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NASA NTRS1992

Evolution of luminous IRAS sources - Radio imaging

Observations of the compact radio morphology of 111 luminous IRAS-selected active galaxies covering a wide range of IR and optical properties are presented and discussed. Of these sources, 72 are observed for the first time with the VLA A configuration. The circumnuclear radio sources are generally small and weak, with 15 nondetections to a limit of about 0.4 mJy. Comparison with the IR and optical properties of the objects indicates that the radio sources turn on within 10 exp 8 yr of the tidal encounter that is presumed to generate the IR activity. However, the radio sources do not all appear at the same time. The radio observations are consistent with the evolution scenario for luminous IRAS galaxies suggested by Hutchings and Neff (1991).

Neff, S. G.↗
NASA NTRS1992

Distribution of tropospheric ozone in the tropics from satellite and ozonesonde measurements

Measurements from two independent satellite data sets have been used to derive the climatology of the integrated amount of ozone in the troposphere. These data have led to the finding that large amounts of ozone pollution are generated by anthropogenic activity originating from both the industrialized regions of the Northern Hemisphere and from the southern tropical regions of Africa. To verify the existence of this ozone anomaly over this region of the world, an ozonesonde capability has been established at Ascension Island, located downwind of the primary source region of this ozone pollution, which likely results from the photochemical oxidation of emissions emanating from the widespread burning of savanna. These first ozonesonde profiles suggest that much of the ozone generated over Africa during the 'burning season' (primarily July-October) reaches Ascension Island. These high levels of ozone in the lower troposphere become much lower by December. Elevated ozone concentrations in the middle troposphere are once again evident in February, which may be the result of biomass burning emissions being transported from western and northern Africa.

Fishman, J.↗
NASA NTRS1984

Investigation of arc cloud lines

The natural mechanisms that lead to the development of deep convective storms through the integration of radio scan satellite data with research aircraft observations is discussed. The aircraft measurements are designed to provide detailed air motion and thermodynamic data near and in the arc cloud line region at the same time GOES rapid scan data is taken. Inspection of the data indicates: (1) Arc cloud lines are important in both the production of convergence and vorticity, and in the interaction with intense thunderstorms which may act to trigger tornado activity. (2) The lateral extent of the vertical motion field compared to the cloud scale indicates that the main driving force for the initial cloud development along the arc-line is controlled by the thunderstorm outflow(s) interacting with the convectively unstable air of the environment. (3) Arc cloud lines and their associated DSL region can pose extreme hazards to aircraft operations. (4) An arc cloud line's major threat to space shuttle operations lie in its ability to generate new thunderstorm activity along the shuttle glide path.

Purdom, J. F. W.↗
NASA NTRS2020

Blackbird: Object-Oriented Planning, Simulation, and Sequencing Framework Used by Multiple Missions

Every JPL flight mission relies on activity planningand sequence generation software to perform operations. Mostsuch tools in use at JPL and elsewhere use attribute-basedschemas or domain-specific languages (DSLs) to defineactivities. This reliance poses user training, softwaremaintenance, performance, and other challenges. To solve thisproblem for future missions, a new software called Blackbirdwas developed which allows engineers to specify behavior instandard Java. The new code base has over an order ofmagnitude fewer lines of code than other JPL planningsoftware, since no DSL or schema interpreter is needed. Theuse of Java for defining activities also allows mission adaptersto debug their code in an integrated development environment,seamlessly call external libraries, and set up truly multimissionmodels. These efficiency gains have significantlyreduced the amount of development effort required to supportthe software. This paper discusses Blackbird’s design,principles, and use cases.

Rothstein-Dowden, Ansel↗
NASA NTRS2022

Plasma Activated Water for Crewed Transit and Planetary Habitation: A Study of Gas Type, Electrode Material, and Power Supply Selection and the Impact on the Final Frontier - FY21 CIF

