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NASA NTRS2001

Rocket Design for the Future

The focus of the AA MDO team is to reduce product development cost through the capture and automation of best design and analysis practices and through increasing the availability of low-cost, high-fidelity analysis. Implementation of robust designs reduces costs associated with the Test-Fall-Fix cycle. RD is currently focusing on several technologies to improve the design process, including optimization and robust design, expert and rule-based systems, and collaborative technologies.

Follett, William W.↗

NASA NTRS1981

Structures performance, benefit, cost-study

New technology concepts and structural analysis development needs which could lead to improved life cycle cost for future high-bypass turbofans were studied. The NASA-GE energy efficient engine technology is used as a base to assess the concept benefits. Recommended programs are identified for attaining these generic structural and other beneficial technologies.

Woike, O. G.↗

NASA NTRS1993

Software forecasting as it is really done: A study of JPL software engineers

This paper presents a summary of the results to date of a Jet Propulsion Laboratory internally funded research task to study the costing process and parameters used by internally recognized software cost estimating experts. Protocol Analysis and Markov process modeling were used to capture software engineer's forecasting mental models. While there is significant variation between the mental models that were studied, it was nevertheless possible to identify a core set of cost forecasting activities, and it was also found that the mental models cluster around three forecasting techniques. Further partitioning of the mental models revealed clustering of activities, that is very suggestive of a forecasting lifecycle. The different forecasting methods identified were based on the use of multiple-decomposition steps or multiple forecasting steps. The multiple forecasting steps involved either forecasting software size or an additional effort forecast. Virtually no subject used risk reduction steps in combination. The results of the analysis include: the identification of a core set of well defined costing activities, a proposed software forecasting life cycle, and the identification of several basic software forecasting mental models. The paper concludes with a discussion of the implications of the results for current individual and institutional practices.

Griesel, Martha Ann↗

NASA NTRS2003

Static Analysis of C Programs

Contents include the following: Motivation. Cost of losing missions. Introduction to Static Analysis:definition, defect classes, applicability issues, specialization, analysis of MPF. C Global Surveyor (CGS): fact sheet, CGS phases, example. Conclusions.

Venet, Arnaud↗

NASA NTRS1985

Preliminary structural analysis of Shuttle payloads using a base drive method with synthetic inputs

A transient base drive (TBD) analytical method for the support of the preliminary design analysis of Space Shuttle payloads, which could potentially reduce the cost of the payload structural analysis, is derscribed. The validity of TBD predictions depends on the ability to provide accurate synthetic base inputs. Acceleration inputs with a frequency content and magnitude which are not associated with a specific configuration or condition were synthesized. The use of frequency envelopes in the derivation of synthetic inputs can provide appropriate predictions independent of the payload modal frequencies.

Nelson, D. A. R., Jr.↗

NASA NTRSDate not supplied

Subsonic Single Aft Engine Narrowbody (SUSAN) Freighter Concept and Market Analysis

The dedicated air cargo and freight market has the potential to be a critical early pathway for emerging technologies in low to zero emission propulsion. This study analyzes the cargo aviation market to understand current market trends and future market viability of a mid-sized all-electric or hybrid-electric concept aircraft. While cargo aviation’s overall emissions footprint is small relative to commercial passenger aviation, it remains an important and challenging transportation sector to decarbonize. Past research has focused on small, less than 19-seat electrified aircraft propulsion concepts that could serve both passenger and air cargo markets This study extends the electrified market space into larger aircraft classes, considering if a purpose-built large hybrid electric turboprop freighter can compete in the market currently served primarily by conversion narrowbody freighters. Specifically, this paper focuses on the mid-sized cargo market with payload ranges of 40,000-50,000lbs, and an all-electric range potential up to 750 miles. The concept aircraft is based on a 4-engine turboprop configuration, with mounted wing battery packs and an aft cargo door to allow for standardized palletization. The market analysis indicates broad market coverage with 73% of the existing mid-sized cargo network within the range of 750 miles. A breakeven analysis of operating and capital costs shows potential for market competition, however, additional energy and acquisition cost savings from the concept aircraft are needed. Evidence from the breakeven analysis also points to higher rates of aircraft utilization being a critical path to lowering costs and increasing cost effectiveness.

