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Il-1Β Amplification Of Nitric Oxide Production And Its Inhibitory Effects On Glucose Induced Early Growth Response-1 Expression In Ins-1 Cells, Ada Young Aug 2012

Il-1Β Amplification Of Nitric Oxide Production And Its Inhibitory Effects On Glucose Induced Early Growth Response-1 Expression In Ins-1 Cells, Ada Young

Electronic Theses and Dissertations

The pathophysiology of cytokines released by infiltrating white blood cells upon pancreatic beta cells is not fully understood. Early growth response gene-1 (Egr-1) expression is specifically and transiently up regulated in pancreatic beta cells in response to glucose. We hypothesized that interleukin-1 beta (IL-1▀) induction of nitric oxide alters glucose induced Egr-1 transcription levels. Egr-1 levels were assessed via western blot, nitric oxide was measured with a Griess Reagent kit and insulin levels via ELISA. Glucose induced both insulin and Egr-1 production in INS-1 cells. IL-1▀ dose dependently increased nitric oxide production over time and significantly attenuated glucose induced Egr-1 …

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Examining Attention, Impulsiveness, And Cognitive Failures In Driving Behaviors, Russell Thomas Fox Aug 2012

Examining Attention, Impulsiveness, And Cognitive Failures In Driving Behaviors, Russell Thomas Fox

Electronic Theses and Dissertations

Dangerous driving behaviors are influenced by multiple factors including cognitive processes such as impulse inhibition and attentiveness. Impulsiveness, inattention, and cognitive failures have been linked to other risky behaviors, but a comprehensive evaluation using multiple methods of measurement of these has never been conducted to analyze their impact on dangerous driving. The purpose of this study was to examine influences of attentional abilities, impulsiveness, and cognitive failures on reported and demonstrated dangerous driving behaviors. Seventy-five participants completed a self-report dangerous driving measure, a self-report ADHD measure, a self-report impulsiveness measure, a continuous performance task to measure behavioral impulsivity and inattention, …

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Health-Related Quality Of Life In The Working Uninsured: Conditional Indirect Effects Of Perceived Stigma Via Vitality And Interpersonal Needs, Preston Lee Visser Aug 2012

Health-Related Quality Of Life In The Working Uninsured: Conditional Indirect Effects Of Perceived Stigma Via Vitality And Interpersonal Needs, Preston Lee Visser

Electronic Theses and Dissertations

Stigmatization involves the application of labels to individuals in social contexts, leading to impaired access to social, economic, and political power. Although actual stigmatizing beliefs that society holds about particular groups are important, the extent to which individuals themselves perceive stigma from others and internalize stigmatizing beliefs is being increasingly recognized as a cause of psychological and physical distress. Little research has been done on explanatory mechanisms of the relations between perceived stigma and health outcomes, particularly in the area of stigma related to finances. Two important dimensions of overall health include depressive symptoms and health-related quality of life. According …

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Nested (2,R)-Regular Graphs And Their Network Properties., Josh Daniel Brooks Aug 2012

Nested (2,R)-Regular Graphs And Their Network Properties., Josh Daniel Brooks

Electronic Theses and Dissertations

A graph G is a (t, r)-regular graph if every collection of t independent vertices is collectively adjacent to exactly r vertices. If a graph G is (2, r)-regular where p, s, and m are positive integers, and m ≥ 2, then when n is sufficiently large, then G is isomorphic to G = Ks+mKp, where 2(p-1)+s = r. A nested (2,r)-regular graph is constructed by replacing selected cliques with a (2,r)-regular graph and joining the vertices of the peripheral cliques. For …

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Immobilized Bis-Indenyl Ligands For Stable And Cost-Effective Metallocene Catalysts Of Hydrogenation And Polymerization Reactions, Thomas Max Simerly Aug 2012

Immobilized Bis-Indenyl Ligands For Stable And Cost-Effective Metallocene Catalysts Of Hydrogenation And Polymerization Reactions, Thomas Max Simerly

