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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

Design of small Stirling dynamic isotope power system for robotic space missions

Design of a multihundred-watt Dynamic Isotope Power System (DIPS) based on the U.S. Department of Energy (DOE) General Purpose Heat Source (GPHS) and small (multihundred-watt) free-piston Stirling engine (FPSE) technology is being pursued as a potential lower cost alternative to radioisotope thermoelectric generators (RTG's). The design is targeted at the power needs of future unmanned deep space and planetary surface exploration missions ranging from scientific probes to Space Exploration Initiative precursor missions. Power level for these missions is less than a kilowatt. Unlike previous DIPS designs which were based on turbomachinery conversion (e.g. Brayton), this small Stirling DIPS can be advantageously scaled down to multihundred-watt unit size while preserving size and mass competitiveness with RTG's. Preliminary characterization of units in the output power ranges 200-600 We indicate that on an electrical watt basis the GPHS/small Stirling DIPS will be roughly equivalent to an advanced RTG in size and mass but require less than a third of the isotope inventory.

Bents, D. J.↗

Proposed CTV design reference missions in support of Space Station Freedom

Use of design reference missions (DRM's) for the cargo transfer vehicle (CTV) in support of Space Station Freedom (SSF) can provide a common baseline for the design and assessment of CTV systems and mission operations. These DRM's may also provide baseline operations scenarios for integrated CTV, Shuttle, and SSF operations. Proposed DRM's for CTV, SSF, and Shuttle operations envisioned during the early post-PMC time frame and continuing through mature, SSF evolutionary operations are described. These proposed DRM's are outlines for detailed mission definition; by treating these DRM's as top-level input for mission design studies, a range of parametric studies for systems/operations may be performed. Shuttle flight design experience, particularly rendezvous flight design, provides an excellent basis for DRM operations studies. To begin analysis of the DRM's, shuttle trajectory design tools were used in single case analysis to define CTV performance requirements. A summary of these results is presented.

Saucillo, Rudy J.↗

Mars Aerocapture Studies for the Design Reference Mission

The recent discovery of possible fossilized microbes in a Martian meteorite sample and the spectacular success of the Mars Pathfinder mission have substantially increased public interest and support for future robotic and manned exploration of Mars. NASA is currently refining a plan known as the Design Reference Mission (DRM) in which the first human landing would occur in 2014 after a series of cargo launches which would place surface systems and an Earth return vehicle at Mars two years prior to the crew's arrival. At each subsequent launch opportunity (which occur approximately every twenty-six months), an additional Earth return vehicle, surface facility and crew would depart for Mars, with each crew employing the systems launched during the previous opportunity. The mission design calls for a long-duration surface stay, rapid crew transits, in-situ manufacture of the Mars ascent propellant, nuclear thermal propulsion for the trans-Mars injection burn, and the use of aerocapture for both the cargo and crew vehicles at Mars.

Lyne, James Evans↗

NASA's RPS Design Reference Mission Set for Solar System Exploration

NASA's 2006 Solar System Exploration (SSE) Strategic Roadmap identified a set of proposed large Flagship, medium New Frontiers and small Discovery class missions, addressing key exploration objectives. These objectives respond to the recommendations by the National Research Council (NRC), reported in the SSE Decadal Survey. The SSE Roadmap is down-selected from an over-subscribed set of missions, called the SSE Design Reference Mission (DRM) set. Missions in the Flagship and New Frontiers classes can consider Radioisotope Power Systems (RPSs), while small Discovery class missions are not permitted to use them, due to cost constraints. In line with the SSE DRM set and the SSE Roadmap missions, the RPS DRM set represents a set of missions, which can be enabled or enhanced by RPS technologies. At present, NASA has proposed the development of two new types of RPSs. These are the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), with static power conversion; and the Stirling Radioisotope Generator (SRG), with dynamic conversion. Advanced RPSs, under consideration for possible development, aim to increase specific power levels. In effect, this would either increase electric power generation for the same amount of fuel, or reduce fuel requirements for the same power output, compared to the proposed MMRTG or SRG. Operating environments could also influence the design, such that an RPS on the proposed Titan Explorer would use smaller fins to minimize heat rejection in the extreme cold environment; while the Venus Mobile Explorer long-lived in-situ mission would require the development of a new RPS, in order to tolerate the extreme hot environment, and to simultaneously provide active cooling to the payload and other electric components. This paper discusses NASA's SSE RPS DRM set, in line with the SSE DRM set. It gives a qualitative assessment regarding the impact of various RPS technology and configuration options on potential mission architectures, which could support NASA's RPS technology development planning, and provide an understanding of fuel need trades over the next three decades.

