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Van Allen radiation belt

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37 pointsfisian14 comments

It was interesting how they dealt with this for the Apollo missions.

Shortly before the launches Operation Starfish Prime took place and one hope was that detonating nuclear bombs in the upper atmosphere might deform the Van Allen belts or indeed that the extra energy might displace them entirely.

However, it actually strengthened the radiation belt, fortunately it dissipated relatively quickly and it was safe for the lunar missions.

https://thewire.in/the-sciences/apollo-11-van-allen-radiatio...

That explosion also eventually disabled over a half-dozen satellites. Whoops.

http://blogs.discovermagazine.com/badastronomy/2012/07/09/th...

https://apps.dtic.mil/dtic/tr/fulltext/u2/a531197.pdf

https://www.wired.com/2012/03/starfishandapollo-1962/

I love the "hold my beer" era of US / USSR atomic testing.

An interesting one that was considered was Project A119:

>...Project A119, also known as A Study of Lunar Research Flights, was a top-secret plan developed in 1958 by the United States Air Force. The aim of the project was to detonate a nuclear bomb on the Moon ...

https://en.wikipedia.org/wiki/Project_A119

https://en.m.wikipedia.org/wiki/Project_Plowshare

Non-mobile: https://en.wikipedia.org/wiki/Project_Plowshare

https://en.m.wikipedia.org/wiki/Nuclear_Explosions_for_the_N...

Non-mobile: https://en.wikipedia.org/wiki/Nuclear_Explosions_for_the_Nat...

using nukes to improve petroleum extraction. oh the irony.

These belts are created (at least mostly) by Earth's magnetic field capturing or deflecting incident radiation, which therefore shields Earth's surface from the radiation and (I believe) protects life.

Earth's magnetic field isn't stable with time and has (geologically) frequent pole reversals. We don't have a great idea of how long this process takes, whether it is near-instantaneous or takes hundreds of years (or perhaps longer?). The poles are currently 'wandering' relatively fast and some geophysicists think this may be a sign of a pole reversal to come.

I wonder about how the Van Allen belts fair during a pole reversal, and if for some time interval the amount of incoming radiation on the Earth's surface is much greater, perhaps at dangerous levels.

Earth also has a much stronger geomagnetic field than other rocky planets because it has a solid iron-nickel inner core that rotates inside of a liquid iron-nickel outer core, inducing the magnetic field (the so-called 'geodynamo'. If the resulting Van Allen belt is indeed a safeguard to the development of life on Earth, it may be part of the reason that Earth is unique in life development versus its neighbors.

One important thing they do is protect our atmosphere from blowing away in the solar wind, which is more of a law of averages sort of thing and not much gets lost in just a hundred years. I'm not sure that the charged particles the Van Allen belt stops would actually reach all the way to the surface of the Earth. I haven't heard of radiation danger up at the poles when the aurora is out.

Our low-Earth orbit satellites go a bit berserk each time they pass through the SAA. Star trackers used for orientation estimation pick up lots of pixel snow.

Couple of nice references:

Observation of high intensity radiation by satellites 1958 Alpha and Gamma J A Van Allen Journal of Jet Propulsion http://www-pw.physics.uiowa.edu/ProfVanAllen/1958_VanAllen_O...

Apollo Experience Report - Protection from Radiation Technical Note TN D-7080, March 1973 https://www.hq.nasa.gov/alsj/tnD7080RadProtect.html

The "Proposed Removal" is interesting. I also read elsewhere that it was thought nuclear blasts could clear holes for astronauts to travel through.

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