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Articles 1051 - 1080 of 1869

Full-Text Articles in Space Vehicles

Improved Performance By The Tie-Gcm With The Inclusion Of Helium As A Major Species, Fredrick R. Schmidt Mar 2016

Improved Performance By The Tie-Gcm With The Inclusion Of Helium As A Major Species, Fredrick R. Schmidt

Theses and Dissertations

When considering the neutral constituents in the upper thermosphere and exosphere, helium needs to be accounted for as a major species. As detailed by Emmert [2015], most first-principle models do not consider helium a major species when solving for diffusion and collisions within the atmosphere. First-principle, physics-based models hold a distinct advantage of seasonal variations and spatial resolution over empirical models which leads to a more realistic depiction of the atmosphere. The National Center for Atmospheric Research’s (NCAR) self-consistent, physics-based Thermosphere-Ionosphere-Electrodynamic General Circulation Model (TIE-GCM) has been updated to take into account this neutral constituent in its calculations. The major …

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Minimum-Fuel Trajectory Design In Multiple Dynamical Environments Utilizing Direct Transcription Methods And Particle Swarm Optimization, Alfredo G. Zurita Jr. Mar 2016

Minimum-Fuel Trajectory Design In Multiple Dynamical Environments Utilizing Direct Transcription Methods And Particle Swarm Optimization, Alfredo G. Zurita Jr.

Theses and Dissertations

Particle swarm optimization is used to generate an initial guess for designing fuel-optimal trajectories in multiple dynamical environments. Trajectories designed in the vicinity of Earth use continuous or finite low-thrust burning and transfer from an inclined or equatorial circular low-Earth-orbit to a geostationary orbit. In addition, a trajectory from near-Earth to a periodic orbit about the cislunar Lagrange point with minimized impulsive burn costs is designed within a multi-body dynamical environment. Direct transcription is used in conjunction with a nonlinear optimizer to find locally-optimal trajectories given the initial guess. The near-Earth transfers are propagated at low-level thrust where neither the …

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Lunar Icecube Space Mission, Robert J. Twiggs, Eric Jerde Mar 2016

Lunar Icecube Space Mission, Robert J. Twiggs, Eric Jerde

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Professors Bob Twiggs and Eric Jerde titled "Lunar IceCube Space Mission" from March 1, 2016.

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Overview Of Eps-1 For Spacecraft, Robert J. Twiggs Feb 2016

Overview Of Eps-1 For Spacecraft, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on an "Overview of EPS-1 for Spacecraft" from Febuary 15, 2016.

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Overview Of Eps-2 For Spacecraft, Robert J. Twiggs Feb 2016

Overview Of Eps-2 For Spacecraft, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on an "Overview of EPS-2 for Spacecraft" from February 15, 2016.

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Citizen Satellite: A Way To Have Low Cost Space Missions For The Unordinary Innovator, Robert J. Twiggs, Amin Djamshidpour, Ted Tagami, Tony So Feb 2016

Citizen Satellite: A Way To Have Low Cost Space Missions For The Unordinary Innovator, Robert J. Twiggs, Amin Djamshidpour, Ted Tagami, Tony So

Robert "Bob" Twiggs STEM Education Collection

A report written by Robert Twiggs, Amin Djamshidpour, Ted Tagami, and Tony So on February 9, 2016.

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Tu-Pod: Deployment Mechanism & Antenna Mounting, Robert J. Twiggs Feb 2016

Tu-Pod: Deployment Mechanism & Antenna Mounting, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Tu-POD: Deployment Mechanism & Antenna Mounting" from February 8, 2016.

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Off The Lip Conference - Transdisciplinary Approaches To Cognitive Innovation. Conference Proceedings, Sue Denham, Michael Punt, Edith Doove, Martha Blassnigg, Raluca Briazu, Kathryn Francis, Agi Haynes, Guy Edmonds, Adam Benjamin, Matthew Emmett, Iris Garrelfs, Christopher B. Germann, Joanna Griffin, Diane Humphrey, Bryanna Lucyk, Christie Purchase, Rachel Sansone, Emily Baxter, Amy Ione, Frank Loesche, Abigail Jackson, Alexis Kirke, Eduardo Miranda, Luke Rendell, Simon Ingram, Yutaka Nakamura, Gi Taek Ryoo, Eugenia Stamboliev, Michael Straeubig, Chun-Wei Hsu, Pinar Oztop, Mihaela Taranu, Sundar Sarukkai, James Sweeting, Minami Hirayama Feb 2016

