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Exploring the Moon and Mars: Choices for the Nation
This report, the result of an assessment of the potential for automation and robotics technology to assist in the exploration of the Moon and Mars, raises a number of issues related to the goals of the U.S. civilian space program. Among other things, the report discusses how greater attention to automation and robotics technologies could contribute to U.S. space exploration efforts.
Date:
July 1991
Creator:
United States. Congress. Office of Technology Assessment.
System:
The UNT Digital Library
Nuclear rockets: High-performance propulsion for Mars
A new impetus to manned Mars exploration was introduced by President Bush in his Space Exploration Initiative. This has led, in turn, to a renewed interest in high-thrust nuclear thermal rocket propulsion (NTP). The purpose of this report is to give a brief tutorial introduction to NTP and provide a basic understanding of some of the technical issues in the realization of an operational NTP engine. Fundamental physical principles are outlined from which a variety of qualitative advantages of NTP over chemical propulsion systems derive, and quantitative performance comparisons are presented for illustrative Mars missions. Key technologies are described for a representative solid-core heat-exchanger class of engine, based on the extensive development work in the Rover and NERVA nuclear rocket programs (1955 to 1973). The most driving technology, fuel development, is discussed in some detail for these systems. Essential highlights are presented for the 19 full-scale reactor and engine tests performed in these programs. On the basis of these tests, the practicality of graphite-based nuclear rocket engines was established. Finally, several higher-performance advanced concepts are discussed. These have received considerable attention, but have not, as yet, developed enough credibility to receive large-scale development.
Date:
May 1, 1994
Creator:
Watson, C. W.
System:
The UNT Digital Library
Design and Analysis of RTGs for Solar and Martian Exploration Missions
The paper described the results of design, analysis and spacecraft integration studies of Radioisotope Thermoelectric Generators (RTGs) for three unmanned space exploration missions. The three missions, consisting of the Mars Rover and Sample Return (MRSR) mission, the Solar Probe mission, and the Mars Global Net work (MGN) mission, are under study by the Jet Propulsion Laboratory (JPL) for the U.S. National Aeronautics and Space Administration (NASA). The NASA/JPL mission studies are supported by the U.S. Department of Energy's Office of Special Applications (DOE/OSA), which has commissioned Fairchild Space Company to carry out the required RTG design studies.
Date:
May 1, 1990
Creator:
Schock, Alfred
System:
The UNT Digital Library
New vision solar system exploration missions study: Analysis of the use of biomodal space nuclear power systems to support outer solar system exploration missions. Final report
This report presents the results of an analysis of the capability of nuclear bimodal systems to perform outer solar system exploration missions. Missions of interest include orbiter mission s to Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. An initial technology baseline consisting of a NEBA 10 kWe, 1000 N thrust, 850 s, 1500 kg bimodal system was selected, and its performance examined against a data base for trajectories to outer solar system planetary destinations to select optimal direct and gravity assisted trajectories for study. A conceptual design for a common bimodal spacecraft capable of performing missions to all the planetary destinations was developed and made the basis of end to end mission designs for orbiter missions to Jupiter, Saturn, and Neptune. Concepts for microspacecraft capable of probing Jupiter`s atmosphere and exploring Titan were also developed. All mission designs considered use the Atlas 2AS for launch. It is shown that the bimodal nuclear power and propulsion system offers many attractive option for planetary missions, including both conventional planetary missions in which all instruments are carried by a single primary orbiting spacecraft, and unconventional missions in which the primary spacecraft acts as a carrier, relay, and mother ship for a fleet of …
Date:
December 8, 1995
Creator:
unknown
System:
The UNT Digital Library
A 50-100 kWe gas-cooled reactor for use on Mars.
