75 results on '"Gerrish, Harold P"'
Search Results
2. Nuclear Thermal Propulsion (NTP) and Power A New Capability for Outer Planet Science and Exploration
- Author
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Johnson, Charles L, Houts, Michael G, Rodriguez, Mitchell A, and Gerrish, Harold P
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Lunar And Planetary Science And Exploration ,Astronautics (General) ,Spacecraft Propulsion And Power - Published
- 2018
3. Solar Thermal Propulsion at MSFC
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Gerrish, Harold P., Jr
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Energy Production And Conversion ,Spacecraft Propulsion And Power ,Solar Physics - Published
- 2016
4. NASA's Nuclear Thermal Propulsion Project
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Houts, Michael G, Mitchell, Doyce P, Kim, Tony, Emrich, William J, Hickman, Robert R, Gerrish, Harold P, Doughty, Glen, Belvin, Anthony, Clement, Steven, Borowski, Stanley K, Scott, John, and Power, Kevin P
- Subjects
Nuclear Physics - Abstract
The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation NTP system could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of a first generation NTP in the development of advanced nuclear propulsion systems could be analogous to the role of the DC- 3 in the development of advanced aviation. Progress made under the NTP project could also help enable high performance fission power systems and Nuclear Electric Propulsion (NEP).
- Published
- 2015
5. The NASA Advanced Exploration Systems Nuclear Thermal Propulsion Project
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Houts, Michael G, Mitchell, Doyce P, Kim, Tony, Emrich, William J, Hickman, Robert R, Gerrish, Harold P, Doughty, Glen, Belvin, Anthony, Clement, Steven, Borowski, Stanley K, Scott, John, and Power, Kevin P
- Subjects
Spacecraft Propulsion And Power - Abstract
The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation NTP system could provide high thrust at a specific impulse (Isp) above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of a first generation NTP in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation systems.
- Published
- 2015
6. Review of Nuclear Thermal Propulsion Ground Test Options
- Author
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Coote, David J, Power, Kevin P, Gerrish, Harold P, and Doughty, Glen
- Subjects
Spacecraft Propulsion And Power - Abstract
High efficiency rocket propulsion systems are essential for humanity to venture beyond the moon. Nuclear Thermal Propulsion (NTP) is a promising alternative to conventional chemical rockets with relatively high thrust and twice the efficiency of highest performing chemical propellant engines. NTP utilizes the coolant of a nuclear reactor to produce propulsive thrust. An NTP engine produces thrust by flowing hydrogen through a nuclear reactor to cool the reactor, heating the hydrogen and expelling it through a rocket nozzle. The hot gaseous hydrogen is nominally expected to be free of radioactive byproducts from the nuclear reactor; however, it has the potential to be contaminated due to off-nominal engine reactor performance. NTP ground testing is more difficult than chemical engine testing since current environmental regulations do not allow/permit open air testing of NTP as was done in the 1960's and 1970's for the Rover/NERVA program. A new and innovative approach to rocket engine ground test is required to mitigate the unique health and safety risks associated with the potential entrainment of radioactive waste from the NTP engine reactor core into the engine exhaust. Several studies have been conducted since the ROVER/NERVA program in the 1970's investigating NTP engine ground test options to understand the technical feasibility, identify technical challenges and associated risks and provide rough order of magnitude cost estimates for facility development and test operations. The options can be divided into two distinct schemes; (1) real-time filtering of the engine exhaust and its release to the environment or (2) capture and storage of engine exhaust for subsequent processing.
- Published
- 2015
7. Raising Nuclear Thermal Propulsion (NTP) Technology Readiness Above 3
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Gerrish, Harold P., Jr
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Spacecraft Design, Testing And Performance - Published
- 2014
8. The Nuclear Cryogenic Propulsion Stage
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Houts, Michael G, Kim, Tony, Emrich, William J, Hickman, Robert R, Broadway, Jeramie W, Gerrish, Harold P, Doughty, Glen, Belvin, Anthony, Borowski, Stanley K, and Scott, John
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Launch Vehicles And Launch Operations ,Spacecraft Propulsion And Power - Published
- 2014
9. Safe, Affordable, Nuclear Thermal Propulsion Systems
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Houts, Michael G, Kim, Tony, Emrich, William J, Hickman, Robert R, Broadway, Jeramie W, Gerrish, Harold P, and Doughty, Glen E
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Spacecraft Propulsion And Power - Published
- 2014
10. Nuclear Thermal Propulsion Ground Test History
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Gerrish, Harold P., Jr
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Spacecraft Propulsion And Power - Published
- 2014
11. Current Ground Test Options for Nuclear Thermal Propulsion (NTP)
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Gerrish, Harold P., Jr
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Spacecraft Propulsion And Power - Published
- 2014
12. A Research Reactor Concept to Support NTP Development
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Eades, Michael J, Blue, T. E, Gerrish, Harold P, and Hardin, Leroy A
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Spacecraft Propulsion And Power - Abstract
In support of efforts for research into the design and development of man rated Nuclear Thermal Propulsion (NTP), the National Aeronautics and Space Administration (NASA), Marshall Space Flight Center (MSFC), is evaluating the potential for building a Nuclear Regulatory Commission (NRC) licensed NTP based research reactor (NTPRR). The proposed NTPRR would be licensed by NASA and operated jointly by NASA and university partners. The purpose of the NTPRR would be used to perform further research into the technologies and systems needed for a successful NTP project and promote nuclear training and education.
