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NASA NTRS2016

Magnetospheric Multiscale Observations of Magnetic Reconnection Associated with Kelvin-Helmholtz Waves

The four Magnetospheric Multiscale (MMS) spacecraft recorded the first direct evidence of reconnection exhausts associated with Kelvln-Helmholtz (KH) waves at the duskside magnetopause on 8 September 2015 which allows for local mass and energy transport across the flank magnetopause. Pressure anisotropy-weighted Walen analyses confirmed in-plane exhausts across 22 of 42 KH-related trailing magnetopause current sheets (CSs). Twenty-one jets were observed by all spacecraft, with small variations in ion velocity, along the same sunward or antisunward direction with nearly equal probability. One exhaust was only observed by the MMS-1,2 pair, while MMS-3,4 traversed a narrow CS (1.5 ion inertial length) in the vicinity of an electron diffusion region. The exhausts were locally 2-D planar in nature as MMS-1, 2 observed almost identical signatures separated along the guide-field. Asymmetric magnetic and electric Hall fields are reported in agreement with a strong guide-field and a weak plasma density asymmetry across the magnetopause CS.

Eriksson, S.↗

NASA NTRS2016

Electrodynamic Context of Magnetopause Dynamics Observed by Magnetospheric Multiscale

Magnetopause observations by Magnetospheric Multiscale (MMS) and Birkeland currents observed by the Active Magnetosphere and Planetary Electrodynamics Response Experiment are used to relate magnetopause encounters to ionospheric electrodynamics. MMS magnetopause crossings on 15 August and 19 September 2015 occurred earthward of expectations due to solar wind ram pressure alone and coincided with equatorward expansion of the Birkeland currents. Magnetopause erosion, consistent with expansion of the polar cap, contributed to the magnetopause crossings. The ionospheric projections of MMS during the events and at times of the magnetopause crossings indicate that MMS observations are related to the main path of flux transport in one case but not in a second. The analysis provides a way to routinely relate in situ observations to the context of in situ convection and flux transport.

Anderson, Brian J.↗

NASA NTRS2017

Magnetospheric Multiscale Mission Navigation Performance During Apogee-Raising and Beyond

The primary objective of the Magnetospheric Multiscale (MMS) Mission is to study the magnetic reconnection phenomena in the Earths magnetosphere. The MMS mission consists of four identical spinning spacecraft with the science objectives requiring a tetrahedral formation in highly elliptical orbits. The MMS spacecraft are equipped with onboard orbit and time determination software, provided by a weak-signal Global Positioning System (GPS) Navigator receiver hosting the Goddard Enhanced Onboard Navigation System (GEONS). This paper presents the results of MMS navigation performance analysis during the Phase 2a apogee-raising campaign and Phase 2b science segment of the mission.

Farahmand, Mitra↗

NASA NTRS1978

Testing programs for the Multimission Modular Spacecraft

The Multimission Modular Spacecraft (MMS) provides a standard spacecraft bus to a user for a variety of space missions ranging from near-earth to synchronous orbits. The present paper describes the philosophy behind the MMS module test program and discusses the implementation of the test program. It is concluded that the MMS module test program provides an effective and comprehensive customer buy-off at the subsystem contractor's plant, is an optimum approach for checkout of the subsystems prior to use for on-orbit servicing in the Shuttle Cargo Bay, and is a cost-effective technique for environmental testing.

Greenwell, T. J.↗

NASA NTRS1982

Flight support system mechanisms

The Flight Support System (FSS) which contains twelve mechanisms (six different types) which are used for retention and positioning of a Multimission Modular Spacecraft (MMS) within the Space Shuttle's cargo bay during launch, retrieval, and servicing missions is described. Retention latches were designed to provide the capability for structural support of the MMS during launch and retrieval, and during servicing operations the mechanisms on the Positioning Platform provide the capability for positioning the MMS in virtually any orientation necessary for the work to be performed. In addition, there are mechanisms for matching and demating umbilical connectors and a mechanism for locking the Positioning Platform during maneuvers. Each Mechanism is driven by a Common Drive Unit. Manual overrides were provided for those mechanisms that would present a safety hazard for the crew, if they should fail.

