National Aeronautics and Space Administration

RADIATION EFFECTS ON HUMANS

ACUTE

• Felt almost immediately when a large dose of radiation is TYPES OF RADIATION accumulated in a short amount of time • Causes n ausea, vomiting fatigue, and cen tral nervous system diseases , which can lead to changes in motor function and behavior The radiation environment of deep space is very different from that at Earth's surface or in low-Earth orbit. For people outside the protection of Earth's magnetic field, space radiation is a serious hazard. ORION AMERICA'S NEXT-GENERATION SPACECRAFT

This type of radiation This type of radiation Solar energetic particles Ultraviolet radiation is less is emitted as immense occurs when charged are released by the Sun energetic. Particles impart clouds of high-energy particles become trapped in solar particle events. energy on to the atoms and charged particles in Earth’s magnetic field This can result in sudden, molecules with which they thought to originate and spiral around intense storms. interact, but do not strip from supernovas. inside the field. off electrons.

IONIZING NON-IONIZING CHRONIC • Effects can be GALACTIC COSMIC TRAPPED SOLAR ENERGETIC ULTRAVIOLET experienced decades after exposure RADIATION RADIATION PARTICLES RADIATION • Results from an accumulated dose of radiation over a long period of time • Causes inc reas ed risk of cancer, cataracts and vision impairment, degenerative cardiac disease CAN NOT BE PROTECTED AGAINST ONLY INSIDE EARTH’S MAGNETIC FIELD EASIEST TO PROTECT FROM LIGHT FROM THE SUN

www.nasa.gov Challenges of Spaceflight: The second form is trapped radiation, which occurs Spacecraft are built with materials that act as shields when radiation becomes trapped in Earth’s magnetic against radiation. Some of the best materials available Dealing with Space Radiation field. This type of radiation is not a problem outside of are those that have a high concentration of hydrogen Earth’s magnetic field. atoms, such as water. Most spacecraft include a Orion, America’s next-generation spacecraft, will place with additional radiation shielding where the take astronauts to destinations beyond low-Earth Finally, solar energetic particles are released by the astronauts can shelter in place during solar particle orbit and thus outside the protective shield of Earth’s Sun in what are called solar particle events. This events. atmosphere and magnetic field. Without the protection type of radiation is lower in energy, and is easier to Earth provides, the crew and systems of Orion will be protect astronauts and electronics from with shielding exposed to the full spectrum of space radiation. To ORION’S SPACE RADIATION PROTECTION materials. prepare for the effects of that exposure, scientists and Orion is designed for both short missions to nearby engineers are working now to develop methods to destinations and long-distance missions to Mars protect them. EFFECTS OF SPACE RADIATION ON HUMANS that will last more than three years. As the average Space radiation can cause radiation sickness and long-duration spaceflights for Americans have lasted THE DIFFERENCES BETWEEN RADIATION ON other health problems. These effects are classified about six months and have taken place entirely within EARTH AND IN SPACE as either acute, which have immediate impacts on low-Earth orbit, NASA must be prepared to deal with humans, or chronic, which affect humans over longer significantly more radiation than astronauts have Radiation on Earth periods of time. experienced in the past. On Earth’s surface, we are protected from most of the radiation of the universe and the Sun by our Acute Effects atmosphere and magnetosphere. Orion will use the mass that is already on board to Acute effects can be felt almost immediately when protect its crew by creating a temporary shelter in the a large dose of radiation is accumulated in a short aft bay of the spacecraft, which is the inside portion Non-ionizing Radiation amount of time. These effects can include acute closest to the heat shield. This location minimizes Non-ionizing radiation refers to a less energetic – radiation syndrome, which causes nausea, vomiting the amount of equipment to move around while but still harmful – radiation in which particles impart and fatigue. maximizing the amount of material that can be placed energy on to the atoms and molecules with which it between the crew and the outside environment. The interacts, but does not strip off electrons. One form of Chronic Effects mass that will be used includes supplies, equipment non-ionizing radiation is ultraviolet, or UV, radiation, and launch and re-entry seats, as well as water which you may be familiar with – we use sunscreen on Chronic effects are the results of an accumulated and food. By using the items already on board, the Earth to shield ourselves from harmful UV rays. dose of radiation over longer periods of time. Chronic astronauts benefit from additional shielding without effects include an increased risk of cancer, for adding to Orion’s mass. example. The onset of these diseases can happen Radiation in Space decades after the exposure to radiation occurs. Ionizing Radiation Radiation Sensors Flying on Orion’s First Mission There are several forms of ionizing radiation in space. COUNTERMEASURES Ionizing radiation deposits energy onto the atoms and The Orion spacecraft will have two types of radiation NASA protects astronauts from radiation in several molecules with which it interacts, causing electrons to sensors on board during its first mission, Exploration ways during spaceflight. One that requires no special be lost. The resulting ions, or charged particles, give Test Flight-1. The first type of sensor is called a equipment is to limit the time humans spend exposed this form of radiation its name. Radiation Area Monitor, or RAM. There will be several to radiation. For example, spacewalks are scheduled of these sensors on board to record the peak level of so that they do not occur during times of intense solar radiation Orion is exposed to during the flight. The One form of ionizing radiation is galactic cosmic activity. Also, NASA limits the amount of radiation second type of radiation sensor being flown is the radiation. This type of radiation is thought to come astronauts are exposed to during their careers. Every Battery-operated Independent Radiation Detector from supernovae, or exploding stars. While this astronaut is required to wear a dosimeter during (BIRD). The BIRD sensor will be recording radiation radiation is low intensity, the particles associated with missions to keep track of the radiation to which they levels throughout the mission for comparison to the galactic cosmic radiation have a high level of energy have been exposed. mission telemetry after the completion of the flight. and cannot be shielded with current spacecraft design This will reveal where the radiation was encountered. technologies.

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