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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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NASA NTRS2005

A Methodology for the Design and Verification of Globally Asynchronous/Locally Synchronous Architectures

Recent advanced in model-checking have made it practical to formally verify the correctness of many complex synchronous systems (i.e., systems driven by a single clock). However, many computer systems are implemented by asynchronously composing several synchronous components, where each component has its own clock and these clocks are not synchronized. Formal verification of such Globally Asynchronous/Locally Synchronous (GA/LS) architectures is a much more difficult task. In this report, we describe a methodology for developing and reasoning about such systems. This approach allows a developer to start from an ideal system specification and refine it along two axes. Along one axis, the system can be refined one component at a time towards an implementation. Along the other axis, the behavior of the system can be relaxed to produce a more cost effective but still acceptable solution. We illustrate this process by applying it to the synchronization logic of a Dual Fight Guidance System, evolving the system from an ideal case in which the components do not fail and communicate synchronously to one in which the components can fail and communicate asynchronously. For each step, we show how the system requirements have to change if the system is to be implemented and prove that each implementation meets the revised system requirements through modelchecking.

Miller, Steven P.↗

NASA NTRS1998

Evolvable Electronic Systems

Explore the source record for details and available documents.

Evolvable Systems hardware engineered electronics ↗

NASA NTRS1971

Use of thermal analyses of systems to evolve development projects in spacecraft thermal control concepts

System and component models for spacecraft thermal control design, considering materials, environmental degradation, measurement errors, manufacturing and quality assurance

Turner, M. A.↗

NASA NTRS2016

NASA's Space Launch System: An Evolving Capability for Exploration

A foundational capability for international human deep-space exploration, NASA's Space Launch System (SLS) vehicle represents a new spaceflight infrastructure asset, creating opportunities for mission profiles and space systems that cannot currently be executed. While the primary purpose of SLS, which is making rapid progress towards initial launch readiness in two years, will be to support NASA's Journey to Mars, discussions are already well underway regarding other potential utilization of the vehicle's unique capabilities. In its initial Block 1 configuration, capable of launching 70 metric tons (t) to low Earth orbit (LEO), SLS will propel the Orion crew vehicle to cislunar space, while also delivering small CubeSat-class spacecraft to deep-space destinations. With the addition of a more powerful upper stage, the Block 1B configuration of SLS will be able to deliver 105 t to LEO and enable more ambitious human missions into the proving ground of space. This configuration offers opportunities for launching co-manifested payloads with the Orion crew vehicle, and a class of secondary payloads, larger than today's CubeSats. Further upgrades to the vehicle, including advanced boosters, will evolve its performance to 130 t in its Block 2 configuration. Both Block 1B and Block 2 also offer the capability to carry 8.4- or 10-m payload fairings, larger than any contemporary launch vehicle. With unmatched mass-lift capability, payload volume, and C3, SLS not only enables spacecraft or mission designs currently impossible with contemporary EELVs, it also offers enhancing benefits, such as reduced risk, operational costs and/or complexity, shorter transit time to destination or launching large systems either monolithically or in fewer components. This paper will discuss both the performance and capabilities of Space Launch System as it evolves, and the current state of SLS utilization planning.

Creech, Stephen D.↗

NASA NTRS2016

NASA's Space Launch System: An Evolving Capability for Exploration An Evolving Capability for Exploration

A foundational capability for international human deep-space exploration, NASA's Space Launch System (SLS) vehicle represents a new spaceflight infrastructure asset, creating opportunities for mission profiles and space systems that cannot currently be executed. While the primary purpose of SLS, which is making rapid progress towards initial launch readiness in two years, will be to support NASA's Journey to Mars, discussions are already well underway regarding other potential utilization of the vehicle's unique capabilities. In its initial Block 1 configuration, capable of launching 70 metric tons (t) to low Earth orbit (LEO), SLS is capable of propelling the Orion crew vehicle to cislunar space, while also delivering small CubeSat-class spacecraft to deep-space destinations. With the addition of a more powerful upper stage, the Block 1B configuration of SLS will be able to deliver 105 t to LEO and enable more ambitious human missions into the proving ground of space. This configuration offers opportunities for launching co-manifested payloads with the Orion crew vehicle, and a class of secondary payloads, larger than today's CubeSats. Further upgrades to the vehicle, including advanced boosters, will evolve its performance to 130 t in its Block 2 configuration. Both Block 1B and Block 2 also offer the capability to carry 8.4- or 10-m payload fairings, larger than any contemporary launch vehicle. With unmatched mass-lift capability, payload volume, and C3, SLS not only enables spacecraft or mission designs currently impossible with contemporary EELVs, it also offers enhancing benefits, such as reduced risk, operational costs and/or complexity, shorter transit time to destination or launching large systems either monolithically or in fewer components. This paper will discuss both the performance and capabilities of Space Launch System as it evolves, and the current state of SLS utilization planning.