Jacob M. Wishart↗

NASA NTRS2021

Financial feasibility of water conservation in agriculture

Global water use for food production needs to be reduced to remain within planetary boundaries, yet the financial feasibility of crucial measures to reduce water use is poorly quantified. Here, we introduce a novel method to compare the costs of water conservation measures with the added value that reallocation of water savings might generate if used for expansion of irrigation. Based on detailed water accounting through the use of a high-resolution hydrology-crop model, we modify the traditional cost curve approach with an improved estimation of demand, increasing marginal cost per water conservation measure combination and add a correction to control for impacts on downstream water availability. We apply the method to three major river basins in the Indo-Gangetic plain (Indus, Ganges and Brahmaputra), a major global food producing region but increasingly water stressed. Our analysis shows that at basin level only about 10% (Brahmaputra) to just over 20% (Indus and Ganges) of potential water savings would be realised; the equilibrium price for water is too low to make the majority of water conservation measures cost effective. The associated expansion of irrigated area is moderate, about 7% in the Indus basin, 5% in the Ganges and negligible in the Brahmaputra, but farmers' gross profit increases more substantially, by 11%. Increasing the volumetric cost of irrigation water influences supply and demand in a similar way and has little influence on water reallocation. Controlling for the impact on return flows is important and more than halves the amount of water available for reallocation.

Geography / Land Utilization↗

NASA NTRS1980

Solar cells and modules from dentritic web silicon

Some of the noteworthy features of the processes developed in the fabrication of solar cell modules are the handling of long lengths of web, the use of cost effective dip coating of photoresist and antireflection coatings, selective electroplating of the grid pattern and ultrasonic bonding of the cell interconnect. Data on the cells is obtained by means of dark I-V analysis and deep level transient spectroscopy. A histogram of over 100 dentritic web solar cells fabricated in a number of runs using different web crystals shows an average efficiency of over 13%, with some efficiencies running above 15%. Lower cell efficiency is generally associated with low minority carrier time due to recombination centers sometimes present in the bulk silicon. A cost analysis of the process sequence using a 25 MW production line indicates a selling price of $0.75/peak watt in 1986. It is concluded that the efficiency of dentritic web cells approaches that of float zone silicon cells, reduced somewhat by the lower bulk lifetime of the former.

Campbell, R. B.↗

NASA NTRS1993

GRYPHON: Air launched space booster

The project chosen for the winter semester Aero 483 class was the design of a next generation Air Launched Space Booster. Based on Orbital Sciences Corporation's Pegasus concept, the goal of Aero 483 was to design a 500,000 pound air launched space booster capable of delivering 17,000 pounds of payload to Low Earth Orbit and 8,000 pounds of payload to Geosynchronous Earth Orbit. The resulting launch vehicle was named the Gryphon. The class of forty senior aerospace engineering students was broken down into eight interdependent groups. Each group was assigned a subsystem or responsibility which then became their field of specialization. Spacecraft Integration was responsible for ensuring compatibility between subsystems. This group kept up to date on subsystem redesigns and informed those parties affected by the changes, monitored the vehicle's overall weight and dimensions, and calculated the mass properties of the booster. This group also performed the cost/profitability analysis of the Gryphon and obtained cost data for competing launch systems. The Mission Analysis Group was assigned the task of determining proper orbits, calculating the vehicle's flight trajectory for those orbits, and determining the aerodynamic characteristics of the vehicle. The Propulsion Group chose the engines that were best suited to the mission. This group also set the staging configurations for those engines and designed the tanks and fuel feed system. The commercial satellite market, dimensions and weights of typical satellites, and method of deploying satellites was determined by the Payloads Group. In addition, Payloads identified possible resupply packages for Space Station Freedom and identified those packages that were compatible with the Gryphon. The guidance, navigation, and control subsystems were designed by the Mission Control Group. This group identified required tracking hardware, communications hardware telemetry systems, and ground sites for the location of the Gryphon's mission control center. The Structures group was responsible for ensuring the structural integrity of the vehicle. Their designs included the payload shroud, payload support structure, exterior hull and engine support struts. The Gryphon's power requirements were determined by the Power/Thermal/Attitude Control Group. This group then selected suitable batteries and other components to meet these requirements. The group also designed heat shielding and cooling systems to ensure subsystem performance. In addition to these responsibilities this group designed the attitude control methods and RCS components for the vehicle. The Aircraft Integration Group was responsible for all aspects of the booster aircraft connection. This included the design of the connection structure and the drop mechanism. This group also designed the vehicle assembly facility and identified possible ground bases for the plane.

