A University Deep Space CubeSat Mission: Lessons Learned from the University of Colorado Boulder Earth Escape Explorer (CU-E3)

The University of Colorado Boulder Earth Escape Explorer (CU-E3) CubeSat is a student designed and built CubeSat initially slated for launch into deep space on Artemis-1, the inaugural launch of the NASA Space Launch System (SLS). CU-E3 was designed to compete in the Cube Quest Challenge’s (CQC) Deep Space Derby for monetary prizes associated with deep space communication system performance, while also serving as a technology demonstration platform for a series of innovative university CubeSat technologies and practices, including a low-cost X-band CubeSat transmitter, an X-band reflectarray antenna, and the use of solar radiation pressure to control reaction wheel momentum build-up. An overview of the CU-E3 project, including mission concept of operations, system architecture, and major component descriptions are provided. Emphasis is focused the challenges and lessons learned as a participant of the CQC with a student designed and built deep space CubeSat. These challenges include student turnover, limited commercial ground station capabilities and availability, deep space thermal environment, secondary payload safety procedures for the human space rated SLS, and deep space trajectory variance

[Wallace-Hardeman correspondence, May 19, 1945-October 3, 1945]

https://digitalcommons.acu.edu/crs_books/1424/thumbnail.jp

John Nelson Armstrong folder of correspondence

The folder of correspondence labeled John Nelson Armstrong has been digitized and the original order maintained. The correspondence between J. N. Armstrong, N. B. Hardeman, Foy E. Wallace, and J. W. Shepherd is discussing the premillennialism teaching of R. H. Boll and others

Closing the Deep Space Communications Link with Commercial Assets

Growing commercial and governmental interest in lunar and asteroid resource extraction, as well as continuing interest in deep space scientific missions, means an increase in demand for deep space communications systems. Jet Propulsion Laboratory’s MarCo demonstrated the viability and usefulness of cubesats as relay stations for deep space communications. Given their relatively low cost of construction and launch, cubesats can decrease the cost of building deep space communication systems. This has the potential to make it feasible for a group without a large budget, such as a university cubesat team, to build such a system. However, while minimizing the cost of the satellite is important, it is only one part of the communications link. The ground station is the other. The cost of accessing the Deep Space Network puts it out of reach for most operations that are not NASA programs, including our student-designed and built University of Colorado Earth Escape Explorer (CU-E3) 6U cubesat. This means that a project such as ours has to look at options provided by commercial ground station services. As a competitor in the NASA Cubequest Challenge Deep Space Derby, the CU-E3 team’s goal is to demonstrate it is possible to build a deep space communications system that is small, powerful, and (relatively) low cost. This means not just the hardware on the satellite but also the ground station. On the satellite side, we have developed custom hardware to interface with an AstroDev Li-2 radio for C-band uplink. For downlink, we will be using an X-band radio developed for low earth applications at the University of Colorado Boulder under the NASA Small Satellite Technology Development program. For ground station services, we will be partnering with a commercial provider, ATLAS. This paper describes the architecture of the CU-E3 communications system, the challenges of developing a communications system small enough to fit in a 6U cubesat yet powerful enough for deep space, and the process we used to research and partner with a commercial ground station service to help us fulfill our mission

Evolutionarily stable defence and signalling of that defence

We examine the evolution and maintenance of defence and conspicuousness in prey species using a game theoretic model. In contrast to previous works, predators can raise as well as lower their attack probabilities as a consequence of encountering moderately defended prey. Our model predicts four distinct possibilities for evolutionarily stable strategies (ESSs) featuring maximum crypsis. Namely that such a solution can exist with (1) zero toxicity, (2) a non-zero but non-aversive level of toxicity, (3) a high, aversive level of toxicity or (4) that no such maximally cryptic solution exists. Maximally cryptic prey may still invest in toxins, because of the increased chance of surviving an attack (should they be discovered) that comes from having toxins. The toxin load of maximally cryptic prey may be sufficiently strong that the predators will find them aversive, and seek to avoid similar looking prey in future. However, this aversiveness does not always necessarily trigger aposematic signalling, and highly toxic prey can still be maximally cryptic, because the increased initial rate of attack from becoming more conspicuous is not necessarily always compensated for by increased avoidance of aversive prey by predators. In other circumstances, the optimal toxin load may be insufficient to generate aversion but still be non-zero (because it increases survival), and in yet other circumstances, it is optimal to make no investment in toxins at all. The model also predicts ESSs where the prey are highly defended and aversive and where this defence is advertised at a cost of increased conspicuousness to predators. In many circumstances there is an infinite array of these aposematic ESSs, where the precise appearance is unimportant as long as it is highly visible and shared by all members of the population. Yet another class of solutions is possible where there is strong between-individual variation in appearance between conspicuous, poorly defended prey

GLIMPSE-CO1: the most massive intermediate-age stellar cluster in the Galaxy

The stellar cluster GLIMPSE-C01 is a dense stellar system located in the Galactic Plane. Though often referred to in the literature as an old globular cluster traversing the Galactic disk, previous observations do not rule out that it is an intermediate age (less than a few Gyr) disk-borne cluster. Here, we present high-resolution near-infrared spectroscopy of over 50 stars in the cluster. We find an average radial velocity is consistent with being part of the disk, and determine the cluster's dynamical mass to be (8 \pm 3)x10^4 Msun. Analysis of the cluster's M/L ratio, the location of the Red Clump, and an extremely high stellar density, all suggest an age of 400-800Myr for GLIMPSE-C01, much lower than for a typical globular cluster. This evidence therefore leads us to conclude that GLIMPSE-C01 is part of the disk population, and is the most massive Galactic intermediate-age cluster discovered to date.Comment: 10 pages, 9 figures, accepted for publication in MNRA

