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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 883 records · Page 49
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Analysis of an algae-based CELSS. II - Options and weight analysis

Life support components are evaluated for application to an idealized closed life support system which includes an algal reactor for food production. Weight-based trade studies are reported as 'break-even' time for replacing food stores with a regenerative bioreactor. It is concluded that closure of the life support gases (oxygen recovery) depends on the carbon dioxide reduction chemistry and that an algae-based food production can provide an attractive alternative to re-supply for longer duration missions.

Holtzapple, Mark T.↗
NASA NTRS1989

Definition of avionics concepts for a heavy lift cargo vehicle. Volume 1: Executive summary

A cost effective, multiuser simulation, test, and demonstration facility to support the development of avionics systems for future space vehicles is examined. The technology needs and requirements of future Heavy Lift Cargo Vehicles (HLCVs) are analyzed and serve as the basis for sizing of the avionics facility, although the lab is not limited in use to support of HLCVs. Volume 1 provides a summary of the vehicle avionics trade studies, the avionics lab objectives, a summary of the lab's functional requirements and design, physical facility considerations, and cost estimates.

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NASA NTRS1989

Definition of avionics concepts for a heavy lift cargo vehicle, volume 2

A cost effective, multiuser simulation, test, and demonstration facility to support the development of avionics systems for future space vehicles is defined. The technology needs and requirements of future Heavy Lift Cargo Vehicles (HLCVs) are analyzed and serve as the basis for sizing of the avionics facility although the lab is not limited in use to support of HLCVs. Volume 2 is the technical volume and provides the results of the vehicle avionics trade studies, the avionics lab objectives, the lab's functional requirements and design, physical facility considerations, and a summary cost estimate.

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NASA NTRS1990

Photovoltaic power for Space Station Freedom

Space Station Freedom is described with special attention given to its electric power system. The photovoltaic arrays, the battery energy storage system, and the power management, and distribution system are also discussed. The current design of Freedom's power system and the system requirements, trade studies, and competing factors which lead to system selections are referenced. This will be the largest power system ever flown in space. This system represents the culmination of many developments that have improved system performance, reduced cost, and improved reliability. Key developments and their evolution into the current space station solar array design are briefly described. The features of the solar cell and the array including the development, design, test, and flight hardware production status are given.

Baraona, Cosmo R.↗
NASA NTRS1989

Combined control-structure optimization

An approach for combined control-structure optimization keyed to enhancing early design trade-offs is outlined and illustrated by numerical examples. The approach employs a homotopic strategy and appears to be effective for generating families of designs that can be used in these early trade studies. Analytical results were obtained for classes of structure/control objectives with linear quadratic Gaussian (LQG) and linear quadratic regulator (LQR) costs. For these, researchers demonstrated that global optima can be computed for small values of the homotopy parameter. Conditions for local optima along the homotopy path were also given. Details of two numerical examples employing the LQR control cost were given showing variations of the optimal design variables along the homotopy path. The results of the second example suggest that introducing a second homotopy parameter relating the two parts of the control index in the LQG/LQR formulation might serve to enlarge the family of Pareto optima, but its effect on modifying the optimal structural shapes may be analogous to the original parameter lambda.

Salama, M.↗
NASA NTRS1990

Assembly vs. direct launch of transfer vehicles

A top level assessment is performed of the relative impacts of on-orbit assembly of the lunar or Mars transfer vehicles versus direct launch. The objective is to identify the major option paths for the Earth-to-orbit, ETO, transportation systems. Heavy lift launch vehicles, if large enough, could reduce or eliminate on-orbit assembly. However, with every new approach, there are always counter-balancing considerations and it is the objective to begin the delineation of the necessary follow-on trade study issues.

Katzberg, Stephen J.↗
NASA NTRS1989

The cryogenic subsystem for the X-ray spectrometer on the Advanced X-Ray Astrophysics Facility (AXAF)

The X-ray Spectrometer (XRS) instrument on the Advanced X-ray Astrophysics Facility (AXAF) will use X-ray detectors that operate at 0.1 K. The detectors will be maintained at 0.1 K by an Adiabatic Demagnetization Refrigerator (ADR) that operates inside a liquid helium dewar. The ADR rejects approximately 2 mW of heat to the stored liquid helium. With this low instrument heat load, the liquid helium dewar will have a long lifetime if the parasitic heat load on the helium from the surrounding warm facility is minimized. Spaceborne helium dewars typically use up to 3 vapor cooled shields to intercept the parasitic heat load. The XRS will add mechanical coolers to provide additional cooling to the outer vapor cooled shield. The cryogenic system consists of an ADR, a liquid helium dewar, mechanical coolers, and a thermal strap to connect the coolers to the dewar. The lifetime of the stored cryogen is calculated to be up to 5 years. This cryogenic system is described, with particular attention given to the dewar, mechanical cooler, and ADR design, testing, and trade studies. A breadboard ADR is presently being fabricated and tested. The status of the construction and testing of this breadboard will be described.

Castles, Stephen H.↗
NASA NTRS1989

Mars Rover/Sample Return mission definition

Mission trade studies for a preliminary definition of a flight-separable Mars Rover/Sample Return (MRSR) mission are presented. The MRSR initiative consists of two separate mission elements: a Mars Rover and a Mars Sample Return. Various strategies are discussed for completing the interplanetary portion of the MRSR mission. Five mission options which are characterized by different launch configurations are discussed, and the resulting spacecraft mass needed to accomplish the mission is presented relative to the capabilities of launch vehicles assumed to be available during the timeframe under consideration.

