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 Post subject: Space Travel Through the Van Allen Radiation Belt?
PostPosted: Sat Sep 26, 2015 2:53 pm 
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Joined: Wed Nov 07, 2001 6:10 am
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I have always thought the Van Allen Radiation Belt would be a real stumbling block to more space travel but now that I have read more about it I understand it is not that big a deal. Just normal, everyday solar radiation in space will pose a much greater problem on very long space flights such as to Mars as well as maintaining a habitat for humans on Mars. I spent quite a few years in broadcasting at a time when it was more common for radio stations to have their transmitters/towers near the studios. This was necessary since at the time it was not practical to send the audio a long distance to the transmitter sight without losing a lot of frequency response in the process. Nowadays, this is not a problem at all. To my point, we had to basically build a wire cage inside the walls of any room that we did not want to be inundated with RF from the signal that was so strong and so close. Similar to the way you probably have noticed that commercial AM radio signals fail when you go across a steel bridge with overhead steel girders. A sort of cage that won't let the signals through. Ever noticed the fine wire mesh criss-crossing in the back glass on some cars? It's there of course to defrost the window with heat but it also would probably stop nearly all radiation if it were in the face shield of a space suit and meshed close enough. Everything will have to be properly shielded one way or another but it can be done.


Implications for space travel

Spacecraft traveling beyond low Earth orbit leave the protection of earth's geomagnetic field and transit the Van Allen belts. Beyond these, they face additional hazards from cosmic rays and solar flares. A region between the inner and outer Van Allen belts lies at two to four Earth radii and is sometimes referred to as the "safe zone".[26][27]

Solar cells, integrated circuits, and sensors can be damaged by radiation. Geomagnetic storms occasionally damage electronic components on spacecraft. Miniaturization and digitization of electronics and logic circuits have made satellites more vulnerable to radiation, as the total electric charge in these circuits is now small enough so as to be comparable with the charge of incoming ions. Electronics on satellites must be hardened against radiation to operate reliably. The Hubble Space Telescope, among other satellites, often has its sensors turned off when passing through regions of intense radiation.[28] A satellite shielded by 3 mm of aluminum in an elliptic orbit (200 by 20,000 miles (320 by 32,190 km)) passing the radiation belts will receive about 2,500 rem (25 Sv) per year. Almost all radiation will be received while passing the inner belt.[29]

The Apollo missions marked the first event where humans traveled through the Van Allen belts, which was one of several radiation hazards known by mission planners.[30] The astronauts had low exposure in the Van Allen belts due to the short period of time spent flying through them. Apollo flight trajectories bypassed the inner belts completely to send spacecraft though only the thinner areas of the outer belts.[31][32] The command module's inner structure was an aluminum "sandwich" consisting of a welded aluminium inner skin, a thermally bonded honeycomb core, and a thin aluminum "face sheet". The steel honeycomb core and outer face sheets were thermally bonded to the inner skin.

Astronauts' overall exposure was actually dominated by solar particles once outside Earth's magnetic field. The total radiation received by the astronauts varied from mission to mission but was measured to be between 0.16 and 1.14 rads (1.6 and 11.4 mGy), much less than the standard of 5 rem (50 mSv) per year set by the United States Atomic Energy Commission for people who work with radioactivity.[30]

Keep looking at the sky.....
 Post subject: Re: Space Travel Through the Van Allen Radiation Belt?
PostPosted: Sat Sep 26, 2015 6:07 pm 
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Joined: Wed Mar 20, 2013 5:58 pm
Posts: 56
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Very interesting m8, thanks for posting.

 Post subject: Re: Space Travel Through the Van Allen Radiation Belt?
PostPosted: Sat Dec 19, 2015 5:29 pm 
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Joined: Tue Oct 16, 2001 2:07 am
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yes, thanks...

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