Results for “SOP” — Page 4

NASA NTRS2008

Design and Testing of a Variable Pressure Regulator for the Constellation Space Suit

The next generation space suit requires additional capabilities for controlling and adjusting internal pressure than previous design suits. Next generation suit pressures will range from slight pressure, for astronaut prebreath comfort, to hyperbaric pressure levels for emergency medical treatment. Carleton was awarded a contract in 2008 to design and build a proof of concept bench top demonstrator regulator having five setpoints which are selectable using input electronic signaling. Although the basic regulator architecture is very similar to the existing SOP regulator used in the current EMU, the major difference is the electrical selectivity of multiple setpoints rather than the mechanical On/Off feature found on the SOP regulator. The concept regulator employs a linear actuator stepper motor combination to provide variable compression to a custom design main regulator spring. This concept allows for a continuously adjustable outlet pressures from 8.2 psid (maximum) down to "firm" zero thus effectively allowing it to serve as a shutoff valve. This paper details the regulator design and presents test results on regulation band width, command set point accuracy; slue rate and regulation stability, particularly when the set point is being slued. Projections for a flight configuration version are also offered for performance, architectural layout and weight.

Gill, Larry↗

NASA NTRS2014

Design and Development of Aerogel-Based Antennas for Aerospace Applications: A Final Report to the NARI Seedling

As highly porous solids possessing low density and low dielectric permittivity combined with good mechanical properties, polyimide (PI) aerogels offer great promise as an enabling technology for lightweight aircraft antenna systems. While they have been aggressively explored for thermal insulation, barely any effort has been made to leverage these materials for antennas or other applications that take advantage of their aforementioned attributes. In Phase I of the NARI Seedling Project, we fabricated PI aerogels with properties tailored to enable new antenna concepts with performance characteristics (wide bandwidth and high gain) and material properties (low density, environmental stability, and robustness) superior to the state of practice (SOP). We characterized electromagnetic properties, including permittivity, reflectivity, and propagation losses for the aerogels. Simple, prototype planar printed circuit patch antennas from down-selected aerogel formulations were fabricated by molding the aerogels to net shapes and by gold-metalizing the pattern onto the templates via electron beam evaporation in a clean room environment. These aerogel based antennas were benchmarked against current antenna SOP, and exhibited both broader bandwidth and comparable or higher gain performance at appreciably lower mass. Phase II focused on the success of the Phase I results pushing the PI aerogel based antenna technology further by exploring alternative antenna design (i.e., slot coupled antennas) and by examining other techniques for fabricating the antennas including ink jet printing with the goal of optimizing antenna performance and simplifying production. We also examined new aerogel formulations with better moisture and solvent resistance to survive processing conditions. In addition, we investigated more complex antenna designs including passive phased arrays such as 2x4 and 4x8 element arrays to assess the scalability of the aerogel antenna concept. Furthermore, we explored the possibility of developing these arrays in thin, flexible form to make conformable antennas.

