Space Radiation

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Slide 1

Discovery of X-rays Wilhelm Roentgen (1845-1923)

Slide 2

Radiation 101

Non ionizing radiation – Microwaves, UV, laser and etc.

Ionizing radiation – X-rays, alpha, beta and gamma radiation

Energetic particles – Charged particles and neutrons

Slide 3

Radiation 101 (continue)

Slide 4

Radiation 101 (continue)

Space radiation is composed of energetic charged particles (atoms with all of the electrons striped)

Astronauts are exposed to secondary neutrons as well

Slide 5

S

The Space Radiation Environment

N

Slide 6

James Van Allen (1914 – 2006)

Van Allen Belt (Trapped radiation)

Energy spectrum of trapped protons

Slide 7

Galactic Cosmic Radiation (GCR)

Slide 8

Solar particle event (Aurora)

Slide 9

Slide 10

Neutrons

Slide 11

Summary of space radiation environment

Major sources: Trapped protons, GCR, solar particle events

Radiation type: Protons and heavy ions (high-LET)

Energy of interest: 100 MeV/u ~10000 MeV/u

Secondary neutrons

Small amount of other types of radiation

Ultraviolet radiation

Slide 12

Ultraviolet radiation

Ultraviolet (UV) photons harm the DNA molecules of living organisms in different ways. In one common damage event, adjacent bases bond with each other, instead of across the “ladder.” This makes a bulge, and the distorted DNA molecule does not function properly.

Skin cancer and damages to the eye

Most of the spacecraft windows are coated with UV blockers

EVA visors are coated with UV blockers

EVA suit has a layer of material to block UV

Slide 13

DNA damage from ionizing radiation DNA strand breaks

Slide 14

Space Radiation Exposure