- Published
- 2014
13. Nuclear Thermal Propulsion Ground Test History
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Gerrish, Harold P
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Ground Support Systems And Facilities (Space) ,Spacecraft Propulsion And Power - Abstract
Nuclear Thermal Propulsion (NTP) was started in ~1955 under the Atomic Energy Commission as project Rover and was assigned to Los Alamos National Laboratory. The Nevada Test Site was selected in 1956 and facility construction began in 1957. The KIWI-A was tested on July 1, 1959 for 5 minutes at 70MW. KIWI-A1 was tested on July 8, 1960 for 6 minutes at 85MW. KIWI-A3 was tested on October 10, 1960 for 5 minutes at 100MW. The National Aeronautics and Space Administration (NASA) was formed in 1958. On August 31, 1960 the AEC and NASA established the Space Nuclear Propulsion Office and named Harold Finger as Director. Immediately following the formation of SNPO, contracts were awarded for the Reactor In Flight Test (RIFT), master plan for the Nuclear Rocket Engine Development Station (NRDS), and the Nuclear Engine for Rocket Vehicle Application (NERVA). From December 7, 1961 to November 30, 1962, the KIWI-B1A, KIWI-B1B, and KIWI-B4A were tested at test cell A. The last two engines were only tested for several seconds before noticeable failure of the fuel elements. Harold Finger called a stop to any further hot fire testing until the problem was well understood. The KIWI-B4A cold flow test showed the problem to be related to fluid dynamics of hydrogen interstitial flow causing fuel element vibrations. President Kennedy visited the NTS one week after the KIWI-B4A failure and got to see the engine starting to be disassembled in the maintenance facility. The KIWI-B4D and KIWI-B4E were modified to not have the vibration problems and were tested in test cell C. The NERVA NRX program started testing in early 1964 with NRX-A1 cold flow test series (unfueled graphite core), NRX-A2 and NRX-A3 power test series up to 1122 MW for 13 minutes. In March 1966, the NRX-EST (Engine System Test) was the first breadboard using flight functional relationship and total operating time of 116 minutes. The NRX-EST demonstrated the feasibility of a hot bleed cycle. The NRX-A5 had multiple start-ups in May-June 1966 with 30.75 minutes accumulative operating time at or above 1GW. The NRX-A6 was tested in December 1969 and ran for 62 minutes at 1100 MW. Each engine had post-test examination and found various structure anomalies which were identified for correction and the fuel element corrosion rate was reduced. The Phoebus series of research reactors began testing at test cell C, in June 1965 with Phoebus 1A. Phoebus 1A operated for 10.5 minutes at 1100 MW before unexpected loss of propellant and leading to an engine breakdown. Phoebus 1B ran for 30 minutes in February of 1967. Phoebus 2A was the highest steady state reactor built at 5GW. Phoebus 2A ran for 12 minutes at 4100 MW demonstrating sufficient power is available. The Peewee test bed reactor was tested November- December 1968 in test cell C for 40 minutes at 500MW with overall performance close to pre-run predictions. The XE' engine was the only engine tested with close to a flight configuration and fired downward into a diffuser at the Engine Test Stand (ETS) in 1969. The XE' was 1100 MW and had ~28 start-ups. The nuclear furnace NF-1 was operated at 44 MW with multiple test runs at 90 minutes in the summer of 1972. The NF-1 was the last NTP reactor tested. The Rover/NERVA program was cancelled in 1973. However, before cancellation, a lot of other engineering work was conducted by Aerojet on a 75, 000 lbf prototype flight engine and by Los Alamos on a ~16,000 lbf "Small Engine" nuclear rocket design. The ground test history of NTP at the NRDS also offers many lessons learned on how best to setup, operate, emergency shutdown, and post-test examine NTP engines. The reactor and engine maintenance and disassembly facilities were used for assembly and inspection of radioactive engines after testing. Most reactor/ engines were run at test cell A or test cell C with open air exhaust. The Rover/NERVA program became aware of a new environmental regulation that would restrict the amount of radioactive particulates allowed to be release in open air and successfully demonstrated a scrubber concept with the NF-1. The ETS stand was the only one with a high altitude test chamber used for XE'. The ETS and other test cells showed the effects the engine's radiation had on the facility materials and instrumentation as well as side effects the ground test facility has back on the engine operation. The breakdown of Phoebus 1A at test cell C showed how the site was cleaned up and back to operation for five more engines before the program was cancelled.
- Published
- 2014
14. A Nuclear Cryogenic Propulsion Stage for Near-Term Space Missions
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Houts, Michael G, Kim, Tony, Emrich, William J, Hickman, Robert R, Broadway, Jeramie W, Gerrish, Harold P, Doughty, Glen E, Adams, Robert B, Bechtel, Ryan D, Borowski, Stanley K, and Scott, John H
- Subjects
Launch Vehicles And Launch Operations ,Spacecraft Propulsion And Power - Abstract
Development efforts in the United States have demonstrated the viability and performance potential of NTP systems. For example, Project Rover (1955 - 1973) completed 22 high power rocket reactor tests. Peak performances included operating at an average hydrogen exhaust temperature of 2550 K and a peak fuel power density of 5200 MW/m3 (Pewee test), operating at a thrust of 930 kN (Phoebus-2A test), and operating for 62.7 minutes on a single burn (NRXA6 test).1 Results from Project Rover indicated that an NTP system with a high thrust-toweight ratio and a specific impulse greater than 900 s would be feasible. Binary and ternary carbide fuels may have the potential for providing even higher specific impulses.