Off The Lip Conference - Transdisciplinary Approaches To Cognitive Innovation. Conference Proceedings, Sue Denham, Michael Punt, Edith Doove, Martha Blassnigg, Raluca Briazu, Kathryn Francis, Agi Haynes, Guy Edmonds, Adam Benjamin, Matthew Emmett, Iris Garrelfs, Christopher B. Germann, Joanna Griffin, Diane Humphrey, Bryanna Lucyk, Christie Purchase, Rachel Sansone, Emily Baxter, Amy Ione, Frank Loesche, Abigail Jackson, Alexis Kirke, Eduardo Miranda, Luke Rendell, Simon Ingram, Yutaka Nakamura, Gi Taek Ryoo, Eugenia Stamboliev, Michael Straeubig, Chun-Wei Hsu, Pinar Oztop, Mihaela Taranu, Sundar Sarukkai, James Sweeting, Minami Hirayama

Off the Lip Conference - Transdisciplinary Approaches to Cognitive Innovation

The promise of cognitive innovation as a collaborative project in the sciences, arts and humanities is that we can approach creativity as a bootstrapping cognitive process in which the energies that shape the poem are necessarily indistinguishable from those that shape the poet. For the purposes of this conference the exploration of the idea of cognitive innovation concerns an understanding of creativity that is not exclusively concerned with conscious human thought and action but also as intrinsic to our cognitive development. As a consequence, we see the possibility for cognitive innovation to provide a theoretical and practical platform from which …

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Tu-Pod: Safety Review, Robert J. Twiggs Feb 2016

Tu-Pod: Safety Review, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Tu-POD: Safety Review" from February of 2016.

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Early Afternoon Concurrent Panel Sessions: Commercial Space Industry Snapshot: Presentation: Small Catapult-Assisted Horizontal-Launch Reusable Rbcc Ssto Spaceplane For Economical Short-Duration Leo Access, Nihad E. Daidzic, Jan 2016

Early Afternoon Concurrent Panel Sessions: Commercial Space Industry Snapshot: Presentation: Small Catapult-Assisted Horizontal-Launch Reusable Rbcc Ssto Spaceplane For Economical Short-Duration Leo Access, Nihad E. Daidzic,

Aviation / Aeronautics / Aerospace International Research Conference

This article discusses the conceptual design, flight trajectory calculations, and utilization of the possible future horizontally-launched reusable Single-Stage-to-Orbit (SSTO) spaceplane for small payload short-duration manned/unmanned access to Low-Earth-Orbit (LEO). The 10,000 lb spaceplane would use 5,000 ft catapult-assist horizontal-launch facility and conduct powered approach and landing on conventional horizontal paved runways following the gliding atmospheric re-entry. To increase the economy of operation, the launch facility located at high elevations (4,000+ ft) equatorial region is required, such as, the plateaus in Kenya and Tanzania in Africa and/or Ecuador in South America. A 500-lb payload, including pilot-commander, is envisioned. The propulsion cycle …

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Apollo 13: The Longest Hour, Sy Libergot Jan 2016

Apollo 13: The Longest Hour, Sy Libergot

ERAU Prescott Aviation History Program

The epic story of Apollo 13 is well known, but hear the inside details from the NASA flight controller who was on duty when the unthinkable happened. Author of Apollo EECOM, Journey of a Lifetime, Sy Libergot’s space experience began in 1966 and spanned the entire Apollo Lunar Program; Skylab; the Apollo-Soyuz project; early Shuttle and even the International Space Station, but Apollo 13 would become the unwelcome highlight of his flight controller career. Don’t miss this exciting talk by the man who was at the console when it all happened.

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Comparisons Of Ablator Experimental Performance To Response Modeling And Effects Of Water Phase Transition In Porous Tps Materials, David L. Smith Jan 2016

Comparisons Of Ablator Experimental Performance To Response Modeling And Effects Of Water Phase Transition In Porous Tps Materials, David L. Smith

Theses and Dissertations--Mechanical and Aerospace Engineering

The Mars Science Laboratory Entry Descent and Landing Instrumentation (MEDLI) project performed extensive arc jet tests for development, qualification, and calibration of instrumented heat shield plugs. These plugs each contained several thermocouples for recording near-surface and in-depth temperature response of the Phenolic Impregnated Carbon Ablator (PICA) heat shield. The arc jet test results are entered into a comprehensive database so that broad trends across the test series can be compared. One method of analysis is to compare with ablator material response calculations and solve the in-depth heat conduction equations. Using the near-surface thermocouple measurements as a boundary condition in numerical …