Active megadetachment beneath the western United States

Geodetic data, interpreted in light of seismic imaging, seismicity, xenolith studies, and the late Quaternary geologic history of the northern Great Basin, suggest that a subcontinental-scale extensional detachment is localized near the Moho. To first order, seismic yielding in the upper crust at any given latitude in this region occurs via an M7 earthquake every 100 years. Here we develop the hypothesis that since 1996, the region has undergone a cycle of strain accumulation and release similar to “slow slip events” observed on subduction megathrusts, but yielding occurred on a subhorizontal surface 5–10 times larger in the slip direction, and at temperatures >800°C. Net slip was variable, ranging from 5 to 10 mm over most of the region. Strain energy with moment magnitude equivalent to an M7 earthquake was released along this “megadetachment,” primarily between 2000.0 and 2005.5. Slip initiated in late 1998 to mid-1999 in northeastern Nevada and is best expressed in late 2003 during a magma injection event at Moho depth beneath the Sierra Nevada, accompanied by more rapid eastward relative displacement across the entire region. The event ended in the east at 2004.0 and in the remainder of the network at about 2005.5. Strain energy thus appears to have been transmitted from the Cordilleran interior toward the plate boundary, from high gravitational potential to low, via yielding on the megadetachment. The size and kinematic function of the proposed structure, in light of various proxies for lithospheric thickness, imply that the subcrustal lithosphere beneath Nevada is a strong, thin plate, even though it resides in a high heat flow tectonic regime. A strong lowermost crust and upper mantle is consistent with patterns of postseismic relaxation in the southern Great Basin, deformation microstructures and low water content in dunite xenoliths in young lavas in central Nevada, and high-temperature microstructures in analog surface exposures of deformed lower crust. Large-scale decoupling between crust and upper mantle is consistent with the broad distribution of strain in the upper crust versus the more localized distribution in the subcrustal lithosphere, as inferred by such proxies as low P wave velocity and mafic magmatism

Coordinating Development of the SWARM-EX CubeSat Swarm Across Multiple Institutions

The Space Weather Atmospheric Reconfigurable Multiscale Experiment (SWARM-EX) is a National Science Foundation (NSF) sponsored CubeSat mission distributed across six colleges and universities in the United States. The project has three primary goals: (1) contributing to aeronomy and space weather knowledge, (2) demonstrating novel engineering technology, and (3) advancing higher education. The scientific focus of SWARM-EX is to study the spatial and temporal variability of ion-neutral interactions in the equatorial Ionosphere-Thermosphere (I-T) region. Since the mission consists of three spacecraft operating in a swarm, SWARM-EX will take in-situ measurements of the neutral and ion composition on timescales of less than an orbital period to study the persistence and correlation between different phenomena in the I-T region. The engineering objectives of SWARM-EX are focused on advancing the state of the art in spacecraft formation flying. In addition to being the first passively safe, autonomous formation of more than two spacecraft, SWARM-EX will demonstrate several other key innovations. These include a novel hybrid propulsive/differential drag control scheme and the realization of a distributed aeronomy sensor. Asa project selected by the NSF for its broader impacts as well as its intellectual merit, SWARM-EX aims to use CubeSat development as a vehicle for education. The six collaborating institutions have varying levels of CubeSat experience and involve students who range from first-year undergraduates to Ph.D. candidates. These differences in knowledge, as well as the distributed nature of the program, present a tremendous educational opportunity, but also raise challenges such as cross-institutional communication and coordination, document sharing and file management, and hardware development. By detailing its procedures for overcoming these challenges, the SWARM-EX team believes that it may serve as a case study for the coordination of a successful CubeSat program distributed across multiple institutions

A case study for teaching information literacy skills

<p>Abstract</p> <p>Background</p> <p>The Internet has changed contemporary workplace skills, resulting in a need for proficiency with specific digital, online and web-based technologies within the fields of medicine, dentistry and public health. Although younger students, generally under 30 years of age, may appear inherently comfortable with the use of technology-intensive environments and digital or online search methods, competence in information literacy among these students may be lacking.</p> <p>Methods</p> <p>This project involved the design and assessment of a research-based assignment to help first-year, graduate-level health science students to develop and integrate information literacy skills with clinical relevance.</p> <p>Results</p> <p>One cohort of dental students (n = 78) was evaluated for this project and the results demonstrate that although all students were able to provide the correct response from the content-specific, or technology-independent, portion of the assignment, more than half (54%) were unable to demonstrate competence with a web-based, technology-dependent section of this assignment. No correlation was found between any demographic variable measured (gender, age, or race).</p> <p>Conclusion</p> <p>More evidence is emerging that demonstrates the need for developing curricula that integrates new knowledge and current evidence-based practices and technologies, traditionally isolated from graduate and health-care curricula, that can enhance biomedical and clinical training for students. This study provides evidence, critical for the evaluation of new practices, which can promote and facilitate the integration of information literacy into the curriculum.</p