- Published
- 2013
15. Affordable Development and Qualification Strategy for Nuclear Thermal Propulsion
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Gerrish, Harold P., Jr and Bhattacharyya, Samit K
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Spacecraft Propulsion And Power - Abstract
Nuclear Thermal Propulsion (NTP) is a concept which uses a nuclear reactor to heat a propellant to high temperatures without combustion and can achieve significantly greater specific impulse than chemical engines. NTP has been considered many times for human and cargo missions beyond low earth orbit. A lot of development and technical maturation of NTP components took place during the Rover/NERVA program of the 60's and early 70's. Other NTP programs and studies followed attempting to further mature the NTP concept and identify a champion customer willing to devote the funds and support the development schedule to a demonstration mission. Budgetary constraints require the use of an affordable development and qualification strategy that takes into account all the previous work performed on NTP to construct an existing database, and include lessons learned and past guidelines followed. Current guidelines and standards NASA uses for human rating chemical rocket engines is referenced. The long lead items for NTP development involve the fuel elements of the reactor and ground testing the engine system, subsystem, and components. Other considerations which greatly impact the development plans includes the National Space Policy, National Environmental Policy Act, Presidential Directive/National Security Council Memorandum #25 (Scientific or Technological Experiments with Possible Large-Scale Adverse Environmental Effects and Launch of Nuclear Systems into Space), and Safeguards and Security. Ground testing will utilize non-nuclear test capabilities to help down select components and subsystems before testing in a nuclear environment to save time and cost. Existing test facilities with minor modifications will be considered to the maximum extent practical. New facilities will be designed to meet minimum requirements. Engine and test facility requirements are based on the driving mission requirements with added factors of safety for better assurance and reliability. Emphasis will be placed on small engines, since the smaller the NTP engine, the easier it is to transport, assemble/disassemble, and filter the exhaust during tests. A new ground test concept using underground bore holes (modeled after the underground nuclear test program) to filter the NTP engine exhaust is being considered. The NTP engine system design, development, test, and evaluation plan includes many engine components and subsystems, which are very similar to those used in chemical engines, and can be developed in conjunction with them Other less mature NTP engine components and subsystems (e.g., reactor) will be thoroughly analyzed and tested to acceptable levels recommended by the referenced standards and guidelines. The affordable development strategy also considers a prototype flight test, as a final step in the development process. Preliminary development schedule estimates show that an aggressive development schedule (without much margin) will be required to be flight ready for a 2033 human mission to Mars.
- Published
- 2013
16. MSFC's Advanced Space Propulsion Formulation Task
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Huebner, Lawrence D, Gerrish, Harold P, Robinson, Joel W, and Taylor, Terry L
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Spacecraft Propulsion And Power - Published
- 2012
17. Advanced Space Propulsion
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Gerrish, Harold P
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Spacecraft Propulsion And Power - Published
- 2012
18. Solar Concentrator Demonstrator for Lunar Regolith Processing
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Fikes, John C, Howell, Joe T, Gerrish, Harold P, and Patrick, Stephen L
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Lunar And Planetary Science And Exploration - Abstract
NASA at the Marshall Space Flight Center (MSFC) is building a portable inflatable solar concentrator ground demonstrator for use in testing in-situ resource utilization (ISRU) lunar regolith processing methods. Of primary interest is the production of oxygen as a propellant oxidizer and for life support. There are various processes being proposed for the in-situ reduction of the lunar regolith, the leading processes are hydrogen reduction, carbothermal reduction and vapor phase pyrolysis. The concentrator system being built at MSFC could support demonstrations of all of these processes. The system consists of a light inflatable concentrator that will capture sunlight and focus it onto a receiver inside a vacuum chamber. Inflatable concentrators are good for space based applications due to their low weight and dense packaging at launch. The hexapod design allows the spot size to be increased to reduce the power density if needed for the process being demonstrated. In addition to the hardware development, a comprehensive simulation model is being developed and will be verified and validated using the system hardware. The model will allow for the evaluation of different lunar locations and operational scenarios for the lunar regolith processing with a high confidence in the predicted results.
- Published
- 2008
19. A Programmatic and Engineering Approach to the Development of a Nuclear Thermal Rocket for Space Exploration
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Bordelon, Wayne J., Jr, Ballard, Rick O, and Gerrish, Harold P., Jr
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Spacecraft Propulsion And Power - Abstract
With the announcement of the Vision for Space Exploration on January 14, 2004, there has been a renewed interest in nuclear thermal propulsion. Nuclear thermal propulsion is a leading candidate for in-space propulsion for human Mars missions; however, the cost to develop a nuclear thermal rocket engine system is uncertain. Key to determining the engine development cost will be the engine requirements, the technology used in the development and the development approach. The engine requirements and technology selection have not been defined and are awaiting definition of the Mars architecture and vehicle definitions. The paper discusses an engine development approach in light of top-level strategic questions and considerations for nuclear thermal propulsion and provides a suggested approach based on work conducted at the NASA Marshall Space Flight Center to support planning and requirements for the Prometheus Power and Propulsion Office. This work is intended to help support the development of a comprehensive strategy for nuclear thermal propulsion, to help reduce the uncertainty in the development cost estimate, and to help assess the potential value of and need for nuclear thermal propulsion for a human Mars mission.