Source record↗

NASA NTRS2001

A Two-Dimensional Variational Analysis Method for NSCAT Ambiguity Removal: Methodology, Sensitivity, and Tuning

In this study, we apply a two-dimensional variational analysis method (2d-VAR) to select a wind solution from NASA Scatterometer (NSCAT) ambiguous winds. 2d-VAR determines a "best" gridded surface wind analysis by minimizing a cost function. The cost function measures the misfit to the observations, the background, and the filtering and dynamical constraints. The ambiguity closest in direction to the minimizing analysis is selected. 2d-VAR method, sensitivity and numerical behavior are described. 2d-VAR is compared to statistical interpolation (OI) by examining the response of both systems to a single ship observation and to a swath of unique scatterometer winds. 2d-VAR is used with both NSCAT ambiguities and NSCAT backscatter values. Results are roughly comparable. When the background field is poor, 2d-VAR ambiguity removal often selects low probability ambiguities. To avoid this behavior, an initial 2d-VAR analysis, using only the two most likely ambiguities, provides the first guess for an analysis using all the ambiguities or the backscatter data. 2d-VAR and median filter selected ambiguities usually agree. Both methods require horizontal consistency, so disagreements occur in clumps, or as linear features. In these cases, 2d-VAR ambiguities are often more meteorologically reasonable and more consistent with satellite imagery.

Hoffman, R. N.↗

NASA NTRS2006

Model-Based Safety Analysis

System safety analysis techniques are well established and are used extensively during the design of safety-critical systems. Despite this, most of the techniques are highly subjective and dependent on the skill of the practitioner. Since these analyses are usually based on an informal system model, it is unlikely that they will be complete, consistent, and error free. In fact, the lack of precise models of the system architecture and its failure modes often forces the safety analysts to devote much of their effort to gathering architectural details about the system behavior from several sources and embedding this information in the safety artifacts such as the fault trees. This report describes Model-Based Safety Analysis, an approach in which the system and safety engineers share a common system model created using a model-based development process. By extending the system model with a fault model as well as relevant portions of the physical system to be controlled, automated support can be provided for much of the safety analysis. We believe that by using a common model for both system and safety engineering and automating parts of the safety analysis, we can both reduce the cost and improve the quality of the safety analysis. Here we present our vision of model-based safety analysis and discuss the advantages and challenges in making this approach practical.

Joshi, Anjali↗

NASA NTRS2009

Computing Bounds on Resource Levels for Flexible Plans

A new algorithm efficiently computes the tightest exact bound on the levels of resources induced by a flexible activity plan (see figure). Tightness of bounds is extremely important for computations involved in planning because tight bounds can save potentially exponential amounts of search (through early backtracking and detection of solutions), relative to looser bounds. The bound computed by the new algorithm, denoted the resource-level envelope, constitutes the measure of maximum and minimum consumption of resources at any time for all fixed-time schedules in the flexible plan. At each time, the envelope guarantees that there are two fixed-time instantiations one that produces the minimum level and one that produces the maximum level. Therefore, the resource-level envelope is the tightest possible resource-level bound for a flexible plan because any tighter bound would exclude the contribution of at least one fixed-time schedule. If the resource- level envelope can be computed efficiently, one could substitute looser bounds that are currently used in the inner cores of constraint-posting scheduling algorithms, with the potential for great improvements in performance. What is needed to reduce the cost of computation is an algorithm, the measure of complexity of which is no greater than a low-degree polynomial in N (where N is the number of activities). The new algorithm satisfies this need. In this algorithm, the computation of resource-level envelopes is based on a novel combination of (1) the theory of shortest paths in the temporal-constraint network for the flexible plan and (2) the theory of maximum flows for a flow network derived from the temporal and resource constraints. The measure of asymptotic complexity of the algorithm is O(N O(maxflow(N)), where O(x) denotes an amount of computing time or a number of arithmetic operations proportional to a number of the order of x and O(maxflow(N)) is the measure of complexity (and thus of cost) of a maximumflow algorithm applied to an auxiliary flow network of 2N nodes. The algorithm is believed to be efficient in practice; experimental analysis shows the practical cost of maxflow to be as low as O(N1.5). The algorithm could be enhanced following at least two approaches. In the first approach, incremental subalgorithms for the computation of the envelope could be developed. By use of temporal scanning of the events in the temporal network, it may be possible to significantly reduce the size of the networks on which it is necessary to run the maximum-flow subalgorithm, thereby significantly reducing the time required for envelope calculation. In the second approach, the practical effectiveness of resource envelopes in the inner loops of search algorithms could be tested for multi-capacity resource scheduling. This testing would include inner-loop backtracking and termination tests and variable and value-ordering heuristics that exploit the properties of resource envelopes more directly.

