Search Results

This paper describes the current USL outfitting with design and development changes incorporated during the past year. The International Space Station (ISS) USL is outfitted with eleven systems racks, an optical quality nadir window for earth viewing experiments and accommodations for thirteen International Standard Payload Racks (ISPRs). International payloads utilize this outfitting in a “shirt sleeve” environment by sharing allocated system resources and flight crew time to perform long term microgravity experiments. Recent changes in Command and Data Handling, 120 Vdc power, liquid and air cooling, audio and video communication, space vacuum and microgravity systems resources are included. User interfaces, systems performance and environmental conditions, in addition to the ISS USL outfitting configuration, are also updated in this ICES paper.

ESATAN, a thermal network solver, and ESARAD, a radiative analysis preprocessor, are now used widely throughout the European community for performing satellite thermal analysis. Although these serve the community well it is time to look ahead at the next generation of thermal analysis tool. This paper addresses the problems inherent in the present thermal analysis tools and proposes a specification of a new tool to be developed over the next four years. The major aims of the proposed tool are to provide; complete node and conductor generation, integration of the radiative and thermal analysis processes, a simple interface to other analysis disciplines and a complete and intuitive graphical user interface.

TSS is an integrated thermal analysis program. Using examples from the Space Station buildup sequence and the STS72 Shuttle mission, the TSS analysis process was compared with the standard process~from model building through temperature calculation and the display of results. TSS is shown to be computationally efficient in comparison to another program, TRASYS, that is commonly used for radiation analysis.

The trend towards concurrent engineering requires that designers and engineers of all disciplines share a common engineering database. Incorporation of existing radiation solvers into the CAD environment has had limited success, chiefly due to the limited set of surface types that can be analyzed and the incompatibility with FEM generated meshes. This paper describes RadCAD™, a new radiation analyzer integrated within the CAD environment. In addition to the basic set of conic surfaces, RadCAD also analyzes arbitrary free form surfaces and directly supports FEM meshes. The motivation, design approach, and algorithmic improvements for RadCAD are presented.

A PC-based computer program called ITAS is presented for spacecraft thermal analysis. The code supports full Monte Carlo ray tracing and/or conventional algorithms for view factors, shadow factors, orbital incident/absorbed fluxes, radiation interchange factors, and steady-state and/or transient temperature computations for stationary or spinning spacecraft. The geometry generator is based on primitives: polygon, box, hole-in-a-plate, cylinder, cone, disc, sphere, generic surface of revolution, generic parallelopiped, and elbow. The integrated thermal analyzer allows power and temperature profiles, thermostats, temperature-dependent thermal conductivity, user-defined nodes and conductances. Automatic 2D and/or box/plate conductance generation, single-phase fluid-flow modeling, sub-models, beta angle variation with time, spacecraft foot-print on the earth, integrated libraries for optical and physical properties and interfaces with SINDA, TRASYS, and NASTRAN.

The Thermal Control System (TCS) ensuring the Allowable Flight Temperature (AFT) at extremly different thermal loads, caused from mission conditions for the Cosmic Dust Analyzer (CDA) on board of the NASA/ESA-CASSINI-Satellite, is considered. The CDA is an extremly lightweight and large instrument with a large instrument boreside in space- direction. Important for the thermal situation of CDA are emittance and solar absorptance of the large space-exposed inner surfaces. For these surfaces we used gold sputtered films. Gold has a good long term stability, heat losses will be limited and the quite often external heat load will be harmless. For heat power supplementation and temperature stabilization CDA receives additional heat from S/C by radiation and conduction.

The MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) instrument is part of the payload of the European Space Agency's (ESA) earth observation satellite ENVISAT-1. Most of the optical imaging equipment of MIPAS is required to operate at a temperature level around 200 K. The detectors and their optics have to be cooled down to approximately 70 K. Various thermal design measures have been taken to achieve these goals. In order to verify the thermal design the instrument behaviour has been represented in a mathematical model. A software tool for reduction of thermal models has been used to obtain small models for various purposes. The verification of the instrument thermal design also includes a thermal balance test.

