slide1 l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Understanding and Mitigating Radiation Belt Hazards for Space Exploration PowerPoint Presentation
Download Presentation
Understanding and Mitigating Radiation Belt Hazards for Space Exploration

Loading in 2 Seconds...

play fullscreen
1 / 27

Understanding and Mitigating Radiation Belt Hazards for Space Exploration - PowerPoint PPT Presentation


  • 293 Views
  • Uploaded on

Understanding and Mitigating Radiation Belt Hazards for Space Exploration Geoffrey Reeves Space Science and Applications, ISR-1, Los Alamos National Laboratory, Why is radiation belt physics relevant to the Vision for Space Exploration? The radiation belts aren’t going to kill astronauts

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Understanding and Mitigating Radiation Belt Hazards for Space Exploration' - benjamin


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Understanding and Mitigating

Radiation Belt Hazards for Space Exploration

Geoffrey Reeves

Space Science and Applications, ISR-1, Los Alamos National Laboratory,

why is radiation belt physics relevant to the vision for space exploration
Why is radiation belt physics relevant to the Vision for Space Exploration?
  • The radiation belts aren’t going to kill astronauts
  • But, radiation belt doses to Apollo astronauts were ‘non-negligable’ and can be reduced with more knowledge - the goal is ALARA and this is achievable
  • Radiation belt physics is critical for the space-based infrastructure that will support any significant exploration program - communications, staging, etc.
  • As with other elements of LWS the radiation belt programs were designed to have direct, practical benefit to life and society - within and beyond VSE
  • The goals are achievable and timely
there are three classes of problems we want to solve
There are three classes of problems we want to solve
  • Climatology
    • What are the long-term conditions and variability?
    • Primarily for spacecraft and systems design/optimization
  • Now-Casting
    • Primarily for rapid (and cost effective) anomaly assessment
    • Typically requires near real time data (which is scarce)
    • Can be significantly enhanced with minor investments such as ground stations to collect NRT data from operational assets
  • Prediction
    • Requires physical understanding, data, and models
    • Global knowledge - e.g. plasmapause location, global field…
    • Detailed physics such as the chain of causality from plasma distributions to wave growth to electron acceleration and loss
extreme events while rare dramatically change statistics and climatological models
Extreme events, while rare, dramatically change statistics and climatological models

J. B. Blake

SEEWG 2004

new models like pole can provide significant benefits for minimal cost
New models like POLE can provide significant benefits for minimal cost

Under-shielding increases

risk of component, system, or mission failure

Over-shielding increasescosts and/or reduces capability by flying oldor less capable technologies

D. G. Boscher et al. 2003,

Trans IEEE Nuc. Sci.,

a fundamental predication challenge will a storm increase or decrease the belts
A Fundamental Predication Challenge:Will a storm increase or decrease the belts?
  • Geomagnetic storms change the radiation belts dramatically but unpredictably
  • Radiation belt fluxes vary asa function of time, altitude (L),and energy
  • The challenge is to reliably extrapolate in time, space, and/or energy

CRRES - full mission

100X Increase

10X Decrease

No Change

acceleration and losses low energies coupled to high through waves

The same wave fieldscan produce pitchangle scattering and loss

Acceleration and Losses - Low energies coupled to High through waves

Unstable plasma distributions

produce waves that couple

energy into the relativisticpopulation

predictive understanding requires coupling observations with the right physical models

Dynamic

Radiation

Environment

Assimilation

Model

Predictive understanding requires coupling observations with the right physical models
data assimilation utilizing observations and models for prediction and understanding
Data Assimilation - Utilizing observations and models for prediction and understanding

A Pictorial Representation of the Kalman Filter

slide15

Diffusion function:

  • Exact solution compared to Data Assimilation Solution
  • Just 2 satellites (measuring witherrors) can determine radial diffusionrates - and precision of result

1D Radial Diffusion: Identical Twin Test

Exact Solution

Error Matrix

Error Matrix

Data Assimilation

Model Solution

slide20

Self-Consistent Magnetic & Ring Current Model

  • Euler Potential based Equilibrium Magnetic Field model calculated from UNH-RAM ring current pressure distributions
  • Feed back new B equilibrium into RAM and solve iteratively
  • Self consistent results produce different current strength, drift paths, anisotropies, wave growth rates, etc…
slide21

Self-Consistent Magnetic & Ring Current Model

  • Euler Potential based Equilibrium Magnetic Field model based on RAM pressure distributions
  • Feed back new B equilibrium into RAM and solve iteratively
  • Changes: current strength, drift path, anisotropies, wave growth rates…
lws radiation belt storm probes rbsp understanding and application
LWS Radiation Belt Storm Probes (RBSP)Understanding and Application
  • LWS missions were designed to achieve physical understanding that is critical to life and society
  • VSE’s needs are closely coupled to the needs of our technological society and inquisitive nature

Radiation BeltStorm Probes

we have
We Have:
  • A vast collection of archival data spanning several solar cycles (but of variable quality)
  • A well-ordered system in which most of the basic physical equations are known (but not which processes dominate)
  • Excellent physical models for parts of the system that have high fidelity when they have the right inputs
  • A new satellite mission to fill critical gaps in physical understanding and in observations
  • Clear, achievable goals in the 3, 5, and 10 year time scales
we need
We Need:
  • To develop new empirical, but dynamic, climatological models
  • To understand which processes operate and when
  • A second equatorial satellite orbit and low-altitude precipitation measurements to significantly extend the science return from RBSP (as identified by the GMDT)
  • To develop global physical models that provide context for observations as well as predictive capability
  • Integrate new & continuing observations with these new tools
relevance to vse

The Acid Test

  • We will have failed if we cannot predict which events will increase radiation belt fluxes, which events will decrease radiation belt fluxes, and how large those changes will be
Relevance to VSE
  • The radiation belts are only one component of the VSE space environment problem but improvements in our ability to understand and predict dynamic radiation environments at Earth will directly benefit human and robotic exploration missions and the infrastructure needed to support them.
  • Dramatic improvements are both achievable and timely
  • Better radiation belt models can reduce risk, reduce costs, and enable new space capabilities and technologies