are validated against state of the art simulation techniques and observations. A superposition framework is developed to determine the perturbations for composite geometries. This framework is used to model the aerodynamic perturbations of a low orbiting nanosatellite. Analytic modeling of these perturbations can enable rapid trajectory and uncertainty propagation of Earth-orbiting objects
In Situ Magnetohydrodynamic Energy Generation for Planetary Entry Systems

(Georgia Institute of Technology, 2015-01-05) Ali, Hisham K.

Proposed missions such as a Mars sample return mission and a human mission to Mars require landed payload masses in excess of any previous Mars mission. Whether human or robotic, these missions present numerous engineering challenges due to their increased mass and complexity. To overcome these challenges, new technologies must be developed, and existing technologies advanced. Mass reducing technologies are particularly critical in this effort. The proposed work aims to study the suitability of various entry trajectories for reclaiming vehicle kinetic energy through magnetohydrodynamic energy generation from the high temperature entry plasma. Potential mission and power storage configurations are explored, with results including recommended trajectories, amount of kinetic energy reclaimed, and additional system mass for various energy storage technologies.
Design and Development of RED-Data2: A Data Recording Reentry Vehicle

(Georgia Institute of Technology, 2014-08-01) Sidor, Adam T.

Defunct, manmade objects in orbit regularly reenter Earth’s atmosphere in an uncon trolled manner causing risk of both personal injury and property damage. To reduce uncertainty and improve our ability to predict surviving debris, impact time and impact location, reentry breakup dynamics and aerothermodynamics data is needed. The Reentry Breakup Recorder has demonstrated the ability to obtain inertial and thermal measure ments during reentry that are pertinent to spacecraft breakup. Building on this concept, the present investigation explores the design space for this device and matures a smaller, lighter and more operationally flexible system, termed RED-Data2.
A Comparison of Three Algorithms for Orion Drogue Parachute Release

(Georgia Institute of Technology, 2014-04-28) Matz, Daniel A.

The Orion Multi-Purpose Crew Vehicle is susceptible to flipping apex forward between drogue parachute release and main parachute inflation. A smart drogue release algorithm is required to select a drogue release condition that will not result in an apex forward main parachute deployment. The baseline algorithm is simple and elegant, but does not perform as well as desired in drogue failure cases. A simple modification to the baseline algorithm can improve performance, but can also sometimes fail to identify a good release condition. A new algorithm employing simplified rotational dynamics and a numeric predictor to minimize a rotational energy metric is proposed. A Monte Carlo analysis of a drogue failure scenario is used to compare the performance of the algorithms. The numeric predictor prevents more of the cases from flipping apex forward, and also results in an improvement in the capsule attitude at main bag extraction. The sensitivity of the numeric predictor to aerodynamic dispersions, errors in the navigated state, and execution rate is investigated, showing little degradation in performance
Preliminary Design Study of Asymmetric Hypersonic Inflatable Aerodynamic Decelerators for Mars Entry

(Georgia Institute of Technology, 2014-04-28) Harper, Brooke P.

The Mars missions envisioned in the future require payload mass in excess of the current capable limit for entry vehicle technology. Deployable Hypersonic Inflatable Aerodynamic Decelerators offer one solution to successfully improve drag performance and reduce ballistic coefficient to mitigate entry, descent, and landing concerns as payload mass increases. The majority of the research that has been conducted on these structures thus far only focuses on axisymmetric geometries. In this investigation, aerodynamic and aerothermodynamic performance is examined for three proposed asymmetric families that can generate non-zero lift-to-drag ratios at 0° angle of attack and are compared to a symmetric counterpart. Ideal results include favorable lift-to-drag ratios with reduced ballistic coefficients. The blunt, asymmetric Hypersonic Inflatable Aerodynamic Decelerator designs considered are assembled from stacked tori configurations with a base diameter of 20 m and the capability to interface with a 10 m diameter rigid center body. The configurations reviewed are capable of producing hypersonic lift-to-drag ratios between ~0.1 and ~0.6 for angles of attack ranging from -30° to 20°. A 40 Mt entry mass, approximate mass of large robotic or human scale mission is assumed. Advantageous ballistic coefficient data is retrieved for some asymmetric geometries. All HIAD configurations are determined to be statically stable as well. An initial assessment of the aerothermodynamic response predicts significant heating with radiative heating being much greater than convective heating. From the analyses completed thus far, encouraging results project asymmetric Hypersonic Inflatable Aerodynamic Decelerators as conceivable candidates for future large scale Mars missions