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This part of the manual presents methods for arriving at a solution to the problem of spacecraft inflight equipment environmental control. The temperature aspect of this problem may be defined as the maintenance of a proper balance and integration of the following thermal loads: equipment-generated, personnel-generated, and transmission through external boundary.

The prediction of vehicle temperatures during ascent through the earth’s atmosphere requires an accurate knowledge of the aerodynamic heating rates occurring at the vehicle surface. Flight parameters required in heating calculations include the local airstream velocity, pressure, and temperature at the boundary layer edge for the vehicle location in question. In addition, thermodynamic and transport air properties are required at these conditions. Both laminar and turbulent boundary layers occur during the boost trajectory. Experience has shown that laminar and turbulent heating are of equivalent importance. Laminar heating predominates in importance in the stagnation areas, but the large afterbody surfaces are most strongly affected by turbulent heating. Once the local flow conditions and corresponding air properties have been obtained, the convective heating rate may be calculated for a particular wall temperature.

Several research programs which have applied thermal scale modeling to a radiation-conduction heat transfer system (unmanned spacecraft) and to a radiation-conduction-convection heat transfer system (manned spacecraft) are reviewed and evaluated. ...The utilization of scaled models in the development of spacecraft thermal control systems is discussed. The criteria necessary to establish thermal similitude are developed as well as techniques for designing scaled thermal models.

This paper highlights the role of electrochemical processes in spacecraft environmental systems development and, by example, describes the fundamentals of these processes.

A method that exploits certain properties of a recirculating gas has been investigated as a means of achieving a sustained accelerative vector force without either the expulsion of mass from or a reaction against an external mass by the accelerated body. A theory of operation is presented that defines the capabilities and limitations of the method, and which has resulted in functioning prototypes. The prototype devices require only a source of electric power and a means of cooling to achieve an internally generated, externally measurable accelerative vector force that is sustained for as long as power is supplied to the device.

Research in microgravity (low-gravity) combustion promises innovations and improvements in fire prevention and response for human-crew spacecraft. Findings indicate that material flammability and fire spread in microgravity are significantly affected by atmospheric flow rate, oxygen concentration, and diluent composition. ...Research on smoke-particle changes in microgravity promises future improvements and increased sensitivity of smoke detectors in spacecraft. Research on fire suppression by extinguishing agents and venting can yield new information on effective control of the rare, but serious fire events in spacecraft. ...Research on fire suppression by extinguishing agents and venting can yield new information on effective control of the rare, but serious fire events in spacecraft.

The Ranger Telerobotic Flight Experiment is a highly complex teleoperated spacecraft, requiring direct human control of 36 major degrees of freedom. The University of Maryland Space Systems Laboratory and the NASA Ames Research Center are cooperating on the development of a virtual reality control station to streamline human interfaces with the Ranger spacecraft. ...The University of Maryland Space Systems Laboratory and the NASA Ames Research Center are cooperating on the development of a virtual reality control station to streamline human interfaces with the Ranger spacecraft. This describes the design and integration of the Ranger Command Chair, a system incorporating fully immersive helmet-mounted stereo displays with head tracking, hand tracking for direct positional control, and supplemental controls and displays to allow a single operator to functionally control the entire vehicle.

(ADA) is developing a handheld fine water mist fire extinguisher for use on manned spacecraft and in future planetary habitats. This design employs only water and nitrogen as suppression agents to allow local refill and reuse. ...Continued development will result in prototype hardware suitable for use on future manned spacecraft.

There are not only large amounts of energy, but also many different kinds of energy in manned spacecraft, which provide chance to optimize a thermal management system in the spacecraft. When water in atmosphere in pressured cabins was removed, waste heat in atmosphere was removed synchronously.

Thermal conductances are computed for relatively simple node geometries that are typical of analytical models of spacecraft. Heat-transfer rates computed with these conductances are compared to heat-transfer rates computed from exact, closed-form mathematical formulas.

