Theory of a cavity around a large floating sphere in complex (dusty) plasma

In the last experiment with the PK-3 Plus laboratory onboard the International Space Station, interactions of millimeter-size metallic spheres with a complex plasma were studied~[M. Schwabe {\it et al.}, New J. Phys. {\bf 19}, 103019 (2017)]. Among the phenomena observed was the formation of cavities (regions free of microparticles forming a complex plasma) surrounding the spheres. The size of the cavity is governed by the balance of forces experienced by the microparticles at the cavity edge. In this article we develop a detailed theoretical model describing the cavity size and demonstrate that it agrees well with sizes measured experimentally. The model is based on a simple practical expression for the ion drag force, which is constructed to take into account simultaneously the effects of non-linear ion-particle coupling and ion-neutral collisions. The developed model can be useful for describing interactions between a massive body and surrounding complex plasma in a rather wide parameter regime.Comment: 9 pages, 4 figures; to be published (2019

Data driven forecast of droplet combustion

The characteristics of a diffusion flame resulting from the gasification of a condensed fuel are predicted from the synthesis of simple models and data. Combustion of a droplet in microgravity is used as a canonical configuration to illustrate the methodology. The simplicity of the spherical configuration and the detail of the measurements make the available experimental data ideal for this study. The approach followed combines the classical analytical solution first proposed by Spalding to describe the condensed phase gasification with a numerical method that describes the gas phase. Available data on flame geometry and regression rates are used to initialize the model and produce adequate predictions of the time evolution of all relevant variables. The method was shown to make proper predictions under numerous configurations and with very small computational cost

Design, Development, and Testing of Research Payloads on Various Suborbital Flight-Test Platforms

With recent advances in the commercial space industry, suborbital payload launches have become more common and accessible to researchers actively seeking solutions for problems involving prolonged space travel and future missions to Moon and Mars. Suborbital payload missions compared to orbital launches are less expensive and offer faster turnaround times; however, the novelty of this domain provides unique challenges. This multidisciplinary research effort aims to tackle some of these challenges by detailing the design, development, and testing techniques followed in the successful launch and recovery of payload experiments in currently active and upcoming suborbital launch vehicles. The research methodology involves collecting payload requirements, CAD design, computational analysis, mass optimization, 3D printing, vibration, and load testing, model rocketry development, simulation, and launch operations. Structural analysis using FEA and vibration testing on a shaker table shows the compliance of the payload prototypes in the maximum predicted flight environments. Multiphase CFD analysis is used as benchmarking technique to characterize the behavior of payloads containing liquids in microgravity. Hands-on model rocketry has proven as a valuable research platform for subsequent payload deliveries

Boulder Capture System Design Options for the Asteroid Robotic Redirect Mission Alternate Approach Trade Study

This paper presents a boulder acquisition and asteroid surface interaction electromechanical concept developed for the Asteroid Robotic Redirect Mission (ARRM) option to capture a free standing boulder on the surface of a 100 m or larger Near Earth Asteroid (NEA). It details the down select process and ranking of potential boulder capture methods, the evolution of a simple yet elegant articulating spaceframe, and ongoing risk reduction and concept refinement efforts. The capture system configuration leverages the spaceframe, heritage manipulators, and a new microspine technology to enable the ARRM boulder capture. While at the NEA it enables attenuation of terminal descent velocity, ascent to escape velocity, boulder collection and restraint. After departure from the NEA it enables, robotic inspection, sample caching, and crew Extra Vehicular Activities (EVA)

Research opportunities in loss of red blood cell mass in space flight

Decreases of red blood cell mass and plasma volume have been observed consistently following manned space flights. Losses of red cell mass by United States astronauts have averaged 10 to 15% (range: 2 to 21%). Based on postflight estimates of total hemoglobin, Soviet cosmonauts engaged in space missions lasting from 1 to 7 months have exhibited somewhat greater losses. Restoration of red cell mass requires from 4 to 6 weeks following return to Earth, regardless of the duration of space flight

NASA/ASEE Summer Faculty Fellowship Program, 1990, Volume 1

The 1990 Johnson Space Center (JSC) NASA/American Society for Engineering Education (ASEE) Summer Faculty Fellowship Program was conducted by the University of Houston-University Park and JSC. A compilation of the final reports on the research projects are presented. The topics covered include: the Space Station; the Space Shuttle; exobiology; cell biology; culture techniques; control systems design; laser induced fluorescence; spacecraft reliability analysis; reduced gravity; biotechnology; microgravity applications; regenerative life support systems; imaging techniques; cardiovascular system; physiological effects; extravehicular mobility units; mathematical models; bioreactors; computerized simulation; microgravity simulation; and dynamic structural analysis

Simulation of three-dimensional incompressible flows with free-surfaces including fluid-structure interaction and microgravity flows

This dissertation describes the evolution of a method for accurately predicting unsteady, three-dimensional, viscous flows with free-surfaces. The special feature of this study is a time-accurate and divergence-free procedure for the computation of the free-surface motion. The method attempts to achieve second order temporal resolution of the free-surface motion through an iterative procedure. The momentum equations are also discretized using a time centered implicit differencing using information from two time levels. The formulation uses a surface-fitting approach which forces the free-surface to coincide with one boundary of the computational domain and solves the three-dimensional incompressible Navier-Stokes equations in primitive variable form within the liquid region. The algebraic equations resulting from a coupled implicit discretization of the governing equations are solved using a vectorized strongly implicit procedure that updates all the primitive variables (the pressure and the three components of velocity) in one calculation sweep. Several axisymmetric and truly three-dimensional cases in a variety of geometries and different levels of gravity have been computed. Results presented include verification of the transient results by comparing with experimental data for the broken dam problem which has served as a standard test case for other free-surface solvers;The procedure is also capable of resolving surface tension or microgravity effects through appropriate boundary conditions on the free surface. This capability is also verified as part of this study by calculating the motion of liquids inside partially filled cylinders. These include computations for widely differing levels of gravity as well as different initial conditions for the spin up from rest. Also included is the description of fluid-structure interaction; the fluid flow calculations are combined with a structural analysis code transferring information back and forth at each time step

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 353)

This bibliography lists 238 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System in August 1991. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, biotechnology, human factors engineering, and flight crew behavior and performance