Source record↗

NASA NTRS1984

On-orbit maintenance and repair - New era in space research and industrialization

During the seventies, NASA was developing a multifunction, economical spacecraft complete with ground and spaceborne support equipment, software, and necessary documentation to facilitate a large variety of space missions on a routine and cost effective basis. In order to reduce costs and time requirements, research was conducted to identify new approaches to a reusable, low-cost spacecraft design. The result of these studies was the development of the Multimission Modular Spacecraft (MMS). Three MMS spacecraft are currently operating in orbit. These spacecraft include the two Landsat-D earth resources satellites, Landsat-4 and -5, and the Solar Maximum Mission (SMM) spacecraft. Attention is given to details regarding the MMS, the STS-41C SMM repair mission, and failure modes and component degradation.

Cepollina, F.↗

NASA NTRS1987

Proposed CMG momentum management scheme for space station

A discrete control moment gyro (CMG) momentum management scheme (MMS) applicable to spacecraft with principal axes misalignments, such as the proposed NASA dual keel space station, is presented in this paper. The objective of the MMS is to minmize CMG angular momentum storage requirements for maintaining the space station near local vertical in the presence of environmental disturbances. It utilizes available environmental disturbances, namely gravity gradient torques, to minimize CMG momentum storage. The MMS is executed once per orbit and generates a commanded torque equilibrium attitude (TEA) time history which consists of a yaw, pitch and roll angle command profile. Although the algorithm is called only once per orbit to compute the TEA profile, the space station will maneuver several discrete times each orbit.

Bishop, L. R.↗

NASA NTRS1988

Temperature and horizontal wind measurements on the ER-2 aircraft during the 1987 airborne Antarctic ozone experiment

The NASA ER-2 aircraft is equipped with special instrumentation to provide accurate in situ measurement of the atmospheric state variables during flight. The Meteorological Measurement System (MMS) on the ER-2 aircraft is described. Since the meteorological parameters (temperature, pressure, and wind vector) are extensively used by other ER-2 experimenters for data processing and interpretation, the accuracy and resolution of each of these parameters are assessed and discussed. During the 1987 Airborne Antarctic Ozone Experiment (AAOE) mission, the ER-2 aircraft was stationed at Punta Arenas, Chile (53 S, 72 W), and successfully flew over Antarctica on 12 occasions between August 17 and September 22, 1987. On each of the 12 flights, the ER-2 aircraft flight plan was to take off at approximately the same local time, fly southward at a near constant potential temperature surface, descend and ascend at the southernmost terminus at about 72 S over Antarctica and return northward at either the same or a different constant potential temperature surface. The measurements of the MMS experiment during the AAOE mission are presented. MMS data are organized to provide a composite view of the polar atmosphere, which is characterized by frigid temperatures and high zonal winds. Altitudinal variations of the temperature measurement (during takeoff/landing at Punta Arenas and during descent/ascent at the southern terminus) and latitudinal variations of the zonal wind (on near constant potential temperature surfaces) are emphasized and discussed.

Chan, K. Roland↗

NASA NTRS1991

Improved visualization of flow field measurements

A capability was developed that makes it possible to apply to measured flow field data the visualization tools developed to display numerical solutions for computational fluid dynamic problems. The measurement monitor surface (MMS) procedure was applied to the analysis of flow field measurements within a low aspect ratio transonic axial flow fan rotor obtained with 2-D laser anemometry. The procedure generates input for the visualization tools developed to display numerical solutions for computational fluid dynamics problems. The relative Mach number contour plots obtained by this method resemble the conventional contour plots obtained by more traditional methods. The results show that the MMS procedure can be used to generate input for the multidimensional processing and analysis tools developed for data from numerical flow field simulations. They show that an experimenter can apply the MMS procedure to his data and then use an interactive graphics program to display scalar quantities like the Mach number by profiles, carpet plots, contour lines, and surfaces using various colors. Also, flow directionality can be shown by display of vector fields and particle traces.