Electronic Theses and Dissertations

Reactions of catalytic hydrogenations and polymerizations are widely used in industry for manufacture of fine chemicals, pharmaceuticals, and plastics. Homogeneous catalysts for the processes that have low stability and their separation is difficult. Therefore, the development of new highly active and stable catalysts for hydrogenations and polymerizations is a necessity. The objective of this research was the development of a strategy for immobilization of heterogeneous metallocene catalysts. First, a methodology of immobilization of bis-indenyl ligands on the surface of mesoporous silica gel was designed. Four bis-indenyl ligands containing functionalized tethers of various lengths with terminal alkene groups were synthesized. All …

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Global Domination Stable Graphs, Elizabeth Marie Harris Aug 2012

Global Domination Stable Graphs, Elizabeth Marie Harris

Electronic Theses and Dissertations

A set of vertices S in a graph G is a global dominating set (GDS) of G if S is a dominating set for both G and its complement G. The minimum cardinality of a global dominating set of G is the global domination number of G. We explore the effects of graph modifications on the global domination number. In particular, we explore edge removal, edge addition, and vertex removal.

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Cursorial Adaptations In The Forelimb Of The Giant Short-Faced Bear, Arctodus Simus, Revealed By Traditional And 3d Landmark Morphometrics, Eric Randally Lynch Aug 2012

Cursorial Adaptations In The Forelimb Of The Giant Short-Faced Bear, Arctodus Simus, Revealed By Traditional And 3d Landmark Morphometrics, Eric Randally Lynch

Electronic Theses and Dissertations

The paleobiology of the Pleistocene North American giant short-faced bear, Arctodus simus, has eluded paleontologists for decades. Its more gracile form has led past researchers to myriad intepretations of the locomotion and feeding ecology of this species. While earlier studies have focused on craniodental morphology and simple postcranial indices, it is forelimb morphology that represents a direct compromise between locomotor and foraging behavior. The study here uses traditional and 3D landmark morphometrics to more completely compare the 3-dimensional shape of the major forelimb elements and their muscle attachment sites between A. simus, extant ursids, and other carnivorans. Results …

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Nanosat Ka-Band Communications - A Paradigm Shift In Small Satellite Data Throughput, Jan King, John Ness, Grant Bonin, Michael Brett, Daniel Faber Aug 2012

Nanosat Ka-Band Communications - A Paradigm Shift In Small Satellite Data Throughput, Jan King, John Ness, Grant Bonin, Michael Brett, Daniel Faber

Small Satellite Conference

Earth observation applications are rapidly being serviced using low-cost small satellites, improving economic and environmental management and creating new markets. The technology driver of this trend is a series of steady improvements in attitude control sensors and microprocessor technologies which have allowed small spacecraft to achieve arc-minute to arc-second pointing capabilities. These advancements have, in turn, enabled high performance and high resolution remote sensing instruments to be deployed on smaller and lower-cost platforms. The constraints placed upon small satellite design for remote sensing missions have traditionally been power availability, heat dissipation and aperture requirements however as small satellite sensor technology …

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The Drag-Free Cubesat, John Conklin, Karthik Balakrishnan, Sasha Buchman, Robert Byer, Grant Cutler, Dan Debra, Eric Hultgren, John Lipa, Shailendhar Saraf, Seiya Shimizu, Andreas Zoellner, Abdul Alfauwaz, Ahmad Aljadaan, Hamoud Aljibreen, Mohammed Almajed, Turki Al-Saud, Badr Alsuwaidan, Salman Althubiti, Haithem Altwaijry Aug 2012

The Drag-Free Cubesat, John Conklin, Karthik Balakrishnan, Sasha Buchman, Robert Byer, Grant Cutler, Dan Debra, Eric Hultgren, John Lipa, Shailendhar Saraf, Seiya Shimizu, Andreas Zoellner, Abdul Alfauwaz, Ahmad Aljadaan, Hamoud Aljibreen, Mohammed Almajed, Turki Al-Saud, Badr Alsuwaidan, Salman Althubiti, Haithem Altwaijry