- Published
- 2006
20. Solar Thermal Propulsion
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Gerrish, Harold P., Jr
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Spacecraft Propulsion And Power - Abstract
This paper presents viewgraphs on Solar Thermal Propulsion (STP). Some of the topics include: 1) Ways to use Solar Energy for Propulsion; 2) Solar (fusion) Energy; 3) Operation in Orbit; 4) Propulsion Concepts; 5) Critical Equations; 6) Power Efficiency; 7) Major STP Projects; 8) Types of STP Engines; 9) Solar Thermal Propulsion Direct Gain Assembly; 10) Specific Impulse; 11) Thrust; 12) Temperature Distribution; 13) Pressure Loss; 14) Transient Startup; 15) Axial Heat Input; 16) Direct Gain Engine Design; 17) Direct Gain Engine Fabrication; 18) Solar Thermal Propulsion Direct Gain Components; 19) Solar Thermal Test Facility; and 20) Checkout Results.
- Published
- 2003
21. Solar Thermal Propulsion Improvements at Marshall Space Flight Center
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Gerrish, Harold P
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Spacecraft Propulsion And Power - Abstract
Solar Thermal Propulsion (STP) is a concept which operates by transferring solar energy to a propellant, which thermally expands through a nozzle. The specific impulse performance is about twice that of chemical combustions engines, since there is no need for an oxidizer. In orbit, an inflatable concentrator mirror captures sunlight and focuses it inside an engine absorber cavity/heat exchanger, which then heats the propellant. The primary application of STP is with upperstages taking payloads from low earth orbit to geosynchronous earth orbit or earth escape velocities. STP engines are made of high temperature materials since heat exchanger operation requires temperatures greater than 2500K. Refractory metals such as tungsten and rhenium have been examined. The materials must also be compatible with hot hydrogen propellant. MSFC has three different engine designs, made of different refractory metal materials ready to test. Future engines will be made of high temperature carbide materials, which can withstand temperatures greater than 3000K, hot hydrogen, and provide higher performance. A specific impulse greater than 1000 seconds greatly reduces the amount of required propellant. A special 1 OkW solar ground test facility was made at MSFC to test various STP engine designs. The heliostat mirror, with dual-axis gear drive, tracks and reflects sunlight to the 18 ft. diameter concentrator mirror. The concentrator then focuses sunlight through a vacuum chamber window to a small focal point inside the STP engine. The facility closely simulates how the STP engine would function in orbit. The flux intensity at the focal point is equivalent to the intensity at a distance of 7 solar radii from the sun.
- Published
- 2003
22. Antimatter Production for Near-Term Propulsion Applications
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Gerrish, Harold P and Schmidt, George R
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Spacecraft Propulsion And Power - Abstract
This presentation discusses the use and potential of power generated from Proton-Antiproton Annihilation. The problem is that there is not enough production of anti-protons, and that the production methods are inefficient. The cost for 1 gram of antiprotons is estimated at 62.5 trillion dollars. Applications which require large quantities (i.e., about 1 kg) will require dramatic improvements in the efficiency of the production of the antiprotons. However, applications which involve small quantities (i.e., 1 to 10 micrograms may be practical with a relative expansion of capacities. There are four "conventional" antimatter propulsion concepts which are: (1) the solid core, (2) the gas core, (3) the plasma core, and the (4) beam core. These are compared in terms of specific impulse, propulsive energy utilization and vehicle structure/propellant mass ratio. Antimatter-catalyzed fusion propulsion is also evaluated. The improvements outlined in the presentation to the Fermilab production, and other sites. capability would result in worldwide capacity of several micrograms per year, by the middle of the next decade. The conclusions drawn are: (1) the Conventional antimatter propulsion IS not practical due to large p-bar requirement; (2) Antimatter-catalyzed systems can be reasonably considered this "solves" energy cost problem by employing substantially smaller quantities; (3) With current infrastructure, cost for 1 microgram of p-bars is $62.5 million, but with near-term improvements cost should drop; (4) Milligram-scale facility would require a $15 billion investment, but could produce 1 mg, at $0.1/kW-hr, for $6.25 million.
- Published
- 1999
23. Space Transportation Options for the 21st Century
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Houts, Michael G, Schmidt, George R, Gerrish, Harold P, and Martin, James J
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Space Transportation - Abstract
Advanced space transportation options may eventually enable rapid, affordable access to any point in the solar system. Advanced propulsion systems with energy densities several orders of magnitude greater than state-of-the art systems may be available in the 21 st century. These propulsion systems include systems based on fission, fusion, antimatter annihilation and other advanced processes. Other transportation options propose using in-situ resources to enable rapid, affordable access to any point in the solar system using more conventional propulsion technologies. This presentation will summarize select space transportation options of current interest to NASA MSFC's Space Propulsion Branch, present progress being made towards developing each of the options, and discuss obstacles that must be overcome before any of the options can be implemented.