solar system↗

The Ganymede Interior Structure, and Magnetosphere Observer (GISMO) Mission Concept

The NASA Planetary Science Summer School (PSSS) at JPL offers graduate students and young professionals a unique opportunity to learn about the mission design process. Program participants select and design a mission based on a recent NASA Science Mission Directorate Announcement of Opportunity (AO). Starting with the AO, in this case the 2009 New Frontiers AO, participants generate a set of science goals and develop a early mission concept to accomplish those goals within the constraints provided. As part of the 2010 NASA PSSS, the Ganymede Interior, Surface, and Magnetosphere Observer (GISMO) team developed a preliminary satellite design for a science mission to Jupiter's moon Ganymede. The science goals for this design focused on studying the icy moon's magnetosphere, internal structure, surface composition, geological processes, and atmosphere. By the completion of the summer school an instrument payload was selected and the necessary mission requirements were developed to deliver a spacecraft to Ganymede that would accomplish the defined science goals. This poster will discuss those science goals, the proposed spacecraft and the proposed mission design of this New Frontiers class Ganymede observer.

radar sounder↗

Satellite tour design for the Cassini mission

The mission design for the Cassini satellite tour of Saturn is described. The use of Titan encounters for gravity-assisted trajectory shaping to satisfy atmosphere, magnetosphere, and satellite science requirements is discussed. Three candidate satellite tours that illustrate the tradeoffs between different strategies to satisfy the science objectives are presented. Tour characteristics for a 4yr mission include at least 30 Titan encounters to provide a minimum of 90 deg orbit rotation for either a magnetotail petal orbit or noon petal orbit; evenly distributed Titan ground tracks for radar mapping coverage; at least 2 Iapetus and 1 Enceladus close flybys; inclined orbits during the first 3 yr to provide Earth and Sun occultations by Saturn and its rings; and Polar orbits during the fourth year.

Diehl, R. E.↗

VIPRE: A Tool Aiding the Design for Entry Probe Missions

Exploring planetary atmospheres uncovers important information for how our solar system formed and evolved. While remote sensing is extensively used, some crucial observations require in-situ measurements by an atmospheric probe. Given their scientific importance, probe missions to Saturn, Uranus and Neptune are considered for the coming decades. In anticipation of future probe missions, the software tool VIPRE was developed as proof-of-concept to facilitate selection of probe entry locations. Currently, there is no analytical way to identify which interplanetary trajectory from thousands of feasible launch opportunities is optimal for a considered mission concept. The search and decision process for that solution is complex and relies on the intuition of mission designers, who focus on a subset of trajectories to make the trade space manageable. The idea of VIPRE is to (1) generate a multi-dimensional data cube showing relevant engineering and science parameters simultaneously for thousands of trajectories, and (2) visualize the data for all entry sites over the body's envelope. VIPRE lays the foundation to make the data available for browsing in a 3-D visualization to identify the best family of solutions for a given mission. The paper introduces the validated and verified core algorithms of VIPRE, published on GitHub. VIPRE serves as a basic framework to be used and extended for different purposes. The paper presents the motivation for the development and algorithms. It explains the computation and data visualization strategy, and gives a list of suggested functionalities to extend and further develop VIPRE to fully leverage its potential.