In the space exploration field there is a general consensus that nuclear reactor powered systems will be extremely desirable for future missions to the outer solar system. Solar systems suffer from the decreasing intensity of solar radiation and relatively low power density. Radioisotope Thermoelectric Generators are limited to generating a few kilowatts electric (kWe). Chemical systems are short-lived due to prodigious fuel use. A well designed 50-100 kWe nuclear reactor power system would provide sufficient power for a variety of long term missions. This thesis will present basic work done on a 50-100 kWe reactor power system that has a reasonable lifespan and would function in an extraterrestrial environment. The system will use a Gas-Cooled Reactor that is directly coupled to a Closed Brayton Cycle (GCR-CBC) power system. Also included will be some variations on the primary design and their effects on the characteristics of the primary design. This thesis also presents a variety of neutronics related calculations, an examination of the reactor's thermal characteristics, feasibility for use in an extraterrestrial environment, and the reactor's safety characteristics in several accident scenarios. While there has been past work for space reactors, the challenges introduced by thin atmospheres like those on Mars …
Date:
April 1, 2006
Creator:
Peters, Curtis D. (.)
System:
The UNT Digital Library
Mars Rover RTG Study
This report summarizes the results of a Radioisotope Thermoelectric Generator (RTG) design study conducted by Fairchild Space Company at the direction of the U.S. Department of Energy's Office of Special Applications, in support of the Mars Rover and Sample Return mission under investigation at NASA's Jet Propulsion Laboratory. Presented at the 40th Congress of the IAF, Oct. 7-13, 1989 in Torremolinos, Malaga-Spain. The paper describes the design and analysis of Radioisotope Thermoelectric Generators (RTGs) for powering the Mars Rover vehicle, which is a critical element of the unmanned Mars Rover and Sample Return mission (MRSR). The RTG design study was conducted by Fairchild Space for the U.S. DOE in support of the JPL MRSR Project. The paper briefly describes a reference mission scenario, an illustrative Rover design and activity pattern on Mars, and its power system requirements and environmental constraints, including the RTG cooling requirements during transit to Mars. It summarizes the baseline RTG's mass breakdown, and presents a detailed description of its thermal, thermoelectric, and electrical analysis. The results presented show the RTG performance achievable with current technology, and the performance improvements that would be achievable with various technology developments. It provides a basis for selecting the optimum strategy …
Date:
November 27, 1989
Creator:
Schock, Alfred
System:
The UNT Digital Library
Science Priorities for Mars Sample Return
None
Date:
February 11, 2008
Creator:
Borg, L.; Des Marais, D. & Beaty, D.
System:
The UNT Digital Library
Exploration of the Planets: A History, A Prospect, and Some Issues
This report discusses the history and future of planetary exploration programs by the U.S. and the Soviet Union. Topics covered are motivations for planetary exploration, unmanned missions sent to Mars and Venus by the U.S. and Soviet Union, plans for manned missions to planets such as Mars, technical needs and costs for planetary space missions, and long-term plans and ideas.
Date:
December 15, 1969
Creator:
Devoe, Barbara M. & Sheldon, Charles S., II
System:
The UNT Digital Library
Mars Rover RTG Study
This report summarizes the results of a Radioisotope Thermoelectric Generator (RTG) design study conducted by Fairchild Space Company at the direction of the U.S. Department of Energy's Office of SpecialApplications, in suppport of the Mars Rover and Sample Return mission under investigation at NASA's Jet Propulsion Laboratory. The report is a rearranged, updated, and significantly expanded amalgam of three interrelated papers presented at the 24th Intersocity Energy Conversion Engineering Conference (IECEC) at Arlington, Virginia, on August 10, 1989.
Date:
August 25, 1989
Creator:
Schock, Alfred
System:
The UNT Digital Library
Space Exploration: Issues Concerning the "Vision for Space Exploration"
Report detailing the vision for space exploration, including budget changes for NASA, public reaction, and more.
Date:
January 4, 2006
Creator:
Smith, Marcia S.
System:
The UNT Digital Library
Space Exploration: Issues Concerning the "Vision for Space Exploration"
Report detailing the vision for space exploration, including budget changes for NASA, public reaction, and more.
Date:
November 18, 2005
Creator:
Smith, Marcia S.
System:
The UNT Digital Library
Space Exploration: Issues Concerning the "Vision for Space Exploration"
Report detailing the vision for space exploration, including budget changes for NASA, public reaction, issues, and more.
Date:
June 9, 2005
Creator:
Smith, Marcia S.