Muscvettola, Nicola↗

NASA NTRS2009

Status and Mission Applicability of NASA's In-Space Propulsion Technology Project

The In-Space Propulsion Technology (ISPT) project develops propulsion technologies that will enable or enhance NASA robotic science missions. Since 2001, the ISPT project developed and delivered products to assist technology infusion and quantify mission applicability and benefits through mission analysis and tools. These in-space propulsion technologies are applicable, and potentially enabling for flagship destinations currently under evaluation, as well as having broad applicability to future Discovery and New Frontiers mission solicitations. This paper provides status of the technology development, near-term mission benefits, applicability, and availability of in-space propulsion technologies in the areas of advanced chemical thrusters, electric propulsion, aerocapture, and systems analysis tools. The current chemical propulsion investment is on the high-temperature Advanced Material Bipropellant Rocket (AMBR) engine providing higher performance for lower cost. Investments in electric propulsion technologies focused on completing NASA's Evolutionary Xenon Thruster (NEXT) ion propulsion system, a 0.6-7 kW throttle-able gridded ion system, and the High Voltage Hall Accelerator (HiVHAC) thruster, which is a mid-term product specifically designed for a low-cost electric propulsion option. Aerocapture investments developed a family of thermal protections system materials and structures; guidance, navigation, and control models of blunt-body rigid aeroshells; atmospheric models for Earth, Titan, Mars and Venus; and models for aerothermal effects. In 2009 ISPT started the development of propulsion technologies that would enable future sample return missions. The paper describes the ISPT project's future focus on propulsion for sample return missions. The future technology development areas for ISPT is: Planetary Ascent Vehicles (PAV), with a Mars Ascent Vehicle (MAV) being the initial development focus; multi-mission technologies for Earth Entry Vehicles (MMEEV) needed for sample return missions from many different destinations; propulsion for Earth Return Vehicles (ERV), transfer stages to the destination, and Electric Propulsion for sample return and low cost missions; and Systems/Mission Analysis focused on sample return propulsion. The ISPT project is funded by NASA's Science Mission Directorate (SMD).

Anderson, David J.↗

NASA NTRS2005

CoMET: Cost and Mass Evaluation Tool for Spacecraft and Mission Design

New technology in space exploration is often developed without a complete knowledge of its impact. While the immediate benefits of a new technology are obvious, it is harder to understand its indirect consequences, which ripple through the entire system. COMET is a technology evaluation tool designed to illuminate how specific technology choices affect a mission at each system level. COMET uses simplified models for mass, power, and cost to analyze performance parameters of technologies of interest. The sensitivity analysis that CoMET provides shows whether developing a certain technology will greatly benefit the project or not. CoMET is an ongoing project approaching a web-based implementation phase. This year, development focused on the models for planetary daughter craft, such as atmospheric probes, blimps and balloons, and landers. These models are developed through research into historical data, well established rules of thumb, and engineering judgment of experts at JPL. The model is validated by corroboration with JpL advanced mission studies. Other enhancements to COMET include adding launch vehicle analysis and integrating an updated cost model. When completed, COMET will allow technological development to be focused on areas that will most drastically improve spacecraft performance.

Bieber, Ben S.↗

NASA NTRS2017

Conceptual Feasibility Study of the Hyperloop Vehicle for Next-Generation Transport

The Hyperloop concept is proposed as a faster, cheaper alternative to high-speed rail and traditional short-haul aircraft. It consists of a passenger pod traveling through a tube under light vacuum while being propelled and levitated by a combination of permanent and electro-magnets. The concept addresses NASA's research thrusts for growth in demand, sustainability, and technology convergence for high-speed transport. Hyperloop is a radical departure from other advanced aviation concepts, however it remains an aeronautics concept that tackles the same strategic goals of low-carbon propulsion and ultra-effcient vehicles. System feasibility was investigated by building a multidisciplinary vehicle sizing model that takes into account aerodynamic, thermodynamic, structures, electromagnetic, weight, and mission analyses. The sizing process emphasized the strong coupling between the two largest systems: the tube and the passenger pod. The model was then exercised to examine Hyperloop from a technical and cost perspective. The structural sizing analysis of the travel tube demonstrates potential for signi cant capital cost reductions by considering an underwater route. Examination of varying passenger capacity indicates that the system can be operated with a wide range of passenger loads without significant change in operating expenses. Lastly, a high-level sizing study simulated variations in tube area, pressure, pod speed, and passenger capacity showing that there is a tube pressure that minimizes operating energy usage. The value of this optimal tube pressure is highly sensitive to numerous design details. These combined estimates of energy consumption, passenger throughput, and mission analyses all support Hyperloop as a faster and cheaper alternative to short-haul flights. The tools and expertise used to quantify these results also demonstrate how traditional aerospace design methods can be leveraged to handle the complex and coupled design process. Much of the technology development required for the Hyperloop is shared with next-generation aircraft. Furthermore, the substantial public interest and active commercial development make it an ideal candidate as an aircraft technology driver and test bed.