Small Satellite Conference

A drag-free spacecraft utilizes a Gravitational Reference Sensor (GRS) to shield an internal free-floating test mass (TM) from (a) external disturbances and (b) from disturbances caused by the spacecraft itself. The GRS measures the position of the spacecraft with respect to the TM and a feedback control system commands thrusters to maintain that position. In principle, the test mass is then completely freed from non-gravitational disturbances so that it and its “tender” spacecraft follow a pure geodesic. To date, three drag-free spacecraft have flown: TRIAD I in 1972, which provided the first navigation by satellite, Gravity Probe B in 2004, …

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X Band Downlink For Cubesat, E. Peragin, H. Diez, F. Darnon, D. Belot, J-P Millerioux, J-L Issler, T. Dehaene, Y. Richard, G. Guillois, F Sépot, D. Simon Aug 2012

X Band Downlink For Cubesat, E. Peragin, H. Diez, F. Darnon, D. Belot, J-P Millerioux, J-L Issler, T. Dehaene, Y. Richard, G. Guillois, F Sépot, D. Simon

Small Satellite Conference

Six years ago, CNES started R&D studies related to telemetry in X band, with the goal of providing to micro satellite platform manufacturers a low cost but high performances X band transmitter. The promising results achieved have led to the decision to develop a transmitter for ESA PROBA-V spacecraft to be launched in 2013. The first flight models have been designed in only 18 months and will be delivered to ESA in February 2012. In the same way, CNES is now studying a solution to download telemetry in X band for cube and nano satellites. The aim is to provide …

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Microhard Mhx2420 Orbital Performance Evaluation Using Rt Logic T400cs, Stuart Kearney, Mark Lombardi, Watson Attai, Ken Oyadomani, Ahmed Saleh Nasser Al Rumhi, Sébastien Rakotonarivo, Loïc Chardon, Oriol Tintore Gazulla, Jasper Wolfe, Alberto Guillen Salas, Jon Dewald, Richard Alena Aug 2012

Microhard Mhx2420 Orbital Performance Evaluation Using Rt Logic T400cs, Stuart Kearney, Mark Lombardi, Watson Attai, Ken Oyadomani, Ahmed Saleh Nasser Al Rumhi, Sébastien Rakotonarivo, Loïc Chardon, Oriol Tintore Gazulla, Jasper Wolfe, Alberto Guillen Salas, Jon Dewald, Richard Alena

Small Satellite Conference

A major upfront cost of building low cost Nanosatellites is the communications sub-system. Most radios built for space missions cost over $4,000 per unit. This exceeds many budgets. One possible cost effective solution is the Microhard MHX2420, a commercial off-the-shelf transceiver with a unit cost under $1000. This paper aims to support the Nanosatellite community seeking an inexpensive radio by characterizing Microhard’s performance envelope. Though not intended for space operations, the ability to test edge cases and increase average data transfer speeds through optimization positions this radio as a solution for Nanosatellite communications by expanding usage to include more missions. …

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Miniature Ion Electrospray Thrusters And Performance Test On Cubesats, Francois Martel, Louis Perna, Paulo Lozano Aug 2012

Miniature Ion Electrospray Thrusters And Performance Test On Cubesats, Francois Martel, Louis Perna, Paulo Lozano

Small Satellite Conference

Miniature ion electrospray thrusters under development at MIT are opening a new range of possibilities for applications requiring precision thrusting, or for nano-satellite mission design. With a specific impulse (Isp) in excess of 2500 seconds, no moving parts and unpressurized tanks containing zero-vapor pressure liquid propellant, they can be integrated into cubesat compatible multi-thruster assemblies. The technology and the thruster performances are described in this paper in addition to the current development of cubesat compatible prototype assemblies for performance tests in space. The assembly under development in this research effort fits within 1/3 of one 1U cubesat and is designed …

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Development And Testing Of A Multiple Use Plug Hybrid (For) Nanosats (Muphyn), Shannon Eilers, Stephen Whitmore Aug 2012

Development And Testing Of A Multiple Use Plug Hybrid (For) Nanosats (Muphyn), Shannon Eilers, Stephen Whitmore