Ice Giants↗

Design of Grand Tour missions

Grand Tour mission design, discussing navigation, trajectory parameters, launch vehicles and satellite flybys

Bourke, R. D.↗

NASA's SPICE System Models the Solar System

SPICE is NASA's multimission, multidiscipline information system for assembling, distributing, archiving, and accessing space science geometry and related data used by scientists and engineers for mission design and mission evaluation, detailed observation planning, mission operations, and science data analysis.

mission design↗

Aerocapture at Saturn

The feasibility and benefits of using aerocapture for orbit insertion in the Saturn atmosphere are assessed in the context of existing technologies and likely science mission architectures in the Saturn system. We model aerocapture in-atmosphere flight performance in the presence of expected day-of-flight uncertainties, including those driven by limited knowledge of Saturn, to determine aerocapture flight system needs. We assess the impact of aerocapture on overall mission design for future science missions by including aerocapture in an end-to-end mission design and optimization scheme. Results indicate that aerocapture may feasible and beneficial with limited-to-no technology investment for missions designed to address near-term science priorities in the Saturn system.

Aerocapture↗

Low power DIPS design for NASA missions

Conceptual designs of low power dynamic isotope power systems (DIPS) for NASA's future deep space missions are being developed to characterize the power system's unique features in the 0.5-1.0 kilowatt-electric (kWe) range. The August 1990 Mariner Mark II spacecraft design was used for the spacecraft integration study. One basic design with slight mission specific variations was developed for the Cassini, Comet Nucleus Sample Return, and Outer Planet Orbiter Probe missions. A low power DIPS flight unit offers comparable specific power values to the MOD-RTG unit with a factor-of-three improvement in radioisotope fuel requirements. This was accomplished by fully exploiting the dynamic power conversion technology available in the DIPS program.

Johnson, Richard A.↗

High Earth Orbit Design for Lunar-Assisted Medium Class Explorer Missions

This study investigates the application of high-Earth orbit (HEO) trajectories to missions requiring long on-target integration times, avoidance of the Earth's radiation belt, and minimal effects of Earth and Lunar shadow periods which could cause thermal/mechanical stresses on the science instruments. As used here, a HEO trajectory is a particular solution to the restricted three-body problem in the Earth-Moon system with the orbit period being either 1/2 of, or 1/4 of, the lunar sidereal period. A primary mission design goal is to find HEO trajectories where, for a five-year mission duration, the minimum perigee radius is greater than seven Earth radii (R(sub E)). This minimum perigee radius is chosen so that, for the duration of the mission, the perigee is always above the relatively heavily populated geosynchronous radius of 6.6 R(sub E). A secondary goal is to maintain as high an ecliptic inclination as possible for the duration of the mission to keep the apsis points well out of the Ecliptic plane. Mission design analysis was completed for launch dates in the month of June 2003, using both direct transfer and phasing loop transfer techniques, to a lunar swingby for final insertion into a HEO. Also provided are analysis results of eclipse patterns for the trajectories studied, as well as the effects of launch vehicle errors and launch delays.

McGiffin, Daniel A.↗

A NASA study of the impact of technology on future sea based attack aircraft

A conceptual aircraft design study was recently completed evaluating carrier-based, subsonic attack aircraft using contemporary and future technology assumptions. The study examined a configuration matrix that was made up of light and medium bomb loads, one and two man crews, internal and external weapons carriage, as well as conventional and flying wing planforms. Use of common technology assumptions, engine cycle simulation code, design mission, and consistent application of methods allow for direct comparison of the aircraft. This paper describes the design study ground rules and the aircraft designed. The aircraft descriptions include weights, dimensions, layout, design mission, design constraints, maneuver performance, and fallout mission performance. The strengths, and weaknesses of each aircraft are highlighted.

Hahn, Andrew S.↗

The Venus Orbiting Imaging Radar Mission

The scientific objectives and rationale for a Venus Orbiting Imaging Radar Mission are presented. A provisional science payload responsive to these objectives is described and a reference set of measurement requirements and their priorities is established. Those high priority measurements that are most demanding on spacecraft and mission design are used to develop a reference spacecraft design and a reference mission design. A discussion of mission performance issues is also included.