Hyperloop Vehicle↗

NASA NTRS1995

Advanced Transportation System Studies Technical Area 2 (TA-2) Heavy Lift Launch Vehicle Development Contract: Technical Results - Volume 2

The purpose of the Advanced Transportation System Studies (ATSS) Technical Area 2 (TA-2) Heavy Lift Launch Vehicle Development contract was to provide advanced launch vehicle concept definition and analysis to assist NASA in the identification of future launch vehicle requirements. Contracted analysis activities included vehicle sizing and performance analysis, subsystem concept definition, propulsion subsystem definition (foreign and domestic), ground operations and facilities analysis, and life cycle cost estimation. This document is Volume 2 of the final report for the contract. It provides documentation of selected technical results from various TA-2 analysis activities, including a detailed narrative description of the SSTO concept assessment results, a user's guide for the associated SSTO sizing tools, an SSTO turnaround assessment report, an executive summary of the ground operations assessments performed during the first year of the contract, a configuration-independent vehicle health management system requirements report, a copy of all major TA-2 contract presentations, a copy of the FLO launch vehicle final report, and references to Pratt & Whitney's TA-2 sponsored final reports regarding the identification of Russian main propulsion technologies.

Source record↗

NASA NTRS1993

Advanced launch system. Advanced development oxidizer turbopump program

On May 19, 1989, Pratt & Whitney was awarded contract NAS8-37595 by the National Aeronautics and Space Administration, Marshall Space Flight Center, Huntsville Alabama for an Advanced Development Program (ADP) to design, develop and demonstrate a highly reliable low cost, liquid oxygen turbopump for the Advanced Launch System (ALS). The ALS had an overall goal of reducing the cost of placing payloads in orbit by an order of magnitude. This goal would require a substantial reduction in life cycle costs, with emphasis on recurring costs, compared to current launch vehicles. Engine studies supporting these efforts were made for the Space Transportation Main Engine (STME). The emphasis on low cost required design simplification of components and subsystems such that the ground maintenance and test operations was minimized. The results of the Oxygen Turbopump ADP technology effort would provide data to be used in the STME. Initially the STME baseline was a gas generator cycle engine with a vacuum thrust level of 580,000 lbf. This was later increased to 650,000 lbf and the oxygen turbopump design approach was changed to reflect the new thrust level. It was intended that this ADP program be conducted in two phases. Phase 1, a basic phase, would encompass the preliminary design effort, and Phase II, an optional contract phase to cover design, fabrication and test evaluation of an oxygen turbopump at a component test facility at the NASA John C. Stennis Space Center in Mississippi. The basic phase included preliminary design and analysis, evaluation of low cost concepts, and evaluation of fabrication techniques. The option phase included design of the pump and support hardware, analysis of the final configuration to ensure design integrity, fabrication of hardware to demonstrate low cost, DVS Testing of hardware to verify the design, assembly of the turbopump and full scale turbopump testing. In December 1990, the intent of this ADP to support the design and development was changed. The design effort for the oxygen turbopump became part of the STME Phase B contract. The status of the pump design funded through this ADP was presented at the Preliminary Design Review (PDR) at the MSFC on October 24, 1990. Advancements in the design of the pump were subsequently continued under the Phase B Contract. The emphasis of this ADP became the demonstration of individual technologies that would have the greatest potential for reducing the recurring cost and increasing reliability. In October of 1992, overall program funding was reduced and work on this ADP was terminated.

Source record↗

NASA NTRS1974

The Energy Systems Optimization Computer Program /ESOP/ developed for Modular Integrated Utility Systems /MIUS/ analysis

A significant energy and cost savings can be obtained by integrating various utility services (space heating and cooling, electrical power generation, solid waste disposal, potable water, and waste water treatment) into a single unit which provides buildings or groups of buildings with these services. This paper presents a description of a computer program, called the Energy Systems Optimization Program (ESOP). This program predicts the loads, energy requirements, equipment sizes, and life-cycle costs of alternative methods of meeting these utility requirements. The program has been used extensively for performing energy analyses of Modular Integrated Utility Systems (MIUS).

Ferden, S. L.↗