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All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Resonance quasi-projection operators - Calculation of the super 2 S autoionization state of He/-/.

Development of a method to remedy the defects of the projection-operator technique for calculating electron resonances in scattering from many-electron targets. It is recommended that the projection operator Q be replaced by a quasi-projection operator which yields a discrete spectrum which can be made to be in essentially a unique correspondence with resonance energies. By relaxing the idempotency requirement, it is found possible to define two forms of this quasi-projection operator. The simpler of the two forms is tested on e-H and e-H(+) systems; the two lowest resonant energies differ by less than 0.01 eV from rigorous QHQ results. For many-electron targets it is further argued that replacement of the exact target eigenfunction by reasonable approximations in constructing the quasi-projection operator will affect neither the discreteness of the above-mentioned discrete spectrum nor the proximity of its eigenvalues to the resonant energies.

Temkin, A.↗
NASA NTRS2010

Projection Operator: A Step Towards Certification of Adaptive Controllers

One of the major barriers to wider use of adaptive controllers in commercial aviation is the lack of appropriate certification procedures. In order to be certified by the Federal Aviation Administration (FAA), an aircraft controller is expected to meet a set of guidelines on functionality and reliability while not negatively impacting other systems or safety of aircraft operations. Due to their inherent time-variant and non-linear behavior, adaptive controllers cannot be certified via the metrics used for linear conventional controllers, such as gain and phase margin. Projection Operator is a robustness augmentation technique that bounds the output of a non-linear adaptive controller while conforming to the Lyapunov stability rules. It can also be used to limit the control authority of the adaptive component so that the said control authority can be arbitrarily close to that of a linear controller. In this paper we will present the results of applying the Projection Operator to a Model-Reference Adaptive Controller (MRAC), varying the amount of control authority, and comparing controller s performance and stability characteristics with those of a linear controller. We will also show how adjusting Projection Operator parameters can make it easier for the controller to satisfy the certification guidelines by enabling a tradeoff between controller s performance and robustness.

Larchev, Gregory V.↗
NASA NTRS1985

Projection and quasi-projection operators for electron impact resonances on many-electron atomic targets

A framework is established for deriving true projection operators in electron resonance calculations involving many electron targets (ions and atoms). The analytical approach is based on Feshbach's formalism the true and quasi-projection operators (QPO) one-electron systems. In the case of QPOs, the formalism is explicitly generalized to treat autoionization states lying in the region of inelastic scattering. In order to illustrate the analytical method, a recent calculation of the lowest 2P0 resonance in He is described. The application of the modified Feshbach formalism to calculation of nonresonant phase shifts in many electron systems is also discussed.

Temkin, A.↗
NASA NTRS1985

Sum rules and other properties involving resonance projection operators

A sum rule is derived for the auxiliary eigenvalues of an equation whose eigenspectrum pertains to projection operators which describe electron scattering from multielectron atoms and ions. The sum rule's right-hand side depends on an integral involving the target system eigenfunctions. The sum rule is checked for several approximations of the two-electron target. It is shown that target functions which have a unit eigenvalue in their auxiliary eigenspectrum do not give rise to well-defined projection operators except through a limiting process. For Hylleraas target approximations, the auxiliary equations are shown to contain an infinite spectrum. However, using a Rayleigh-Ritz variational principle, it is shown that a comparatively simple aproximation can exhaust the sum rule to better than five significant figures. The auxiliary Hylleraas equation is greatly simplified by conversion to a square root equation containing the same eigenfunction spectrum and from which the required eigenvalues are trivially recovered by squaring.

Berk, A.↗
NASA NTRS2007

Constellation Program Mission Operations Project Office Status and Support Philosophy

The Constellation Program Mission Operations Project Office (CxP MOP) at Johnson Space Center in Houston Texas is preparing to support the CxP mission operations objectives for the CEV/Orion flights, the Lunar Lander, and and Lunar surface operations. Initially the CEV will provide access to the International Space Station, then progress to the Lunar missions. Initial CEV mission operations support will be conceptually similar to the Apollo missions, and we have set a challenge to support the CEV mission with 50% of the mission operations support currently required for Shuttle missions. Therefore, we are assessing more efficient way to organize the support and new technologies which will enhance our operations support. This paper will address the status of our preparation for these CxP missions, our philosophical approach to CxP operations support, and some of the technologies we are assessing to streamline our mission operations infrastructure.

Smith, Ernest↗
NASA NTRS1996

The Mars surveyor operations project command generation process

The methods employed by the Mars surveyor operations project (MSOP) flight team to accelerate the command generation process are described. The approach adopted was to develop a ground system which could simultaneously support as many as three spacecraft in various phases of flight and two in development. The uplink element of the MSOP is discussed, including the control of the science instruments and the spacecraft bus using real-time commands as well as time-tagged stored sequences. The non-interactive payload command process, the express command process, the coordinated command process and the stored sequence process are described. The automation of these processes resulted in flight operations cost savings while maintaining a minimum of risk.

