ACUTE

• Felt almost immediately

when a large dose

of radiation is

accumulated in a short

amount of time

• Causes n ausea, vomiting

fatigue, and central

nervous system

diseases , which can lead

to changes in motor

function and behavior

CHRONIC

• Effects can be

experienced decades

after exposure

• Results from an 

accumulated dose of

radiation over a long

period of time

• Causes incre asedrisk of

cancer, cataracts and

vision impairment,

degenerative cardiac

disease

GALACTIC COSMIC 

RADIATION

TRAPPED

RADIATION

SOLAR ENERGETIC

PARTICLES

ULTRAVIOLET

RADIATION

CAN NOT BE PROTECTED AGAINST ONLY INSIDE EARTH’S MAGNETIC FIELD EASIEST TO PROTECT FROM LIGHT FROM THE SUN

TYPES OF RADIATION

RADIATION EFFECTS 

ON HUMANS

This type of radiation 

is emitted as immense 

clouds of high-energy 

charged particles 

thought to originate 

from supernovas.

Solar energetic particles 

are released by the Sun 

in solar particle events. 

This can result in sudden, 

intense storms. 

ORION

AMERICA'S NEXT-GENERATION SPACECRAFT

This type of radiation

occurs when charged 

particles become trapped 

in Earth’s magnetic field 

and spiral around 

inside the field.

IONIZING NON-IONIZING

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.

Ultraviolet radiation is less 

energetic. Particles impart 

energy on to the atoms and 

molecules with which they 

interact, but do not strip

off electrons.

National Aeronautics and Space Administration

www.nasa.gov
The second form is trapped radiation, which occurs 

when radiation becomes trapped in Earth’s magnetic 

field. This type of radiation is not a problem outside of 

Earth’s magnetic field.

Finally, solar energetic particles are released by the 

Sun in what are called solar particle events. This type 

of radiation is lower in energy, and is easier to protect 

astronauts and electronics from with shielding 

materials.

EFFECTS OF SPACE RADIATION ON HUMANS

Space radiation can cause radiation sickness and 

other health problems. These effects are classified as 

either acute, which have immediate impacts on 

humans, or chronic, which affect humans over longer 

periods of time.

Acute Effects

Acute effects can be felt almost immediately when 

a large dose of radiation is accumulated in a short 

amount of time. These effects can include acute 

radiation syndrome, which causes nausea, vomiting 

and fatigue. 

Chronic Effects

Chronic effects are the results of an accumulated 

dose of radiation over longer periods of time. Chronic 

effects include an increased risk of cancer, for 

example. The onset of these diseases can happen 

decades after the exposure to radiation occurs.

COUNTERMEASURES

NASA protects astronauts from radiation in several 

ways during spaceflight. One that requires no special 

equipment is to limit the time humans spend exposed 

to radiation. For example, spacewalks are scheduled 

so that they do not occur during times of intense solar 

activity. Also, NASA limits the amount of radiation 

astronauts are exposed to during their careers. Every 

astronaut is required to wear a dosimeter during 

missions to keep track of the radiation to which they 

have been exposed.

Spacecraft are built with materials that act as shields 

against radiation. Some of the best materials available 

are those that have a high concentration of hydrogen 

atoms, such as water. Most spacecraft include a 

place with additional radiation shielding where the 

astronauts can shelter in place during solar particle 

events. 

ORION’S SPACE RADIATION PROTECTION

Orion is designed for both short missions to nearby 

destinations and long-distance missions to Mars that 

will last more than three years. As the average longduration spaceflights for Americans have lasted about 

six months and have taken place entirely within lowEarth orbit, NASA must be prepared to deal with 

significantly more radiation than astronauts have 

experienced in the past.

Orion will use the mass that is already on board to 

protect its crew by creating a temporary shelter in the 

aft bay of the spacecraft, which is the inside portion 

closest to the heat shield. This location minimizes the 

amount of equipment to move around while 

maximizing the amount of material that can be placed 

between the crew and the outside environment. The 

mass that will be used includes supplies, equipment 

and launch and re-entry seats, as well as water 

and food. By using the items already on board, the 

astronauts benefit from additional shielding without 

adding to Orion’s mass. 

Radiation Sensors Flying on Orion

The Orion spacecraft will have three "passengers" 

equipped with radiation sensors flying on Artemis I. 

The Moonikin, a male-bodied manikin, will be 

equipped with two radiation sensors. Also on board 

are two female-bodied model human torsos, called 

phantoms, also equipped with sensors. "Zohar" and 

"Helga," named by the Israel Space Agency (ISA) and 

the German Aerospace Center (DLR), will support the 

Matroshka AstroRad Radiation Experiment (MARE). 

MARE will provide valuable data on radiation levels 

during missions to the Moon, and assess a new 

radiation-shielding vest for crew. Data from all three 

"passengers" will help NASA protect astronauts from 

radiation during future crewed missions.

Challenges of Spaceflight: 

Dealing with Space Radiation

Orion, America’s next-generation spacecraft, will take 

astronauts to destinations beyond low-Earth orbit and 

thus outside the protective shield of Earth’s 

atmosphere and magnetic field. Without the protection 

Earth provides, the crew and systems of Orion will be 

exposed to the full spectrum of space radiation. To 

prepare for the effects of that exposure, scientists and 

engineers are working now to develop methods to 

protect them. 

THE DIFFERENCES BETWEEN RADIATION ON 

EARTH AND IN SPACE

Radiation on Earth

On Earth’s surface, we are protected from most of the 

radiation of the universe and the Sun by our 

atmosphere and magnetosphere. 

Non-ionizing Radiation

Non-ionizing radiation refers to a less energetic – 

but still harmful – radiation in which particles impart 

energy on to the atoms and molecules with which it 

interacts, but does not strip off electrons. One form of 

non-ionizing radiation is ultraviolet, or UV, radiation, 

which you may be familiar with – we use sunscreen on 

Earth to shield ourselves from harmful UV rays.

Radiation in Space

Ionizing Radiation

There are several forms of ionizing radiation in space. 

Ionizing radiation deposits energy onto the atoms and 

molecules with which it interacts, causing electrons to 

be lost. The resulting ions, or charged particles, give 

this form of radiation its name.

One form of ionizing radiation is galactic cosmic 

radiation. This type of radiation is thought to come 

from supernovae, or exploding stars. While this 

radiation is low intensity, the particles associated with 

galactic cosmic radiation have a high level of energy 

and cannot be shielded with current spacecraft 

design technologies.

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