Small Satellite Conference

The Multiple Use Plug Hybrid (for) Nanosats prototype is being developed to fill a niche application for NanoSat scale spacecraft propulsion. The MUPHyN thruster uses safe-handling and inexpensive nitrous oxide (N2O) and acrylonitrile-butadiene-styrene (ABS) as propellants. The MUPHyN system provides attitude control using secondary-injection thrust vectoring and allows large impulse ÄV and small impulse attitude control and proximity burns to be performed with the same system. To insure survivability during extend duration burns, the MUPHyN incorporates a novel regenerative cooling design where the N2O oxidizer flows through a cooling path embedded in the aerospike nozzle before being injected into the …

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Releasing The Cloud: A Deployment System Design For The Qb50 Cubesat Mission, C.A. Bernal, M. Van Bolhuis Aug 2012

Releasing The Cloud: A Deployment System Design For The Qb50 Cubesat Mission, C.A. Bernal, M. Van Bolhuis

Small Satellite Conference

For the QB50 project a constellation of tens of CubeSats will be launched and injected in 2014 into a 320 km orbit to perform in situ observations of the thermosphere as well as science and technology in-orbit-demonstration. Developing, deploying and operating such a system presents a whole range of challenges. One of the biggest challenges to be solved is how to safely launch and properly deploy the QB50 constellation of satellites. This paper will present the StackPack or ISIS’ concept design of the deployment system designed for deploying the QB50 satellites. Conceptually, the StackPack is a custom, reliable, non hazardous, …

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Enabling Dexterous Manipulation And Servicing By Smallsats, David Akin, Nicholas Limparis, Katherine Mcbryan Aug 2012

Enabling Dexterous Manipulation And Servicing By Smallsats, David Akin, Nicholas Limparis, Katherine Mcbryan

Small Satellite Conference

The University of Maryland Space Systems Laboratory is currently developing two flight-ready smallsats to demonstrate and validate the critical technologies for this new class of smallsat servicing system. The Dynamic FLight MAnipulation EXperiment (DYMAFLEX) , supported by the U. S. Air Force University Nanosat Program, is a smallsat incorporating a four degree-of-freedom high-performance manipulator and a fully maneuvering spacecraft bus, including a cold-gas reaction control system. Unlike past manipulator-equipped spacecraft such as ETS-VII or Orbital Express, the DYMAFLEX manipulator inertia (depending on payload) equals or exceeds that of the spacecraft bus, resulting in significant base reaction dynamics in response to …

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Technical And Programmatic Challenges For Dedicated Ride Share Missions, Gregory Kehrl, Matt Steele Aug 2012

Technical And Programmatic Challenges For Dedicated Ride Share Missions, Gregory Kehrl, Matt Steele

Small Satellite Conference

The Athena RideShare™ launch service, announced by Lockheed Martin and ATK in 2011, is a game-changing approach that lowers launch costs and provides scheduled access to space for small satellites and cubesats. The Athena RideShare launch service is an extension of a familiar concept, the Post Office’s Priority Mail Flat Rate Boxes. If payload fits into the designated volume envelope and mass limit, the customer pays one low flat rate to get to space. Despite the simplicity of the model, there are significant challenges to execute this idea. Both technical and programmatic challenges have surfaced in the pursuit of setting …

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Μlambda Rocket Concept For Micro Satellites, Yuichi Noguchi, Kazuhiro Yagi, Takumi Kanzawa, Takashi Arime, Seiji Matsuda, Hideki Kanayama, Yoichi Harada, Takayoshi Fuji Aug 2012

Μlambda Rocket Concept For Micro Satellites, Yuichi Noguchi, Kazuhiro Yagi, Takumi Kanzawa, Takashi Arime, Seiji Matsuda, Hideki Kanayama, Yoichi Harada, Takayoshi Fuji