System:
The UNT Digital Library
Requirements and Designs for Mars Rover RTGs
The current-generation RTGs (both GPHS and MOD) are designed for operation in a vacuum environment. The multifoil thermal insulation used in those RTGs only functions well in a good vacuum. Current RTGs are designed to operate with an inert cover gas before launch, and to be vented to space vacuum after launch. Both RTGs are sealed with a large number of metallic C-rings. Those seals are adequate for retaining the inert-gas overpressure during short-term launch operations, but would not be adequate to prevent intrusion of the Martian atmospheric gases during long-term operations there. Therefore, for the Mars Rover application, those RTGs just be modified to prevent the buildup of significant pressures of Mars atmosphere or of helium (from alpha decay of the fuel). In addition, a Mars Rover RTG needs to withstand a long-term dynamic environment that is much more severe than that seen by an RTG on an orbiting spacecraft or on a stationary planetary lander. This paper describes a typical Rover mission, its requirements, the environment it imposes on the RTG, and a design approach for making the RTG operable in such an environment. Specific RTG designs for various thermoelectric element alternatives are presented.; Reference CID #9268 and …
Date:
unknown
Creator:
Schock, Alfred; Shirbacheh, M. & Sankarankandath, V.
System:
The UNT Digital Library
Propulsion engineering study for small-scale Mars missions
Rocket propulsion options for small-scale Mars missions are presented and compared, particularly for the terminal landing maneuver and for sample return. Mars landing has a low propulsive {Delta}v requirement on a {approximately}1-minute time scale, but at a high acceleration. High thrust/weight liquid rocket technologies, or advanced pulse-capable solids, developed during the past decade for missile defense, are therefore more appropriate for small Mars landers than are conventional space propulsion technologies. The advanced liquid systems are characterize by compact lightweight thrusters having high chamber pressures and short lifetimes. Blowdown or regulated pressure-fed operation can satisfy the Mars landing requirement, but hardware mass can be reduced by using pumps. Aggressive terminal landing propulsion designs can enable post-landing hop maneuvers for some surface mobility. The Mars sample return mission requires a small high performance launcher having either solid motors or miniature pump-fed engines. Terminal propulsion for 100 kg Mars landers is within the realm of flight-proven thruster designs, but custom tankage is desirable. Landers on a 10 kg scale also are feasible, using technology that has been demonstrated but not previously flown in space. The number of sources and the selection of components are extremely limited on this smallest scale, so some customized …
Date:
September 12, 1995
Creator:
Whitehead, J.
System:
The UNT Digital Library
Space Exploration
This report discusses the contributions from both the government and private sector towards space exploration.
Date:
March 20, 2015
Creator:
Morgan, Daniel
System:
The UNT Digital Library
Effects of dust accumulation and removal on radiator surfaces on Mars
Tests were carried out to assess the impact of wind blown dust accumulation and abrasion on radiator surfaces on Mars. High emittance arc-textured copper (Cu) and niobium-1%-zirconium (Nb-1%Zr) samples were subjected to basaltic dust laden wind at Martian pressure (1000 Pa) at speeds varying from 19 to 97 m/s in the Martian Surface Wind Tunnel at NASA Ames Research Center. The effect of accumulated dust was also observed by pre-dusting some of the samples before the test. Radiator degradation was determined by measuring the change in the emittance after dust was deposited and/or removed. The principal mode of degradation was abrasion. Arc-textured Nb-1%Zr proved to be more susceptible to degradation than Cu, and pre-dusting appeared to have lessened the abrasion.
Date:
January 1, 1991
Creator:
Gaier, J. R.; Perez-Davis, M. E.; Rutledge, S. K.; Hotes, D. & Olle, R.
System:
The UNT Digital Library
Structural Analyses of the JPL Mars Pathfinder Impacts
None
Date:
April 1, 1999
Creator:
Gwinn, K.W.
System:
The UNT Digital Library
Space Exploration: Overview of President Bush's New Exploration Initiative for NASA, and Key Issues for Congress
Report detailing the new goals for the National Aeronautics and Space Administration, including budget changes, public reaction, and more.
Date:
September 10, 2004
Creator:
Smith, Marcia S.
System:
The UNT Digital Library
Space Exploration: Report of the Aldridge Commission on Implementation of President Bush’s Exploration Initiative
This report discusses the commission created to assist the National Aeronautics and Space Administration as it focuses on new exploration goals. Updated June 22, 2004.
Date:
June 22, 2004
Creator:
Smith, Marcia S.
