Final Project

Patti H.

Legislator:  Dan Ellis, Representative

(Click on the image above to enlarge.)

Final Project- Solar Radiation in Space and its Effects on Astronauts

From Unit 4: The Human Factor

The biggest factor in a manned space expedition is to return the astronauts safely.  Solar radiation poses a threat to astronauts on long duration space expeditions.  Because of the lack of an atmosphere in space, there is no protection for the astronauts from solar radiation, except for their shuttle.  This could pose a problem in future attempts to send a manned mission to Mars.

There are three types of radiation: solar radiation, particles from the Van Allen belts, and galactic radiation.  Solar radiation poses the biggest threat because solar flares could happen any time.  Solar radiation can affect structures as well as humans such as the  command and control anomalies on satellite operations and polar cap communications and navigation in aviation.   Between the Apollo 16 and 17 missions, in August of 1972, one of the largest solar proton events ever recorded occurred.  Luckily the astronauts were not in space.  Even inside the spacecraft, the astronauts would have absorbed lethal doses of radiation within 10 hours of the event.  Today, there are early warning systems for solar flares that would give mission controllers time to order astronauts working outside the ship inside before dangerously charged particles could reach the station.  But for time delay, it may not be as effective for a manned mission to Mars, which from Earth could take 7-40 minutes to receive a transmission.  If a solar flare occurred similar to the one in August 1972, the manned mission to Mars could possibly all die.

The amount of solar ration on an astronaut can depend on the structure of the spacecraft, the altitude and inclination of the mission, the orbit phase, EVA start time and duration, and the position of the solar cycle.  NASA provides radiation monitoring on the astronauts to meet the medical and legal requirements, but these could be broken if there is a manned space expedition to Mars, because of the long duration in space.  Mars also has little atmosphere which can allow solar radiation to be almost a bad as it is in space.  A single dose of solar radiation can equal up to hundreds of chest x-rays.  The legal amount is around ten chest x-rays.  Solar storms can often accelerate ions to energies that can penetrate spacesuits and space crafts, which help contribute astronauts receiving more than the recommended amount of radiation.  There are many effects on the human body as a result of exposure to solar radiation.  Large amounts of radiation exposure can lead to radiation sickness and have the potential to damage the body’s chromosomes.  Solar radiation exposure can also lead to cancer, cell damage, and damage to reproductive systems in females and males.  To ward off the effects of radiation sickness, supplementing diets can be helpful.  Bone marrow collection or collection of ova or sperm before the mission can be useful for rebuilding bone and bone tissue loss and having normal offspring upon return to Earth.  Drugs are also now being produced to reduce the effects of radiation from low doses of highly ionizing radiation.  This research may lead to improved responses for patients under going radiation therapy.  To also decrease the amounts of solar radiation, the manned space expedition to Mars should be scheduled during times of decreased solar activity and limit as many expeditions as possible during times of increased solar activity.  If  manned expeditions are planned during times of increased solar activity, the astronauts can be exposed to high enough amounts of radiation to kill them in tow days.  To help NASA with this the space weather operations branch (SWO) continuously monitors, analyzes, and forecasts the environment between the Earth and Sun. 

Solar radiation is one of the leading problems in a manned expedition to Mars.  Until it is safe for astronauts to reach Mars, it should not be attempted.  But with the new technologies happening every day, a solution to the solar radiation problem is near, which will set us one step closer to setting men on Mars.

Sources of information:

1.Unit 4: The Human Factor

2. www.windows.ucar.edu/spaceweather/images/single_dose.html

3. www.indep.k12.mo.us/ths/PW/manned.htm (“Should manned space mission be scheduled during times of increased solar activity?”)

4. www.sec.noda.gov/info/solareffects.html

5. www.nas.edu/ssb/radissch2.htm

6. www.space.cpm/news/astronaut_radiation_991209.html (“Report Warns That Solar Storms Could Harm Space Walking Astronauts”)

7. www.windows.ucar.edu/spaceweather/flare­_dose.html (“How Dangerous are Solar Proton Events to Astronauts”)

8. www.nsbri.org/EarthBenefits/Radiation.html

9. srag-nt.jsc.nasa.gov/FAQ/Protect.htm

Last Updated: 09/07/01