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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 1,513 records · Page 84
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Networks consolidation program

A single consolidated network of ground tracking stations to replace the present two ground-based spacecraft tracking networks is proposed. The proposed consolidated network uses facilities that are now included in the Ground Spaceflight Tracking and Data Network (GSTDN), operated by Goddard Space Flight (GSFC), as well as the existing Deep Space Network (DSN), operated by Jet Propulsion Laboratory (JPL). These facilities are combined and modified to provide a consolidated network managed and operated by JPL and capable of supporting the set of planetary and Highly Elliptical Earth Orbiter (HEEO) missions planned for the Tracking and Data Relay Satellite System (TDRSS) era. The consolidated network is planned to be operational after the TDRSS becomes operational. It will continue to support planetary missions that are now supported by the DSN and also provide support to a broad class of other spacecraft missions which are not compatible with or which, for other reasons, cannot be supported by the TDRSS.

Yeater, M. L.↗
NASA NTRS1981

Measurement of sound absorption in the air

The large temperature gradient in each section of the resonance tube resulting from the liquid nitrogen coolant necessitated a design modification to the cooling system. A timer and four solenoid valves were installed so that the coolant flow can be reversed periodically. The hardware and software for controlling the analog to digital converter and conversion rate were completed, and the system is operational. A duty cycle control circit was implemented so that on the sixteenth conversion a relay shuts off the vibration exciter used to generate the sound wave. Thus the starting point of each decay curve is exactly known. This information is necessary for evaluating the g digital decay information. The data acquisition and digital decay evaluation programs are described.

Meredith, R.↗
NASA NTRS1981

Tank testing of a 2500-cm2 solar panel

A 50 cm by 50 cm solar array panel test patch was investigated for spacecraft charging and arcing effects. Bombardment with monochromatic electron was carried out. Some objectives of the test were: (1) to estimate at what voltage of electron bombardment arcing would be probable; (2) to find whether the arc's energy would be tolerable or damagingly large; (3) to try and separate thermal and photoeffects; and, (4) to see whether materials used were such as to minimize arcing. Some conclusions were: In sunlight the tracking data relay satellite's solar panel which has ceria glass on the front and conductive paint on the backside is probably a good design for reducing charge-up. In a geomagnetic substorm simulated in testing there will be arcing at the interconnects during eclipse and transitions into and out of eclipse in testing especially in view of the very cold temperatures that will be reached by this lightweight array. Ceria-doped glass is preferred to fused silica glass for reducing charge build up. The Kapton bare patch should still be conductively painted. The differential voltages on the panel determine when arcing first begins, and the electron beam voltages vary depending upon whether the metallic structure is directly grounded or semifloating.

Bever, R. S.↗
NASA NTRS1981

Engineering evaluations and studies. Report for IUS studies

The reviews, investigations, and analyses of the Inertial Upper Stage (IUS) Spacecraft Tracking and Data Network (STDN) transponder are reviewed. Carrier lock detector performance for Tracking and Data Relay Satellite System (TDRSS) dual-mode operation is discussed, as is the problem of predicting instantaneous frequency error in the carrier loop. Coastal loop performance analysis is critiqued and the static tracking phase error induced by thermal noise biases is discussed.

Source record↗
NASA NTRS1981

Infrared fiber optic focal plane dispersers

Far infrared transmissive fiber optics as a component in the design of integrated far infrared focal plane array utilization is discussed. A tightly packed bundle of fibers is placed at the focal plane, where an array of infrared detectors would normally reside, and then fanned out in two or three dimensions to individual detectors. Subsequently, the detectors are multiplexed by cryogenic electronics for relay of the data. A second possible application is frequency up-conversion (v sub 1 + v sub 2 = v sub 3), which takes advantage of the nonlinear optical index of refraction of certain infrared transmissive materials in fiber form. Again, a fiber bundle is utilized as above, but now a laser of frequency v sub 1 is mixed with the incoming radiation of frequency v sub 1 within the nonlinear fiber material. The sum, v sub 2 is then detected by near infrared or visible detectors which are more sensitive than those available at v sub 2. Due to the geometrical size limitations of detectors such as photomultipliers, the focal plane dispersal technique is advantageous for imaging up-conversion.