Small Satellite Conference

Sophisticated 3U or 6U Cubesats with modular design approach and plug-and-play technology could accommodate a wide range of missions. Small and medium-sized enterprises nowadays develop and sell standardized Cubesat kit to worldwide users. Some of them even become Cubesat one-stop-shop, providing coordination for launch opportunity in addition to kit distribution. Many space agencies use these companies to manage ride share of multiple users. Current nano/micro satellite users have to rely on piggyback ride and share ride on medium-heavy rocket where they have few choices on launch window and orbit selection. As capability of nano/micro satellites grows and mission utility increases, …

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Orbcomm Generation 2 Access To Leo On The Falcon 9 Using Softride, A Case History, Raman Johal, Jim Christensen, Dustin Doud Aug 2012

Orbcomm Generation 2 Access To Leo On The Falcon 9 Using Softride, A Case History, Raman Johal, Jim Christensen, Dustin Doud

Small Satellite Conference

The design of SpaceX’s Dragon capsule includes an aft structure known as the “Trunk” which can house small payloads for co-manifested missions when re-supplying the International Space Station. One such planned mission includes the ORBCOMM Generation 2 (OG2) spacecraft. The co-manifested approach that SpaceX provides with the Falcon 9 creates affordable and responsive launch opportunities for ORBCOMM and Sierra Nevada Corporation, which built the spacecraft, but presents a unique challenge: The spacecraft were not designed for the measured Trunk environment, but were built and qualified to the environments of other potential launch vehicles. In order to be qualified for the …

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Spaceflight Secondary Payload System (Ssps) And Sherpa Tug - A New Business Model For Secondary And Hosted Payloads, Jason Andrews Aug 2012

Spaceflight Secondary Payload System (Ssps) And Sherpa Tug - A New Business Model For Secondary And Hosted Payloads, Jason Andrews

Small Satellite Conference

Since the termination of the Falcon 1 program, the opportunities for access to space for small spacecraft have been limited. Spaceflight, Inc. (Spaceflight) is addressing this market need by providing commercial launch services for secondary and hosted payloads by using its Spaceflight Secondary Payload System (SSPS) and SHERPA in-space tug. The SSPS is a system designed to transport up to 1,500 kg of secondary and hosted payloads to space using the excess capacity on Medium and Intermediate class commercial launch vehicles. The SSPS can accommodate up to five 300 kg spacecraft, or many smaller spacecraft, on each of its five …

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Elana – Educational Launch Of Nanosatellite: Providing Routine Rideshare Opportunities, Garrett Skrobot, Roland Coelho Aug 2012

Elana – Educational Launch Of Nanosatellite: Providing Routine Rideshare Opportunities, Garrett Skrobot, Roland Coelho

Small Satellite Conference

Since the creation of the NASA CubeSat Launch Initiative (NCSLI), the need for CubeSat rideshares has dramatically increased. After only three releases of the initiative, a total of 66 CubeSats now await launch opportunities. So, how is this challenge being resolved? NASA’s Launch Services Program (LSP) has studied how to integrate PPODs on Athena, Atlas V, and Delta IV launch vehicles and has been instrumental in developing several carrier systems to support CubeSats as rideshares on NASA missions. In support of the first two ELaNa missions the Poly-Picosatellite Orbital Deployer (P-POD) was adapted for use on a Taurus XL (ELaNa …

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Round The World Ticket For Your Smallsat, Abe Bonnema, Jason Andrews, Joost Elstak Aug 2012

Round The World Ticket For Your Smallsat, Abe Bonnema, Jason Andrews, Joost Elstak

Small Satellite Conference

With the significant increase in small satellite developments in Europe, the US, Asia, and other upcoming parts of the world, finding a timely and affordable ‘round the world ticket’ for your small satellite becomes more and more challenging. There can be many complicating factors in arranging a launch for your small satellite. These can be technical and programmatic mismatches between the available launch opportunity and the small satellite mission objectives and planning. But often these complicating factors also relate to regulatory and legal restrictions, political considerations. As a result, in practice it is actually quite difficult to find an available, …

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Secondary Launch Services And Payload Hosting Aboard The Falcon And Dragon Product Lines, Dustin Doud, Brian Bjelde, Christian Melbostad, Lauren Dreyer Aug 2012

