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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 415 records · Page 23

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NASA NTRS1989

Hot ion plasmas from the cloud of neutral gases surrounding the Space Shuttle

Large intensities of hot positive ions are observed out to distances of several hundred meters from the Space Shuttle with a plasma analyzer on a small free-flying satellite, the Plasma Diagnostics Package. This ion plasma is inferred to be generated by the charge exchange of ionospheric O+ ions with a large cloud of water molecules from the Space Shuttle. The measured ion density ranges from about 30 to 10,000 H2O+ ions/cu cm. A model for the water vapor cloud provides the basis for density estimates as high as 10 to the 9th H2O molecules/cu cm at a distance of 50 m from the Space Shuttle. Thus, the Space Shuttle possesses a substantial coorbiting atmosphere.

Paterson, W. R.↗

NASA NTRS1989

Shuttle flight rate - An inside look

A detailed description of the Shuttle's four major hardware elements (Orbiter, Main Engine, Solid Rocket Booster, and External Tank) is given. Their design complexity and the Kennedy Space Center Space Shuttle processing capability are the main factors determining Shuttle flight frequency. In addition to KSC efficiency, the National Space Transportation System program management and strategic planning techniques are also factors toward improving the Shuttle flight rate. As a result, the KSC facilities are being upgraded, new facilities are being added, and necessary plans are in place to support the flight rate requirements.

Ellis, Larry C.↗

NASA NTRS1989

Payloads simulation in the Shuttle Mission Training Facility

The Shuttle Mission Training Facility (SMFT) at the NASA Johnson Space Center is the primary facility for full mission training of astronauts. The training provided in the SMTF includes payload operations that are performed by the astronauts while the Space Shuttle is in orbit. This training requires real-time simulation of the operational aspects of Shuttle payloads as well as simulation of the interaction between payloads and the Orbiter. For this purpose the SMTF contains Payloads Simulators (PLS) that are coupled to and operated in synchronization with the Shuttle Vehicle Simulators. The PLS are used for simulating all payloads with the exception of the European Space Agency's Spacelab. The SMTF contains a separate Spacelab Simulator for training Spacelab astronauts. This paper provides a synopsis of actual payload operations, the methodology for payload simulation in the SMTF, and the system architecture of the PLS.

Hajare, Ankur R.↗

NASA NTRS1989

Conceptual design of liquid droplet radiator shuttle-attached experiment

The conceptual design of a shuttle-attached liquid droplet radiator (LDR) experiment is discussed. The LDR is an advanced, lightweight heat rejection concept that can be used to reject heat from future high-powered space platforms. In the LDR concept, submillimeter-sized droplets are generated, pass through space, radiate heat before they are collected, and recirculated back to the heat source. The LDR experiment is designed to be attached to the shuttle longeron and integrated into the shuttle bay using standard shuttle/experiment interfaces. Overall power, weight, and data requirements of the experiment are detailed. The conceptual designs of the droplet radiator, droplet collector, and the optical diagnostic system are discussed in detail. Shuttle integration and safety design issues are also discussed.

Pfeiffer, Shlomo L.↗

NASA NTRS1989

Conceptual design of liquid droplet radiator shuttle-attached experiment technical requirements document

The technical requirements of a shuttle-attached Liquid Droplet Radiator (LDR) experiment are discussed. The Liquid Droplet Radiator is an advanced lightweight heat rejection concept that can be used to reject heat from future high powered space platforms. In the LDR concept, submillimeter sized droplets are generated, pass through space, and radiate heat before they are collected and recirculated back to the heat source. The LDR experiment is designed to be attached to the shuttle longeron and integrated into the shuttle bay using standard shuttle/experiment interfaces. Overall power, weight, and data requirements of the experiment are detailed. Shuttle integration and safety design issues are discussed. An overview of the conceptual design of the experiment is presented. Details of the conceptual design are not discussed here, but rather in a separate Final Report.

