Digital Commons Network^™

Range-Wide Sources Of Variation In Reproductive Rates Of Northern Spotted Owls, Jeremy T. Rockweit, Julianna M. Jenkins, James E. Hines, James D. Nichols, Katie M. Dugger, Alan B. Franklin, Peter C. Carlson, William L. Kendall, Damon B. Lesmeister, Christopher Mccafferty, Steven H. Ackers, L. Steven Andrews, Larissa L. Bailey, Jesse Burgher, Kenneth P. Burnham, Tara Chestnut, Mary M. Conner, Raymond J. Davis, Krista E. Dilione, Eric D. Forsman, Elizabeth M. Glenn, Scott A. Gremel, Keith A. Hamm, Dale R. Herter, J. Mark Higley, Rob B. Horn, David W. Lamphear, Trent L. Mcdonald, Janice A. Reid, Carl J. Schwarz, David C. Simon, Stan G. Sovern, James K. Swingle, J. David Wiens, Heather Wise, Charles B. Yackulic

Wildland Resources Faculty Publications

We conducted a range-wide investigation of the dynamics of site-level reproductive rate of northern spotted owls using survey data from 11 study areas across the subspecies geographic range collected during 1993–2018. Our analytical approach accounted for imperfect detection of owl pairs and misclassification of successful reproduction (i.e., at least one young fledged) and contributed further insights into northern spotted owl population ecology and dynamics. Both nondetection and state misclassification were important, especially because factors affecting these sources of error also affected focal ecological parameters. Annual probabilities of site occupancy were greatest at sites with successful reproduction in the previous year …

Precision Irrigation Guide For Center Pivots, Elisa Flint, Matt Yost, Troy Peters, Clara Anderson, Burdette Barker, Neil Hansen

All Current Publications

This factsheet discusses the different variable rate irrigation (VRI) options for center pivots, when they might reduce water use and energy, produce higher crop yields, and when it might be unreasonable to expect these kinds of benefits.

Your Syllabus Matters: Creating A Sense Of Belonging On Day 1, Harrison Kleiner, Heidi Kesler

Empowering Teaching Excellence Conference

The pandemic shown a light on the importance of students having a sense of belonging, which research shows is an important indicator of student success. However our syllabi can unintentionally signal "you don't belong" to some of our students. In this presentation, we will discuss ways we can change our course syllabi to better serve as a welcome mat for students, particularly first-generation and historically minoritized students. Relying on the work done in the Student Experience Project, participants will learn about evidence-based changes they can make to their syllabi, with particular focus on "low-lift" changes that can be made in …

Three Options For Mixing And Loading Spray Tanks, Kalen Taylor, Cody Zesiger, Corey Ransom, Earl Creech, Matt Yost

All Current Publications

Correctly mixing a tank for chemical applications is something most farmers, ranchers, and home gardeners do regularly. However, understanding how to properly mix and calculate rates can be complicated. Follow one of the three options outlined in this fact sheet to accurately obtain application rates and mix chemical products safely and effectively.

Teacher As Student: Matters Of Exploration And Radical Vulnerability In The Classroom, Elizabeth Giardina

Exploring How We Teach

• GSIs can find pedagogical value in demonstrating an exploratory learning process, and, in sharing the partialities that come with that process, we can find opportunities for our own intellectual development and well-being.
• Radical vulnerability is a powerful tool for building a community of responsibility and care.
• Acts of transparent vulnerability can reframe course content as relevant to students’ broader lives, while also modeling a method of community- and self-care.

Validating Students' Diverse Identities, Erin Hughes

Exploring How We Teach

• Recognizing and appreciating students’ identities is important for learning and feelings of academic empowerment.
• The ways in which we can amplify students feeling validated is by being responsive to their needs and respecting who they are both inside and outside the classroom.
• The ways students may feel invalidated are by perpetuating the power dynamics between student and teacher, disregarding students’ mental health, and engaging in inflexible standards.
• Students may feel more able to take on the difficulties of academia when we help them take a strengths-based approach to who they are.

