Chapter 31 -- The Human Body in Outer Space
"There is a more insidious and dangerous part of the space environment
which must be studied extensively before humans can journey much
beyond our immediate planetary system. Radiation occurs in several
different forms.
...
One mystery which has not been solved yet is the missing
white blood cells, the lymphocytes. When astronauts go into space the
lymphocytes decrease. Where did they go? Do these blood cells decrease
even more when a body stays longer in space? What are the implications
for space voyages to Mars? Will the body be able to fight infections
which may occur. Astronauts who have returned from space have had a
tough time fighting infections due to lymphocyte depletions. This is one
mystery which has far-reaching implications for long space flight.
...
Perhaps the most dangerous problem which the human body faces in
space travel is radiation."
Pedemonte: Space Radiation Environment and its Biological Effects
Basically, a review, but definitely discussing the right stuff.
"Along with the long-term space exploration comes various potential
health risks due to unique physical factors of the space environment.[1]
Space radiation is one of the primary environmental hazards associated
with space flight. Crew members are subjected to greater amounts of
natural radiation in space than they receive on Earth, which can result in
immediate and long-term risks. The three major sources of radiation in
space are the trapped belt radiation, the galactic cosmic rays (GCRs),
and the solar particle events (SPEs)."
"the basic mechanism(s) of radiation carcinogenesis remains to be
elucidated. Even less known are the effects of charged particles on
normal tissues."
HUMANS IN SPACE*********good********
starts off with a list of bio-study areas,e.g.
http://www.jsc.nasa.gov/sa/sd/intro/immune.html
"post-flight studies showed that the lymphocytes were
not as effective in responding to challenges. However, astronauts have
shown no increased susceptibility to disease, and lymphocyte counts
returned to normal a few weeks after landing. In spite of this, the
changes in the immune system must be understood and controlled, if
possible, because such changes could have undesirable consequences on
longer space missions."
but reveals some good "hard data" on exposures
Figure 1. Ionizing radiation hazards of space. GALACTIC COSMIC RAYS Hazardous and continuous Annual dose: 10 REM SOLAR WIND No hazard and continuous Protons, electrons, and other particles are low energy with a velocity of 500 km/sec SOLAR FLARE Very hazardous and intermittent but may persist for 1 to 2 days. High energy protons travel at the speed of light so there is no time to get under cover Protected dose 1O-100 REM/hr Unprotected dose Fatal Select here for more information about space radiation.mailto:ken.jenks@jsc.nasa.gov
Space Radiation Health Program*********good********
"The present volume is a collection of abstracts of radiation research
sponsored by the NASA Space Radiation Health Program,
Humans engaged in space activities are exposed to extraterrestrial
radiation, consisting of protons and heavier charged particles. Doses and
dose rates typical of those caused by solar disturbances may impair
crew performance whereas doses and dose rates typical of the galactic
cosmic ray environment are likely to result in longer term effects, most
notably an increase in the probability of cancer induction. The goal of the
NASA Space Radiation Health Program is to establish the scientific basis
for the radiation protection of humans in space. It supports scientific
research into the fundamental mechanisms of radiation effects on living
systems and the interaction of radiation with cells, tissues and organs,
as well as the development of instruments and processes dealing with
the measurement of radiation and its effects. In pursuit of the Space
Radiation Health Program, the Life Sciences Division supports
researchers at universities, NASA centers and national laboratories,
establishes interagency agreements for cooperative use and development
of facilities, and promotes international collaboration with similar
organizations in other spacefaring nations. "
Primer on the Solar Space Environment :
You need to scroll way down the page, but then you'll find the dope:
"Skylab is an example of a spacecraft re-entering Earth's
atmosphere prematurely as a result of higher-than-expected solar
activity. During the great geomagnetic storm of March 1989, four
of the Navy's navigational satellites had to be taken out of service
for up to a week."
...
"Radiation Hazards to Humans
Intense solar flares release very-high-energy particles that can
be as injurious to humans as the low-energy radiation from
nuclear blasts. Earth's atmosphere and magnetosphere allow
adequate protection for us on the ground, but astronauts in space
are subject to potentially lethal dosages of radiation. The
penetration of high-energy particles into living cells, measured as
radiation dose, leads to chromosome damage and, potentially,
cancer. Large doses can be fatal immediately. Solar protons with
energies greater than 30 MeV are particularly hazardous. In
October 1989, the Sun produced enough energetic particles that an
astronaut on the Moon, wearing only a space suit and caught out in
the brunt of the storm, would probably have died. (Astronauts who
had time to gain safety in a shelter beneath moon soil would have
absorbed only slight amounts of radiation.)
Solar proton events can also produce elevated radiation aboard
supersonic aircraft fly ing at high altitudes over the polar caps. To
minimize this risk, routine forecasts and alerts are sent through
the FAA so that a flight in potential danger can alter its course
and reduce altitude to minimize radiation exposure. "
...
