Model%20Mission:%20Magnetospheric%20Multiscale%20(MMS)

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Model MissionMagnetospheric Multiscale (MMS)

• Mission Goal
• To study the microphysics of three fundamental
  plasma processes magnetic reconnection,
  energetic particle acceleration, and turbulence

• Constellation composed of 4 identical spacecraft
  maintaining a tetrahedral formation in regions of
  scientific interest within the magnetosphere
• Each spacecraft has a suite of 4 primary payload
  sensors/subsystems (FPI, FIELDS, HPCA, EPD)
• SWRI MMS webpage http//mms.space.swri.edu/

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MMS Mission (cont.)

• Plasma processes under investigation are
  inherently transient (magnetic reconnection in
  particular)
• Specific need for reactive on-board autonomy to
  enable high temporal and spatial resolution data
  acquisition during transient events (i.e. changes
  in particle, ion, and electromagnetic field
  measurements)
• Limited intra-constellation communication
  dedicated to coordinating reactive data
  acquisition
• Only a measure of the quality of scientific
  data is transmitted (1 byte every 10 seconds) by
  each spacecraft
• Quality byte is used as a trigger for the other
  spacecraft in the constellation to start high
  resolution data acquisition

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Operating Modes

• Each spacecraft has three modes of operation
• Slow Survey
• Fast Survey
• Burst
• Slow Survey Mode is entered when a spacecraft is
  outside the regions of scientific interest
  (approx 60 of orbit)
• Only a subset of payload sensors are active,
  providing a minimal amount of data (primarily for
  health monitoring)
• Acquired data is not stored for downlink
• Fast Survey Mode is entered when a spacecraft is
  inside a region of interest (approx 40 of
  orbital period)
• All payload sensors are active, and data taken at
  moderate rates
• Acquired data is analyzed for quality on-board
  and stored for later downlink
• Quality data is communicated throughout the
  constellation

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Operating Modes (cont.)

• Burst Mode is initiated by time-triggered
  commands or autonomously when measured conditions
  satisfy a set of rules
• It can only be triggered while the spacecraft is
  already in Fast Survey Mode
• Approximately 40 min allowable per day (due to
  storage constraints)
• All sensors acquire high temporal resolution data
• Acquired data is analyzed for quality and stored
  for downlink
• Transition to Burst Mode is communicated
  throughout the constellation via the quality byte
• Does not necessarily force Burst Mode transition
  in other spacecraft
• Transition based on weighted combination of
  conditions, local data quality, and communicated
  quality

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Phases of MMS Mission

• Three phases of operation targeting different
  regions of the magnetosphere
• Priority of payload data dependent on phase of
  mission as well as location in orbit
• Image from SWRI MMS CSR p. F-16

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Payload Sensor Specifications
Image from SWRI MMS CSR p. E-18
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Demonstration Scenarios based on MMS Mission Model

• Simplifying assumptions
• Only three spacecraft in a triangular formation
  (allowing potential use of Microbots as hardware
  testbed)
• Simulate payload sensor data and orbital
  information for operating mode transitions
• Use representative algorithms for compression,
  on-board processing, etc.
• Three potential scenarios of increasing
  complexity
• Nominal Day in the Life of MMS
• Support of science community requests for
  alternate on-board processing
• Management of solid-state storage overflow
  conditions

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Demonstration Scenarios (cont.)

• Day in the Life scenario will demonstrate
  several aspects of mission operations under
  nominal conditions
• Mode transitions based on orbital location
  (Slow/Fast)
• Mode transition based on burst trigger commands,
  measured conditions, and inter-constellation
  communication
• Ground station interaction with the constellation
• User Request scenario will demonstrate support
  for multiple scientific user requests beyond the
  nominal operations
• Users can modify or add to the on-board
  processing
• Alternate data rates
• Compression schemes
• Quality of data for downlink/storage
• Users can set time triggered commands to control
  mode transitions based on time (i.e. location in
  orbit)

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Demonstration Scenarios (cont.)

• Storage Overflow scenario will demonstrate
  autonomous management of a fault or off-nominal
  conditions
• Limited data storage space could be filled (by
  entering Burst Mode often) or fail, while
  sensors/processors still operational
• Several potential methods of managing situation
• Overwrite low quality or priority data
• Balance stored data across constellation during
  Slow Survey Mode
• Stream acquired data in realtime to other
  spacecraft for storage (assuming communication
  bandwidth sufficient)
• Specific methods to be implemented still under
  consideration

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• Science Agent Architecture

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Adaptive Network Architecture (ANA)
Executive Agent
CCM Layer
Sensors
Gizmo Agent
CORBA Notification Service Component (Data/Messag
e Filtering for Remote Delivery)
Science Agent
Actuators
CCM Layer
InterAgent Messages (FIPA ACL)
CCM Layer
SpaceWire/USB/ 802.11/Legacy
GNC Agent
Agent Registration
CORBA Notification Service Component (Data/Messa
ge Filtering for local Delivery)
CCM Layer
CORBA Federated Naming Service (Agent Locator)
Comm. Agent
CCM Layer
SpaceWire/ USB/ 802.11/Legacy
Current LMCO ANA Configuration
Science Payload
Gizmo Agent
CCM Layer
Science Instrument e.g. Camera