Nothing About Us Without Us: Practical Strategies For Accessible Pedagogy, Jennie Baker, Heath J. Wooten

Exploring How We Teach

• This chapter explores practical strategies based on the lived experiences of the authors, who are disabled graduate instructors.
• Theoretical approaches to accessible pedagogy should be rooted in praxis that accounts for the material realities of the disabled people it professes to be for.
• Most classroom interventions at present are accommodations, which are based on the medical model of disability; this chapter describes an approach to accessible pedagogy rooted in the social model of disability, and an ethics of disability justice.
• Instructors can explore ways of implementing accessible praxis by rethinking the ableist assumptions inherent in such areas as time, space, …

Teaching For Black Girls: What Every Graduate Student Instructor Can Learn From Balck Girlhood Studies, Theresa Hice-Fromille

Exploring How We Teach

• The neoliberal university undervalues teaching and upholds standardization practices that reproduce harm towards marginalized students. Black Studies approaches to education challenge these education standards.
• Teaching for Black girls is a pedagogical approach derived from Black Girlhood Studies in which the instructor commits to engage students as their co-creator, co-witness, and co-conspirator.
• All graduate student instructors can implement curricular tools and instill pedagogical values, such as instructor responsibility, student agency, collaboration, and reflexivity, to engage a practice of teaching for Black girls. In so doing, instructors model behaviors that promote Black girl thriving within and beyond the classroom.
• Instructors in STEM …

Teaching To Fail: Creating Vulnerable Learning Communities To Facilitate Students' Growth, Avaneesh Narla

Exploring How We Teach

• In today’s academic environment, students perceive no room for failure. Thus, they do not explore or take risks, and this limits their growth. As a result, the instructor must create opportunities for failure while mitigating the stress associated with failure.
• Opportunities for failure can be created in the curriculum and course structure through scaffolding, formative assessments, and extensive feedback. The instructor must also adopt a growth mindset when it comes to the students’ abilities.
• Instructors can create an environment where failure is expected by being vulnerable in the classroom themselves and highlighting their failures and subsequent growth. Graduate students are …

Planttracker: An R Package To Translate Maps Of Plant Occurrence Into Demographic Data, Alice E. Stears, Peter B. Adler, Shannon E. Albeke, David H. Atkins, Jared Studyvin, Daniel C. Laughlin

Wildland Resources Faculty Publications

1. Long-term demographic data are rare yet invaluable for conservation, management, and basic research on the underlying mechanisms of population and community dynamics. Historical and contemporary mapped datasets of plant location and basal area present a relatively untapped source of demographic records that, in some cases, span over 20 years of sequential data collection. However, these maps do not uniquely mark individual plants, making the process of collecting growth, survival, and recruitment data difficult.
2. Recent efforts to translate historical maps of plant occurrence into shapefiles make it possible to use computer algorithms to track individuals through time and determine individual growth …

A Complete Receiver For A Multi-H Continuous Phase Frequently Shift Keyed Signal In The Presence Of Doppler, Brendan Hill, Nazia Mozaffar, Salwan Damman

Small Satellite Conference

In the absence of signal imperfections other than the presence of additive white Gaussian (AWGN) noise, Continuous Phase Frequency Shift Keyed (CPFSK) signals with a changing modulation index (referred to in the literature as "multi-h") will have only a few possible starting and end phases at each symbol interval. This allows them to be represented in a trellis diagram where they inherently possess coding gain that can be realized with a Viterbi decoder. However, with a low earth orbit altitude small satellite exhibiting a large time-varying Doppler, the Viterbi decoder fails to maintain this coding gain advantage if the receiver …