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Approximated Control Affine Dynamics Mode For An Agricultural Field Robot Considering Wheel Terrain Interaction, Pablo Menendez-Aponte Jan 2016

Approximated Control Affine Dynamics Mode For An Agricultural Field Robot Considering Wheel Terrain Interaction, Pablo Menendez-Aponte

Electronic Theses and Dissertations

As populations and the demand for higher crop yields grow, so to does the need for efficient agricultural wheeled mobile robots. To achieve precise navigation through a field it is desirable that the control system is designed based on an accurate dynamic model. In this paper a control affine model for a custom designed skid-steer differential drive wheeled mobile robot is found. The Terramechanic wheel terrain interaction is adopted and modified to consider wheels with a torus geometry. Varying slip ratios and slip angles are considered in the terrain reaction forces, which is curve-fitted using a nonlinear least squares approach …

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Kinematical Modelling And Its Analytical Inverse Kinematic Solution For The Handling Mechanism Of An Agricultural Robot, Sinem Gozde Defterli Jan 2016

Kinematical Modelling And Its Analytical Inverse Kinematic Solution For The Handling Mechanism Of An Agricultural Robot, Sinem Gozde Defterli

Electronic Theses and Dissertations

Early detection of the crop diseases helps to prevent failure in the amount and the quality of the production. In agricultural robotics, the idea of a disease detection robot is a fresh and an innovative hot-button topic. The exclusion of the diseased parts from the strawberry plants for further analyses is one of the main tasks of a recently developed strawberry robot. To this purpose, the handling mechanism in the robot needs to achieve an accurate manipulation task to reach the target. Reaching, cutting and storing the diseased leaf are challenging and delicate processes during the procedure of the handling …

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Small Satellite Noncommutative Rotation Sequence Attitude Control Using Piezoelectric Actuators, Joshua L. Evans Jan 2016

Small Satellite Noncommutative Rotation Sequence Attitude Control Using Piezoelectric Actuators, Joshua L. Evans

Theses and Dissertations--Electrical and Computer Engineering

Attitude control remains one of the top engineering challenges faced by small satellite mission planning and design. Conventional methods for attitude control include propulsion, reaction wheels, magnetic torque coils, and passive stabilization mechanisms, such as permanent magnets that align with planetary magnetic fields. Drawbacks of these conventional attitude control methods for small satellites include size, power consumption, dependence on external magnetic fields, and lack of full control authority. This research investigates an alternative, novel approach to attitude-control method for small satellites, utilizing the noncommutative property of rigid body rotation sequences. Piezoelectric bimorph actuators are used to induce sinusoidal small-amplitude satellite …

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Optimal Attitude Control Of Agile Spacecraft Using Combined Reaction Wheel And Control Moment Gyroscope Arrays, Cole C. Doupe Dec 2015

Optimal Attitude Control Of Agile Spacecraft Using Combined Reaction Wheel And Control Moment Gyroscope Arrays, Cole C. Doupe

Theses and Dissertations

This dissertation explores the benefits of combined control moment gyroscope (CMG) and reaction wheel array (RWA) actuation for agile spacecraft. Agile spacecraft are capable of slewing to multiple targets in minimum time. CMGs provide the largest torque capability of current momentum exchange actuation devices but also introduce singularity events in operation. RWAs produce less torque capability than CMGs but can achieve greater pointing accuracy. In this research, a combined RWA and CMG (RWCMG) system is evaluated using analytical simulations and hardware experiments. A closed-loop control scheme is developed which takes advantage of the strengths of each actuator set.The CMGs perform …

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Lightweight Deployment Mechanism Of Solar Arrays For Use In Cubesats, John Wood Ellis Dec 2015

Lightweight Deployment Mechanism Of Solar Arrays For Use In Cubesats, John Wood Ellis

Undergraduate Honors Capstone Projects

Cube satellites, also referred to as CubeSats, were developed in the late twentieth century, and have since served as a cost-effective method of gathering out-of-this-world data. The development of these small-scale satellites have helped universities and small companies worldwide to perform important experiments, as well as gather critical data in order to provide for further space exploration. Cube satellites are designed to be self-sustaining, by using solar cells to capture impinging thermal energy and convert it to power to be consumed by the electronics housed within the satellite itself. In order to function properly, these cells are extended in an …

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Sub-Orbital Spaceflight – An Addition To Our Multi-Modal Transportation System, Scott Haeffelin Nov 2015

Sub-Orbital Spaceflight – An Addition To Our Multi-Modal Transportation System, Scott Haeffelin