Pfeiffer, Shlomo L.↗

NASA NTRS1990

Automated terminal guidance for a Shuttle rendezvous to Space Station Freedom

An automated terminal guidance for a Shuttle rendezvous based on the Clohessy-Wiltshire (CW) linear equations of relative motion is described. The algorithm guides the Shuttle from the last rendezvous midcourse maneuver (MC4) through docking with Space Station Freedom (SSF). The uniqueness of this algorithm is that it makes it possible to use the CW equations to fly a line-of-sight (LOS) Vbar or Rbar in the final-approach docking phase. The algorithm is made of two parts, in and out-of-plane, and can also be used for station keeping during final approaches. Simulation results of the guidance integrated with the Shuttle's flight control system in the Systems Engineering Simulator (SES) at NASA Johnson are discussed. Plans to add a laser radar docking sensor to the SES and integrate it with the Shuttle's rendezvous navigation are examined.

Olszewski, Oscar W.↗

NASA NTRS1990

Plasma waves associated with the space shuttle

Water molecules outgassed from the Space Shuttle suffer collisional charge-exchange with ionospheric oxygen ions, thereby forming unstable distributions of pick-up water ions and leading to high levels of plasma waves near the Shuttle. Liouville's equation with a charge-exchange source term is solved for the water ion distribution function as a function of position relative to the Shuttle. The observational characteristics of the near zone Shuttle waves are summarized. A linear theory in which beam like distributions of water ions drive Doppler shifted lower hybrid waves via the modified two stream instability is developed. This theory explains many characteristics of the near zone waves. Further work on the effects of wave nonlinearities and spatial inhomogeneity is required to explain the detailed frequency spectrum of the waves. The observed wave levels apparently satisfy the threshold condition for modulational instability of lower hybrid waves.

Cairns, I. H.↗

NASA NTRS1990

Attached shuttle payload carriers: Versatile and affordable access to space

The shuttle has been primarily designed to be a versatile vehicle for placing a variety of scientific and technological equipment in space including very large payloads; however, since many large payloads do not fill the shuttle bay, the space and weight margins remaining after the major payloads are accommodated often can be made available to small payloads. The Goddard Space Flight Center (GSFC) has designed standardized mounting structures and other support systems, collectively called attached shuttle payload (ASP) carriers, to make this additional space available to researchers at a relatively modest cost. Other carrier systems for ASP's are operated by other NASA centers. A major feature of the ASP carriers is their ease of use in the world of the Space Shuttle. ASP carriers attempt to minimized the payload interaction with Space Transportation System (STS) operations whenever possible. Where this is not possible, the STS services used are not extensive. As a result, the interfaces between the carriers and the STS are simplified. With this near autonomy, the requirements for supporting documentation are considerably lessened and payload costs correspondingly reduced. The ASP carrier systems and their capabilities are discussed in detail. The range of available capabilities assures that an experimenter can select the simplest, most cost-effective carrier that is compatible with his or her experimental objectives. Examples of payloads which use ASP basic hardware in nonstandard ways are also described.

Source record↗

NASA NTRS1991

AI mass spectrometers for space shuttle health monitoring

The facility Hazardous Gas Detection System (HGDS) at Kennedy Space Center (KSC) is a mass spectrometer based gas analyzer. Two instruments make up the HGDS, which is installed in a prime/backup arrangement, with the option of using both analyzers on the same sample line, or on two different lines simultaneously. It is used for monitoring the Shuttle during fuel loading, countdown, and drainback, if necessary. The use of complex instruments, operated over many shifts, has caused problems in tracking the status of the ground support equipment (GSE) and the vehicle. A requirement for overall system reliability has been a major force in the development of Shuttle GSE, and is the ultimate driver in the choice to pursue artificial intelligence (AI) techniques for Shuttle and Advanced Launch System (ALS) mass spectrometer systems. Shuttle applications of AI are detailed.

Adams, F. W.↗

NASA NTRS1990

Development and implementation of a shuttle modal inspection system

One of the major tasks between Space Shuttle flights is inspection of the orbiter subsystems such as control surfaces, vertical tail, and wings. To date, inspection techniques have consisted primarily of visual and X-ray methods, which are not only time consuming but not as comprehensive as desired. Previous shuttle component and orbiter ground modal testing revealed that orbiter component damage could be identified using standard modal test methods. As a result, NASA has procured a dedicated shuttle modal inspection system (SMIS) that will be used for subsystem inspection. This paper presents a background on the use of modal testing to detect shuttle component damage, details on this new implementation, and an early use of the SMIS capability to investigate a potential orbiter vibration problem.