Implementing The New Ccsds Housekeeping Data Compression Standard 124.0-B-1 (Based On Pocket+) On Ops-Sat-1, David Evans, Georges Labrèche, Dominik Marszk, Sam Bammens, Miguel Hernández-Cabronero, Vladimir Zelenevskiy, Vasundhara Shiradhonkar, Milenko Starcik, Maximilian Henkel

Small Satellite Conference

The number of telemetry parameters available in a typical spacecraft is constantly increasing. At the same time, the bandwidth available to download all that information is rather static. Operators must therefore make hard choices between which parameters to downlink or not, in which different situations, and at which sampling rates. This tradeoff is more problematic for missions with higher communication latency beyond LEO. Since 2009, The European Space Agency’s European Space Operations Center (ESA/ESOC) has been promoting the compression of housekeeping telemetry as a solution to this problem. Most spacecraft housekeeping telemetry parameters compress extremely well if they are pre-processed …

Catsat: A 6u Inflatable Antenna Technology Demonstration Mission, Aman Chandra, Terrance Pat, Christopher Walker

Small Satellite Conference

This paper describes the design, development and flight testing of a half-meter spherical membrane reflector antenna built out of reflective and clear Mylar segments. A custom-built line feed optimized for operation at 10.5 GHz is used for spherical correction. The antenna system has been jointly developed by the University of Arizona and FreeFall Aerospace, Inc as primary payload to be demonstrated on-orbit on the University of Arizona’s 6U LEO mission CATSAT, nominally scheduled to launch no earlier than September 2022. The launch is a part of NASA’s CSLI program. The mission has been designed for a low earth sun-synchronous orbit. …

Mission Operations, Cubed: Nasa Marshall Operations Support For Smallsats, Darren S. Wallace, Sam Digesu, Clifton Jones, Geoff Lochmaier, David Hitt

Small Satellite Conference

SmallSats have come a long way since the Huntsville Operations Support Center (HOSC) at NASA’s Marshall Space Flight Center supported its first “minisatellite” mission in 2010. And just as SmallSats themselves have evolved in those 12 years, so too has the HOSC’s mission support for SmallSats. Marshall Space Flight Center has a long history with payload and mission operations, including support for the Apollo missions to the moon, the Space Shuttle program, and 21 years of continuous around-the-clock science operations support for research aboard the International Space Station. Today, the HOSC is a multi-tenant facility, supporting not only ISS, but …

Reconnaissance And Documentation, Terra Gordon, Richard Harold, Cayli Farias, Logan Hill, Sharik Joseph, Julia Kjenstad, Michael Lauber, Dakota Ross, Dominick Uzzardo

Small Satellite Conference

The Reconnaissance and Documentation (RAD) project aims to be a Low Earth Orbit (LEO) based satellite that will utilize image recognition and optical remote sensing technology to target countries currently experiencing Stage Seven or higher on the United Nations’ Ten Stages of Genocide. Once a target is located, the Leza satellite will capture images and downlink to a ground station based in Prescott, Arizona. These images will be processed internally and then reviewed before being sent to the United Nations and mainstream media outlets to assist in providing the legal evidence needed for the conviction of war criminals. The system …

Evaluation Of Parameter-Scaling For Efficient Deep Learning On Small Satellites, Calvin B. Gealy, Alan D. George

Small Satellite Conference

Parameter-scaling techniques change the number of parameters in a machine-learning model in an effort to make the network more amenable to different device types or accuracy requirements. This research compares the performance of two such techniques. NeuralScale is a neural architecture search method which claims to generate deep neural networks for devices that are resource-constrained. It shrinks a network to a target number of parameters by adjusting the width of layers independently to achieve a higher accuracy than previous methods. The novel NeuralScale algorithm is compared to the baseline uniform scaling of MobileNet-style models, where the width of each layer …