Space Traffic Management Conference

The number of commercial spaceflights will be increasing by orders of magnitude over the next several decades. The current volume of space traffic can be managed on a case-by-case basis and there is little impact to the National Airspace System (NAS). This will change as more spaceports become operational, commercial sub-orbital flight companies begin serving their customers and as the cost of these flights begin to decrease. Current regulatory paths seek to allow the flexibility in the regulations for this industry to flourish while also maintaining a high standard of safety. There are, however, many nearsighted and old fashioned assumptions …

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Lunar Icecube: Nextstep Lunar Cubesat Mission And Instrument Concept, Robert J. Twiggs Nov 2015

Lunar Icecube: Nextstep Lunar Cubesat Mission And Instrument Concept, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Professor Bob Twiggs associates titled "Lunar IceCube: NEXTSTEP Lunar Cubesat Mission and Instrument Concept" from November 12, 2015.

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Estimating Terrace Agriculture: Implications Towards Archaeology And Ancient Civilizations, Zachary Burkhardt, Kel Markert Oct 2015

Estimating Terrace Agriculture: Implications Towards Archaeology And Ancient Civilizations, Zachary Burkhardt, Kel Markert

Von Braun Symposium Student Posters

No abstract provided.

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Design And Development Of A Sensor Payload For Low-Altitude Rocket Deployment, Alex Christley Oct 2015

Design And Development Of A Sensor Payload For Low-Altitude Rocket Deployment, Alex Christley

Von Braun Symposium Student Posters

No abstract provided.

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Design And Fabrication Of A Boosted Dart Rocket System, Davis Hunter, Bradley Henderson Oct 2015

Design And Fabrication Of A Boosted Dart Rocket System, Davis Hunter, Bradley Henderson

Von Braun Symposium Student Posters

No abstract provided.

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Small Packages Can Get Big Results, Robert J. Twiggs Oct 2015

Small Packages Can Get Big Results, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Professor Bob Twiggs titled "Small Packages can get Big Results" from October 16, 2015.

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A Nonequilibrium Finite-Rate Carbon Ablation Model For Radiating Earth Re-Entry Flows, Christopher R. Alba Sep 2015

A Nonequilibrium Finite-Rate Carbon Ablation Model For Radiating Earth Re-Entry Flows, Christopher R. Alba

Theses and Dissertations

Vehicles entering planetary atmospheres at high speed require an ablative heat shield in order to withstand the high thermal energy flux to the body. The interaction between the ablative products and the flow field is not well characterized. Numerical simulations were conducted to investigate the influence of carbon ablation on shock layer radiation. Data collected from experiments performed in the X-2 expansion tunnel at the University of Queensland was used to compare to the simulations. The model was a short half-cylinder made of isomolded graphite and was tested in 8.6 km/s Earth entry flow. The model surface was heated within …

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Modular Heat Dissipation Technique For A Cubesat, Melih Eken Sep 2015

Modular Heat Dissipation Technique For A Cubesat, Melih Eken

Theses and Dissertations

In recent years, due to their many advantages, interest in larger scale CubeSats, such as 3U and 6U, has been increased. Correspondingly, dissipating the heat from the heat generating components in the CubeSat has become a challenge for thermal control. In this research, a modular approach was developed to dissipate heat from the overheating components in a CubeSat. To accomplish this, both experimental and computational methodologies were used. A 6U CubeSat was computationally modeled and the model correlated by experimental test results. Subsequently, validated CubeSat thermal model was used to design a modular heat dissipater. Validation and performance experiments of …

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Brief Look At The Environment Of Space, Robert J. Twiggs Sep 2015

Brief Look At The Environment Of Space, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Brief Look at the Environment of Space" from September 10, 2015.

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A Brief History Of Space - Sse 120 Session 1, Robert J. Twiggs Aug 2015

A Brief History Of Space - Sse 120 Session 1, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "A Brief History of Space - Session 01" from August 30, 2015.

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A Brief History Of Space - Sse 120 Questions 01, Robert J. Twiggs Aug 2015

A Brief History Of Space - Sse 120 Questions 01, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "A Brief History of Space - Questions 01" from August 26, 2015.

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A Brief History Of Space - Sse 120 Questions 02, Robert J. Twiggs Aug 2015

A Brief History Of Space - Sse 120 Questions 02, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "A Brief History of Space - Questions 02" from August 25, 2015.

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A Brief History Of Space - Sse 120 Questions 04, Robert J. Twiggs Aug 2015

A Brief History Of Space - Sse 120 Questions 04, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "A Brief History of Space - Questions 04" from August 25, 2015.

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