"It has been realized and appreciated only in the last few decades that
solar flares, CMEs, and magnetic storms affect people and their
activities. The list of consequences grows in proportion to our
dependence on technological systems. The subtleties of the interactions
between Sun and Earth, and between solar particles and delicate
instruments, have become factors that affect our well being. Thus there
will be continued and intensified need for space environment services to
address health, safety, and commercial needs. "
Space Radiation Risk Assessment
at Armstrong Laboratory
"The Delayed Effects Colony (DEC) of rhesus monkeys includes subjects
exposed to low and intermediate doses of particulate radiations (of the
sorts that are encountered in space or on polar flight routes) in the mid-
to late 1960's. The DEC, declared a "national treasure" by a blue-ribbon
review panel in 1989, continues to provide data on late radiation effects
as it ages, and it is anticipated that the most valuable data from the
survivors will be obtained in the years 1994-1997."
[R]adiation in Free Space
"Due the variability
between events, the radiation dose accumulated due to solar protons may
vary from negligible to well above lethal. The occurence of solar flares
is basically not predictible and, thus, the warning period is only a few
minutes to hours at best. The large fluxes associated with major solar
flare events are potentially lethal to humans in space or on the surfaces
of planets, moons, or asteroids."
Life Science Space Station Program at NASA:Space Radiation Health Program
"...emphasis on the establishment of a firm knowledge base to support
future planetary exploration, and to predict the probabilities of
deleterious health effects due to radiation exposure during human space
activities. The emphasis of this program is on mechanistic studies with
the potential to enable extrapolation of scientific research results to
human beings in space."
http://bnlstb.bio.bnl.gov/www_root/webdocs/nasa/bkgd.html
BETTER (but brief) leads to Joint NASA-BNL Project Background:
"Knowledge of the biological effects of HZE ions has important
implications for human exploration of space. The principal source of HZE
ions in nature is galactic cosmic rays (GCR), which consist mostly of
protons, with small components of helium and heavier nuclei, electrons
and positrons. Although the GCR will be attenuated and fragmented by
electromagnetic and nuclear interactions in shielding material, crew
members will still be exposed to significant radiation from both primary
and secondary nuclei. "
Mars Information Page - Radiation Protection
*%%%I think this document has been altered since I first discovered it!!! fortunately I downloaded a copy!!!! It used to be VERY VERY*good******MY Favorite????**
"Radiation Unknowns & Experiments:
The effects of radiation on humans are not fully understood. For obvious
reasons, experiments are not performed with humans and radiation. Data
comes from experiments with controlled irradiation of cell cultures and
nonhuman organisms. Much of our data for humans comes from analysis
of Japanese atom-bomb survivors. There were also some classified
experiments carried out by the U. S. Department of Defense in the early
days of atomic weaponry. The Russians have a good amount of experience
with the radiation effects of long-term spaceflight, but their space
doctors do not have all the answers."
Space Studies Board
Commission on Physical Sciences, Mathematics,
and Applications
National Research Council
Radiation Hazards to Crews of Interplanetary
Missions:
Biological Issues and Research Strategies
EXECUTIVE SUMMARY
1.INTRODUCTION
Statement of Problem
Contributions and Use of Past Radiation Research
Current Understanding of Biological Effects of Radiation
Types of Effects
Effects Induced by Protons
Effects Induced by Heavy Ions
References
2.ISSUES OF CONCERN TO NASA: DISCUSSION AND CONCLUSIONS
Types of Particles and Their Energies
Galactic Cosmic Rays
Solar Particles
Secondary Particles
Estimates of Uncertainty in Radiation Risk Factors
Conclusions
Biological Effects of Radiation
Early Effects
General Considerations
Early Systemic Effects
Skin
Fertility
Other Organ Systems
Conclusions
Late Effects
General Considerations
Cancer and Uncertainty in Estimates of Its
Induction
Central Nervous System
Cataracts
Heritable Effects
Variation in Susceptibility to Radiation Across
Subject Types
DNA Repair
Repair of Oxidative Damage and Double-Strand
Breaks
Other Studies
Conclusion
Loss of Research Programs
References
3.HOW TO REDUCE RISK AND THE UNCERTAINTY IN RISK ESTIMATES
NASAthesau.radiation: word12523.html
?!?o.k. not much info, just a web of terms, very few of which have actual definitions given, e.g.: "RADIATION DOSAGE
RADIATION EFFECTS
RADIATION HARDENING
RADIATION HAZARDS
RADIATION INJURIES " but gives a sense of the nexus of issues
MedicalPsychological.html
"13 Medical, Psychological, and Social
Considerations on a Lunar Base
13.2 Physiological Effects of the Space Environment on
Humans
In any long-term space endeavor, human beings will invariably be the
weak link in the chain. The human component of any manned space system
is the one part that cannot redesigned by the engineer. Man has evolved
over the past hundreds of millions of years in a terrestrial environment
which provides gravity, atmospheric pressure, and relative safety from
harmful solar and cosmic radiations. Only a small amount is known about
the performance of the human machine in the space environment, and
much more research is needed before many pressing questions can be
answered in even a rudimentary fashion."