S-Band Qpsk Transmitter For Picosatellites, Jay Deorukhkar, Peter W. Pachowicz

Small Satellite Conference

The small satellite field has become popular amongst academia, amateur satellite (AMSAT) community, and commercial businesses due to the miniaturization of components and smaller form factors. Specifically, the picosatellite structure has gained attraction for its size and affordability of launch fees. However, the size constraint makes it difficult to generate power and limits the transmit power for downlink. Therefore, efficient data modulation is key to providing high data downlink rates. Also, the typical VHF and UHF frequency spectrum used for satellites is getting congested. Hence, the higher frequency bands such as S-band and X-band are gaining attraction and offer higher …

18 Sds Small Satellite Support, Cynthia Wilson, Diana Mckissock

Small Satellite Conference

In addition to its primary mission, the U.S. Space Force’s 18th Space Defense Squadron (18 SDS) provides orbital data and services at no cost to satellite owners and operators worldwide in the interests of spaceflight safety. We track all artificial objects in Earth orbit, generate orbital elements and forecast reentries, and publish the data on the website, www.space-track.org. In concert with our sister squadron, the 19th Space Defense Squadron (19 SDS), the data produced by the 18 SDS is used to predict close approaches to support collision avoidance by satellite operators including small satellite owners. Of note, however, neither the …

A Small Launch Per Month? - 2022 Edition Of The Annual Industry Survey, Carlos Niederstrasser

Small Satellite Conference

While many, including this author, have publicly stated that the number of small launch vehicles under development is not sustainable, investor money continues to flow into this market segment. New announcements of multimillion funding rounds are occurring several times a year. Even the challenges posed by the worldwide COVID pandemic, have not slowed down this trend. In 2015 we first presented this survey at the AIAA/USU Conference on Small Satellites1, and we identified twenty small launch vehicles under development. By mid-2022 eleven vehicles in this class were operational, 47 were identified under development, and another 47 more were potential new …

Development Of Ascent Propellant Thrusters And Propulsion Systems, Mackenzie Kilcoin, Daniel Cavender, Tomas Hasanof, Michael Zaluki, Tim Mckechnie, Corinne Sedano, Hunter Williams

Small Satellite Conference

Since the 1960s, hydrazine technology has dominated the market of propulsion technology by providing reliable performance on a wide variety of spacecraft. Efforts to replace hydrazine with a higher-performance and safer alternative have engaged numerous emerging technologies in the industry to mature. ASCENT propellant, also known as AF-M315E, is an example of one such green propellant. Initially developed to provide a safer handling environment than hydrazine, ASCENT offers higher overall performance than a hydrazine equivalent by creating more heat during ignition. The next generation of propulsion technology, based on ASCENT propellant, produces a higher impulse and energy density, expanding the …

Pre-Flight Testing Results Of Multiple Water Propulsion Systems - Resistojet And Ion Thruster For Smallsats, Jun Asakawa, Hiroyuki Koizumi, Kazuya Yaginuma, Yuichi Nakagawa

Small Satellite Conference

This paper described re-flight flight testing results of the miniature water propulsion system combined an ion thruster and resistojet thrusters which is to be demonstrated on-orbit by JAXA’s program named Innovative Satellite Technology Demonstration-3. The unified propulsion system has a huge potential to expand micro/nano-spacecraft utilization and decrease the risk of debris.

Additively Manufactured Rcs For Small Satellites And Landers, James F. Horton, Joseph A. Helali, Mela H. Fung, Bryan M. Webb, Stephen A. Yows, William S. Brown, Shawn D. Buckley, William F. Sack

Small Satellite Conference

After a fifty year absence, NASA’s return to the lunar surface under the Artemis Program – for long term human exploration and utilization – is driving commercial and academic opportunities for small satellite and small lander platforms (e.g., Commercial Lunar Payload Services program – CLPS). Bipropellant thrusters are a reliable, low risk, and flight proven method for the propulsion and attitude control that is required for complex maneuvers such entry, descent, and landing (EDL) or in-space proximity operations. However, due to the increasingly competitive commercial spaceflight market in the last decade, satellite subsystems must also be affordable to buy their …