- Published
- 1999
24. Vacuum Plasma Spray (VPS) Forming of Solar Thermal Propulsion Components Using Refractory Metals
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Zimmerman, Frank R, Hissam, David A, Gerrish, Harold P, and Davis, William M
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Spacecraft Propulsion And Power - Abstract
The Thermal Spray Laboratory at NASA's Marshall Space Flight Center has developed and demonstrated a fabrication technique using Vacuum Plasma Spray (VPS) to form structural components from a tungsten/rhenium alloy. The components were assembled into an absorber cavity for a fully-functioning, ground test unit of a solar then-nal propulsion engine. The VPS process deposits refractory metal onto a graphite mandrel of the desired shape. The mandrel acts as a male mold, forming the required contour and dimensions of the inside surface of the deposit. Tungsten and tungsten/25% rhenium were used in the development and production of several absorber cavity components. These materials were selected for their high temperature (greater than 25000 C [greater than 4530 F]) strength. Each absorber cavity comprises 3 coaxial shells with two, double-helical flow passages through which the propellant gas flows. This paper describes the processing techniques, design considerations, and process development associated with forming these engine components.
- Published
- 1999
25. Analysis of Low-Level Atmospheric Refraction over Miami during July 1970
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Chatterjee, Kalipada and Gerrish, Harold P.
- Published
- 1971
26. A Model of Summer Convection in South Florida
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Gerrish, Harold P.
- Published
- 1971
27. The NASA Advanced Exploration Systems Nuclear Thermal Propulsion Project
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Houts, Michael G., primary, Mitchell, Doyce P., additional, Kim, Tony, additional, Emrich, William J., additional, Hickman, Robert R., additional, Gerrish, Harold P., additional, Doughty, Glen, additional, Belvin, Anthony, additional, Clement, Steven, additional, Borowski, Stanley K., additional, Scott, John H., additional, and Power, Kevin P., additional
- Published
- 2015
- Full Text
- View/download PDF
28. Review of Nuclear Thermal Propulsion Ground Test Options
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Coote, David J., primary, Power, Kevin P., additional, Gerrish, Harold P., additional, and Doughty, Glen, additional
- Published
- 2015
- Full Text
- View/download PDF
29. The Nuclear Cryogenic Propulsion Stage Recent Accomplishments
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Kim, Tony, primary, Houts, Michael G., additional, Emrich, William J., additional, Hickman, Robert R., additional, Gerrish, Harold P., additional, Borowski, Stanley K., additional, Scott, John, additional, Belvin, Anthony, additional, and Broadway, Jeramie, additional
- Published
- 2014
- Full Text
- View/download PDF
30. The Nuclear Cryogenic Propulsion Stage
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Houts, Michael G., primary, Kim, Tony, additional, Emrich, William J., additional, Hickman, Robert R., additional, Broadway, Jeramie, additional, Gerrish, Harold P., additional, Belvin, Anthony, additional, Borowski, Stanley K., additional, and Scott, John H., additional
- Published
- 2014
- Full Text
- View/download PDF
31. Affordable Development and Qualification Strategy for Nuclear Thermal Propulsion
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Gerrish, Harold P., primary, Doughty, Glen E., additional, and Bhattacharyya, Samit K., additional
- Published
- 2013
- Full Text
- View/download PDF
32. The Atlantic hurricane season; quietest in 52 years
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Gerrish, Harold P. and Case, Robert A.
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Cyclones ,Hurricanes ,Wind shear -- Statistics ,Atlantic Ocean -- Natural history ,Caribbean Islands -- Natural history - Published
- 1984
33. PROCEEDINGS OF THE 1965 ARMY CONFERENCE ON TROPICAL METEOROLOGY HELD IN MIAMI BEACH, FLORIDA ON 6-7 MAY 1965
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Hiser, Homer W., primary and Gerrish, Harold P., primary
- Published
- 1965
- Full Text
- View/download PDF
34. MESOSCALE STUDIES OF INSTABILITY PATTERNS AND WINDS IN THE TROPICS
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Gerrish, Harold P., primary and Hiser, Homer W., primary
- Published
- 1963
- Full Text
- View/download PDF
35. MESOSCALE STUDIES OF INSTABILITY PATTERNS AND WINDS IN THE TROPICS
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Hiser, Homer W., primary and Gerrish, Harold P., primary
- Published
- 1963
- Full Text
- View/download PDF
36. Satellite and Radar Analysis of Mesoscale Weather Systems.
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ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE MIAMI FLA, Gerrish,Harold P, ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE MIAMI FLA, and Gerrish,Harold P
- Abstract
Relationships between satellite visible and I.R. gray levels, and such parameters as the existence of radar echoes, ceiling height and surface visibility are studied using SMS-1/GOES satellite data, digital radar data, surface observations from first order stations, and the Kennedy Space Center Image 100 Multispectral Image Analyzer. Radar echo/rainfall relationships are also studied using rain gauge data from the 1975 FACE mesonetwork. The results from four case studies during August 1975 show that radar echoes occurred, without exception, when both types of satellite gray levels exceeded a value of 183 based on a scale of 0 (black) to 255 (white). Other joint relationships are described for lower gray levels. It is shown that the lowest ceilings and surface visibilities occurred with the satellite visible levels near 100 and the I.R. levels near 130 and 110 respectively. An example is presented showing the simulation of a radar echo pattern from themed satellite visible data on 14 August 1975. And computer programs are appended for converting 7-track NHEML KART digital radar tapes to 9-track tapes with suitable block size and format for the KSC PDP 11/35 computer system. (Author), Original contains color plates: All DDC reproductions will be in black and white.