Secondary Launch Services And Payload Hosting Aboard The Falcon And Dragon Product Lines, Dustin Doud, Brian Bjelde, Christian Melbostad, Lauren Dreyer

Small Satellite Conference

SpaceX is committed to revolutionizing access to space for the small-satellite community. With over 40 missions on our manifest, Falcon 9 is poised to become the industry workhorse for space launch services. The Dragon spacecraft, developed in part to resupply the International Space Station, is capable of hosting missions for up to 2 years on orbit. In short, SpaceX offers highly reliable, cost-effective launch services and payload hosting opportunities. This paper defines the company’s secondary launch services and options, and how they will impact the small-satellite community. Secondary payloads, by definition, must accompany and minimally impact the primary payload. Despite …

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Small Satellite Rideshares On Commercial Resupply Missions To The International Space Station, Joshua Robinson, Daniel Kwon Aug 2012

Small Satellite Rideshares On Commercial Resupply Missions To The International Space Station, Joshua Robinson, Daniel Kwon

Small Satellite Conference

Gaining access to space is currently a major challenge facing small satellites. Developers must find reliable, affordable, and most importantly compatible rideshares to put their small satellites on orbit. Commercial Resupply Service (CRS) missions to the International Space Station (ISS) have the potential to provide a robust and repetitive platform for small satellite rideshares. There are currently nine planned missions of the Cygnus spacecraft to the ISS extending through 2016, with a strong potential for additional missions beyond 2016. Cygnus enables hosting and rideshare opportunities at a regular interval, thus filling the void left after the retirement of the space …

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Atlas V Aft Bulkhead Carrier Rideshare System, Maj Travis Willcox Aug 2012

Atlas V Aft Bulkhead Carrier Rideshare System, Maj Travis Willcox

Small Satellite Conference

This paper gives the background and details of the Atlas V Aft Bulkhead Carrier to be flown on the National Recoinnassance Office Launch 36 with the Operationally Unique Technologies Satellite Auxiliary Payload. The CubeSats included are from a number of labs, universities and government entities for the purpose of technology demonstration, science experimentation and operational proof of concepts. This mission will pave the way for rideshare on NRO missions and other Atlas V launches.

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Geoscan: A Geoscience Facility From Space, Lars Dyrud, Jonathan Fentzke, Gary Bust, Bob Erlandson, Brian Bauer, Aaron Rogers, Warren Wiscombe, Shawn Murphy, Rebecca Bishop, Om Gupta, Brian Gunter, Kerri Cahoy, Chad Fish Aug 2012

Geoscan: A Geoscience Facility From Space, Lars Dyrud, Jonathan Fentzke, Gary Bust, Bob Erlandson, Brian Bauer, Aaron Rogers, Warren Wiscombe, Shawn Murphy, Rebecca Bishop, Om Gupta, Brian Gunter, Kerri Cahoy, Chad Fish

Small Satellite Conference

GEOScan, proposed as a globally networked orbiting facility utilizing Iridium NEXT’s 66-satellite constellation, will provide revolutionary, massively dense global geoscience observations and targets questions scientists have not been able to answer, and will not answer, until simultaneous global measurements are made. GEOScan dramatically lowers the logistical and cost barriers for transmitting “big data” from 66 satellites by using Iridium’s communications platform and commercial-off-the-shelf components. Iridium’s Hosted Payload Program facilitates the effort, but it could be executed using any small-sat constellation. Each GEOScan sensor suite consists of 6 instruments: a Radiometer to measure Earth’s total outgoing radiation; a GPS Compact Total …

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Feasibility Study Of Using A Small Satellite Constellation To Forecast, Monitor And Mitigate Natural And Man-Made Disasters In Chile And Similar Developing Countries, Alex Becena, Marcos Diaz, Juan Cristobal Zagal Aug 2012

Feasibility Study Of Using A Small Satellite Constellation To Forecast, Monitor And Mitigate Natural And Man-Made Disasters In Chile And Similar Developing Countries, Alex Becena, Marcos Diaz, Juan Cristobal Zagal

Small Satellite Conference

The humanitarian and economical effects that disasters have on developing countries might be diminished by using a satellite system. Although this capability has not been largely exploited by developing countries, the current trends on small satellite development encourage them to use the new paradigm possibilities. Today Chile, a developing country with high-frequency and diverse-type of disasters, is facing the problem of forecasting, monitoring and mitigating disasters. This work studies the feasibility of using small satellites to perform this activity. The need of ground-based sensor network in combination with satellite constellation for robustness is also analyzed.

