Lessons Learned During the Implementation of a Cold Gas Propulsion System for the SunRISE Mission

The SunRISE mission utilizes a two-phase cold gas propulsion system, which provides several advantages over other cold gas systems but experienced challenges during assembly and testing. Since 2020, Georgia Tech Research Corporation (GTRC), Utah State University Space Dynamics Laboratory (SDL), and the Jet Propulsion Laboratory (FPL) have implemented several improvements to the SunRISE propulsion system. The SunRISE propulsion system leverages an additively manufactured monolithic structure, commercial off-the-shelf (COTS) valves and transducers, and the benign working fluid R-236fa to provide a suitable propulsion system for the SunRise mission. While the GTRC propulsion system had been developed for other missions, the multi-organizational team found and corrected several previously undetected design issues, including filters with highly variable flow performance, solenoid valve drive circuit issues, and inconsistencies in the tank additive manufacturing process that impacted manufacturing yield, thrust consistency, and quality of seals. Leaks in metallic fittings were also identified, and process improvements were put in place to mitigate them. Solenoid valve stiction was the last issue which was mitigated through valve screening and drive circuit adjustments. In this paper, we present lessons learned from the SunRISE propulsion system effort to aid future teams in identifying and addressing similar issues

Energetic particle influence on the Earth's atmosphere

This manuscript gives an up-to-date and comprehensive overview of the effects of energetic particle precipitation (EPP) onto the whole atmosphere, from the lower thermosphere/mesosphere through the stratosphere and troposphere, to the surface. The paper summarizes the different sources and energies of particles, principally galactic cosmic rays (GCRs), solar energetic particles (SEPs) and energetic electron precipitation (EEP). All the proposed mechanisms by which EPP can affect the atmosphere are discussed, including chemical changes in the upper atmosphere and lower thermosphere, chemistry-dynamics feedbacks, the global electric circuit and cloud formation. The role of energetic particles in Earth’s atmosphere is a multi-disciplinary problem that requires expertise from a range of scientific backgrounds. To assist with this synergy, summary tables are provided, which are intended to evaluate the level of current knowledge of the effects of energetic particles on processes in the entire atmosphere

A systematic review of the clinical utility of the concept of self‐disgust

This systematic literature review examined the clinical utility of the construct of self disgust in understanding mental distress. Specifically, the review assessed whether there is a shared conceptual definition of self-disgust, the face and construct validity of the quantitative assessment measures of self-disgust, and the predictive validity of self-disgust in formulating the development of a range of psychological difficulties. A systematic database search supplemented by manual searches of references and citations identified thirty-one relevant papers (27 quantitative, 3 qualitative, 1 mixed). Analysis of qualitative papers indicated a number of shared features in the definition of self-disgust, including a visceral sense of self elicited nausea accompanied by social withdrawal and attempts at cleansing or suppressing aspects of the self. Quantitative assessment measures appeared to capture these dimension and evidenced good psychometric properties, although some measures may have only partially captured the full self-disgust construct. Strong relationships were observed between self disgust and a range of mental health presentations, in particular depression, body-image difficulties, and trauma-related difficulties. However, these relationships are smaller when the effects of other negative self-referential emotions were controlled, and stronger conclusions about the predictive validity of self-disgust are limited by the cross-sectional nature of many of the studies

Isothermal Structural Panels for Spacecraft Thermal Management

Realization of Responsive Space (RS) program goals requires further progress in reducing the time required for spacecraft system design, analysis, fabrication, assembly, integration, testing, and deployment. Of particular need is an enabling technology that will reduce the design and integration-test time of the thermal subsystem. One such technology is the Thermal Control Panel (TCP) being developed by Thermal Management Technologies under SBIR contract to AFRL Space Vehicles Directorate (AFRL/RV). This technology provides isothermal structural panels and low thermal impedance joints for use in an isothermal spacecraft structure. Each light weight panel provides the spacecraft structure while simultaneously exhibiting an effective thermal conductivity/mass ratio much greater than traditional spacecraft materials. In various forms the TCP can be used to spread heat, create nearly isothermal spacecraft structures, and to provide highly efficient space radiators. The technology is applicable to spacecraft structures at all levels of size and complexity. The panels have an operating temperature range of -30 to +65 C. The technology development is on track to complete space qualification testing in early 2012