- Published
- 1976
37. Satellite and Radar Analysis of Mesoscale Weather Systems.
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ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE MIAMI FLA, Gerrish,Harold P., ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE MIAMI FLA, and Gerrish,Harold P.
- Abstract
Gridded ESSA 5 and 7 and ATS-3 satellite data for selected 1968 dates are analyzed in conjunction with gridded MIAC WSR-57 radar data to determine the percentage of cloud area covered by radar echo in South Florida. It is found that the percentage tends to increase with increasing convective regime number. Also, the highest percentage occurs progressively further inland as the regime number increases. DAPP visible, DAPP IR and ATS-3 visible satellite data on eleven September 1973 dates are analyzed using color densitometer techniques and correlations are made with radar and other meteorological data to gain insight into relationships between satellite, radar, ceiling height and surface visibility data in South Florida. It is shown that the correlation coefficients are dependent upon location of the data with respect to the coast and with respect to the type of convective regime. Radar echo area conrrelates best with the DAPP IR cloud area at 18,000 feet and at 30,000 feet. On the average, radar echoes occupy 42 percent of the cloud area at those altitudes. (Author)
- Published
- 1975
38. MESOSCALE STUDIES OF INSTABILITY PATTERNS AND WINDS IN THE TROPICS
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MIAMI UNIV FL MARINE LAB, Gerrish, Harold P., Hiser, Homer W., MIAMI UNIV FL MARINE LAB, Gerrish, Harold P., and Hiser, Homer W.
- Abstract
The synoptic situation and an analysis of the cloud cover as seen by Tiros III satellite is presented for a case study of 1800Z, 26 August 1961. Particular reference is made to the translational motion of precipitation echoes in the tropics, as determined by tracking selected small echoes and cells. Comparisons of these motions are made with winds aloft. The space smoothed translational motion of precipitation echoes in this case study most nearly represented the wind flow at 10,000 ft.
- Published
- 1963
39. PROCEEDINGS OF THE 1965 ARMY CONFERENCE ON TROPICAL METEOROLOGY HELD IN MIAMI BEACH, FLORIDA ON 6-7 MAY 1965
- Author
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ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE CORAL GABLES FL RADAR METEOROLOGICAL LAB, Hiser, Homer W., Gerrish, Harold P., ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE CORAL GABLES FL RADAR METEOROLOGICAL LAB, Hiser, Homer W., and Gerrish, Harold P.
- Abstract
The primary interest of the meeting was in the realm of local, small scale meteorological phenomena and problems in the tropics, specifically excluding hurricanes and typhoons, although the papers were not completely limited to those topics. One objective was to learn as much as possible about the recent results and future research plans in tropical meteorology of the U. S. Army contractors as well as other invited guests from the United States and abroad. Nineteen papers were presented at the two-day meeting. Discussions of the papers were recorded and are included in the Proceedings.
- Published
- 1965
40. Satellite and Radar Analysis of Mesoscale Features in the Tropics.
- Author
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ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE MIAMI FL, Gerrish, Harold P., ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE MIAMI FL, and Gerrish, Harold P.
- Abstract
Tropical convection in the Florida, Cuba and upper Bahamas areas are studied using once-daily ESSA 5 and 7 satellite cloud mosaics during the period 14 June to 22 October 1968. The approach utilizes cloud cover information which are tabulated for each element of a 20 x 20 grid array and processed using the computer. It is found that the average coverage over Florida is 38 percent, over Cuba is 38 percent, and over the open water is 24 percent. Daily anomalies of cloudiness are discussed. Computations show that the cloud cover over South Florida correlates quite well with rain data and with humidity between 700 and 500 mb, but poorly with low-level divergence and vorticity. Other types of correlations are made and maps are presented showing the correlation coefficients of cloudiness on a square-by-square basis with rain data in South Florida during various wind regimes at 850 mb. The satellite data are then stratified into five convective activity regimes which are determined on the basis of the number of stations receiving rain during the day. It is shown that the rainfall and cloud cover are characteristically different in each regime. Maps are presented showing typical cloud cover during and preceding each type of activity regime. Rainfall analysis covering the entire period reveals that the sea-breeze regime was quite active. (Author)
- Published
- 1970
41. Mesoscale Studies of Instability Patterns and Winds in the Tropics.
- Author
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ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE CORAL GABLES FL RADAR MET EOROLOGICAL LAB, Gerrish, Harold P., ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE CORAL GABLES FL RADAR MET EOROLOGICAL LAB, and Gerrish, Harold P.
- Abstract
The trade-wind inversion and other rapidly drying layers in the lower troposphere over Miami are studied using a diagnostic technique based upon the vertical gradient of atmospheric refractivity. The resulting climatology is presented and discussed. Fluctuations in 10-cm radar video from a diffuse evening angel pattern are analyzed using spectral techniques. The resulting motions suggest that this type of angel provides a convenient tracer for short-period atmospheric waves. A model of summer convection in South Florida as revealed by gridded radar data is described and illustrated. Various correlations are also made between two-dimensional indicies of cloud and echo coverages versus daily rainfall. Our satellite ground station with its unique electronic-expansion display capability is described. Finally, the observation of intersecting radar fine lines and a South Florida tornado provides the small-scale documentation of earlier pressure-jump theories. (Author), Also available as Rept. no. ML-69186.