Creech, Stephen D.↗

NASA NTRS2002

Rapid evolution of analog circuits configured on a field programmable transistor array

The purpose of this paper is to illustrate evolution of analog circuits on a stand-alone board-level evolvable system (SABLES). SABLES is part of an effort to achieve integrated evolvable systems. SABLES provides autonomous, fast (tens to hundreds of seconds), on-chip circuit evolution involving about 100,000 circuit evaluations. Its main components are a JPL Field Programmable Transistor Array (FPTA) chip used as transistor-level reconfigurable hardware, and a TI DSP that implements the evolutionary algorithm controlling the FPTA reconfiguration. The paper details an example of evolution on SABLES and points out to certain transient and memory effects that affect the stability of solutions obtained reusing the same piece of hardware for rapid testing of individuals during evolution.

SABLES analog circuits field programmable transist↗

NASA NTRS1992

QSO absorbers - Evidence for a primeval galaxy population

Analyses of QSO absorption-line data including Ly-alpha forest lines, metal-line absorbers, and damped Ly-alpha systems indicate that the various classes of absorbers belong to the same parent population. In particular, the different absorber systems form a contiguous sequence on a total hydrogen surface density, velocity dispersion plane. Thus the Ly-alpha forest absorbers represent the low column density, low-mass end of the larger metallic systems. In the majority of the absorption systems, cooling appears to have played an important role at the epoch of observation, although most systems have not evolved sufficiently to resemble the local galaxy population. Thus they represent a population of primeval, dynamically evolving systems. The data are more easily interpretable for a dark matter dominated universe than for a purely baryonic universe. For a dark to baryonic matter ratio of 10, observations suggest that the ultimate fate of all QSO absorbers is to evolve into the local galaxy population.

Chokshi, Arati↗

NASA NTRS1979

Potential applications of a high altitude powered platform in the ocean/coastal zone community

The results of a survey of the ocean/coastal zone community conducted for the NASA Wallops Flight Center to identify potential applications of a high altitude powered platform (HAPP) are presented. Such a platform would stationkeep at 70,000 feet for up to a year over a given location and make frequent high resolution observations, or serve as a regional communications link. The survey results indicate user interest among scientific researchers, operational agencies and private industry. It is felt that such a platform would combine the desirable characteristics of both geostationary satellites (wide area, frequent observation) and aircraft (high resolution). As a result a concept for an operational HAPP system in the form of a 'mesoscale geostationary satellite' system evolved. Such a system could employ many of the same technologies used in current NASA and NOAA geostationary satellite programs. A set of generalized instrument requirements for HAPP borne sensors is also presented.

Escoe, D.↗

NASA NTRS2002

Toward a Concept of Operations for Aviation Weather Information Implementation in the Evolving National Airspace System

The capacity of the National Airspace System is being stressed due to the limits of current technologies. Because of this, the FAA and NASA are working to develop new technologies to increase the system's capacity which enhancing safety. Adverse weather has been determined to be a major factor in aircraft accidents and fatalities and the FAA and NASA have developed programs to improve aviation weather information technologies and communications for system users The Aviation Weather Information Element of the Weather Accident Prevention Project of NASA's Aviation Safety Program is currently working to develop these technologies in coordination with the FAA and industry. This paper sets forth a theoretical approach to implement these new technologies while addressing the National Airspace System (NAS) as an evolving system with Weather Information as one of its subSystems. With this approach in place, system users will be able to acquire the type of weather information that is needed based upon the type of decision-making situation and condition that is encountered. The theoretical approach addressed in this paper takes the form of a model for weather information implementation. This model addresses the use of weather information in three decision-making situations, based upon the system user's operational perspective. The model also addresses two decision-making conditions, which are based upon the need for collaboration due to the level of support offered by the weather information provided by each new product or technology. The model is proposed for use in weather information implementation in order to provide a systems approach to the NAS. Enhancements to the NAS collaborative decision-making capabilities are also suggested.