insulation↗

NASA NTRS2016

The IOAG Recommendations on Spacecraft Emergency Cross Support

In 2014, the Inter-agency Operations Advisory Group (IOAG) chartered a multi-agency team effort to study how to best handle spacecraft emergency as part of cross support among network assets. The original intent is to put in place for the first time a process and guidelines to make emergency support as part of a permanent cross-support capability between space agencies. From the perspective of space communications service providers, a few key issues, common to all agencies, concerning the Spacecraft Emergency Cross Support (SECS) have been explored. They are: context of emergency support, provision of emergency support under a cross-support agreement, provision of emergency support with no cross-support agreement, legal and liability issues, response time, support priority, services provided, sustaining emergency support capabilities, and charge for the support. The positions of the various participating agencies with respect to these issues have been collected, analyzed, and finally harmonized to form the recommended IOAG positions. A central challenge most communications service providers are facing is that since the spacecraft emergency is an unplanned critical event, it typically requires fast response to the emergency call, hence lacking an international standard process for the operational interfaces seems to exacerbate the difficulty in providing SECS. For reducing the response time, i.e. from the time of accepting a request for SECS to the readiness for support, it is recommended that a “cross-support emergency system” be established by IOAG member agencies. Along with it, the IOAG core services, just-in-time ground communications line, cross support service management (CSSM), and standard operations procedures (SOP) for operational interfaces form the basic foundation of the “cross support emergency system”. Of the above, new to the cross support conducted thus far in the IOAG community is the concept of the SOP specifically for the interfaces between the service provider and service user during the SECS. Use cases, salient features, and definition of the key operational activities/tasks relevant to the interfaces are addressed by the effort. Underpinning such a system is the availability of the RF license granted by the local authority, at national and/or regional level, for a given ground station to communicate with and track the spacecraft in emergency mode at the uplink and downlink frequencies assigned to that spacecraft. That means it is critical for the IOAG member agencies to obtain a priori all-band licenses (for the entire X-band or S-band) for some, if not all, of their ground stations that are most capable of or likely to provide SECS. It is also recommended that certain prior arrangements be made with the relevant local licensing authorities for a process that will allow expedited authorization to transmit/receive signals to/from the declared spacecraft over the declared ground stations specifically and solely for the emergency case. Our analysis of the SECS has also uncovered a few fundamental programmatic issues. Recognizing any IOAG positions reached on these issues do not necessarily lead to any binding authority, it is recommended that they, along with those key attributes of the cross support emergency system, be explicitly stated as multi-agency guidelines to guide the implementation and provision of the SECS. The paper will present the results of the working group on Spacecraft Emergency Cross Support and, in particular, its findings, products and recommendations. It will also identify the next steps of this work that may include the production of some international standards as an extension of this work, or the process to make this emergency system usable by other spacecraft operators beyond the space agencies.

Tai, Wallace S.↗

NASA NTRS2016

The IOAG Recommendations on Spacecraft Emergency Cross Support

In 2014, the Inter-agency Operations Advisory Group (IOAG) chartered a multi-agency team effort to study how to best handle spacecraft emergency as part of cross support among network assets. The original intent is to put in place for the first time a process and guidelines to make emergency support as part of a permanent cross-support capability between space agencies. From the perspective of space communications service providers, a few key issues, common to all agencies, concerning the Spacecraft Emergency Cross Support (SECS) have been explored. They are: context of emergency support, provision of emergency support under a cross-support agreement, provision of emergency support with no cross-support agreement, legal and liability issues, response time, support priority, services provided, sustaining emergency support capabilities, and charge for the support. The positions of the various participating agencies with respect to these issues have been collected, analyzed, and finally harmonized to form the recommended IOAG positions. A central challenge most communications service providers are facing is that since the spacecraft emergency is an unplanned critical event, it typically requires fast response to the emergency call, hence lacking an international standard process for the operational interfaces seems to exacerbate the difficulty in providing SECS. For reducing the response time, i.e. from the time of accepting a request for SECS to the readiness for support, it is recommended that a “cross-support emergency system” be established by IOAG member agencies. Along with it, the IOAG core services, just-in-time ground communications line, cross support service management (CSSM), and standard operations procedures (SOP) for operational interfaces form the basic foundation of the “cross support emergency system”. Of the above, new to the cross support conducted thus far in the IOAG community is the concept of the SOP specifically for the interfaces between the service provider and service user during the SECS. Use cases, salient features, and definition of the key operational activities/tasks relevant to the interfaces are addressed by the effort. Underpinning such a system is the availability of the RF license granted by the local authority, at national and/or regional level, for a given ground station to communicate with and track the spacecraft in emergency mode at the uplink and downlink frequencies assigned to that spacecraft. That means it is critical for the IOAG member agencies to obtain a priori all-band licenses (for the entire X-band or S-band) for some, if not all, of their ground stations that are most capable of or likely to provide SECS. It is also recommended that certain prior arrangements be made with the relevant local licensing authorities for a process that will allow expedited authorization to transmit/receive signals to/from the declared spacecraft over the declared ground stations specifically and solely for the emergency case. Our analysis of the SECS has also uncovered a few fundamental programmatic issues. Recognizing any IOAG positions reached on these issues do not necessarily lead to any binding authority, it is recommended that they, along with those key attributes of the cross support emergency system, be explicitly stated as multi-agency guidelines to guide the implementation and provision of the SECS. The paper will present the results of the working group on Spacecraft Emergency Cross Support and, in particular, its findings, products and recommendations. It will also identify the next steps of this work that may include the production of some international standards as an extension of this work, or the process to make this emergency system usable by other spacecraft operators beyond the space agencies.

