Do Astronauts Need Sunscreen in Space?

Ultraviolet (UV) light is both useful and hazardous. Learn why sunscreen is helpful on Earth but not in space in this episode of BrainStuff, based on this article: https://science.howstuffworks.com/do-astronauts-need-sunscreen-in-space.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff
Lauren vogebom Here. When NASA astronaut Neil Armstrong took his
one small step out of the Apollo Lunar module, he
looked out at the Moon's surface through overlapping shields. He
was wearing a transparent bubble shaped helmet fitted with visors

(00:25):
that could be raised or lowered at will. The innermost
advisor and the bubble itself were made of polycarbonate shielding,
a material that helped protect Armstrong from getting an overdose
of ultraviolet light in the electromagnetic spectrum. Ultraviolet light has
wavelengths that are a little bit shorter than visible light,
but a little bit longer than X rays. We can't

(00:47):
see UV light with our eyes, but some birds, reptiles,
and insects like bees can. The Sun and other stars
give off UV light. One of the ways we categorize
types of this light is into three bands based on
how much shorter they are than visible light waves. UVA
waves are the longest, UVB waves are shorter, and UVC

(01:08):
rays are the shortest. UVA waves are what's produced in
black lights, and it's used in tanning beds and to
detect all kinds of things arranging from refrigerant leaks to scorpions.
When we're exposed to them, UVA waves can cause skin
tanning and skin aging, and can cause eye damage. Meanwhile,

(01:30):
contact with UVB waves prompts our skin to manufacture vitamin
D three, but too much of it can give you
a sunburn, and over time it can irreparably damage the
DNA in your skin, leading to skin cancer. It also
causes eye damage. UVC waves are the most dangerous because
they're a type of ionizing radiation, meaning that they have

(01:51):
enough energy to knock electrons right out of atoms, which
can change the form and function of whatever those atoms
are a part of, from spacecraft instruments to living flesh.
UVC waves can be used to sterilize surfaces of germs,
and they'll definitely damage humanized in skin. I should clarify
here because I just use the word radiation that all

(02:14):
light and other waves in the electromagnetic spectrum are types
of radiation, but ionizing radiation is the really dangerous category,
you know, your Chernobyl or Godzilla category due to the
effects that I just mentioned. Anyway, it's lucky for us
that Earth's ozone layer absorbs nearly all of the UVC
waves that the Sun gives off and about ninety five

(02:36):
percent of the UVB waves as well. Sunscreen, sunglasses, and
appropriate clothing offer us Earth dwelling folks a good measure
of defense against the UV waves that do pass through
the ozone barrier, But once an astronaut leaves low Earth
orbit and thus leaves the ozone layer behind, they need
a bit more protection. The Moon doesn't have much of

(02:59):
an atmosphere, so its surface is a wash in ultraviolet radiation.
There's evidence to suggest that UV waves may be partially
responsible for the levitating clouds of lunar dust that we've observed.
There are also six American flags on the surface of
the Moon, and astronomers think the decades of UV bombardment
have probably bleached them white by now. And on the

(03:21):
Apollo twelve mission, a TV camera was ruined when an
astronaut accidentally aimed at the Sun with so much unfiltered
UV radiation afoot that you might think that astronauts whose
spacewalk on the Moon or otherwise would come home with
terrible sunburns, But spacesuits, including those donned by the Apollo
Explorers are made with heavy fabrics that block out UV rays.

(03:46):
A member of the Gemini nine crew did get a
triangular sunburn on his back in nineteen sixty three, though
astronaut Jen Sernin had been working on the exterior of
his spacecraft when the outer seams on his suit ripped,
exposing him to solar radiation. But what about those partially
transparent helmets. For these and for some of the attached visors,

(04:09):
designers use ultraviolet stabilized polycarbonate, which is a tough plastic
that protects astronauts faces from UV radiation. Without it, it
would leave the space travelers vulnerable to snowblindness and other
conditions that arise when UV waves damage parts of the
human eye. The risk of UV radiation goes way down

(04:29):
when astronauts are inside a spaceship. Aboard the International Space Station,
for example, astronauts regularly do their work in nothing but
ordinary cotton shirts and pants to protect them from sunburns.
The ISS uses UV blocking windows, as do most space
exploration vehicles, but UV radiation is in the only kind

(04:51):
of radiation that astronauts have to contend with on Earth
are planet's magnetic fields or magnetosphere protect us from other
ionizing radiation, like what's emitted from the Sun during solar flares,
or the cosmic rays that come from outside our solar system.
These can cause all kinds of problems in the human body.

(05:11):
A large dose and a short term, as with exposure to,
say a nuclear weapon, can cause symptoms from vomiting and
bleeding to immune system failure to death. Smaller doses over
a long term can cause cataracts, increased risk of cancers,
and permanent damage to our cardiovascular and central nervous systems.

(05:31):
And unfortunately, these types of space radiation are also more
difficult to control. As of now, we don't have good
ways to block them or mitigate their effects, even in
a spacesuit or on a space station. So right now
our best solution is to just not let astronauts stay
in space for too long. This is one of the

(05:52):
many problems that scientists will have to solve before we
can send people into space for longer missions, such as
a crude mission to Mars or for long work on
the Moon, and scientists are working on it. We just
have to stick closer to home for now. Today's episode
is based on the article do Astronauts meets on screen

(06:14):
and space on HowStuffWorks dot Com, written by Mark Mancini.
Brain Stuff is production of iHeartRadio in partnership with how
stuffworks dot Com and is produced by Tyler Klang. Four
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