Propellant Management Of Water-Based Microthruster For Suborbital 0g Testing, Katherine Fowee Gasaway, Steven Pugia, Alina Alexeenko, Anthony Cofer

Small Satellite Conference

Size and power are primary limitations on nanosat missions, especially for propulsion, attitude control, or formation flight. New micropropulsion systems that are smaller, lighter, and less power expensive are required for versatile nanosats for cislunar and interplanetary missions. The Film-Evaporation MEMS Tunable Array (FEMTA) is water-based microthruster for CubeSat attitude adjustment that has been developed at Purdue University. FEMTA will provide an attitude control system for microsatellites that uses < 1 W of power in < 0.5 U of volume. The nozzles on FEMTA use heaters at the base of micro-capillary channels to induce film-evaporation, creating a highly controllable, low-power thrust. The novel capillary action thruster also requires a novel liquid 0G propellant management system. The FEMTA 0G propellant management system is a vapor pressure driven pump. It is self-regulating, does not rely on gravity, and does not require complex pressurization systems, making it suitable for microsatellite applications. The system uses a low vapor pressure fluid pressurant to apply a passive, constant deforming pressure upon a diaphragm that separates the pressurant from the propellant. The ratio of specific volume between the pressurant and the propellant is high enough that, as propellant is expended, the diaphragm compresses as the pressurant expands to fill the volume of the spent propellant. As part of the NASA Space Technology Research, Development, Demonstration, and Insertion (REDDI) program, the FEMTA 0G propellant management system is set to be tested during a suborbital Blue Origin New Shepard flight. In preparation for a 2023 launch, an experiment to test the propellant management system has been designed and built and engineering tests have been performed.

Development Of University-Friendly Cubesat Bus And Ground Station Architecture Using Software-Defined Radios, Jin S. Kang

Small Satellite Conference

The goal of the research and development presented in this paper is to introduce a CubeSat bus and ground station architecture that is made to be much more approachable to schools and universities. The three main pillars of the effort are low-cost, maintaining flexibility, and lowering the bar of entry. The presented CubeSat bus includes PyCubed board which houses most of the core satellite bus components on a single board. The board can handle main processing, data storage, UHF radio communication, telemetry sensors, and power management. This UHF radio is paired with a software-defined radio (SDR) that serves as the …

Flight And Direct To Earth/Space Relay Communication System Architecture For Gsfc Cubesat Missions, Ethan Abele, Serhat Altunc, Obadiah Kegege, Kaitlyn Ryder, Behnam Azimi, Michael Campola, Kevin Lynaugh, Gianfranco Barnaba, Sabit Ekin, John O'Hara

Small Satellite Conference

The CubeSat platform is finding increasing use in space science applications due to its low cost and comparative ease of launch. It is becoming a key scientific discovery tool in low Earth orbit (LEO) and beyond, including geosynchronous equatorial orbit (GEO), the Lagrange Points, Lunar missions, and more. The increasing complexity of these missions and their scientific goals must be supported by equal advancements in communications technology. Higher data rates and greater reliability are required every year. However, the reduced Size, Weight, and Power (SWaP) constraints of CubeSat platforms introduce unique challenges in the area of satellite communications. There is …

System Architecture For A Cubesat Dte Laser Communication System, Pj Du Plooy, Gilles Ackaert, G. Witvoet, W. Crowcombe

Small Satellite Conference

Small satellites and CubeSats are playing an increasingly larger role in technology demonstrations, research, and obtaining data for commercial use from space. As these use cases and applications for CubeSats increase and expand the need to get fast, secure and reliable access to the data gathered by the payloads on these spacecraft also increases. To support these developments AAC Hyperion together with TNO has developed a down-to-earth laser communication module for small satellites and CubeSats with a downlink capability of 1 Gbit/s, namely CubeCAT.