Miles, Jeffrey Hilton↗

NASA NTRS1991

Calibration of the ER-2 meteorological measurement system

The Meteorological Measurement System (MMS) on the high altitude ER-2 aircraft was developed specifically for atmospheric research. The MMS provides accurate measurements of pressure, temperature, wind vector, position (longitude, latitude, altitude), pitch, roll, heading, angle of attack, angle of sideslip, true airspeed, aircraft eastward velocity, northward velocity, vertical acceleration, and time, at a sample rate of 5/s. MMS data products are presented in the form of either 5 or 1 Hz time series. The 1 Hz data stream, generally used by ER-2 investigators, is obtained from the 5 Hz data stream by filtering and desampling. The method of measurement of the meteorological parameters is given and the results of their analyses are discussed.

Bowen, Stuart W.↗

NASA NTRS1991

Applications of the ER-2 meteorological measurement system

The NASA ER-2 aircraft is used as a platform for high altitude atmospheric missions. The Meteorological Measurement System (MMS) was developed specifically for atmospheric research to provide accurate high resolution measurements of pressure, temperature, and the 3-D wind vector with a sampling rate of 5/s. The MMS consist of three subsystems: (1) an air motion sensing system to measure the velocity of the air with respect to the aircraft; (2) a high resolution inertial navigation system (INS) to measure the velocity of the aircraft with respect to the earth; and (3) a data acquisition system to sample, process, and record the measurement quantities. MMS data have been used extensively by ER-2 investigators in elucidating the polar ozone chemistry. Herein, applications on atmospheric dynamics are emphasized. Large scale (polar vortex, potential vorticity, model atmosphere), mesoscale (gravity waves, mountain waves) and microscale (heat fluxes) atmospheric phenomena are investigated and discussed.

Chan, K. Roland↗

NASA NTRS1992

Comparisons of the NASA ER-2 meteorological measurement system with radar tracking and radiosonde data

Measurements of aircraft longitude, latitude, and velocity, and measurements of atmospheric pressure, temperature, and horizontal wind from the meteorological measurement system (MMS) on board the NASA ER-2 aircraft were compared with independent measurements of these quantities from radiosondes and radar tracking of both the ER-2 and radiosonde balloons. In general, the comparisons were good and within the expected measurement accuracy and natural variability of the meteorological parameters. Radar tracking of the ER-2 resolved the velocity and position drift of the inertial navigation system (INS). The rms errors in the horizontal velocity components of the ER-2, due to INS errors, were found to be 0.5 m/s. The magnitude of the drift in longitude and latitude depends on the sign and magnitude of the corresponding component velocity drift and can be a few hundredths of a degree. The radar altitudes of the ER-2 and radiosondes were used as the basis for comparing measurements of atmospheric pressure, temperature, and horizontal wind from these two platforms. The uncertainty in the MMS horizontal wind measurement is estimated to be +/- 2.5 m/s. The accuracy of the MMS pressure and temperature measurements were inferred to be +/- 0.3 hPa and +/- 0.3 K.

Gaines, Steven E.↗

NASA NTRS1993

Using manufacturing message specification for monitor and control at Venus

The flexibility and robustness of a monitor and control (M&C) system are a direct result of the underlying interprocessor communications architecture. A new architecture for M&C at the Deep Space Communications Complexes (DSCC's) has been developed based on the Manufacturing Message Specification (MMS) process control standard of the Open System Interconnection (OSI) suite of protocols. This architecture has been tested both in a laboratory environment and under operational conditions at the Deep Space Network (DSN) experimental Venus station (DSS-13). The Venus experience in the application of OSI standards to support M&C has been extremely successful. MMS meets the functional needs of the station and provides a level of flexibility and responsiveness previously unknown in that environment. The architecture is robust enough to meet current operational needs and flexible enough to provide a migration path for new subsystems. This paper will describe the architecture of the Venus M&C system, discuss how MMS was used and the requirements this imposed on other parts of the system, and provide results from systems and operational testing at the Venus site.

Heuser, W. Randy↗

NASA NTRS1993

DSS-13 - Using an OSI process control standard for monitor and control

The flexibility and robustness of a monitor and control (M&C) system are a direct result of the underlying inter-processor communications architecture. A new architecture for M&C at the Deep Space Communications Complexes has been developed based on the manufacturing message specification (MMS) process control standard of the open system interconnection (OSI) suite of protocols. This architecture has been tested both in a laboratory environment and under operational conditions at the Deep Space Network experimental station (DSS-13). The DSS-13 experience in the application of OSI standards to support M&C has been extremely successful. MMS meets the functional needs of the station and provides a level of flexibility and responsiveness previously unknown in that environment. The architecture is robust enough to meet current operational needs and flexible enough to provide a migration path for new subsystems. This paper describes the architecture of the DSS-13 M&C system, discuss how MMS was used and the requirements this imposed on other parts of the system, and provides results from systems and operational testing at DSS-13.