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‘Charybdis’ – The Next Generation In Ocean Colour And Biogeochemical Remote Sensing, Christopher Lowe, Malcom Macdonald, Steve Greenland, David Mckee Aug 2012

‘Charybdis’ – The Next Generation In Ocean Colour And Biogeochemical Remote Sensing, Christopher Lowe, Malcom Macdonald, Steve Greenland, David Mckee

Small Satellite Conference

Within the field of Space-based Maritime observation, there exists an opportunity in the form of high spatial, high temporal resolution multi-spectral imaging to map coastal and inland waterway colour and biogeochemistry. Information provided would help environmental agencies and the scientific community to better understand patterns and evolution of ecological systems, sediment suspension in river estuaries and the effects of anthropogenic processes on our water systems. In addition, monitoring of these colour patterns with respect to the well understood tidal sequence would provide significant benefits to our understanding of the way in which tidal forcing affects ocean colour. This paper describes …

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Moderately Elliptical Very Low Orbits (Mevlos) As A Long-Term Solution To Orbital Debris, James Wertz, Nicola Sarzi-Amade, Anthony Shao, Christianna Taylor, Richard Van Allen Aug 2012

Moderately Elliptical Very Low Orbits (Mevlos) As A Long-Term Solution To Orbital Debris, James Wertz, Nicola Sarzi-Amade, Anthony Shao, Christianna Taylor, Richard Van Allen

Small Satellite Conference

Long-term orbital debris is a continually growing problem that has proven challenging to overcome. A straightforward solution to the problem is to put the majority of future LEO spacecraft into Moderately Elliptical Very Low Orbits (MEVLOs) with perigees below approximately 300 km, apogees below approximately 500 km, and eccentricities in the range of 0.015 to 0.030. Orbital debris clouds cannot be sustained in this altitude regime and will decay and re-enter in times ranging from a few weeks to at most the time until the next solar maximum. This means that the debris population at this altitude is, and will …

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The Ability Of A Small Satellite Constellation To Tip And Cue Other Commercial Assets, Becky Cudzilo, K.C. Foley, Chandler Smith Aug 2012

The Ability Of A Small Satellite Constellation To Tip And Cue Other Commercial Assets, Becky Cudzilo, K.C. Foley, Chandler Smith

Small Satellite Conference

Small satellite constellations could be utilized to tip-off or cue existing Electrical Optical (EO) satellite systems such as a GeoEye class satellite. This paper addresses a specific case of this capability for the current problem of maritime domain awareness. If a constellation of small Automated Identification System (AIS) satellites, a small Synthetic Aperture Radar (SAR) satellite, and a large EO satellite is used for both routine and ad hoc global satellite coverage of high-interest areas, that constellation could monitor ship activities in support of Maritime Domain Awareness (MDA). This could be achieved over larger areas than Coast Guard or other …

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Global Coverage From Ad‐Hoc Constellations In Rideshare Orbits, Armin Ellis, Michael Mercury, Shannon Brown Aug 2012

Global Coverage From Ad‐Hoc Constellations In Rideshare Orbits, Armin Ellis, Michael Mercury, Shannon Brown

Small Satellite Conference

A promising area of small satellite development is in providing higher temporal resolution than larger satellites. Traditional constellations have required specific orbits and dedicated launch vehicles. In this paper we discuss an alternative architecture in which the individual elements of the constellation are launched as rideshare opportunities. We compare the coverage of such an ad-hoc constellation with more traditional constellations. Coverage analysis is based on actual historical data from rideshare opportunities. Our analysis includes ground coverage and temporal revisits for Polar, Tropics, Temperate, and Global regions, comparing ad-hoc and Walker constellation.

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