"Question:
According to you, which are the new findings in human
physiology and pathophysiology (including biomechanics)
obtained through space research?
Answers: N° of
quotations
1) Central venus pressure changes; blood volume shift; body 16
fluids and electrolytes changes; cardiovascular system in
general; heart volumes/pressures
2) Vestibular and proprioceptive physiology; postural 13
adjustment; motor skill and control
3) Bone metabolism and redistribution; functional and 11
tructural changes in skeletal muscles and in myocardium
4) Physical performance; exercise, LBNP and other 8
countermeasure
5) Neurohormonal system; autonomic system balance; 8
circadian rhythm
6) Applications of telescience. New methods for 4
physiological monitoring
7) Improvement and/or amendment of human physiology 4
"classical" knowledge
8) Blood distribution in lung inhomogeneity; 4
ventilation/perfusion rate; respiratory mechanics;
intrathoracic/intracardiac blood volumes similar to those
standing at 1 g
9) Orthostatic mechanism, intolerance and prevention. 3
Bed rest physiopathology
10) Hypodinamics and physical unloading in space flight 3
11) Nervous and mental phenomena. Plasticity of sensory- 3
motor system
12) Cell division; embriogenesis and development of the 2
otholit system in microgravity
13) Decreased red cells mass 1
14) Plant growth 1
TABLE II
Q uestion:Did they have or might have in the future any
medical application?
Answers: N° of
quotations
1) No answer 11 "how many impacts during EVA? space debris . . .
The Ultimate Space Debris Home Page
Russell D. Hoffman Discusses SPACE DEBRIS
Space Medicinehttp://www.marsacademy.com/med.htm**good**brief ... leads back to a real rah!! rah-mars travel site via the problems of creating and sustaining life in artificial gravity
A History of
the Space Radiation Effects (SPACERAD) Program
for the Joint USAF/NASA
Combined Release/Radiation Effects
Satellite (CRRES) Mission
Concerns effects on EQUIPMENT
"A second major issue in shielding is the "bremsstrahlung" effect.
Laboratory tests have shown that when shielding for a system is
increased beyond a certain point, the secondary radiation produced in the
shielding by the primaries increases, actually leading to higher doses of
the radiation. "
Space Life Sciences Data Archive at the NSSDC lots of cookies
shouldn't use this page but maybe there's some particular page . . .e.g.:
Master Catalogue: http://lsda.jsc.nasa.gov/nm.html
"Experiment Information" consists of drop down menues for searches:
http://lsda.jsc.nasa.gov/scripts/ls_script/exp.idc?
This was the search on "radiation" but I'm not sure it can be linked successfully
http://lsda.jsc.nasa.gov/scripts/ls_script/experiment.idc?
http://lsda.jsc.nasa.gov/scripts/ls_script/exper.idc?exp_index=70
Space Radiation Dosimetry Aboard Cosmos 1129: U.S. Portion of
the Experiment (COS 1129-14)
for a 19 experiment:
RESULTS:
The high-LET particles registered, given as Z spectra and LET
spectra, were translated into rem dose as a function of LET. The
total accumulated doses for the particles (LET > 100 keV/um)
were 9.9 mrem inside and 25 mrem outside the spacecraft. The
thermal, resonance, and high-energy neutron doses were found to
be 0.52, 7.4, and 125 mrem, respectively, and the interior TLD dose
was 347 mrad. The estimated error for this value is » 50% and
results from an uncertainty in the correct background subtraction
for the dosimeters due to an unexplained spurious irradiation of
all the detectors.
Space Environment Effects and Interactions from Space Environment Effects Branch-LeRC, concerns effects on equipment! not humans
Space Rad. Shielding ***##o.k.?#***definitely indirect, if atall useful... Check it out again
SPACELINE INFOIf i only had a password . . . but could i hyper-ref it? dubious
Other Radiation Effects Links???too indirect. All links about radiation effects on equipment.
NO!Individual Exposure Takes Heat in Radiation StudyThis article seems to maintain the absurd proposition that we should eliminate on end of the curve in order to get a better statistical picture. The author argues that "radio-sensitive" people are skewing the curve.
Space Adaptation Syndrome Experimentsnot very good, just a few motion experiments
STS-78 Shuttle Launch Countdown Home Page
Spacelab Life Sciences 2 (SLS-2)
The Astrobiology WebNO....
Radiation Physiology and Protectionnot very useful.....
Space Medicine and Human Factors
???
http://medlib.jsc.nasa.gov/intro/humans.html
GROLIER'S: [DUBIOUS, as if safety could be assured
http://web.idirect.com/~headly/grolier3.html
Should look for links to reports of the Challenger disaster, Apollo 1, Soyuz 11 . . .