An in-depth study of plasma activated water (PAW) generation was conducted to link changes in power supply, electrode material, input gas, and treatment time to the resulting reaction chemistry. These changes in chemistry can help tailor PAW for different space applications. An AC, DC, and nanosecond (ns) pulsed power supply were each used to generate PAW with stainless steel, copper, tungsten, or platinum (Pt) electrodes while utilizing air, nitrogen (N2), carbon dioxide (CO2), helium (He), or argon (Ar) as the feed gas. Tap or deionized (DI) water was treated for 1 to 15 minutes, and the generated PAW was tested for changes in pH, conductivity, oxidation reduction potential, nitrates (NO3-), ammonium (NH4+), and peroxide. Calculations showed that the production of reactive nitrogen species was the leading cause of pH and conductivity changes. The DC generated air plasma was able to reduce the pH of DI water and generate NO3‑. The pulsed supply, operating at 20% of the input power of the DC supply, lowered the pH generated NO3‑. When a simulated Martian gas mixture of 95% CO2 and 5% N2 was used as the feed gas, NO3‑ was generated with the DC and pulsed supplies, respectively. Mixing PAW with plasma generated ash from inedible biomass allowed pH control, thus enhancing PAW’s potential use for sanitation applications. The large shift in pH was used to study sanitation effects of Escherichia coli (E. coli) reduction and Staphylococcus aureus (S. aureus), in which log reductions were found to be negligible. Additionally, the plasma generated ash in combination with PAW was also implemented in 10-day microgreen growth trials, in which PAW and ash resulted in quicker emergence of the microgreens compared to the standard growth conditions and comparable dry masses to Hoagland’s nutrient solution treated samples.

plasma activated water (PAW)↗
NASA NTRS1992

A status of the activities of the NASA/MSFC pump stage technology team

The Consortium for Computational Fluid Dynamics (CFD) Application in Propulsion Technology was established to aid the transfer of CFD related advancements among academia, government agencies, and industry. The specific goals of the Consortium are to develop CFD methodologies necessary to solve propulsion problems, to validate these methodologies, and to apply these methodologies in the design process. To accomplish these goals, a team of experts in various related fields was formed, a schedule of activities necessary to meet the goals was generated, and funding for the activities was obtained from NASA. During the past year (Mar. 1991 - Mar. 1992) the team's activities have focused on preliminary code validation and on the design of an advanced impeller. Six codes were used to calculate the flow in a Rocketdyne 0.3 flow coefficient inducer, and the results were compared to L2F data available for the inducer. This activity identified shortcomings in the experimental data sets and in the analytical solutions which must be surmounted in any future team activity. The design of the advanced impeller relied heavily on CFD results to obtain an optimized geometry. The optimized geometry was analyzed using four different codes, at design and off-design conditions. Activities for the next year include the optimization of a tandem blade impeller design, benchmark of CFD codes for diffuser and volute flows, the collection of L2F data for 'state-of-the-art' impeller and inducer, and the verification of the advanced pump team impeller design in a water rig.

Garcia, R.↗
NASA NTRS2009

21st Century Extravehicular Activities: Synergizing Past and Present Training Methods for Future Spacewalking Success

Neil Armstrong's understated words, "That's one small step for man, one giant leap for mankind." were spoken from Tranquility Base forty years ago. Even today, those words resonate in the ears of millions, including many who had yet to be born when man first landed on the surface of the moon. By their very nature, and in the the spirit of exploration, extravehicular activities (EVAs) have generated much excitement throughout the history of manned spaceflight. From Ed White's first space walk in June of 1965, to the first steps on the moon in 1969, to the expected completion of the International Space Station (ISS), the ability to exist, live and work in the vacuum of space has stood as a beacon of what is possible. It was NASA's first spacewalk that taught engineers on the ground the valuable lesson that successful spacewalking requires a unique set of learned skills. That lesson sparked extensive efforts to develop and define the training requirements necessary to ensure success. As focus shifted from orbital activities to lunar surface activities, the required skill-set and subsequently the training methods, changed. The requirements duly changed again when NASA left the moon for the last time in 1972 and have continued to evolve through the Skylab, Space Shuttle; and ISS eras. Yet because the visits to the moon were so long ago, NASA's expertise in the realm of extra-terrestrial EVAs has diminished. As manned spaceflight again shifts its focus beyond low earth orbit, EVA success will depend on the ability to synergize the knowledge gained over 40+ years of spacewalking to create a training method that allows a single crewmember to perform equally well, whether performing an EVA on the surface of the Moon, while in the vacuum of space, or heading for a rendezvous with Mars. This paper reviews NASA's past and present EVA training methods and extrapolates techniques from both to construct the basis for future EVA astronaut training.