McAdaragh, Raymon M.↗

NASA NTRS2015

NASA's Space Launch System: An Evolving Capability for Exploration

Designed to enable human space exploration missions, including eventually landings on Mars, NASA's Space Launch System (SLS) represents a unique launch capability with a wide range of utilization opportunities, from delivering habitation systems into the "proving ground" of lunar-vicinity space to enabling high-energy transits through the outer solar system. Substantial progress has been made toward the first launch of the initial configuration of SLS, which will be able to deliver more than 70 metric tons of payload into low Earth orbit (LEO). Preparations are also underway to evolve the vehicle into more powerful configurations, culminating with the capability to deliver more than 130 metric tons to LEO. Even the initial configuration of SLS will be able to deliver greater mass to orbit than any contemporary launch vehicle, and the evolved configuration will have greater performance than the Saturn V rocket that enabled human landings on the moon. SLS will also be able to carry larger payload fairings than any contemporary launch vehicle, and will offer opportunities for co-manifested and secondary payloads. Because of its substantial mass-lift capability, SLS will also offer unrivaled departure energy, enabling mission profiles currently not possible. The basic capabilities of SLS have been driven by studies on the requirements of human deep-space exploration missions, and continue to be validated by maturing analysis of Mars mission options, including the Global Exploration Roadmap. Early collaboration with science teams planning future decadal-class missions have contributed to a greater understanding of the vehicle's potential range of utilization. As SLS draws closer to its first launch, the Program is maturing concepts for future capability upgrades, which could begin being available within a decade. These upgrades, from multiple unique payload accommodations to an upper stage providing more power for inspace propulsion, have ramifications for a variety of missions, from human exploration to robotic science.

Robinson, Kimberly F.↗

NASA NTRS1998

Determining Fault Insertion Rates for Evolving Software Systems

In developing a software system, we would like to be able to estimate the way in which the fault content changes during its development, as well as determining the locations, having the highest concentration of faults.

faults incremental code enhancements↗

NASA NTRS2016

NASA's Space Launch System: An Evolving Capability for Exploration

Designed to meet the stringent requirements of human exploration missions into deep space and to Mars, NASA's Space Launch System (SLS) vehicle represents a unique new launch capability opening new opportunities for mission design. While SLS's super-heavy launch vehicle predecessor, the Saturn V, was used for only two types of missions - launching Apollo spacecraft to the moon and lofting the Skylab space station into Earth orbit - NASA is working to identify new ways to use SLS to enable new missions or mission profiles. In its initial Block 1 configuration, capable of launching 70 metric tons (t) to low Earth orbit (LEO), SLS is capable of not only propelling the Orion crew vehicle into cislunar space, but also delivering small satellites to deep space destinations. With a 5-meter (m) fairing consistent with contemporary Evolved Expendable Launch Vehicles (EELVs), the Block 1 configuration can also deliver science payloads to high-characteristic-energy (C3) trajectories to the outer solar system. With the addition of an upper stage, the Block 1B configuration of SLS will be able to deliver 105 t to LEO and enable more ambitious human missions into the proving ground of space. This configuration offers opportunities for launching co-manifested payloads with the Orion crew vehicle, and a new class of secondary payloads, larger than today's cubesats. The evolved configurations of SLS, including both Block 1B and the 130 t Block 2, also offer the capability to carry 8.4- or 10-m payload fairings, larger than any contemporary launch vehicle. With unmatched mass-lift capability, payload volume, and C3, SLS not only enables spacecraft or mission designs currently impossible with contemporary EELVs, it also offers enhancing benefits, such as reduced risk and operational costs associated with shorter transit time to destination and reduced risk and complexity associated with launching large systems either monolithically or in fewer components. As this paper will demonstrate, SLS represents a unique new capability for spaceflight, and an opportunity to reinvent space by developing out-of-the-box missions and mission designs unlike any flown before.

Crumbly, Christopher M.↗

NASA NTRS2015

NASA's Space Launch System: An Evolving Capability for Exploration

Robinson, Kimberly F.↗

NASA NTRS2016

NASA's Space Launch System: An Evolving Capability for Exploration

Designed to meet the stringent requirements of human exploration missions into deep space and to Mars, NASA's Space Launch System (SLS) vehicle represents a unique new launch capability opening new opportunities for mission design. NASA is working to identify new ways to use SLS to enable new missions or mission profiles. In its initial Block 1 configuration, capable of launching 70 metric tons (t) to low Earth orbit (LEO), SLS is capable of not only propelling the Orion crew vehicle into cislunar space, but also delivering small satellites to deep space destinations. The evolved configurations of SLS, including both the 105 t Block 1B and the 130 t Block 2, offer opportunities for launching co-manifested payloads and a new class of secondary payloads with the Orion crew vehicle, and also offer the capability to carry 8.4- or 10-m payload fairings, larger than any contemporary launch vehicle, delivering unmatched mass-lift capability, payload volume, and C3.