- Published
- 1969
42. MESOSCALE STUDIES OF INSTABILITY PATTERNS AND WINDS IN THE TROPICS.
- Author
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ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE CORAL GABLES FL RADAR MET EOROLOGICAL LAB, Gerrish, Harold P., Andrews, George F., ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE CORAL GABLES FL RADAR MET EOROLOGICAL LAB, Gerrish, Harold P., and Andrews, George F.
- Abstract
Fluctuations in 10-cm radar video from a diffuse angel pattern on the evening of 20 October 1967 are analyzed using spectral techniques. Time and range variations in the fluctuations from resolution cell samples along an azimuth of 288 degrees from Miami indicate wave motions along the beam. These motions are described. It is concluded that this type of angel provides a convenient tracer for short-period atmospheric waves. Preparations for data collection during the summer of 1968 are described. Along with making extensive modifications on our radar system, we have added a satellite ground station to the facility. A brief description of the ground station, its capability and plans for use are given. (Author), Also available as Rept. no. ML-68295.
- Published
- 1968
43. Satellite and Radar Analysis of Mesoscale Weather Systems in the Tropics.
- Author
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MIAMI UNIV FLA RADAR METEOROLOGICAL LAB, Gerrish,Harold P., MIAMI UNIV FLA RADAR METEOROLOGICAL LAB, and Gerrish,Harold P.
- Abstract
Gridded Miami WSR-57 radar PPI data during the summer of 1968 are used to study the coverages and frequencies of radar echoes typically associated with five convective regimes in South Florida. Three sets of maps are presented showing the average coverage considering all of the data, the average coverage per echo incident and the frequency distribution of grid squares containing echoes at 0800, 1200, 1600 and 2000 EST. The maps are discussed with respect to convective echo activity, and with regard to preferred regions for the formation of anomalous propagation (A.P.). Various local effects are noted and one outstanding 'hot spot' of convection is observed in the Lostman's River area along the southwest coast of Florida. A detailed analysis of the areal, volume, and frequency patterns of convective radar echoes on six highly disturbed dates in July 1968 reveals several interesting findings on the nature of tropical convection and the so-called atmospheric recovery period. (Author)
- Published
- 1972
44. PROCEEDINGS OF THE 1967 ARMY CONFERENCE ON TROPICAL METEOROLOGY, CORAL GABLES, FLORIDA 8-9 JUNE 1967
- Author
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MIAMI UNIV FLA RADAR METEOROLOGICAL LAB, Hiser,Homer W., Gerrish,Harold P., MIAMI UNIV FLA RADAR METEOROLOGICAL LAB, Hiser,Homer W., and Gerrish,Harold P.
- Abstract
The primary interest of the meeting was in the realm of local, small-scale meteorological phenomena and problems in the tropics, specifically excluding hurricanes and typhoons, although the papers were not completely limited to those topics. The objective was to learn as much as possible about the recent results and future research plans of the U.S. Army Contractors in tropical meteorology and to benefit by the experience and special knowledge of other invited guests from the United States and abroad. Twenty papers were presented at the two-day meeting. Discussions of the papers were recorded and are included in the report. (Author), See also Rept. no. 6, AD-611 852.
- Published
- 1968
45. MESOSCALE STUDIES OF INSTABILITY PATTERNS AND WINDS IN THE TROPICS.
- Author
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MIAMI UNIV FLA RADAR METEOROLOGICAL LAB, Gerrish,Harold P., MIAMI UNIV FLA RADAR METEOROLOGICAL LAB, and Gerrish,Harold P.
- Abstract
Rainfall rates in easterly wave and air mass showers at the University of Miami are studied using raindrop camera data collected for the Illinois State Water Survey in 1957-58. It is observed that the first minutes of air mass rain are typically heavier than easterly wave rain. Two severe rainstorms in South Florida are discussed and analytical techniques are appraised. A revised climatology of tornadoes and waterspouts in this area is presented and discussed. Review of the pertinent synoptic maps substantiates that the bulk of this type of activity occurs in unsuspicious summer trade-wind or ridge patterns at the surface with the jet stream well removed from the area. Radar signatures are studied and illustrated. Some tornadoes and waterspouts in South Florida are observed to be associated with intersecting 'fine lines' from convection. This is visualized as a new application of the earlier pressure-jump theories. Here the piston mechanism is convection itself and the leading edge of the cold outflow acts like a rapidly moving cold front. Refractive conditions associated with tornadoes, waterspouts and hail are also described, and mean temperature soundings are illustrated for these events. (Author), See also AD-629 952.
- Published
- 1967
46. PROCEEDINGS OF THE 1966 ARMY CONFERENCE ON TROPICAL METEOROLOGY HELD IN MIAMI BEACH, FLORIDA, MAY 26-27, 1966
- Author
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MIAMI UNIV FLA MARINE LAB, Hiser,Homer W., Gerrish,Harold P., MIAMI UNIV FLA MARINE LAB, Hiser,Homer W., and Gerrish,Harold P.