Moore, Sandra K.↗
NASA NTRS1985

Electrical measurements in the atmosphere and the ionosphere over an active thunderstorm. I - Campaign overview and initial ionospheric results

The first simultaneous electric field observations performed in the ionosphere and atmosphere over an active nighttime thunderstorm are reported here. In the stratosphere, typical storm-related dc electric fields were detected from a horizontal distance of about 100 km, and transient electric fields due to lightning were measured at several different altitudes. In the ionosphere and mesosphere, lightning-induced transient electric fields in the range of tens of millivolts per meter were detected with rise times at least as fast as 0.2 ms and typical duration of 10-20 ms. The transients had significant components parallel to the magnetic field at 150 km altitude. This implies that either considerable Joule heating occurs or a collective instability is present because of the high drift velocities induced by the transient electric fields. Copious numbers of whistlers were generated by the storm and were detected above but not below the base of the ionosphere. The outline of a new model for direct whistler wave generation over an active thunderstorm is presented based on these observations. The intensity of the observed two-hop whistlers implies that they were amplified along their propagation path and suggests that particles were precipitated in both hemispheres.

Kelley, M. C.↗
NASA NTRS2011

Comment on "An Analysis of VLF Electric Field Spectra Measured in Titan's Atmosphere by The Huygens Probe" By J. A. Morente et al.

Morente et al. have recently revisited the VLF electric field measurements made with the Permittivity, Wave and Altimetry (PWA) instrument during the descent of the Huygens Probe through the atmosphere of Titan. They assert that they have identified several harmonics of the transverse resonance mode of the surface?]ionosphere cavity, which would prove the existence of an electrical activity in the atmosphere of the largest satellite of Saturn. We refute this finding on the basis that it results from an artifact due to an improper analysis of the data set. [2] The investigators of the Permittivity, Wave and Altimetry (PWA) experiment on the Huygens Probe have reported the extremely low frequency (ELF) and very low frequency (VLF) electric signals recorded during the descent through the atmosphere of Titan. The PWA data are archived in the Planetary Science Archive (PSA) of ESA, and an extensive description of the instrument is at the disposal of the scientific community. Morente and his coworkers have revisited this data set and reported the results of their investigations in two papers. In a first paper, they claim that they have detected in the ELF range (0.100 Hz) several harmonics of a global resonance allegedly generated by lightning activity in the spherical cavity guide formed by the surface of Titan and the inner boundary of the ionosphere, a phenomenon similar to the Schumann resonance observed at EartH In the second paper dedicated to the VLF electric signal recorded by PWA, in the range 0.10 kHz, they argue that they can also bring out the transverse resonance and its harmonics, a more local phenomenon that develops around the excitation source and whose frequency is controlled by the separation between Titan?fs surface and the inner ionospheric boundary. [3] The PWA investigators have analyzed the narrowband ELF signal at about 36 Hz effectively observed during the entire descent. They have not endorsed, however, the alternative approach of Morente et al. that discloses additional ELF narrow-band signals and numerous related harmonics. Hamelin et al. and Beghin et al. have questioned the work of Morente and his coworkers and demonstrated unambiguously that their findings are mere artifacts entirely due to a faulty procedure. Morente et al. refuted this critical analysis of their ELF paper in a rebuttal. The present comment draws a parallelism between the ELF and VLF papers and demonstrates that the VLF signal carries no evidence whatever of any transverse resonance. The analyses of the ELF and VLF signals by Morente and his coworkers are flawed, and their conclusions are shown here to be invalid. A more comprehensive and thorough assessment of the numerical approaches proposed by Morente et al. is given by Berthelin et al..

Grard, Rejean↗
NASA NTRS1988

Optically reconfigured active phased array antennas

Future generations of phased array antennas for space-based and airborne platforms are designed based on a large number of active T/R modules. The constructed radiating beam is degraded in the event of modules failure. Simulation results indicate that the control of frequency, interelement spacing, and the individual radiating element pattern alongside the more conventional technique of amplitude and phase can be used to reconfigure the desired radiating beam in the event of the active T/R module failure.