Heuser, W. R.↗

NASA NTRS1994

Delivering spacecraft control centers with embedded knowledge-based systems: The methodology issue

Matra Marconi Space (MMS) occupies a leading place in Europe in the domain of satellite and space data processing systems. The maturity of the knowledge-based systems (KBS) technology, the theoretical and practical experience acquired in the development of prototype, pre-operational and operational applications, make it possible today to consider the wide operational deployment of KBS's in space applications. In this perspective, MMS has to prepare the introduction of the new methods and support tools that will form the basis of the development of such systems. This paper introduces elements of the MMS methodology initiatives in the domain and the main rationale that motivated the approach. These initiatives develop along two main axes: knowledge engineering methods and tools, and a hybrid method approach for coexisting knowledge-based and conventional developments.

Ayache, S.↗

NASA NTRS1994

The meteorological monitoring system for the Kennedy Space Center/Cape Canaveral Air Station

The Kennedy Space Center (KSC) and Cape Canaveral Air Station (CCAS) are involved in many weather-sensitive operations. Manned and unmanned vehicle launches, which occur several times each year, are obvious example of operations whose success and safety are dependent upon favorable meteorological conditions. Other operations involving NASA, Air Force, and contractor personnel, including daily operations to maintain facilities, refurbish launch structures, prepare vehicles for launch, and handle hazardous materials, are less publicized but are no less weather-sensitive. The Meteorological Monitoring System (MMS) is a computer network which acquires, processes, disseminates, and monitors near real-time and forecast meteorological information to assist operational personnel and weather forecasters with the task of minimizing the risk to personnel, materials, and the surrounding population. CLIPS has been integrated into the MMS to provide quality control analysis and data monitoring. This paper describes aspects of the MMS relevant to CLIPS including requirements, actual implementation details, and results of performance testing.

Dianic, Allan V.↗

NASA NTRS1994

Formalizing procedures for operations automation, operator training and spacecraft autonomy

The generation and validation of operations procedures is a key task of mission preparation that is quite complex and costly. This has motivated the development of software applications providing support for procedures preparation. Several applications have been developed at MATRA MARCONI SPACE (MMS) over the last five years. They are presented in the first section of this paper. The main idea is that if procedures are represented in a formal language, they can be managed more easily with a computer tool and some automatic verifications can be performed. One difficulty is to define a formal language that is easy to use for operators and operations engineers. From the experience of the various procedures management tools developed in the last five years (including the POM, EOA, and CSS projects), MMS has derived OPSMAKER, a generic tool for procedure elaboration and validation. It has been applied to quite different types of missions, ranging from crew procedures (PREVISE system), ground control centers management procedures (PROCSU system), and - most relevant to the present paper - satellite operation procedures (PROCSAT developed for CNES, to support the preparation and verification of SPOT 4 operation procedures, and OPSAT for MMS telecom satellites operation procedures).

Lecouat, Francois↗

NASA NTRS1997

Application of Modular Modeling System to Predict Evaporation, Infiltration, Air Temperature, and Soil Moisture

Models are used for numerous application including hydrology. The Modular Modeling System (MMS) is one of the few that can simulate a hydrology process. MMS was tested and used to compare infiltration, soil moisture, daily temperature, and potential and actual evaporation for the Elinsboro sandy loam soil and the Mattapex silty loam soil in the Microwave Radiometer Experiment of Soil Moisture Sensing at Beltsville Agriculture Research Test Site in Maryland. An input file for each location was created to nut the model. Graphs were plotted, and it was observed that the model gave a good representation for evaporation for both plots. In comparing the two plots, it was noted that infiltration and soil moisture tend to peak around the same time, temperature peaks in July and August and the peak evaporation was observed on September 15 and July 4 for the Elinsboro Mattapex plot respectively. MMS can be used successfully to predict hydrological processes as long as the proper input parameters are available.

Boggs, Johnny↗