Goebel, J. H.↗
NASA NTRS1981

ATS-6 engineering performance report. Volume 3: Telecommunications and power

Functional design requirements and in-orbit operations, performance, and anomalies are discussed for (1) the communications subsystem, (2) the electrical power system, and (3) the telemetry and command subsystem. The latter includes a review of ground support. Tracking and data relay experiments and the Apollo-Soyuz test program are reviewed.

Wales, R. O.↗
NASA NTRS1981

Satellite applications to electric-utility communications needs

Significant changes in the Nation's electric power systems are expected to result from the integration of new technology, possible during the next decade. Digital communications for monitor and control, exclusive of protective relaying, are expected to double or triple current traffic. A nationwide estimate of 13 Mb/s traffic is projected. Of this total, 8 Mb/s is attributed to the bulk-power system as it is now being operated (4 Mb/s). This traffic could be accommodated by current communications satellites using 3- to 4.5-m-diameter ground terminals costing $35,000 to $70,000 each. The remaining 5-Mb/s traffic is attributed to new technology concepts integrated into the distribution system. Such traffic is not compatible with current satellite technology because it requires small, low-cost ground terminals. Therefore, a high effective isotropic radiated power satellite, such as the one being planned by NASA for the Land Mobile Satellite Service, is required.

Horstein, M.↗
NASA NTRS1981

Operational procedures relative to severe weather

Severe weather impact on both safety and the economics of all types of aviation, and reduction of elimination are discussed. The functions and responsibilities of the dispatcher are outlined. All surface weather reports showing inclement weather, SIGMET REPORTS, forecasting turbulence or icing, convective SIGMETS: (1) tornadoes; (2) hail 3/4 of an inch or greater; (3) imbedded thunderstorms; (4) squall lines or (5) an area of level four or greater thunderstorms. This information along with PIREPs of severe weather are relayed to affected flights. It is concluded that operational procedures must be timely and well conceived to assure the least amount of impact on airline operations.

Sullivan, J. F.↗
NASA NTRS1982

Thermal monitoring, measurement, and control system for a Volatile Condensable Materials (VCM) test apparatus

A thermal monitoring and control concept is described for a volatile condensable materials (VCM) test apparatus where electric resistance heaters are employed. The technique is computer based, but requires only proportioning ON/OFF relay control signals supplied through a programmable scanner and simple quadrac power controllers. System uniqueness is derived from automatic temperature measurements and the averaging of these measurements in discrete overlapping temperature zones. Overall control tolerance proves to be better than + or - 0.5 C from room ambient temperature to 150 C. Using precisely calibrated thermocouples, the method provides excellent temperature control of a small copper VCM heating plate at 125 + or - 0.2 C over a 24 hr test period. For purposes of unattended operation, the programmable computer/controller provides a continual data printout of system operation. Real time operator command is also provided for, as is automatic shutdown of the system and operator alarm in the event of malfunction.

Ives, R. E.↗
NASA NTRS1982

New CCIR papers on telecommunications for deep space research

The selection of preferred frequency bands for deep space telecommunications in the 20 to 120 GHz range is discussed. The performance of links between Earth stations and stations in deep space is affected by the atmosphere of the Earth. Attenuation and emission by the atmosphere generally limits deep space telecommunications to frequencies below 20 GHz. There are, however, certain frequency bands in the 20 to 120 GHz range where atmospheric attenuation is low enough to permit links between Earth stations and deep space stations. Additionally there are certain other bands in the 20 to 120 GHz range that would be particularly suitable for links between an Earth orbiting relay station and deep space stations.

Oldegroot, N. F.↗
NASA NTRS1981

Preliminary design for a Zero Gravity Test Facility (ZGTF). Volume 1: Technical

The functional requirements and best conceptual design of a test facility that simulates weightless operating conditions for a high gain antenna systems (HGAS), that will broadcast to the Tracking Data Relay Satellites were defined. The typical HGAS defined is mounted on a low Earth orbiting satellite, and consists of an antenna with a double gimbal pointing system mounted on a 13 foot long mast. Typically, the gimbals are driven by pulse modulated dc motors or stepper motors. These drivers produce torques on the mast, with jitter that excites the satellite and may cause disturbances to sensitive experiments. The dynamic properties of the antenna support structure (mast), including flexible mode characteristics were defined. The torque profile induced on the spacecraft by motion of the high gain antenna was estimated. Gain and phase margins of the servo control loop of the gimbal drive electronics was also verified.