One of the challenges that needed to be solved to ensure success was how to deal …

Ops-Sat Leop And Commissioning: Running A Nanosatellite Project In A Space Agency Context, David Evans, Georges Labrèche, Tom Mladenov, Dominik Marszk, Vladimir Zelenevskiy, Vasundhara Shiradhonkar

Small Satellite Conference

OPS-SAT is a 3U CubeSat launched by the European Space Agency (ESA) on December 18, 2019. It is the first nanosatellite to be directly owned and operated by ESA. The spacecraft is a flying platform that is easily accessible to European industry, institutions, and individuals, enabling rapid prototyping, testing, and validation of their software and firmware experiments in space at no cost and no bureaucracy. The spacecraft is equipped with a full set of sensors and actuators including a camera, GNSS, star tracker, reaction wheels, high speed X band and S band communication, laser receiver, software defined radio receiver, and …

Remote Sensing Experiments Using The Rogue-Alpha,Beta Cubesats As A Constellation: High Frame Rate Environmental Observations From Agile, Taskable, Infrared And Visible Sensors In Low Earth Orbit, Dee W. Pack, Pradeep Thiyanaratnam, Tom Freeze, Brian S. Hardy, John R. Santiago, David Pietrowski, Jon C. Mauerhan, Patrick D. Johnson, Paul F. Zittel, Cameron R. Purcell

Small Satellite Conference

The Aerospace Corporation’s Rogue-alpha,beta program built and launched two 3-Unit CubeSats in 18-months, each equipped with modified commercial infrared camera payloads, visible context cameras, laser communications and precision pointing capabilities. Launched on November 2, 2019, the two spacecraft (Rogue-alpha and beta) were boosted and released from the International Space Station Cygnus NG-12 robotic resupply spacecraft on January 31, 2020 into a circular 460-km, 52° inclined orbit. The primary Rogue IR sensor is a 1.4-micron band, 640x512 pixel, 28° field of view, InGaAs short wavelength infrared (SWIR) camera. It is accompanied by a panchromatic, 10-megapixel, 37° field of view visible context …

Multi-Spectral Imaging From Leo: High-Resolution Images And Data From The Napa-2 Turn-Key Mission, Hugo Brouwer, George Dimitriadis, Hong Yang Oei, Zeger De Groot, Ferenc Nemeth, Philip Bouwer, Thinus Prinsloo

Small Satellite Conference

Napa-2 is a 6U Earth observation satellite flying the Simera Sense MultiScape 100CIS: a 7-band multi-spectral line-scan imager. Together with an on-ground calibration and processing chain from Pinkmatter Solutions, the Napa-2 system can deliver high-quality multi-spectral line scan images at an impressive ground sampling distance of 5m. After its launch and deployment in July 2021, hundreds of line scan images have been taken and valuable (and critical) data was obtained from the spacecraft platform related to attitude and control and timing. Imperative to the success of obtaining high-quality images, was the implementation of the newly developed ISISPACE Attitude Determination and …

Near Earth Asteroid Scout - Mission Update, Les Johnson, Erin Betts, Andrew Heaton, Clif Jones, Leslie Mcnutt, Matt Pruitt, Jim Stott, Darren Wallace, Rick Wilson, Julie Castillo-Rogez, Gregory Lantoine, Calina Seybold, Ted Sweetser

Small Satellite Conference

After its deployment from NASA’s Space Launch System (SLS), the Near-Earth Asteroid (NEA) Scout mission will travel to and image an asteroid during a close flyby using an 86m2 solar sail as its primary propulsion. Solar sails are large, mirror-like structures made of a lightweight material that reflects sunlight to propel the spacecraft. The continuous solar photon pressure provides thrust with no need for the heavy, expendable propellants used by conventional chemical and electric propulsion systems. Developed by NASA’s Marshall Space Flight Center (MSFC) and Jet Propulsion Laboratory (JPL), the NEA Scout is based on the industry-standard CubeSat form factor. …