Tai, Wallace S.↗

NASA NTRS2023

Safety Case for Small Uncrewed Aircraft Systems (sUAS) Beyond Visual Line of Sight (BVLOS) Operations at NASA Langley Research Center

This Technical Memorandum (TM) is written to provide for dissemination of the methods and safety considerations for operations of small Uncrewed Aerial Systems (sUAS) Beyond Visual Line-of-Sight (BVLOS)at NASA Langley Research Center. It includes the Safety Case used to acquire a BVLOS Certificate of Authorization (COA) from the FAA and is being published to enable others to benefit from this work. The intended operations, subject to approval from the Federal Aviation Administration (FAA) and the National Aeronautics and Space Administration (NASA), will include a combination of Within Visual Line of Sight (WVLOS) and Beyond Visual Line of Sight (BVLOS) flights, comprising of at most five sUAS operating concurrently, with no more than three operating BVLOS. Flights will occur in a subset of the Langley Air Force Base (LAFB) Class D airspace (KLFI) at a maximum altitude of 400 ft AGL. Most operations within this subset will take place in the City Environment Range Testing for Autonomous Integrated Navigation (CERTAIN) Range. The CERTAIN Range includes airspace inside the borders of NASA Langley Research Center (LaRC). Additional airspace over the northern section of CERTAIN will be requested as part of the Certificate of Authorization (COA). NASA LaRC BVLOS operations on the CERTAIN Range can be broken down into five critical components needed to meet the 14 CFR § 91.113 see and avoid requirement: 1) procedural deconfliction with LAFB for UAS operations at or below 400 ft and manned aircraft at or above 900’ AGL; 2) ground equipment for detection of intruder aircraft and to support communications between crewmembers ; 3) sUAS vehicles with advanced onboard automation capable of autonomously maintaining safe separation; 4) BVLOS standardized operating procedures (SOPs); 5) and personnel to execute the flight operations in accordance with the SOPs and respond to airborne contingencies. The introduction of new ground equipment includes the use of the Remote Operations for Autonomous Missions (ROAM) UAS Operations Center, development and use of an Integrated Airspace Display (IAD), use of the L-STAR and GA-9120 radars, and the incorporation of standardized Vertiports. The ROAM Operations Center will be the central point for all BVLOS sUAS operations. All command and control (C2), voice communications and airspace awareness displays will reside inside ROAM. The IAD will provide raw data from ADS-B, FLARM, radar tracks and telemetered GPS vehicle positions for interpretation by an Airspace Monitor. The radars will search the class D airspace around the CERTAIN Range and serve as a backup to procedural deconfliction procedures coordinated with LAFB. In the event of a procedural deconfliction breakdown, radar detections of non-participating aircraft will be available so that the 91.113 see and avoid requirement can still be safely met. Finally, the incorporation of Vertiports will have video and network connectivity that enables large numbers of sUAS launches and recoveries from a single location. This is a continuation of the remote command and control of unpiloted aircraft component focused on evaluating unpiloted aircraft flight crew roles and responsibilities, control interfaces and the associated data links needed to operate a fleet of aircraft within a UAM Ecosystem. This work supports the development of future aviation operational concepts based on an Urban Air Mobility Maturity Level (UML) 4 environment (Patterson, 2020). It is assumed that future airspace will include hundreds of simultaneous aircraft operations within the airspace, therefore scalable operations are essential for enabling this future airspace to become a reality. Follow on work includes envisioned flights that expand operations beyond the CERTAIN range and lead to an effective Maritime Surveillance capability.