Hunt, David L.↗

NASA NTRS1990

STS-41 Space Shuttle mission report

The STS-41 Space Shuttle Program Mission Report contains a summary of the vehicle subsystem activities on this thirty-sixth flight of the Space Shuttle and the eleventh flight of the Orbiter vehicle, Discovery (OV-103). In addition to the Discovery vehicle, the flight vehicle consisted of an External Tank (ET) (designated as ET-39/LWT-32), three Space Shuttle main engines (SSME's) (serial numbers 2011, 2031, and 2107), and two Solid Rocket Boosters (SRB's), designated as BI-040. The primary objective of the STS-41 mission was to successfully deploy the Ulysses/inertial upper stage (IUS)/payload assist module (PAM-S) spacecraft. The secondary objectives were to perform all operations necessary to support the requirements of the Shuttle Backscatter Ultraviolet (SSBUV) Spectrometer, Solid Surface Combustion Experiment (SSCE), Space Life Sciences Training Program Chromosome and Plant Cell Division in Space (CHROMEX), Voice Command System (VCS), Physiological Systems Experiment (PSE), Radiation Monitoring Experiment - 3 (RME-3), Investigations into Polymer Membrane Processing (IPMP), Air Force Maui Optical Calibration Test (AMOS), and Intelsat Solar Array Coupon (ISAC) payloads. The sequence of events for this mission is shown in tabular form. Summarized are the significant problems that occurred in the Orbiter subsystems during the mission. The official problem tracking list is presented. In addition, each Orbiter problem is cited in the subsystem discussion.

Camp, David W.↗

NASA NTRS1992

Recommendations for a wind profiling network to support Space Shuttle launches

The feasibility is examined of a network of clear air radar wind profilers to forecast wind conditions before Space Shuttle launches during winter. Currently, winds are measured only in the vicinity of the shuttle launch site and wind loads on the launch vehicle are estimated using these measurements. Wind conditions upstream of the Cape are not monitored. Since large changes in the wind shear profile can be associated with weather systems moving over the Cape, it may be possible to improve wind forecasts over the launch site if wind measurements are made upstream. A radar wind profiling system is in use at the Space Shuttle launch site. This system can monitor the wind profile continuously. The existing profiler could be combined with a number of radars located upstream of the launch site. Thus, continuous wind measurements would be available upstream and at the Cape. NASA-Marshall representatives have set the requirements for radar wind profiling network. The minimum vertical resolution of the network must be set so that the wind shears over the depths greater than or = 1 km will be detected. The network should allow scientists and engineers to predict the wind profile over the Cape 6 hours before a Space Shuttle launch.

Zamora, R. J.↗

NASA NTRS1992

Coupled loads analysis for Space Shuttle payloads

Described here is a method for determining the transient response of, and the resultant loads in, a system exposed to predicted external forces. In this case, the system consists of four racks mounted on the inside of a space station resource node module (SSRNMO) which is mounted in the payload bay of the space shuttle. The predicted external forces are forcing functions which envelope worst case forces applied to the shuttle during liftoff and landing. This analysis, called a coupled loads analysis, is used to couple the payload and shuttle models together, determine the transient response of the system, and then recover payload loads, payload accelerations, and payload to shuttle interface forces.

Eldridge, J.↗

NASA NTRS1992

Computational fluid dynamics analysis of Space Shuttle main engine multiple plume flows at high-altitude flight conditions

Computational fluid dynamics (CFD) analysis is providing verification of Space Shuttle flight performance details and is being applied to Space Shuttle Main Engine Multiple plume interaction flow field definition. Advancements in real-gas CFD methodology that are described have allowed definition of exhaust plume flow details at Mach 3.5 and 107,000 ft. The specific objective includes the estimate of flow properties at oblique shocks between plumes and plume recirculation into the Space Shuttle Orbiter base so that base heating and base pressure can be modeled accurately. The approach utilizes the Rockwell USA Real Gas 3-D Navier-Stokes (USARG3D) Code for the analysis. The code has multi-zonal capability to detail the geometry of the plumes based region and utilizes finite-rate chemistry to compute the plume expansion angle and relevant flow properties at altitude correctly. Through an improved definition of the base recirculation flow properties, heating, and aerodynamic design environments of the Space Shuttle Vehicle can be further updated.

