A Novel Approach to Space Systems Engineering Education through the Construction of High Altitude Balloons

UC CubeCats is a student organization from the University of Cincinnati dedicated to the education of its members through the development of CubeSats. For every university CubeSat program, there are certain challenges that exist. One of the largest challenges for university CubeSat programs is new member recruitment and retention. New members are often intimidated by the knowledge and experience of more senior members because they have no experience in space systems engineering. In order to mitigate these issues, UC CubeCats has developed a high altitude balloon (HAB) educational program known as the CubeCats Applied Training in Space Exploration (CATiSE) program. By building a HAB, members of the CATiSE program can complete a project using a well-documented space mission engineering process that is similar to the process used for CubeSats. However, unlike CubeSat missions, HAB missions tend to have a shorter lifecycle and lower cost, allowing new members to experiment and learn in a low-risk environment. This CATiSE program includes multiple design reviews, an integration and verification plan, design drawings, and designs of the mission and system architecture. The program was designed to last a full school year, starting with concept exploration in the fall and launch in early April. This is UC CubeCats second HAB launch and the first time the CATiSE program has been implemented. The project to be launched this April, code named project TOYGER, will travel 30km into the stratosphere while the payload measures both radiation energy and light wavelengths. The payload will also take 360-degree images throughout the flight of the balloon. This data will be stored on an external storage device and recovered along with the payload. In order to track the payload, GPS data will be transmitted to the automatic packet reporting system (APRS) as well as a ground station constructed by the members of the CATiSE program. At the end of this 8-month program, new members of UC CubeCats will have a well-founded understanding of the space mission and systems engineering process and will have increased their engineering ability to develop and launch a system that must operate in the harsh environment of space

Delayed Stellar Mass Assembly in the Low Surface Brightness Dwarf Galaxy KDG215

We present HI spectral line and optical broadband images of the nearby low surface brightness dwarf galaxy KDG215. The HI images, acquired with the Karl G. Jansky Very Large Array (VLA), reveal a dispersion dominated ISM with only weak signatures of coherent rotation. The HI gas reaches a peak mass surface density of 6 M$_{\odot}$ pc$^{-2}$ at the location of the peak surface brightness in the optical and the UV. Although KDG215 is gas-rich, the H$\alpha$ non-detection implies a very low current massive star formation rate. In order to investigate the recent evolution of this system, we have derived the recent and lifetime star formation histories from archival Hubble Space Telescope images. The recent star formation history shows a peak star formation rate $\sim$1 Gyr ago, followed by a decreasing star formation rate to the present day quiescent state. The cumulative star formation history indicates that a significant fraction of the stellar mass assembly in KDG215 has occurred within the last 1.25 Gyr. KDG215 is one of only a few known galaxies which demonstrates such a delayed star formation history. While the ancient stellar population (predominantly red giants) is prominent, the look-back time by which 50% of the mass of all stars ever formed had been created is among the youngest of any known galaxy.Comment: Accepted for publication in the Astrophysical Journal Letter

Mixed Nanosphere Assemblies at a Liquid–Liquid Interface

The in-plane packing of gold (Au), polystyrene (PS), and silica (SiO2) spherical nanoparticle (NP) mixtures at a water-oil interface is investigated in situ by UV-vis reflection spectroscopy. All NPs are functionalized with carboxylic acid such that they strongly interact with amine-functionalized ligands dissolved in an immiscible oil phase at the fluid interface. This interaction markedly increases the binding energy of these nanoparticle surfactants (NPSs). The separation distance between the Au NPSs and Au surface coverage are measured by the maximum plasmonic wavelength (λmax) and integrated intensities as the assemblies saturate for different concentrations of non-plasmonic (PS/SiO2) NPs. As the PS/SiO2 content increases, the time to reach intimate Au NP contact also increases, resulting from their hindered mobility. λmax changes within the first few minutes of adsorption due to weak attractive inter-NP forces. Additionally, a sharper peak in the reflection spectrum at NP saturation reveals tighter Au NP packing for assemblies with intermediate non-plasmonic NP content. Grazing incidence small angle X-ray scattering (GISAXS) and scanning electron microscopy (SEM) measurements confirm a decrease in Au NP domain size for mixtures with larger non-plasmonic NP content. The results demonstrate a simple means to probe interfacial phase separation behavior using in situ spectroscopy as interfacial structures densify into jammed, phase-separated NP films