NASA's Earth Observing System (EOS) Program will place a series of unmanned polar-orbiting spacecraft in low-earth orbit to support a variety of scientific and Earth-observing missions. The EOS AM spacecraft has a requirement for an advanced heat transportation system for thermal energy. ...The EOS AM spacecraft has a requirement for an advanced heat transportation system for thermal energy. A Capillary Pumped Heat Transportation System (CPHTS) using Capillary Pumped Loop (CPL) technology was selected to accommodate the instruments requiring advanced heat transport.

Spacecraft have previously used passive cooling or pumped liquid loops to maintain proper thermal environments. ...Future large spacecraft, such as the Space Station, will have higher power levels and longer heat transport distances.

Heat dissipated in conduction cooled spacecraft components must be transported across the component base plate/spacecraft mounting plate interface preparatory to final radiation to the space sink.

New thermal control systems like evaporator heat sinks are integrated into the Active Thermal Control System and into the Flight Control System of Space Planes. The development of these new systems is performed through mathematical process analyses and tests. This paper concerns the establishment of a Thermal Mathematical Model (TMM) for the analyses. The design of the HERMES Water Evaporator Assembly (WEA) is presented. The thermodynamics and numerical requirements upon a TMM for heat exchangers are derived and explained in detail. As an example the WEA TMM is depicted and results of transient analyses are discussed.

A pumped, two-phase heat-transport system is being developed for possible use for temperature control of scientific instruments on future NASA missions. As compared to a single-phase system, this two-phase system can maintain tighter temperature control with less pumping power. A laboratory model of the system has been built and tested. The measured heat transfer coefficients were approximately the same as in heat pipes, 220 Btu/hr-ft2-F, as compared to 25 Btu/hr-ft2-F for single-phase liquid flow. Heat sharing between experiments has been demonstrated wherein vapor generated in the cold plate of an active experiment was condensed in a cold, unhealed experiment. System stability has been observed. However, additional development is needed. The use of non-azeotropic mixtures of coolants appears especially promising as a simple way to determine exit quality and thus control the flow rates to prevent dryout.

Two-phase heat transport systems are currently considered for the thermal management of future large power spacecraft. The monitoring of the quality, being the relative vapour mass content, of the two-phase mixture at various locations in the system, is valuable - possibly indispensable - for the proper operation of such a system. ...Only a few concepts turn out to be suitable for spacecraft applications. Promising concepts are based on the capacitance, sonic velocity and index of refraction.

The operational suitability of using laptop computers in crew work stations for future spacecraft and lunar/planetary bases has been assessed by evaluating conceptual mockups of these work stations. ...Further, the use of laptop computers in place of traditional fixed consoles was found to be suitable for most crew work stations and work sites in future spacecraft and space bases. With these analysis and evaluation results in hand, NASA will be able to take full advantage of capabilities currently available in laptop computers in future crew work station design.

The capability of a multifunction display system to present data regarding malfunctioning manned spacecraft systems is illustrated. The development of formats for abnormal operations is based on the correspondence between cognitive requirements of the crewmember and displayed information. ...Three different stages of cognitive processing are identified and associated spacecraft formats are developed. System architecture provides for the display of required information tailored to crewmember requirements in identifying, understanding, and solving malfunctions via a simple multifunction display interface.

The thermal behaviour of spacecraft especially of manned ones is governed by various thermophysical effects. Heat transfer by radiation, conduction and convection influence the overall behaviour of the spacecraft. ...Heat transfer by radiation, conduction and convection influence the overall behaviour of the spacecraft. Energy production, distribution and consumption have also strong impacts on the temperature field prevailing in the spaceplane. ...Moreover, chemical reactions, metabolic rates of the crew and external heat loads determine the thermal behaviour of the spacecraft. For design and optimisation of the system and its subsystems a mathematical model is required which describes these effects.

The focus is on the unique issues associated with the CEV and future spacecraft including operation in reduced gravity and enriched oxygen ambients. Inert gas agents such as carbon dioxide, nitrogen and helium have different minimum extinguishing concentrations (MEC) in microgravity compared to normal gravity; in most instances the MEC in microgravity being higher than in normal gravity.