Matthew W Coldsnow↗

NASA NTRS1983

Experiments using atmospheric forcing from a FGGE analysis to drive an upper ocean model

Results are presented of a series of numerical experiments in which an upper ocean model is driven by surface heat fluxes and stress fields derived from the FGGE SOP-1 GLAS analysis/forecast system (Halem, et al., 1982). The model results show that most changes in the mixed layer height and horizontal velocity occurs in the first days. On the other hand, changes in the temperature field take a longer time to develop. In the most realistic case (real initial conditions, instantaneous forcing fields from the atmospheric analysis), the resulting changes in temperature were larger than observed and the correlation between observed and predicted changes was poor. The deficiency in the forecast of SST changes may be due to several factors: lack of sufficient ocean resolution, improper initialization, lack of feedback between the ocean and the atmosphere and the absence of transports by the strong boundary currents, and perhaps unrealistic surface fluxes of heat and momentum. Unless these problems are alleviated it is not reasonable to perform coupled atmospheric ocean forecasts.

Camerlengo, A.↗

NASA NTRS1982

Planetary-scale characteristics of the atmospheric circulation during January and February 1979

The global scale mass and wind fields observed during FGGE special observing period (SOP) are studied, with attention given to the time variation and vertical structure of the ultralong waves. A spherical harmonic representation is developed for the global fields. The tropical circulation is found to imprint more amplitude on the lower-order components than the midlatitude circulation does. High amplitude oscillations are determined to be present in the divergent fields on all time scales, i.e., diurnal to monthly. The global scale wind was found to change on scales approaching a week. Good agreement with teleconnection predictions was demonstrated for the cross-equatorial divergent and zonal rotational flow changes. The global scale was concluded to resemble force modes of linear tidal theory, with important contributions from longitudinal heating gradients.

Paegle, J.↗

NASA NTRS1984

Comparison of GLAS retrieved cloud fields with model generated rainfall fields

Monthly mean fractional cloud cover for January and February 1979, retrieved from SOP 1 of FGGE, are compared with the total precipitation field derived diagonally from the GLAS analysis/forecast system for the same time period. The breakdown of cloudiness into day (3 AM) and night (3 PM) is consistent with maps of outgoing long wave and short wave radiation inferred from AVHRR data. Of the many regions of coincidence, there is a particularly striking phenomenon: west of the coast of Peru, at about 20 deg S, there is a distinct small scale maximum in precipitation which coincides precisely with a maximum in the cloudiness field. This maximum in cloudiness and precipitation does not appear in the NOAA/NESS fields of albedo and outgoing long wave radiation which are normally sensitive to cloud fields. These low level clouds with warm tops are a mainly nocturnal phenomenon.

Susskind, J.↗

NASA NTRS1984

Forecast Impact of Components of the FGGE Observing System

Experiments have been conducted to assess the summer and winter forecast impact of the FGGE system, and of its main observing components: temperature sounding data derived from the TIROS-N polar orbiting satellite, cloud track winds determined from geostationary satellite observations and drifting buoy data which were collected by satellite during FGGE. The Analysis/Forecast System used has a number of improvements upon the system utilized by Halen et al. (1982) for the FGGE Special Observing Period-1 (SOP-1). Several modifications were made in the analysis scheme, the most important being the interpolation of the analysis minus 6 h forecast deviations rather than of the analyzed fields themselves. The forecast model is still the 4 deg lat, 5 deg lon and 9 vertical levels GLAS Fourth Order GCM with several minor corrections implemented in the physics and numerics. The improved vertical interpolation in the analysis resulted in better assimilation of rawinsonde data, which has more vertical structure than satellite data. As a result, there was an improvement of the forecasts derived from conventional data only, and, consequently, a small reduction of the positive impact of satellite data from that obtained by Halem et al. (1982).