Brooks, Robert N., Jr.↗
NASA NTRS2013

Apollo Medical Operations Project: Recommendations for EVA and Lunar Surface Operations

The potential risk of injury to crewmembers is inherent in aggressive surface activities, whether they be Moon-, Mars-, or asteroid-based. In December 2005, the Space Medicine Division at JSC requested a study to identify Apollo mission issues that had an impact to crew health or performance or both. This talk focused on the Apollo EVA suit and lunar surface operations concerning crew health and performance. There were roughly 20 recommendations from this study of Apollo for improving these two areas for future exploration missions, a few of which were incorporated into the Human Systems Integration Requirements (HSIR). Dr. Richard Scheuring covered these topics along with some of the analog work that has been done regarding surface operations and medical contingencies.

Scheuring, R. A.↗
NASA NTRS1996

The Mars Surveyor Operations Project Command Generation Process

The Mars Global Surveyor mission (MGS) will be the first in a series of Mars missions to recover the science lost when the ill fated Mars Observer spacecraft suffered a catastrophic anomaly in its propulsion system and was unable to attain orbital capture at the planet...This paper will describe in detail the methods employed by the MSOP ( Mars Surveyor Operations Project)flight team to accelerate the command generation process.

MGS↗
NASA NTRS1986

Projection-operator calculations of the lowest e(-)-He resonance

The 1s (2s)2:2S Schulz resonance of He(-) is investigated theoretically, applying the full projection-operator formalism developed by Temkin and Bhatia (1985) in a Rayleigh-Ritz variational calculation. The technique is described in detail, and results for five different approximations of the He target state are presented in a table. Good convergence is obtained, but it is found that even the best calculated value of the resonance is about 130 meV higher than the experimentally measured value of 19.367 + or - 0.007 eV (Brunt et al., 1977), a discrepancy attributed to the contribution of the shift in the Feshbach formalism.

Berk, A.↗
NASA NTRS1980

Quasi-projection-operator calculation of autoionization states of O5/+/ /O VI/ and Si11/+/ /Si XII/

A practical approach to calculating diagnostic parameters includes both scattering and statelike (autoionization) elements. The paper presents inelastic quasi-projection-operator calculations of autoionization states of the three-electron ions of oxygen and silicon for states below the n = 3 manifod of the respective two-electron parent (O VI and Si XII). Wave functions containing up to 40 configurations are calculated. The O VI calculated results agree with experimental results within the experimental error (about + or - 2 eV) while for the Si XII case, it was necessary to include relativistic effects. Where formulas are available (states for which p + q = 2), the Si XII results are also in good agreement with experimental results for 2Se, 2Po, and 2De states. Since the calculated results for some of the higher states did not agree with identifications proposed by Trabert et al. (1979), alternative identifications are suggested.

Wakid, S.↗
NASA NTRS1980

Quasi-projection-operator calculation of inelastic resonances in He/-/ and Li

Feshbach resonances of electrons incident of He and Li(+) are calculated below the 3(S-3) target threshold by means of the inelastic quasi-projection-operator technique of Temkin and Bhatia (1972). A configuration-interaction-type wave function is employed with up to 46 configurations. The calculations reveal, with reasonable accuracy, all presently observed Feshbach resonances. The method does not reveal shape resonances, but, for isoelectronic systems with greater nuclear charge, it is argued that shape resonance should become less important. This is already apparent in the case of Li, for which the known resonances are calculated and higher resonances, for which there are as yet no experimental data, are predicted.

Wakid, S.↗
NASA NTRS2007

The Apollo Medical Operations Project: Recommendations to Improve Crew Health and Performance for Future Exploration Missions and Lunar Surface Operations

Medical requirements for the future Crew Exploration Vehicle (CEV), Lunar Surface Access Module (LSAM), advanced Extravehicular Activity (EVA) suits and Lunar habitat are currently being developed. Crews returning to the lunar surface will construct the lunar habitat and conduct scientific research. Inherent in aggressive surface activities is the potential risk of injury to crewmembers. Physiological responses to and the operational environment of short forays during the Apollo lunar missions were studied and documented. Little is known about the operational environment in which crews will live and work and the hardware that will be used for long-duration lunar surface operations.Additional information is needed regarding productivity and the events that affect crew function such as a compressed timeline. The Space Medicine Division at the NASA Johnson Space Center (JSC) requested a study in December 2005 to identify Apollo mission issues relevant to medical operations that had impact to crew health and/or performance. The operationally oriented goals of this project were to develop or modify medical requirements for new exploration vehicles and habitats, create a centralized database for future access, and share relevant Apollo information with the multiple entities at NASA and abroad participating in the exploration effort.