Dallas, S. S.↗

Design of mission operations systems for scientific remote sensing

The present work describes the mission operations system (MOS) design process for remote-sensing missions. A MOS is defined as the system required to perform, monitor, and control an operation, encompassing personnel, hardware, software and/or documentation. Attention is given to telecommunications and remote-sensing instrumentation, MOS definition program phases and reviews, and MOS organization, management, and staffing. Also treated are the uplink and downlink processes, anomalies and contingency plans, the illustrative case of the MOS for the Magellan radar sensing mission, and a projection of future MOSs incorporating AI.

Wall, Stephen D.↗

Generation-based Evolutionary Tool for the Optimization of Constellations (GenETOC)

With the rapid growth in the capabilities of smaller satellites, satellite architectures that replace a single, extremely capable spacecraft with multiple, cheaper ones are gaining in popularity. Unfortunately, the orbit design process for constellations can be significantly more involved, especiallywhen the relative placement of the individual spacecraft within the constellation is not constrained by mission and/or science objectives. Optimizing a satellite constellation in the presence of multiple, competing objectives is a highly complex problem to which many traditional mathematical optimization methods cannot be applied and few tools exist to help mission designers search for promising candidate mission designs. The Generation-based Evolutionary Tool for the Optimization of Constellations (GenETOC) has been created to search for near-optimal constellation design options. GenETOC combines a modified version of the Non-dominated Sorting Genetic Algorithm II (NSGA II) with STK Components libraries (a 3rdparty .NET package created by Analytical Graphics Inc.) to create a framework that enables a mission designer to generate a simulation that models the design problem and obtain a family of potential, near-optimal solutions that can be investigated more in detail. GenETOC was developed in C# using the .NET framework with Windows Presentation Foundation (WPF) serving as the framework from which to create the graphical user interface (GUI). GenETOC user inputs can be categorized into three major data components: definition of the problem (areas of interest, satellite decision parameters, and sensor configurations), definition of performance objectives, and specification of the genetic algorithm (GA) parameters. In the problem definition component, the user is prompted to define the areas of interest against which the performance metrics will be computed, define the sensor parameters and attach them to specific spacecraft, select which satellite orbital parameters will be added to the decision space of the GA, and specify the range of desired values for each optimization parameter. For performance objectives, the user is presented with a list of available coverage and revisit performance based calculation options from which two metrics are chosen to serve as the objective functions that the GA will use to evaluate solutions during the optimization process. Finally, the definition of the GA parameters provides user control over the number of generations (number of optimization iterations), the population size (number of candidate constellations created in each generation), and the adaptive mutation and crossover threshold values (control parameters for how frequently each process occurs during the optimization). GenETOC has been extensively tested to verify the individual components of the optimization process. The GA has been tested against a suite of GA test problems to confirm convergence to the known two and three-dimensional Pareto fronts. The coverage and revisit performance metrics obtained in GenETOC are compared with STK desktop scenarios, confirming the constellations are being appropriately modeled within GenETOC simulations. A walkthrough of a simple, example problem is provided to illustrate the workings of GenETOC and to demonstrate the output available to the mission designer.

mission design↗

Xenia Mission: Spacecraft Design Concept

The proposed Xenia mission will, for the first time, chart the chemical and dynamical state of the majority of baryonic matter in the universe. using high-resolution spectroscopy, Xenia will collect essential information from major traces of the formation and evolution of structures from the early universe to the present time. The mission is based on innovative instrumental and observational approaches: observing with fast reaction gamma-ray bursts (GRBs) with a high spectral resolution. This enables the study of their (star-forming) environment from the dark to the local universe and the use of GRBs as backlight of large-scale cosmological structures, observing and surveying extended sources with high sensitivity using two wide field-of-view x-ray telescopes - one with a high angular resolution and the other with a high spectral resolution.

Hopkins, R. C.↗