Germain, A.↗
NASA NTRS1982

NASA space system technology model future mission system needs

The overall technology model is outlined and the objectives and descriptions of the primary and secondary propulsion drives presented. The primary propulsion driver missions are the geostationary platform; the coherent optical system of modular imaging collectors (COSMIC); the 100 meter thinned aperature telescope; and the orbiting deep space relay station (ODSRS). The secondary propulsion driver missions are space platform alpha, the space station, and the automated planetary station.

Reese, T. G.↗
NASA NTRS1981

Chasing the Space Shuttle

The use and modifications of the T-38 aircraft as chase planes for the STS-1 landing are discussed. Two planes tracked the approach at Edwards AFB, with the lead plane responsible for airspeed and altimetry calibration, technical photography, landing gear status, and height-above-touchdown calls; the second T-38 provided live TV and back-up. Modifications included extension of the landing gear extension speed, increasing the area of the speedbrakes, and installation of a TV system; the goal was to stay with the Shuttle below 40,000 ft while it descended at 15,000 ft/min. Ten T-38's were modified and the deployment of lead and back-up crews during the first Shuttle flight is outlined. Western Test Range C-band radar data of the Orbiter position were transformed into intercept coordinates and VHF relayed to the chase craft. Photographs were taken of the right and left sides and underside of the Shuttle while flying with the speedbrake up to match the Shuttle speed.

Mcbride, J. A.↗
NASA NTRS1981

NASA activities and plans

An overview is provided of the NASA tracking, data acquisition, communications, and mission control systems and capabilities. These systems include the NASA Spaceflight Tracking and Data Network (STDN) which supports earth-orbital spacecraft, the Deep Space Network (DSN) which supports the planetary exploration and deep space missions, and the Tracking and Data Relay Satellite System (TDRSS) currently under development and scheduled to come into service in 1983. TDRSS will then displace STDN for support of low earth orbital spacecraft. A description is presented of the current status of the considered systems, and plans are discussed for future developments and new capabilities.

Smylie, R. E.↗
NASA NTRS1981

Ground-to-ground communications for mission support

The objective of the NASA Communications Division is to provide operational communications in support of NASA projects and mission activities. Nascom is a generic term referring collectively to a global system of circuits and switching and terminal facilities established and operated by NASA to provide longhaul operational communications support for all NASA projects. Aspects of network evolution are discussed, taking into account the integrated Nascom network. A description is presented of the present Nascom network, giving attention to the Spaceflight Tracking and Data Network (STDN), the Deep Space Network (DSN), the voice network, and the Teletypewriter (TTY) Network. Concepts and techniques for the 1980's are also considered. It is pointed out that the Nascom Network will extend the Tracking and Data Relay Satellite System (TDRSS) forward- and return-link services to users of the TDRSS by providing ground-to-ground data communications links between the NASA Ground Terminal at White Sands, New Mexico, and major user spacecraft control centers and data capture/data processing facilities.

Dickinson, W. B.↗
NASA NTRS1981

NASA tracking and data acquisition in the 1990s - High earth orbit and planetary spacecraft support

It is pointed out that during the decade of the 1980's the Deep Space Network (DSN) and the ground stations of the Ground Spaceflight Tracking Data Network (GSTDN) will have been consolidated into one ground-based network to provide services for tracking and data acquisition for NASA deep space probes and highly elliptical earth orbiters. The Tracking and Data Relay Satellite System (TDRSS) will have been implemented to handle low earth orbiters. Anticipated solar system exploration missions of the 1990's are discussed, and a description is presented of the new tracking and data acquisition requirements for supporting these missions. The technology options needed to meet these new requirements are identified, and the impact of these technology options on the consolidated DSN is discussed. Attention is given to the evolution of the DSN of the 1980's into the DSN of the year 2000.

Smith, J. G.↗
NASA NTRS1980

Microwave power - An energy transmission alternative for the year 2000

Recent technological advances related to the feasibility of efficient RF-dc rectification make it likely that by the year 2000 the transmission of power through space will have become a practical reality. Proposals have been made to power helicopters, aircraft, balloons, and rockets remotely. Other proposals consider the transfer of power from point to point on earth via relay through space or a transmission of power from large power sources in space. Attention has also been given to possibilities regarding the transmission of power between various points in the solar system. An outline is provided of the microwave power transmission system envisaged for the solar power satellite, taking into account the transmitting antenna, the receiver on earth, aspects of beam formation and control, transmitter options, the receiving antenna design, and cost and efficiency considerations.

Nalos, E.↗