Friedlander, Alan L.↗
NASA NTRS1990

Experimental results for film cooling in 2-D supersonic flow including coolant delivery pressure, geometry, and incident shock effects

An experimental program was conducted to establish some design parameters important to a supersonic film cooling system in a scramjet engine. A simple non-combusting two-dimensional flow configuration was used to isolate the film cooling phenomena. Parameters investigated include coolant delivery pressure, slot height and lip thickness, and incident shock location and strength. Design guidelines for use in engineering and trade studies are presented.

Olsen, George C.↗
NASA NTRS1990

Manned Mars Mission on-orbit operations metric development

This report describes the effort made to develop a scoring system, or metric, for comparing astronaut Extra Vehicular Activity with various robotic options for the on-orbit assembly of a very large spacecraft, such as would be needed for a Manned Mars Mission. All trade studies comparing competing approaches to a specific task involve the use of some consistent and unbiased method for assigning a score, or rating factor, to each concept under consideration. The relative scores generated by the selected rating system provide the tool for deciding which of the approaches is the most desirable.

Gorin, Barney F.↗
NASA NTRS1990

A homotopy approach for combined control-structure optimization - Constructive analysis and numerical examples

This paper outlines the development of methods for the combined control-structure optimization of physical systems encountered in the technology of large space structures. The objectives of the approach taken in this paper is not to produce the 'best' optimized design, but rather to efficiently produce a family of design options so as to assist in early trade studies, typically before hard design constraints are imposed. The philosophy is that these are candidate designs to be passed on for further considerations, and their function is more to guide the development of the system design rather than to represent the ultimate product. A homotopy approach involving multi-objective functions is developed for this purpose. Analytical and numerical examples are also presented.

Scheid, R. E.↗
NASA NTRS1989

Space Station Freedom photovoltaic power module design status

Electric power generation for the Space Station Freedom will be provided by four photovoltaic (PV) power modules using silicon solar cells during phase I operation. Each PV power module requires two solar arrays with 32,800 solar cells generating 18.75 kW of dc power for a total of 75 kW. A portion of this power will be stored in nickel-hydrogen batteries for use during eclipse, and the balance will be processed and converted to 20 kHz ac power for distribution to end users through the power management and distribution system. The design incorporates an optimized thermal control system, pointing and tracking provision with the application of gimbals, and the use of orbital replacement units to achieve modularization. The design status of the PV power module, as derived from major trade studies, is discussed at hardware levels ranging from component to system. Details of the design are presented where appropriate.

Jimenez, Amador P.↗
NASA NTRS1990

Computing interference flows past cylinder-fin-sting assembly in and near a cavity

The internal carriage of stores by the military aircraft is an option, particularly at high speeds, for a possible reduction in the aerodynamic drag and in the radar observability. Trade studies of this option, which include the safe separation of stores from their bays and aerodynamic complications of a cavity flow, require studying the aircraft and the stores together. With this motivation, the computer code, VISCC, is developed to solve the three-dimensional, Reynolds-averaged, unsteady, compressible, and complete Navier-Stokes equations. The store considered here for simulation is a missile configuration with four tail fins and an L-shaped offset sting. The missile is placed first directly above the opening of a rectangular box cavity, then submerged completely inside the cavity. The freestream Mach and the unit Reynolds numbers are 2.75 and 2.97 million per foot, respectively. The results of the time-accurate computations depict these complex flows and help understanding the interference effects. The time-averaged surface pressures compare favorably with the available wind tunnel data.

Baysal, O.↗
NASA NTRS1990

Integrated model of G189A and Aspen-plus for the transient modeling of extravehicular activity atmospheric control systems

A computerized modeling tool, under development for the transient modeling of an extravehicular activity atmospheric control subsystem is described. This subsystem includes the astronaut, temperature control, moisture control, CO2 removal, and oxygen make-up components. Trade studies evaluating competing components and subsystems to guide the selection and development of hardware for lunar and Martian missions will use this modeling tool. The integrated modeling tool uses the Advanced System for Process Engineering (ASPEN) to accomplish pseudosteady-state simulations, and the general environmental thermal control and life support program (G189A) to manage overall control of the run and transient input output, as well as transient modeling computations and database functions. Flow charts and flow diagrams are included.

Kolodney, Matthew↗
NASA NTRS1990

Advanced launch vehicle upper stages using liquid propulsion and metallized propellants

Metallized propellants are liquid propellants with a metal additive suspended in a gelled fuel or oxidizer. Typically, aluminum particles are the metal additives. These propellants provide increase in the density and/or the specific impulse of the propulsion system. Using metallized propellants for volume- and mass-constrained upper stages can deliver modest increases in performance for Low Earth Orbit to Geosynchronous Earth Orbit and other Earth orbital transfer missions. Metallized propellants, however, can enable very fast planetary missions with a single-stage upper stage system. Trade studies comparing metallized propellant stage performance with non-metallized upper stages and the Inertial Upper Stage are presented. These upper stages are both one- and two-stage vehicles that provide the added energy to send payloads to altitudes and onto trajectories that are unattainable with only the launch vehicle. The stage designs are controlled by the volume and the mass constraints of the Space Transportation System and Space Transportation System-Cargo launch vehicles. The influences of the density and specific impulse increases enabled by metallized propellants are examined for a variety of different stage and propellant combinations.

Palaszewski, B. A.↗
NASA NTRS1990

Space transfer concepts and analysis for exploration missions

The progress and results are summarized for mission/system requirements database; mission analysis; GN and C (Guidance, Navigation, and Control), aeroheating, Mars landing; radiation protection; aerobrake mass analysis; Shuttle-Z, TMIS (Trans-Mars Injection Stage); Long Duration Habitat Trade Study; evolutionary lunar and Mars options; NTR (Nuclear Thermal Rocket); NEP (Nuclear Electric Propulsion) update; SEP (Solar Electric Propulsion) update; orbital and space-based requirements; technology; piloted rover; programmatic task; and evolutionary and innovative architecture.

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