Dougherty, N. S.↗

NASA NTRS1991

Space Shuttle processing - A case study in artificial intelligence

A scheduling system incorporating AI is described and applied to the automated processing of the Space Shuttle. The unique problem of addressing the temporal, resource, and orbiter-configuration requirements of shuttle processing is described with comparisons to traditional project management for manufacturing processes. The present scheduling system is developed to handle the late inputs and complex programs that characterize shuttle processing by incorporating fixed preemptive scheduling, constraint-based simulated annealing, and the characteristics of an 'anytime' algorithm. The Space-Shuttle processing environment is modeled with 500 activities broken down into 4000 subtasks and with 1600 temporal constraints, 8000 resource constraints, and 3900 state requirements. The algorithm is shown to scale to very large problems and maintain anytime characteristics suggesting that an automated scheduling process is achievable and potentially cost-effective.

Mollikarimi, Cindy↗

NASA NTRS1992

Spectral characteristics of Shuttle glow

The glowing cloud near the ram surfaces of the Space Shuttle was observed with a hand-held, intensified spectrograph operated by the astronauts from the aft-flight-deck of the Space Shuttle. The spectral measurements were made between 400 and 800 nm with a resolution of 3 nm. Analysis of the spectral response of the instrument and the transmission of the Shuttle window was performed on orbit using earth-airglow OH Meinel bands. This analysis resulted in a correction of the Shuttle glow intensity in the spectral region between 700 and 800 nm. The data presented in this report is in better agreement with laboratory measurements of the NO2 continuum.

Viereck, R. A.↗

NASA NTRS1993

Shuttle orbiter with telescoping main propulsion unit and payload

An improved Space Shuttle with variable internal volume is provided. The Space Shuttle Orbiter includes a telescoping main propulsion unit. This main propulsion unit contains the main rocket engines and fuel tanks and telescopes into the Space Shuttle. A variable cavity is located between this unit and the crew compartment. Accordingly, the positioning of the telescoping main propulsion unit determines the volume of the variable cavity. Thus, the volume of the variable length of the entire Space Shuttle may be increased or decreased to achieve desired configurations for optimal storage. In one embodiment of the invention, the payload also telescopes within the variable cavity.

Macconochie, Ian O.↗

NASA NTRS1991

Results of prototype software development for automation of shuttle proximity operations

The effort involves demonstration of expert system technology application to Shuttle rendezvous operations in a high-fidelity, real-time simulation environment. The JSC Systems Engineering Simulator (SES) served as the test bed for the demonstration. Rendezvous applications were focused on crew procedures and monitoring of sensor health and trajectory status. Proximity operations applications were focused on monitoring, crew advisory, and control of the approach trajectory. Guidance, Navigation, and Control areas of emphasis included the approach, transition and stationkeeping guidance, and laser docking sensor navigation. Operator interface displays for monitor and control functions were developed. A rule-based expert system was developed to manage the relative navigation system/sensors for nominal operations and simple failure contingencies. Testing resulted in the following findings; (1) the developed guidance is applicable for operations with LVLH stabilized targets; (2) closing rates less than 0.05 feet per second are difficult to maintain due to the Shuttle translational/rotational cross-coupling; (3) automated operations result in reduced propellant consumption and plume impingement effects on the target as compared to manual operations; and (4) braking gates are beneficial for trajectory management. A versatile guidance design was demonstrated. An accurate proximity operations sensor/navigation system to provide relative attitude information within 30 feet is required and redesign of the existing Shuttle digital autopilot should be considered to reduce the cross-coupling effects. This activity has demonstrated the feasibility of automated Shuttle proximity operations with the Space Station Freedom. Indications are that berthing operations as well as docking can be supported.

Hiers, Hal↗