Planetside vs. space-based WAS Maintaining very small ecosystems

Ron,

Thanks for those remarks.

Regarding the safety of air travel, by coincidence I ran across and
interesting web site the toehr day which list some hazard of air travel,
interestingly those hazards would not apply to space colonies, making
them safer by comparison.

http://expat.ft.com/ft/gx.cgi/ftc?pagename=View&c=Article&cid=FT3P9PIZTEC&live=true&tagid=FTDP4AZ4QDC§ion=Travel

And even that site neglects to mention the radiation hazard.

Specificially:-

Poor quality of air conditioning is common, bacteria thrive in aircraft
air conditioning systems, transmission of airborne infections between
passengers is common.

Bloot clots and thrombosis (especially in the legs) due to sitting in
cramped conditions for long periods of time.

Indigestion problems due to expanding gases in the digestive tract

Dehydration due to the low pressure.

Elevated radiaiton levels due to increased exposure to cosmic rays at
high altitude.

Reference:-

Radiation Protection Training Course For Radiation Producing Devices
RADIATION PROTECTION TRAINING MANUAL & STUDY GUIDE FOR RADIATION
PRODUCING DEVICES. Jump to the Table of Contents. MAY 1994. LESSON PLAN
OUTLINE....
URL: http://www.inform.umd.edu/CampusInfo/Dep...rpd/device.html

Comparison of Calculated Cosmic-Ray
Doses to a Person Flying in Subsonic and Supersonic Aircraft
Average Solar Conditions

Subsonic Flight Supersonic Flight

at 11 km at 19 km

Dose

per per

Flight round Flight round

duration trip duration trip

Route (hr) (mrad) (hr) (mrad)

Los Angles-Paris 11.1 4.0 3.8 3.7

Chicago-Paris 8.3 3.6 2.8 2.6

New York-Paris 7.4 3.1 2.6 2.4

New York-London 7.0 2.9 2.4 2.2

Los Angles-New York 5.2 1.9 1.9 1.3

Sydney-Acapulco 17.4 4.4 6.2 2.1

Source: UNSCEAR 1977 Report

The table below shows the doses received by astronauts on various space
missions. The largest part of the dose was received when the spacecraft
passed through the earth's radiation belts. The belts contain protons,
electrons, and alpha particles trapped by the earth's magnetic fields.

Absorbed Dose in Chests of Astronauts on Space Missions

Mission or Launch Date Duration of Type of Orbit Dose

Mission Series (Yr-Mo-Dy) Mission (Hr) (mrad)

Apollo VII 68-08-11 260 Earth Orbital 157

Apollo VIII 68-12-21 147 Circumlunar 150

Apollo IX 69-02-03 241 Earth Orbital 196

Apollo X 69-05-18 192 Circumlunar 480

Vostok 18-6 Earth Orbital 2-80

Voskhad 1,2 Earth Orbital 30,70

Soyuz 3-9 Earth Orbital 62-234

Source: UNSCEAR 1977 Report
Individuals living around coal-fired power

Subj: Re: [ssi_list] Planetside vs. space-based WAS Maintaining very
small ecosystems
Date: 06/06/2001 6:37:39 AM Pacific Daylight Time
ssi_list@...

And let me further your comments regarding the safety of space colonies
versus airplanes. Airplanes have to be light in order to fly. A space
colony located a few kilometers away from an NEA could have concrete
walls
of arbitrary thickness --- quite a difference from an airplane. An
airplane has to endure takeoffs and landings, fly through rain, sleet
and
snow. A space colony just has to endure radiation and an occasional
micrometeoroid, both of which can be countered with heavy shielding
built
from local materials.