Kalnay, E.↗

NASA NTRS1984

Global Scale Diagnosis of FGGE Data

The objective was to perform descriptive global-scale diagnoses of the Goddard Laboratory for Atmospheric Sciences (GLAS) First GARP Global Experiment (GLAS) SOP-1 analyses and to compare these diagnoses against controlled, real-data integrations of the GLAS General Circulation Model (GCM) as well as other data sets. The effects of critical latitudes, the diagnoses of the influence of tropical wind data and latent heating upon the GLAS GCM, investigations of planetary wave structure on various time scales from the diurnal to the monthly, and comparison of the GLAS analyses with other analyses are discussed.

Paegle, J.↗

NASA NTRS1985

Global scale diagnoses of FGGE data

Descriptive global scale diagnoses of the First Global Atmospheric Research Experiment SOP-1 analyses were made and compared against controlled, real data integrations of the Goddard Laboratory of Atmospheric Science (GLAS) general circulation model (GCM) as well as other data sets. The effects of critical latitudes were studied; the influence of tropical wind data and latent heating upon the GLAS GCM was diagnosed; planetary wave structure on various time scales from the diurnal to the monthly was studied; and the GLAS analyses were compared with other analyses. Short term controlled GLAS GCM integrations show that: (1) the inclusion of tropical wind data in real data integrations has an important influence in the mid-latitude prediction in both hemispheres; and (2) the tropical divergent wind reacts almost immediately to alteration of the tropical latent heating. The presence or absence of zonally averaged easterlies depends strongly upon the presence of tropical latent heating.

Paegle, J.↗

NASA NTRS1986

Vertical structure of the wind field during the Special Observing Period I of the Global Weather Experiment

The vertical structure of the global atmosphere is analyzed for selected periods of the Special Observing Period I (SOP-I) for the Global Weather Experiment (GWE). The analysis consists of projection of the stream-function and velocity potential at 200 and 850 mb on spherical harmonics and of the wind and height fields on the normal modes of a linearized form of the primitive equations for a basic state at rest. The kinematic vertical structure is discussed in terms of correlation coefficients of the 200 mb and 850 mb winds and analysis of the internal and external normal modes of the primitive equations. The reliability of the results is checked by applying the same analysis methods to data sets obtained from three different institutions: Geophysical Fluid Dynamics Laboratory (GFDL), European Center for Medium Range Weather Forecasting (ECMWF), and Goddard Laboratory for the Atmospheres (GLA). It is found that, on a global basis, vertically reversing circulations are as important as the equivalent barotropic structures. For the verticaly reversing components, the gravity and mixed Rossby-gravity modes have contributions of the same order of magnitude as those of the Rossby modes in tropical latitudes.

Paegle, J. N.↗

NASA NTRS1986

Moisture transports and budgets of 'moisture bursts'

The paper discusses moisture fluxes and budgets associated with a pair of 'moisture bursts' in the eastern North Pacific Ocean area, described by Smith et al. (1985). The moisture fluxes were calculated using data obtained during the first Special Observing Period (SOP-1) of the FGGE. The area specifically examined extended from the equator to the latitude 20 deg N and from longitude 180 deg to 100 deg W, with concentration on the region south and southeast of the Hawaiian Islands. From the comparison of the calculations based on dropwindsonde and radiosonde data and reports from commercial and military aircraft, it is concluded that the calculations of water vapor flow across latitude lines probably provide a fair representation of reality, especially when based on the dropwindsonde data. However, water vapor flow out of small volumes is not well represented by the results from either data.

Thompson, A. H.↗

NASA NTRS1987

Significance of the South Pacific Convergence Zone (SPCZ) in the energy budget of the Southern Hemisphere tropics

An in-depth investigation of the energetics, including boundary transports, was conducted on four equal-area regions in the tropical Southern Hemisphere during the SOP-1 period in 1979. The regions, each approximately centered on one of the wave axes of maximum warm rising air, include the SPCZ (115 deg W - 155 deg E) and the Australian (155-65 deg E), the African (65 deg E - 25 deg W), and the South American (25-115 deg W) regions. Daily variations of the energy conversions were examined, and time-averaged result of energy contents, conversions, and boundary transports were compiled for January 10-27. Results show that the eddy kinetic energy (KE) exceeds the eddy available potential energy (AE) in all four regions, with the largest excess being in the SPCZ. Of the conversion and flux terms, only the conversion of AE to KE is significant (again, with the greatest value in the SPCZ). An evaluation of boundary fluxes of KE indicates that the only significant transport between regions is a flow of KE from the SPCZ region into the South American region.