System:
The UNT Digital Library
Design of Small Impact-Resistant RTGs for Global Network of Unmanned Mars Landers
Ongoing studies by the National Aeronautics and Space Administration (NASA) for the robotic exploration of Mars contemplate a network of at least twenty small and relatively inexpensive landers distributed over both low and high latitudes of the Martian globe. They are intended to explore the structural, mineralogical, and chemical characteristics of the Martian soil, search for possible subsurface trapped ice, and collect long-term seismological and meteorological data over a period of ten years. They can also serve as precursors for later unmanned and manned Mars missions.; The collected data will be transmitted periodically, either directly to Earth or indirectly via an orbiting relay. The choice of transmission will determine the required power, which is currently expected to be between 2 and 12 watts(e) per lander. This could be supplied either by solar arrays or by Radioisotope Thermoelectric Generators (RTGs). Solar-powered landers could only be used for low Martian latitudes, but RTG-powered landers can be used for both low and high latitudes. Moreover, RTGs are less affected by Martian sandstorms and can be modified to resist high-G-load impacts. High impact resistance is a critical goal. It is desired by the mission designers, to minimize the mass and complexity of the system …
Date:
June 26, 1991
Creator:
Schock, Alfred
System:
The UNT Digital Library
Space Exploration: Overview of President Bush's "Vision for Space Exploration," and Key Issues for Congress
Report detailing the vision for space exploration, including budget changes for NASA, public reaction, and more.
Date:
December 10, 2004
Creator:
Smith, Marcia S.
System:
The UNT Digital Library
Space Exploration: Overview of President Bush's "Vision for Space Exploration," and Key Issues for Congress
Report detailing the vision for space exploration, including budget changes for NASA, public reaction, and more.
Date:
March 15, 2005
Creator:
Smith, Marcia S.
System:
The UNT Digital Library
RTG Impact Response to Hard Landing During Mars Environmental Survey (MESUR) Mission
The National Aeronautics and Space Administration (NASA) is studying a seven-year robotic mission (MESUR, Mars Environmental Survey) for the seismic, meteorological, and geochemical exploration of the Martian surface by means of a network of ~16 small, inexpensive landers spread from pole to pole. To permit operation at high Martian latitudes, NASA has tentatively decided to power the landers with small RTGs (Radioisotope Thermoelectric Generators). To support the NASA mission study, the Department of Energy's Office of Special Applications commissioned Fairchild to perform specialized RTG design studies. Those studies indicated that the cost and complexity of the mission could be significantly reduced if the RTGs had sufficient impact resistance to survive ground impact of the landers without retrorockets. Fairchild designs of RTGs configured for high impact resistance were reported previously. Since the, the size, configuration, and impact velocity of the landers and the power level and integration mode of the RTGs have changed substantially, and the previous impact analysis has been changed substantially, and the previous impact analysis has been updated accordingly. The analytical results, reported here, indicate that a lander by itself experiences much higher g-loads than the lander with an integral penetrator; but that minor modifications of the shape …
Date:
March 6, 1992
Creator:
Schock, Alfred & Mukunda, Meera
System:
The UNT Digital Library
Viking Lander: subsurface water analyzing probe. [Mars subsoil]
A small terradynamic (soil penetrating) vehicle, to be released from the Viking Lander at an altitude of between 5000 and 6000 feet before the terminal descent on the vernier rockets begins, will implant a sensor package 3 to 5 feet beneath the surface to measure water content of Mars subsoil. As it penetrates the soil, the vehicle separates into a probe which carries the primary instrumentation and a tail section which contains the power supply, secondary sensors, and transmitter and antenna assembly. The two sections remain linked by a hard wire umbilical which provides for power and data flow between the sections. After impact, a soil moisture subsystem would be activated to gather approximately 100 milligrams of soil at the depth of the penetrating probe. After the mass of the sample is measured, its water content would be determined by heating in a sealed known volume and measuring the dew point of the resulting water vapor with a specular reflection dew point indicator. The penetrating probe and the tail section each contain a pair of aluminum oxide hygrometer elements and one sensistor temperature sensor which, on request by an on-board programmer will measure temperature and absolute water content of the …
Date:
October 1, 1969
Creator:
Simmons, G.J.
System:
The UNT Digital Library