Creech, Stephen D.↗

NASA NTRS2025

Iterating on a Design – Further Developments in the Evolution of the Ballistic Limit Equations for the Mars Sample Return Project

The goal of the Mars Sample Return–Capture, Containment, and Return System Project is to retrieve samples launched from the Martian surface and return them to Earth for detailed analysis. An important part of this project is the design of the system’s micrometeoroid protection system, which protects the Earth Entry System and the collected samples during their journey back to Earth. As mission parameters and the micrometeoroid and orbital debris threat became better understood, the design of the micrometeoroid protection system evolved. A key element used in the shield development process is the ballistic limit equation, which is an equation that is used to determine whether or not a particular structural element or system will end up in a failed state as a result of a specified impact. As the design of the Earth Entry System and the micrometeoroid protection system evolved, a new set of ballistic limit equations was needed to better predict and assess the performance of developing shield system designs in anticipation of possible damage from micrometeoroid and orbital debris particle impacts. This paper provides a summary of how a set of initial BLEs were either extended or modified so that the resulting equations were better suited to new types of target configurations being considered, as well as how additional ballistic limit equations were developed where none previously existed.

William P Schonberg↗

NASA NTRS1994

A model for the evolution of CO2 on Mars

We have constructed a model that predicts the evolution of CO2 on Mars from the end of the heavy bombardment period to the present. The model draws on published estimates of the main processes believed to affect the fate of CO2 during this period: chemical weathering, regolith uptake, polar cap formation, and atmospheric escape. Except for escape, the rate at which these processes act is controlled by surface temperatures which we calculate using a modified version of the Gierasch and Toon energy balance model. The modifications account for the change in solar luminosity with time, the greenhouse effect, and a polar and equatorial energy budget. Using published estimates for the main parameters, we find no evolutionary scenario in which CO2 is capable of producing a warm (global mean temperatures greater than 250 K) and wet (surface pressures greater than 30 mbar) early climate, and then evolves to present conditions with approximately 7 mbar in the atmosphere, less than 300 mbar in the regolith, and less than 5 mbar in the caps. Such scenarios would only exist if the early sun were brighter than standard solar models suggest, if greenhouse gases other than CO2 were present in the early atmosphere, or if the polar albedo were significantly lower than 0.75. However, these scenarios generally require the storage of large amounts of CO2 (greater than 1 bar) in the carbonate reservoir. If the warm and wet early Mars constraint is relaxed, then we find best overall agreement with present day reservoirs for initial CO2 inventories of 0.5-1.0 bar. We also find that the polar caps can have a profound effect on how the system evolves. If the initial amount of CO2 is less than some critical value, then there is not enough heating of the poles to prevent permanent caps from forming. Once formed, these caps control how the system evolves, because they set the surface pressure and, hence, the thermal environment. If the initial amount of CO2 is greater than this critical value, then caps do not form initially, but can form later on, when weathering and escape lower the surface pressure to a point at which polar heating is no longer sufficient to prevent cap formation and the collapse of the climate system. Our modeling suggests this critical initial amount of CO2 is between 1 and 2 bar, but its true value will depend on all factors affecting the polar heat budget.

Haberle, Robert M.↗

NASA NTRS2005

Evolvable hardware system at extreme low temperatures

This paper describes circuit evolutionary experiments at extreme low temperatures, including the test of all system components at this extreme environment (EE). In addition to hardening-by-process and hardening-by-design, 'hardening-by-reconfiguration ', when applicable, could be used to mitigate drifts, degradation, or damage on electronic devices (chips) in EE, by using re-configurable devices and an adaptive selfreconfiguration of their circuit topology. Conventional circuit design exploits device characteristics within a certain temperature/radiation range; when that is exceeded, the circuit function degrades. On a reconfigurable device, although component parameters change in EE, a new circuit design, suitable for new parameter values, may be mapped into the reconfigurable structure to recover the initial circuit function. This paper demonstrates this technique for circuit evolution and recovery at liquid nitrogen temperatures (-196.6 (deg)C). In addition, preliminary tests are performed to assess the survivability limitations of the evolutionary processor at extreme low temperatures.

evolvable harware↗

NASA NTRS1978

The characteristics of evolving mesoscale systems over mountainous terrain as revealed by radar and PAM

The paper deals with measurements made within the South Park area (which is located near Denver, Colorado, and is a natural genesis area for cumulus clouds) in July and August 1977, using powered aircraft, sailplanes, rawinsondes, boundary layer profilers, acoustic sounders, micrometeorological towers, lidar, research radar, triple-Doppler radar, and a square grid of surface meteorological stations. Extensive analysis revealed a very complex picture of thunderstorm-scale, large-mesoscale, and synoptic-scale interactions.

George, R. L.↗