Spacecraft

1
Spacecraft InstrumentsDesign and Operations
2002 LWS CDAW Solar Particle Events

• Janet L. Barth
• Kenneth A. LaBel
• NASA
• Goddard Space Flight Center
• Flight Electronics Branch

2
Outline

• Space Environment Effects
• Drivers for Space Weather Model Requirements
• SW Model Requirements
• Climate Models
• Event Archive
• Nowcasts
• Forecasts
• Focus areas for this week?

3
Natural Space Environments

• ? Degradation of materials ? Thermal changes ?
• ? Contamination ? Excitation ? Spacecraft glow ?
  Drag ?
• ? Charging/Discharging ? Radiation damage ?
• ? Radiation induced data loss and interference ?

4
LWS Science Support for Spacecraft
Science Missions TMDA Program
Space Environment Testbeds
Perform Research on the Environment
Perform Research on System Response to the
Environment
Inputs for Environment Models (Predict space
environment)
Inputs for Interaction Models (Predict
performance in space environment)
Designers Operators Models to mitigate the
effects of solar variability on technologies
NASA Missions, NASA Human Support Systems, DoD,
Spacecraft Industry, Aircraft Industry
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Sources for Environment Information

• European Space Agency/ESTEC
• Radiation Environment Monitoring Program
• On-line tool development SPENVIS (BIRA with ESA
  support)
• NASA/Code R - Space Environment and Effects
  Program
• Space Environment Models
• CNES/TRAD
• Radiation Environment Monitoring Program
• Integrated tool development OMERE (TRAD with
  CNES ALCATEL support)
• NSSDC
• IMP-8 data
• NOAA
• GOES and TIROS Data
• Forecasts
• DoD - Microelectronics and Photonics Testbed
  (MPTB)
• LET Monitor Dosimeters
• Technology experiments
• Living with a Star Theory and Modeling Program
• Space environment models
• Living with a Star Science Programs

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Drivers for Spacecraft Design Ops

• Small market for spacecraft components
• Driven by commercial demand for electronics
• More demanding mission requirements
• Imagers, on-board processing, data storage, etc.
• Short mission development times
• Cant use long lead time custom designs
• Desire to operate in more severe environments
• MEO, long mission durations
• Smaller, lighter spacecraft
• Low power, reduced shielding

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Risk Management for Missions
Design Minimize Risk
Operations Avoid Risk
Anomaly Resolution Reevaluate Risk
Availability of appropriate space environment
information has not kept pace with technology
developments.
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Space Weather Model Requirements
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Climate Models

• Purpose - minimize risk in spacecraft design
  phase
• Minimum requirements
• Represent long-term variation over the solar
  cycle with at least 1-month resolution
• Provide worst case estimates
• Provide confidence levels
• Broad energy spectra high energies
• Radiation Belts
• Dynamics at GEO
• Validation of trapped particle models for MEO
• Long term variation of slot region filling
• Duration of slot region populations
• Solar particle cutoff latitudes, esp. for low
  inclination orbits
• Solar Particles
• Energies gt 100 MeV
• Energy spectra and ion content
• Statistical distribution of energy spectra of
  events

10
ESP Model Xapsos et al.
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Dependence on Solar Activity
Low Inclination - HST Orbit
CREME96
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SAMPEX Iron
Provided by B. Giles, July 2002
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Event Archive

• Purpose mission planning and operational
  guidelines
• Mission design phase - Understand impact of
  events on mission performance, e.g. degradation
  plans, mitigation requirements, band width
  requirements, estimation of loss of viewing time
• Post-anomaly resolution
• Minimum requirements
• At least one full solar cycle not just solar
  active times
• Spatial coverage from interplanetary to low earth
  orbit
• Time profile of events
• Adequate energy range
• On-line accessibility with analysis tools
• Radiation belts
• SAMPEX protons electrons
• SAMPEX ions for solar particle events
• Solar Particles
• Protons gt 100 MeV
• Event spectra for heavier ions, IMP-8/U of
  Chicago, ACE, WIND

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NGST Mission Design GOES Protons
John C. Isaacs, Space Telescope Science Institute
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Nowcasts

• Purpose - resolve anomalies
• Minimum requirements
• Spatial coverage from interplanetary to low earth
  orbit
• Time profile of event
• Adequate energy range
• Adequate ion composition information
• Specific to effect on technology
• Available quickly, on-line
• Radiation belts
• Need specifics as to location, time, energy
  spectra, etc.
• Detectors or modeling?
• Existing spacecraft are usually in the wrong
  place at the wrong time
• Models do not have capability at this time
• Detectors on spacecraft LET, Dose, Simple
  particle counters
• Solar Particles
• GOES for protons, higher energy needed
• MPTB LET monitor for heavier ions (UK instrument
  so ESA SW page?)

