How were engineers able to shield against the Van Allen radiation belt?

[CuriousStudent]

It's to my understanding that the belt holds high-powered protons and such. So how were they able safely get through it for the moon landing?

- Tried to find this on Google but mainly got moon landing hoax topics

[pzkpfw]

Clavius is a good resource:

 

http://www.clavius.org/envrad.html

 

 

(Yes, focused on rebutting hoax nonsense, but the detail you need is in there.)

 

Similar, with more math: http://www.braeunig.us/apollo/VABraddose.htm

 

 

 

Some history: http://www.popsci.com/blog-network/vintage-space/apollo-rocketed-through-van-allen-belts (note the source links at bottom).

Edited March 27, 2017 by pzkpfw

[Enthalpy]

The does of radiation is reduced by shields AND by short residence time. Apollo crews spent some time on low Earth orbit (just like the space station), "below" the belts because residual atmosphere cleans the particles away there, AND they passed quickly through the belts.

 

The belts are lower near the poles and the atmosphere eliminates low particles there. This leaves some limited room "near" the Equator (51° inclination for the ISS nevertheless) where both the radiations and the density of the residual atmosphere are acceptable.

 

Shielding means mass hence can't be perfect. Heavy elements are more efficient per kg but they create gamma rays when stopping charged particles, so at least the outer layers comprise only light elements like C, H, O, N and where needed Al. Magnetic shielding has been investigated and it failed to convince me. And some fraction of the radiation is too energetic to be stopped but still deposits some energy in the human body, so no miracle happens there. This is a concern for a trip to Mars.

 

I didn't re-check, but from memory, the dose on the Moon was worse than when passing the van Allen belts. And it's said that the Apollo astronauts were lucky with the Sun's activity.