In August 1995, the Microsoft Corporation officially introduced a new operating system for IBM compatible computers. The release of Windows 951 revolutionized the software capabilities of the personal computer -- a true 32-bit operating system without the overhead of expensive hardware. To meet the needs of its customers many companies have migrated their software over to the Windows 95 operating system. Realizing the need for an improved user interface, SSPTA began a transformation toward becoming a true Windows 95 32-bit program. The first step toward this transformation was the development of the SSPTA File Manager5. A Windows 95 menu-driven program used to create input files needed to execute the SSPTA software.

Interplanetary spacecraft which are operating in the outer solar system are normally powered by Radioisotopic Thermoelectric Generators. The European (ESA) scientific spacecraft Rosetta however, which shall explore the comet „Wirtanen” begining in the year 2011, shall be powered by low-intensity, low-temperature solar cells even for Sun distances of up to 5.25 AU. To keep the solar array area within feasible sizes, strict power saving is mandatory. Heater power is saved by mitigating the large solar flux differences between hot and cold cases by the thermal design. The resulting thermal design features are louver radiators, superior performance insulation, two stage radiant cooler and electrical heaters. Heater power is saved by reducing the difference between the external heat load in the hot and cold cases by the configuration and the attitudes of the spacecraft which shadow louver radiators and payload from direct sun radiation.

The Columbus Attached Pressurised Module (APM) is intended to support a shirt-sleeve environment for crew activities. Top level requirements therefore define a cabin air temperature and humidity range (the so-called “Comfort Box”), extreme air velocities for ventilation in the centra aisle, maximum mean radiant temperature of the cabin walls. Air temperature selectability has to be ensured with adequate accuracy across the whole range. The APM environmental control system, in particular the Temperature and Humidity Control (THC) system, is designed and verified against these parameters. Cabin thermal conditions can be evaluated by the APM Integrated Overall Thermal Mathematical Model (IOTMM), representing the general thermal behaviour of the APM, including the THC system. Heat loads due to APM subsystem equipment and payloads, solar flux and the crew itself have been considered in the analyses.

A Temperature and Humidity Control (THC) assembly an essential system in order to provide comfortable environment for crew members in Japanese Experiment Module (JEM). Development of an engineering model (EM) and a proto model (PM) of JEM THC assembly started from March 1991 and completed on March 1995 successfully. In this development phase, it is called JEM EM phase, qualification test of THC was conducted to verify the THC design. This paper presents JEM THC design and an outline of the assembly model development.

A three country effort (U.S., Russia, and Bulgaria) has upgraded the plant growth facilities on the Mir Space Station and used the new facility to grow wheat for 90 days. The Svet plant-growth facility was reactivated and used in an initial experiment as part of the Shuttle/Mir program, August to November, 1995. The Svet system, used first to grow cabbage and radish during a 1990 experiment, was augmented by the addition of a U.S. developed Gas Exchange Measurement System (GEMS) that measures a range of environmental parameters plus transpiration, photosynthesis, and possibly respiration. Environmental parameters include cabin, chamber, root-zones, and leaf temperatures. Light levels, relative humidity, oxygen, and atmospheric pressure are also measured. High-accuracy water-vapor and carbon-dioxide concentrations and differences are measured using specially developed IRGA systems.

Of the possible Life Support Systems evaluation criteria, the criterion of "integral reliability" is proposed. This criterion incorporates three main indices: reliability, mass, and quality of life. It is possible to interrelate these indices only if the space mission is considered as a whole. It is shown that there must exist a LSS mass optimum with respect to mission reliability. The specific form of "integral reliability" expression and the number of terms depend on the mission scenario. This work considers different LSS for orbital station, Lunar base, and Mars mission scenarios.

This paper presents the results of the breadboarding study phase of a Fourier transform infrared spectrometer (FTIR) based trace gas monitor for the use on-board a manned spacecraft. The FTIR system configuration includes a multiple-reflection long path gas cell, a half-wavenumber resolution interferometer, and a mercury-cadmium-telluride (MCT) detector. In the study, the emphasis was put on the achievement of a predefined analytical performance using a state-of-the-art multivariate analysis method. Robustness of the employed algorithms was to the fore rather than a sophisticated FTIR instrumentation. The achieved results show high accuracy in detecting trace gases in the range between the (lower) long-term and (higher) short-term Spacecraft Maximum Allowable Concentration (SMAC) limits. The project has demonstrated a good proof-of-concept for the use of an FTIR system in manned space flights.