16
Distribution of Spacecraft Anomaly Records
Koons et al., Aerospace Technical Report, 1999
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LET Monitor MAP Safehold on Nov. 5, 2001
CREDO on MPTB QinetiQ (Formerly DERA)
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Forecasts

• Purpose - protect investments, mission
  operations, and personnel scheduling
• Minimum requirements
• Spatial coverage from interplanetary to low earth
  orbit
• Level of severity
• Specific to effect on technology
• Maximum energy
• Ion composition
• Radiation belts
• Belt pumping
• Slot region filling
• Solar particles
• Forecasts of ion composition
• Maximum energy of ions
• Quiet times location for near earth orbits

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Focus areas for this week?

• Statistical distribution of ion spectra of SPEs
• Forecasts of ion content of SPEs
• Forecasts of maximum energy of SPEs
• Cutoff latitudes
• Ion penetration to low inclination orbits
• Connection between solar events and radiation
  belt activity
• Connection between activity indices and radiation
  belt flux levels
• New belt formation
• What is the statistical distribution of the
  duration?
• Can the duration be predicted?
• Maximum energy?
• Worst case flux levels?

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Backups
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Seastar - Single Event Upsets
Single Event Upsets on Flight Data
Recorder January 1 - December 25, 1999 705 km
COTS DRAM Technology
No science data lost
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Total Ionizing Dose
Contributing Particles
Environment Spec.

• Solar protons
• Trapped protons
• Trapped electrons
• Secondary
• Bremsstrahlung (high electron environments)

• Mission totals for end-of-life estimates
• Time profiles of accumulation for degradation
  planning
• Specification metric
• Dose-depth curves
• Spacecraft specific dose levels

23
Non-ionizing Dose(Displacement Damage Dose)
Contributing Particles
Environment Spec.

• Solar protons
• Trapped protons
• Trapped electrons
• Neutrons
• Secondary from shielding
• RTGs

• Mission totals for end of life estimates
• Time profiles of accumulation for degradation
  planning
• Specification metric
• Energy spectra
• Shielded or unshielded

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Single Event Effects (SEEs)
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Spacecraft Charging
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Anomaly on NASAs MAP

• Microwave Anisotropy Probe
• Launched on June 30, 2001
• Operated normally at L2 for about 2 months
• MAP entered into a safehold condition on November
  5, 2001.
• Caused by a reset on the spacecrafts processor
• Suspected cause was a Single Event Transient
  (SET) on a voltage comparator (PM139) which
  caused a voltage dropout.
• MAP was restored to normal operation.
• Anomaly review

27
MAP Mission Design

• Environment definition and parts screening
• Pre-launch testing showed that hits by single
  heavy ions induced voltage dropouts
• No rad-hard substitute was available
• Used climate model to predict rate CREME96
• 1 SET/year predicted for GCR background
• 1 SET/October 1989 type event
• Design accommodation SET on PM139? ? Safehold
• Long term forecast
• Used event archive (GOES) to determine long term
  space weather forecast
• Mission assumed the level of risk
• Operational guidelines
• Based on particle level forecasting

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Heavy Ion Climate Model - MAP
Linear Energy Transfer (LET) Spectra
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Anomaly Review

• Anomaly Analysis
• Solar Storm November 3-7, 2001
• GOES showed increase in protons
• Heavy ions? - Need high energy and LET gt 2
  MeV-cm2/mg
• CREDO/MPTB measured increase in 0.1 lt LET lt 10
  MeV-cm2/mg
• Updated guidelines
• Forecasting
• Reiterated operational guidelines to mission
• Shutting down 5 times/month is not acceptable to
  MAP mission
• Need heavy ion forecasting
• Working on cooperative agreement with QinetiQ to
  get LET monitor data
• LWS/SET funded analysis of CRRES LET data from
  Clemson U.

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GOES Proton Instrument
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SW Lessons Learned on MAP

• Risk avoidance ? Risk management
• Do SW accommodation in design phase
• Space Weather information is required in mission
  design through operations.
• Requirements for anomaly resolution are
• Ground tests of components
• Climate models for estimates of rates
• Component response model
• Appropriate Nowcast information LET
• Solar heavy ion information is inadequate
• Need range of events
• Need probability models
• Need LET monitors

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Space Weather Model Characteristics

• Design ? Operations
• Easily integrated into application tools
• Input variables for non-researchers
• Stable
• Output appropriate for the application
• Ion resolution, adequate energy range and
  resolution, time resolution, spatial resolution
• Technology specific
• Small error bars ? Design margins reduce science
  capability
• Validated