Hurrell, James W.↗

NASA NTRS1987

Spacelab Data Processing Facility (SLDPF) quality assurance expert systems development

The Spacelab Data Processing Facility (SLDPF) is an integral part of the Space Shuttle data network for missions that involve attached scientific payloads. Expert system prototypes were developed to aid in the performance of the quality assurance function of the Spacelab and/or Attached Shuttle Payloads processed telemetry data. The Spacelab Input Processing System (SIPS) and the Spacelab Output Processing System (SOPS), two expert systems, were developed to determine their feasibility and potential in the quality assurance of processed telemetry data. The capabilities and performance of these systems are discussed.

Basile, Lisa R.↗

NASA NTRS1986

Independent Orbiter Assessment (IOA): Analysis of the extravehicular mobility unit

The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items (PCIs). To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. This report documents the independent analysis results corresponding to the Extravehicular Mobility Unit (EMU) hardware. The EMU is an independent anthropomorphic system that provides environmental protection, mobility, life support, and communications for the Shuttle crewmember to perform Extravehicular Activity (EVA) in Earth orbit. Two EMUs are included on each baseline Orbiter mission, and consumables are provided for three two-man EVAs. The EMU consists of the Life Support System (LSS), Caution and Warning System (CWS), and the Space Suit Assembly (SSA). Each level of hardware was evaluated and analyzed for possible failure modes and effects. The majority of these PCIs are resultant from failures which cause loss of one or more primary functions: pressurization, oxygen delivery, environmental maintenance, and thermal maintenance. It should also be noted that the quantity of PCIs would significantly increase if the SOP were to be treated as an emergency system rather than as an unlike redundant element.

Raffaelli, Gary G.↗

NASA NTRS1989

Global atmospheric moisture variability

Research efforts during FY-88 have focused on completion of several projects relating to analysis of FGGE data during SOP-1 and on expanded studies of global atmospheric moisture. In particular, a revised paper on the relationship between diabatic heating and baroclinicity in the South Pacific Convergence Zone (SPCZ) was submitted. A summary of completed studies on diagnostic convective parameterization was presented at the Satellite Meteorology and Oceanography Convergence last February. These investigations of diabatic heating in the SPCZ have demonstrated the requirement for a more quantitative description of atmospheric moisture. As a result, efforts were directed toward use of passive remote microwave measurements from the Nimbus-7 SMMR and the DOD's Special Sensor Microwave Imager (SSMI/I) as critical sources of moisture data. Activities this year are summarized.

Robertson, Franklin R.↗

NASA NTRS1992

The diagnosis of a preblocking explosively-developing extratropical cyclone system

This paper presents the diagnosis of an extratropical cyclone that developed explosively from 18 to 19 January 1979 over the North Atlantic Ocean. The diagnosis applies data obtained from the Goddard Laboratory for Atmospheres FGGE SOP-1 level III-b global analyses on a 4 deg latitude by 5 deg longitude grid to the extended height tendency and the Zwack-Okossi development equations. The cyclone developed initially in response to cyclonic vorticity advection downstream from an upper air through, warm air advection in a strongly baroclinic region, and latent heat release in the cyclone domain. As development continued, thermal advection and latent heat release increased their role in forcing height falls in the cyclone domain, while the influence of vorticity advection decreased. Finally, development ceased when anticyclonic vorticity advection below 700 mb and adiabatic cooling in the ascending air combined to neutralize the influence of warm air advection and latent heat release.

Uhl, Mary A.↗