ESARAD is an integrated suite of analysis tools for thermal radiative analysis. The suite provides modules for: • Geometry Definition; • Calculation of view factor, radiative exchange factor and solar, albedo and planet flux results; •Visualization of models in orbit with pre- and post-processing of radiative and thermal results; • Reporting of all aspects of the model; and • Generation of Input Files for Thermal Analysis tools. ESARAD is driven by a fully developed GUI, providing the user with a simple, intuitive windows, menus, forms interface to all its features. A modern, block structured language can also be used to run ESARAD. This gives the advanced user great power and flexibility to perform the most complex analyses. ESARAD was designed and developed between 1988 and 1991 to replace the VWHEAT software used by ESA at that time.

In an on-going harmonized ESA/NIVR project, performed by Stork Comprimo and TNO-MEP, the removal of the carbon dioxide with membranes is studied. The use of membrane gas absorption for carbon dioxide removal is currently hampered by the fact that the commonly used alkanolamines result in leakage problems when using polyolefin membranes. This prevents the use of membrane gas absorption for carbon dioxide in spacecrafts. TNO has recently discovered classes of liquids for carbon dioxide absorption which are suitable for use with cheap polyolefin membranes. This opens the possibility for using membrane gas absorption for carbon dioxide control in spacecrafts. In the project the performance of membrane gas absorption for the removal of carbon dioxide from gas streams having a chemical composition representative of spacecraft conditions are determined experimentally.

Environment Control and Life Support Systems (ECLSS) are necessary for missions of human beings into outer space. The longer the missions are the more the closure of the ECLSS loops is demanded. Since 1985 in a harmonised multi-phased programme under ESA (European Space Agency) and DARA comtract (German Space Agency) the Air Revitalisation System ( ARS )and its technologies are being developed. This paper reviews the current status of the complete system and presents the latest development results of the three key elements: The solid amine CO2 concentrator. The Sabatier reactor. The fixed alkaline electrolyser.

During 1995, we tested instruments and attempted a seed-to-seed experiment with Super-Dwarf wheat in the Russian Space Station Mir. Utah instrumentation included four IR gas analyzers (CO2 and H2O vapor, calculate photosynthesis, respiration, and transpiration) and sensors for air and leaf (IR) temperatures, O2, pressure, and substrate moisture (16 probes). Shortly after planting on August 14, three of six fluorescent lamp sets failed; another failed later. Plastic bags, necessary to measure gas exchange, were removed. Hence, gases were measured only in the cabin atmosphere. Other failures led to manual watering, control of lights, and data transmission. The 57 plants were sampled five times plus final harvest at 90 d. Samples and some equipment (including hard drives) were returned to earth on STS-74 (Nov. 20). Plants were disoriented and completely vegetative. Maintaining substrate moisture was challenging, but the moisture probes functioned well.

NASA has supported a research program in plant space biology as well as supporting ground-based gravitational biology investigations for over three decades. The research in plant space biology is advancing at an increasingly rapid rate as more versatile hardware is developed for flight. The new hardware has supported experiments which have and will continue to allow a greater variety of research approaches. The overall goal is focused on characterizing and explaining the effects of gravity on growth, development, composition and functions of higher plants.

Space: so far so expensive! If the Space Station has a 6-year delay in respect to the initial schedule, Lunar Base will have a 15-year delay, if we continue to think in a conservative way. We need a new approach for the missions' and manned systems' design. The ISU-IACSA (Italian Affiliate Campus for Space Architecture of the International Space University) current activities are focused on "self-constructing" and "self-shaping habitat." The major cost of a space mission is essentially the transfer "flights" from Earth to Space, and, in the case of the Moon, all the steps to go there, space station's stops included. Many flights are necessary to build a Lunar base due to the large number of elements by which it is composed; in particular, the current NASA's Lunar Base configuration for 12 people is based on 5 flights minimum and on a lot of time to be spent by the astronauts once on the surface of Moon to assemble the base (in a space suit).