Daryoush, A. S.↗
NASA NTRS2000

Aerospace Safety Advisory Panel Annual Report for 1999

This report covers the activities of the Aerospace Safety Advisory Panel (ASAP) for the calendar year 1999.This was a year of notable achievements and significant frustrations. Both the Space Shuttle and International Space Station (ISS) programs were delayed.The Space Shuttle prudently postponed launches after the occurrence of a wiring short during ascent of the STS-93 mission. The ISS construction schedule slipped as a result of the Space Shuttle delays and problems the Russians experienced in readying the Service Module and its launch vehicle. Each of these setbacks was dealt with in a constructive way. The STS-93 short circuit led to detailed wiring inspections and repairs on all four orbiters as well as analysis of other key subsystems for similar types of hidden damage. The ISS launch delays afforded time for further testing, training, development, and contingency planning. The safety consciousness of the NASA and contractor workforces, from hands-on labor to top management, continues high. Nevertheless, workforce issues remain among the most serious safety concerns of the Panel. Cutbacks and reorganizations over the past several years have resulted in problems related to workforce size, critical skills, and the extent of on-the-job experience. These problems have the potential to impact safety as the Space Shuttle launch rate increases to meet the demands of the ISS and its other customers. As with last year's report, these work- force-related issues were considered of sufficient import to place them first in the material that follows. Some of the same issues of concern for the Space Shuttle and ISS arose in a review of the launch vehicle for the Terra mission that the Panel was asked by NASA to undertake. Other areas the Panel was requested to assess included the readiness of the Inertial Upper Stage for the deployment of the Chandra X-ray Observatory and the possible safety impact of electromagnetic effects on the Space Shuttle. The findings and recommendations in this report do not highlight any major, immediate issues that might compromise the safe pursuit of the various NASA programs. They do, however, cover concerns that the Panel believes should be addressed in the interest of maintaining NASA's excellent safety record.The Panel is pleased to note that remedial efforts for some of the findings raised are underway. Given appropriate funding and cooperative efforts among the Administration, the Congress and the various contractors, the Panel is convinced that safety problems can be avoided or solved resulting in lower risk for NASA's human space and aeronautics programs. Section II of this report contains specific findings and recommendations generated by Panel activities during the calendar year 1999. Section III presents more detailed information in support of these findings and recommendations. A current roster of Panel members, consultants, and staff is included as Appendix A. Appendix B contains NASA's response to the findings and recommendations from the 1998 annual report. It has been augmented this year to include brief explanations of why the Panel classified the NASA response as " open,""continuing," or "closed." Appendix C lists the fact-finding activities of the Panel in 1999.

Blomberg, Richard D.↗
NASA NTRS1999

Aerospace Safety Advisory Panel

This report covers the activities of the Aerospace Safety Advisory Panel (ASAP) for calendar year 1998-a year of sharp contrasts and significant successes at NASA. The year opened with the announcement of large workforce cutbacks. The slip in the schedule for launching the International Space Station (ISS) created a five-month hiatus in Space Shuttle launches. This slack period ended with the successful and highly publicized launch of the STS-95 mission. As the year closed, ISS assembly began with the successful orbiting and joining of the Functional Cargo Block (FGB), Zarya, from Russia and the Unity Node from the United States. Throughout the year, the Panel maintained its scrutiny of NASA's safety processes. Of particular interest were the potential effects on safety of workforce reductions and the continued transition of functions to the Space Flight Operations Contractor. Attention was also given to the risk management plans of the Aero-Space Technology programs, including the X-33, X-34, and X-38. Overall, the Panel concluded that safety is well served for the present. The picture is not as clear for the future. Cutbacks have limited the depth of talent available. In many cases, technical specialties are 'one deep.' The extended hiring freeze has resulted in an older workforce that will inevitably suffer significant departures from retirements in the near future. The resulting 'brain drain' could represent a future safety risk unless appropriate succession planning is started expeditiously. This and other topics are covered in the section addressing workforce. The major NASA programs are also limited in their ability to plan property for the future. This is of particular concern for the Space Shuttle and ISS because these programs are scheduled to operate well into the next century. In the case of the Space Shuttle, beneficial and mandatory safety and operational upgrades are being delayed because of a lack of sufficient present funding. Likewise, the ISS has little flexibility to begin long lead-time items for upgrades or contingency planning. For example, the section on computer hardware and software contains specific findings related to required longer range safety-related actions. NASA can be proud of its accomplishments this past year, but must remain ever vigilant, particularly as ISS assembly begins to accelerate. The Panel will continue to focus on both the short- and long-term aspects of risk management and safety planning. This task continues to be made manageable and productive by the excellent cooperation the Panel receives from both NASA and its contractors. Particular emphasis will continue to be directed to longer term workforce and program planning issues as well as the immediate risks associated with ISS assembly and the initial flights of the X-33 and X-34. Section 2 of this report presents specific findings and recommendations generated by ASAP activities during 1998. Section 3 contains more detailed information in support of these findings and recommendations. Appendix A is a current roster of Panel members, consultants, and staff. Appendix B contains NASA's response to the findings and recommendations from the 1997 ASAP Annual Report. Appendix C details the fact-finding activities of the Panel in 1998. During the year, Mr. Richard D. Blomberg was elected chair of the Panel and Vice Admiral (VADM) Robert F Dunn was elected deputy chair. VADM Bernard M. Kauderer moved from consultant to member. Mr. Charles J. Donlan retired from the Panel after many years of meritorious service. Ms. Shirley C. McCarty and Mr. Robert L. ('Hoot') Gibson joined the Panel as consultants.

