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LT RBR:

Long Term Radiation Belt Remediation

Joshua Davis

ASTE 527

Space Concepts Studio

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LT RBR:

RBR means removing the trapped electrons and ions from the near Earth environment for the benefit of manned and unmanned spacecraft.

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Radiation Environment’s Impact on Manned Spaceflight

A majority of the radiation Astronauts receive on orbit is attributed to the trapped radiation particles in the inner Van Allen belt.

Time on orbit is limited by an Astronaut’s total radiation exposure, limiting the ability to study long term micro-gravity effects on Humans.

Radiation dosage on the ISS is roughly 4 orders of magnitude higher than at Sea Level.

Temporary and permanent eye damage.

Increased risk of cancers.

The daily dosage of radiation on the ISS is equal to 8 chest X-rays per day.

Increased risk of heart, digestive, and respiratory diseases.

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Solar array power decrease due to radiation damage

Single event effects in microelectronics: bit flips, fatal latch-ups

Spacecraft components become radioactive

False stars in star tracker CCDs

before after

Surface degradation from radiation

Electronics degrade due to total radiation dose

Solar array arc discharge

Cryogenic systems experience notable charged particle heating

Electromagnetic pulse from vehicle discharge

Induced Voltage

Time

Energetic Particle & Plasma Hazards

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Energetic Particle & Plasma Hazards

Arc Discharging

Solar Panel Power Decrease

Bit Flips / Single Event Upsets

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Particle Motion in Earth’s Magnetic Field

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How RBR Works:

Change the particle’s pitch cone angle such that its velocity vector is pointed roughly parallel to the magnetic field lines.

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Tethers Unlimited : HiVOLT

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Neutral Particle Injection

Ion-Cyclotron Turbulence Generation

- Change the velocity vector by inducing wave oscillations into the ambient plasma by releasing a plasma cloud at orbital velocity that will transform the orbital kinetic energy into turbulent wave energy.

- Neutral Particles become photo-ionized and transform the orbital kinetic energy into turbulent wave energy.

- This turbulence is a result of the new artificial plasma cloud and the natural plasma environment attempting to reach a thermodynamic equilibrium.

- This requires lofting a large mass of particles & injection system into orbit and then dispersing the cloud. Estimates of ~ 10 tons of material to be injected

- Once the particles have been released, there is no control of the process.

The new plasma particles may be difficult to get rid of, as they have virtually no parallel velocity component by design.

Chang, Ouliang. "Numerical Simulation of Ion-Cyclotron Turbulence Generated by Artificial Plasma Cloud Release." Thesis. Virginia Tech, 2009. Web. 1 Oct. 2012. <http://scholar.lib.vt.edu/theses/available/etd-07152009-125531/>.

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VLF:

Very Low Frequency Radio Waves

- Change velocity vector by inducing wave oscillations by exciting the plasma using VLF radio waves.

- Potential for rapid remediation (1-3 days)

- Radio transmitters can easily access most regions of the belts. Some facilities are already in place such as the High Frequency Active Auroral Research Program (HAARP) in Alaska

- Proven method for electron remediation. Active transmission of VLF has led to an observed decrease in electron flux

Space based or ground based radio transmitters excite the particles and induce turbulent waves. *Ground based architecture is highly dependant on location to provide remediation benefits.

Gamble, Rory. Et al. "Radiation Belt Electron Precipitation by Man-made VLF Transmissions." Journal of Geophysical Research 113 (2008): American Geophysical Union, 21 Oct. 2008. Web. <http://www.agu.org/pubs/crossref/2008/2008JA013369.shtml>.

http://arizonaskywatch.com/articles/articles/hf1.bmp

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Experimental Data for VLF RBR

1100 km alt

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Issues with RBR

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Conclusion and Future Work for LT RBR

VLF should be further researched as the primary method for LT RBR

Feasibility study of Long Term operation of VLF stations

Additional study on the effects of RBR on the atmosphere should be conducted

VLF should be further researched as the primary method for LTRBR

VLF has the advantage of using ground station already available and in use.

VLF has observational satellite data to back up its methods

Tethers and Neutral Particles require launching a system into orbit. For long term remediation, a ground based system is far less costly.

*Airforce DSX (Demonstrations and Science Experiment) mission to carry out VLF RBR experiments dubbed Wave Particle Interaction Experiment (WPIx)

Avoiding RBR Issues

Experimental data has shown that temporary RBR is possible.

Experts argue that RBR may cause temporary damage to the Ionosphere and Ozone layer.

Initial remediation should be slow or pulsed to allow the atmosphere to “heal” to minimize disruptions caused by the flushing of the high energy particles.

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References

Odenwald, Sten. "What Are Space Radiation Effects?" NASA. <http://radbelts.gsfc.nasa.gov/outreach/effects.html>.
Hess, Wilmot N. "Energetic Particles in the Inner Van Allen Belt." Space Science Reviews 1.2 (1962). <http://rd.springer.com/article/10.1007%2FBF00240580>
Hoyt, Robert P., and Forward, Robert L. "Radiation Remediation." Tethers Unlimited. <http://www.tethers.com/HiVOLT.html>.
Chang, Ouliang. "Numerical Simulation of Ion-Cyclotron Turbulence Generated by Artificial Plasma Cloud Release." Thesis. Virginia Tech, 2009. <http://scholar.lib.vt.edu/theses/available/etd-07152009-125531/>.

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References Cont.

Papadopoulos, Konstantinos. Et al. "Generation and Evolution of Intense Ion Cyclotron Turbulence by Artificial Plasma Cloud in the Magnetosphere." Journal of Geophysical Research 112 (2007)
Gamble, Rory. Et al. "Radiation Belt Electron Precipitation by Man-made VLF Transmissions." Journal of Geophysical Research 113 (2008): American Geophysical Union, 21 Oct. 2008. <http://www.agu.org/pubs/crossref/2008/2008JA013369.shtml>.
Rodger, Craig J. "The Atmospheric Implications of Radiation Belt Remediation." Annales Geophysicae 24 (2006). European Geosciences Union. <http://www.ann-geophys.net/24/2025/2006/angeo-24-2025-2006.pdf>.

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Backup Slides

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Why does the Earth have a Radiation Belt?

A Radiation Belt is

more stylish than

Radiation Suspenders!

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International “Space EPA” to study and control RBR practices and take over NOAA’s space weather responsibilities.