Scheuring, Richard A.↗
NASA NTRS2007

The Apollo Medical Operations Project: Recommendations to Improve Crew Health and Performance for Future Exploration Missions and Lunar Surface Operations

Medical requirements for the future Crew Exploration Vehicle (CEV), Lunar Surface Access Module (LSAM), advanced Extravehicular Activity (EVA) suits and Lunar habitat are currently being developed. Crews returning to the lunar surface will construct the lunar habitat and conduct scientific research. Inherent in aggressive surface activities is the potential risk of injury to crewmembers. Physiological responses and the operational environment for short forays during the Apollo lunar missions were studied and documented. Little is known about the operational environment in which crews will live and work and the hardware will be used for long-duration lunar surface operations. Additional information is needed regarding productivity and the events that affect crew function such as a compressed timeline. The Space Medicine Division at the NASA Johnson Space Center (JSC) requested a study in December 2005 to identify Apollo mission issues relevant to medical operations that had impact to crew health and/or performance. The operationally oriented goals of this project were to develop or modify medical requirements for new exploration vehicles and habitats, create a centralized database for future access, and share relevant Apollo information with the multiple entities at NASA and abroad participating in the exploration effort.

Scheuring, Richard A.↗
NASA NTRS2015

Telerobotic Perception During Asteroid and Mars Regolith Operations Project

Current space telerobotic systems are constrained to only operating in bright light and dust-free conditions. This project will study the effects of difficult lighting and dust conditions on telerobotic perception systems to better assess and refine regolith operations on other neighboring celestial bodies. In partnership with Embry-Riddle Aeronautical University and Caterpillar, Inc., optical, LiDAR and RADAR sensing equipment will be used in performing the study. This project will create a known dust environment in the Swamp Works Granular Mechanics & Regolith Operations (GMRO) Laboratory regolith test bin to characterize the behavior of the sensing equipment in various calibrated lighting and dust conditions. It will also identify potential methods for mitigating the impacts of these undesirable conditions on the performance of the sensing equipment. Enhancing the capability of telerobotic perception systems will help improve life on earth for those working in dangerous, dusty mining conditions, as well as help advance the same technologies used for safer self-driving automobiles in various lighting and weather conditions. It will also prove to be a critical skill needed for advancing robotic and human exploration throughout our solar system, for activities such as mining on an asteroid or pioneering the first colony on Mars.

Technology Portfolio System↗
NASA NTRS1999

The Ceres S'Cool Project: Operational but not Routine

The first Clouds and the Earth's Radiant Energy System (CERES) instrument has been returning useful data on Earth's radiation budget from the Tropical Rainfall Measuring Mission (TRMM) spacecraft since late 1997. Validation of the initial data is now intensively underway. As one component of this validation, the CERES Students' Cloud Observations On-Line (S'COOL) project has been operational since April 1998 - the 2nd CERES validation month. S'COOL involves school children in over 140 schools in 15 countries on 5 continents in making and reporting observations and measurements which they and CERES scientists can then compare to the satellite retrievals. The project is planned to continue through the life of the CERES Project (nominally 15 years), and new participants are invited to join on a continuous basis. This paper will report on the first year of the operational phase of the project, during which a number of exciting events occurred (a demonstration of the project to First Lady Hillary Rodham Clinton, and visits by CERES personnel to participating schools, among others). It will further report on some of the noteworthy observations and comparisons which have been made possible by this project. We have found that schools are often located in interesting places, in terms of the clouds found there and the satellite's ability to observe these clouds. The paper will also report on the learning opportunities delivered by this project, and on new questions about the planet and its climate which arise in the students' minds as a result of their active participation.

Chambers, Lin H.↗
NASA NTRS1999

The CERES S'COOL Project: Operational but not Routine

The first Clouds and the Earth's Radiant Energy System (CERES) instrument has been returning useful data on Earth's radiation budget from the Tropical Rainfall Measuring Mission (TRMM) spacecraft since late 1997. Validation of the initial data is now intensively underway. As one component of this validation, the CERES Students Cloud Observations On-Line (S'COOL) project has been operational since April 1998 - the 2nd CERES validation month. S'COOL involves school children in over 140 schools in 15 countries on 5 continents in making and reporting observations and measurements which they and CERES scientists can then compare to the satellite retrievals. The project is planned to continue through the life of the CERES Project (nominally 15 years), and new participants are invited to join on a continuous basis. This paper will report on the first year of the operational phase of the project, during which a number of exciting events occurred (a demonstration of the project to First Lady Hillary Rodham Clinton, and visits by CERES personnel to participating schools, among others). It will further report on some of the noteworthy observations and comparisons which have been made possible by this project. We have found that schools are often located in interesting places, in terms of the clouds found there and the satellite's ability to observe these clouds. The paper will also report on the learning opportunities delivered by this project, and on new questions about the planet and its climate which arise in the students minds as a result of their active participation.

Chambers, Lin H.↗