- Abstract
The primary interest of the meeting was in the realm of local, small-scale meteorological phenomena and problems in the tropics, specifically excluding hurricanes and typhoons, although the papers were not completely limited to those topics. The objective was to learn as much as possible about the recent results and future research plans of the U. S. Army Contractors in tropical meteorology and to benefit by the experience and special knowledge of other invited guests from the United States and abroad. Fifteen papers were presented at the two-day meeting. Discussions of the papers were recorded and are included in the Proceedings. (Author)
- Published
- 1966
47. MESOSCALE STUDIES OF INSTABILITY PATTERNS AND WINDS IN THE TROPICS.
- Author
-
MIAMI UNIV FLA RADAR METEOROLOGICAL LAB, Gerrish,Harold P., Hiser,Homer W., MIAMI UNIV FLA RADAR METEOROLOGICAL LAB, Gerrish,Harold P., and Hiser,Homer W.
- Abstract
Two of the most remarkable rainstorms in Florida's history are described and analyzed. The storm of 13 to 15 October 1965 produced total amounts in excess of 26 inches with 24.43 inches falling in 24 hours at Bahia Mar in Fort Lauderdale and 21.28 inches in 12 hours at Pompano Beach on the 14th. The Halloween storm of 30 October to 1 November 1965 produced total amounts on the order of 14 inches in the same general area with a questionable report of 20 inches in 24 hours in the Boca Raton area. If this report is correct, it is the first time in history that separate storms have produced 20 inches or more rain in 24 hours over the same level terrain in such a short period of time, at least in this part of the world. The heavy rates for 12 and 24 hours in the mid-October storm are quite rare, being exceeded on the order of only 6 times in the past century in the continental United States. The heaviest rain in both storms was triggered by an asynptote of confluence oriented SE-NW over the area at 850mb. Subsequent vortex development occurred but was confined below the melting level and was of minor importance as far as producing rain in the Fort Lauderdale-Pompano Beach area. Aside from isohyetal analysis and synoptic aspects, particular emphasis is placed on: precipitable water, raob analysis, divergence, vorticity, and preliminary radar aspects. (Author), See also AD-629 952.
- Published
- 1966
48. MESOSCALE STUDIES OF INSTABILITY PATTERNS AND WINDS IN THE TROPICS.
- Author
-
MIAMI UNIV FLA MARINE LAB, Gerrish, Harold P., Hiser,Homer W., MIAMI UNIV FLA MARINE LAB, Gerrish, Harold P., and Hiser,Homer W.
- Abstract
Iso-echo contoured CAPPI radar data collected manually on 16 July and 28 September, and non-contoured CAPPI data on 1 October 1964 are used to investigate the motions of individual tropical showers at 'altitudes' of 10,000, 20,000, and 30,000 ft. The motions at these 'altitudes' are tested as possible indicators of wind. Echo-motion shear between 'altitudes' is used to illustrate mechanisms by which the showers grow under baroclinic conditions. Vertical profiles of radar reflectivity and precipitation rate from the showers are examined. Reflectivity equations and nomograms for the MPS-4, modified CPS-6B, and WSR-57 radars are presented. The relationship Z=300R exp 1.4 is used to relate radar reflectivity to tropical rainfall rates. The attenuation problem at a wavelength of 4.7 cm is described and illustrated. (Author), Available copy will not permit fully legible reproduction. Reproduction will be made if requested by users of DDC. Copy is not available for public sale.
- Published
- 1965
49. A MODEL OF ATMOSPHERIC REFRACTIVITY AND THEORETICAL HEIGHTS OF RADIO-RADAR RAYS FOR MIAMI, FLORIDA
- Author
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MIAMI UNIV FLA MARINE LAB, Gerrish,Harold P., MIAMI UNIV FLA MARINE LAB, and Gerrish,Harold P.
- Abstract
The purpose of this work is to start from typical seasonal profiles of atmospheric conditions for Miami, Florida, and step by step develop a model of atmospheric refractivity which is satisfactory for such a warm, moist climate. Theoretical ray paths are traced through this type of atmosphere at various antenna elevations and are summarized in the form of range-height charts. Height anomalies from the standard atmosphere using the 4/3-earth-curvature assumption are also illustrated., Pub. in Proceedings 1964 World Conference on Radio Meteorology, Boulder, Colo., 14-18 Sep 64, p. 56-61.
- Published
- 1964
50. MESOSCALE STUDIES OF INSTABILITY PATTERNS AND WINDS IN THE TROPICS.
- Author
-
MIAMI UNIV FLA MARINE LAB, Gerrish,Harold P., Hiser,Homer W., MIAMI UNIV FLA MARINE LAB, Gerrish,Harold P., and Hiser,Homer W.
- Abstract
Case studies of 27 August 1962 and 30 August 1963 are used to compare echo motions derived from conventional PPI and CAPPI data, respectively, with winds aloft. Brief surveys are made on the trackable lifetime of echoes and the relation of low-cloud patterns to mesoscale features. A climatic rainfall study of South and South-Central Florida is presented with isohyetal analysis based on data from 80 stations. Finally, a comparison is made of concurrent pibal and rawin observations for Merida, Mexico. Aside from problems of continuity associated with manual data collection and typically small displacements of tropical echoes, results of echo motions using CAPPI data were encouraging enough to warrant additional study. (Author)
- Published
- 1963
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