Source record↗
NASA NTRS1974

Development and correlation: Viking Orbiter analytical dynamic model with modal test

The Viking Orbiter (VO) experience in the achievement of a mathematical model is described along with the following project activities: (1) the generation of the overall plan for load analysis, an analytical dynamic model, and development tests; (2) the performance of VO subsystem static and modal tests; and (3) the correlation of the VO system model analysis and test. Success is attributed to the coordination of analysis and test using substructure modal coupling techniques.

Wada, B. K.↗
NASA NTRS1979

The atmospheric electric global circuit

The hypothesis that world thunderstorm activity represents the generator for the atmospheric electric current flow in the earth atmosphere between ground and the ionosphere is based on a close correlation between the magnitude and the diurnal variation of the supply current (thunderstorm generator current) and the load current (fair weather air-earth current density integrated over the earth surface). The advantages of using lightning survey satellites to furnish a base for accepting or rejecting the thunderstorm generator hypothesis are discussed.

Kasemir, H. W.↗
NASA NTRS1980

Materials processing in space: Future technology trends

NASA's materials processing in space- (MPS) program involves both ground and space-based research and looks to frequent and cost effective access to the space environment for necessary progress. The first generation payloads for research are under active design and development. They will be hosted by the Space Shuttle/Spacelab on Earth orbital flights in the early 1980's. hese missions will focus on the acquisition of materials behavior research data, the potential enhancement of Earth based technology, and the implementation of space based processing for specialized, high value materials. Some materials to be studied in these payloads may provide future breakthroughs for stronger alloys, ultrapure glasses, superior electronic components, and new or better chemicals. An operational 25 kW power system is expected to be operational to support sustained, systematic space processing activity beyond shuttle capability for second generation payload systems for SPACELAB and free flyer missions to study solidification and crystal growth and to process metal/alloys, glasses/ceramics, and chemicals and biologicals.

Barter, N. J.↗
NASA NTRS1981

Timeline Resource Analysis Program (TRAP): User's manual and program document

The Timeline Resource Analysis Program (TRAP), developed for scheduling and timelining problems, is described. Given an activity network, TRAP generates timeline plots, resource histograms, and tabular summaries of the network, schedules, and resource levels. It is written in ANSI FORTRAN for the Honeywell SIGMA 5 computer and operates in the interactive mode using the TEKTRONIX 4014-1 graphics terminal. The input network file may be a standard SIGMA 5 file or one generated using the Interactive Graphics Design System. The timeline plots can be displayed in two orderings: according to the sequence in which the tasks were read on input, and a waterfall sequence in which the tasks are ordered by start time. The input order is especially meaningful when the network consists of several interacting subnetworks. The waterfall sequence is helpful in assessing the project status at any point in time.

Sessler, J. G.↗
NASA NTRS1982

Stratospheric CCN sampling program

Two one liter grab samples of stratospheric aerosol were returned from each of six U-2 sampling missions. Cloud condensation nuclei (CCN) spectra from each sample were obtained. Interest was centered on the effects of volcanic activity. Spurious particle generation was found to be a serious problem in container 9 LFT and a much smaller problem in container 9 RT. Initial studies of an option for improved sample containers and values were completed. A CCN spectrometer, able to operate at an internal pressure of 300 mb, was designed.

Rogers, C. F.↗