Subject Matter Expert:
Today’s high temperature? Mostly
cloudy? Chance of rain? Most of us listen to weather reports
to help us decide what to wear and how to plan our day. Lots
of sun in the forecast? Don’t forget to wear sunscreen. Too
much exposure to ultraviolet
rays from the Sun can lead to
sunburn. We’re lucky here on Earth. Earth’s atmosphere contains
a layer of ozone that prevents most of the ultraviolet rays
from reaching us.
Living in space will be more dangerous. With no ozone protection,
we’ll need to find new ways to protect ourselves from ultraviolet
rays. And ultraviolet rays won’t be our biggest worry. Astronauts
who live and work in space are exposed not only to ultraviolet
rays but also to space radiation.
What do scientists know
about space radiation? It is made mostly of energetic
particles that can enter your body. These particles can penetrate many
objects, even if there is extra shielding for protection.
They can cause cancer, heart problems, and cataracts. Space
radiation can break down tissue in your nervous system and
even damage DNA inside your cells.
Solar storms are one source of space radiation. Their biggest
effect here on Earth is an increase in the Earth’s aurora
(Northern and Southern lights). Though an aurora creates
beautiful bursts of color and light, solar storms can damage
satellites, power grids, and communications.
Solar storm effect can damage things on Earth. On March
6, 1989, a solar storm affected a power grid in Quebec, Canada,
causing six million people to lose power for over nine hours.
In May 1998, a solar storm disabled one satellite that caused
automated teller machines, credit card handling machines,
and 80 percent of all pagers in the United States to stop
Within the Earth’s magnetosphere, Earth's magnetic field
is very powerful and protects the Earth from space radiation.
Mars does not have the same kind of magnetic field as Earth.
While on Mars and while traveling to and from Mars, astronauts
will be exposed to space radiation.
Finding out more about space weather is important to NASA.
In 2001, NASA placed a special space traveler on the International
Space Station (ISS). The traveler, nicknamed “Fred,” was
actually a model of the upper human body. Covered with artificial
skin, this 43-kilogram (95-pound), 0.9-meter (3-foot) high
mock-up contained real bones and plastic organs that closely
matched the density of human tissue. “Fred” spent four months
on the ISS to measure how much radiation the human body absorbs.
Results showed an increase in radiation entering the body,
but scientists did not find as much as they expected. The
levels were about 20 percent less than predicted.
While traveling on the ISS, Fred was still protected by
the Earth’s magnetosphere. Traveling farther into space and
beyond Earth’s protective magnetic fields will be more dangerous.
Weather reports from Mars must give us more information
than what to wear or whether we’ll need an umbrella. Preparing
for space weather will be much more difficult than preparing
for Earth’s weather.