This coronal mass ejection, captured by NASA’s Solar Dynamics Observatory, erupted on the Sun Aug. 31, 2012, traveling over 900 miles per second and sending radiation deep into space. Earth’s magnetic field shields it from radiation produced by solar events like this one, while Mars lacks that kind of shielding. NASA/GFSC/SDO
The Sun will be at peak activity this year, providing a rare opportunity to
study how solar storms and radiation could affect future astronauts on the Red
Planet.
In the months ahead, two of NASA’s
Mars spacecraft will have an unprecedented opportunity to study how solar
flares — giant explosions on the Sun’s surface — could affect robots and future
astronauts on the Red Planet.
That’s because the Sun is entering
a period of peak activity called solar maximum, something that occurs roughly
every 11 years. During solar maximum, the Sun is especially prone to throwing
fiery tantrums in a variety of forms — including solar flares and coronal mass ejections — that launch radiation deep into space. When a
series of these solar events erupts, it’s called a solar storm.
Earth’s magnetic field largely
shields our home planet from the effects of these storms. But Mars lost its
global magnetic field long ago, leaving the Red Planet more vulnerable to the
Sun’s energetic particles. Just how intense does solar activity get on Mars?
Researchers hope the current solar maximum will give them a chance to find out.
Before sending humans there, space agencies need to determine, among many other
details, what kind of radiation protection astronauts would require.
Learn how NASA’s MAVEN and the agency’s Curiosity
rover will study solar flares and radiation at Mars during solar maximum – a
period when the Sun is at peak activity. Credit:
NASA/JPL-Caltech/GSFC/SDO/MSSS/University of Colorado
“For humans and assets on the
Martian surface, we don’t have a solid handle on what the effect is from
radiation during solar activity,” said Shannon Curry of the University of
Colorado Boulder’s Laboratory for Atmospheric and Space Physics. Curry is principal
investigator for NASA’s MAVEN (Mars Atmosphere and Volatile EvolutioN)
orbiter, which is managed by NASA’s Goddard Space Flight Center in Greenbelt,
Maryland. “I’d actually love to see the ‘big one’ at Mars this year — a large
event that we can study to understand solar radiation better before astronauts
go to Mars.”
Measuring High
and Low
MAVEN observes radiation, solar
particles, and more from high above Mars. The planet’s thin atmosphere can
affect the intensity of the particles by the time they reach the surface, which
is where NASA’s Curiosity rover comes in. Data from Curiosity’s Radiation
Assessment Detector, or RAD, has helped scientists understand how radiation breaks down carbon-based
molecules on the surface, a process that could affect whether signs of ancient
microbial life are preserved there. The instrument has also provided NASA with
an idea of how much shielding from radiation astronauts could expect by
using caves, lava tubes, or cliff faces for protection.
When a solar event occurs,
scientists look both at the quantity of solar particles and how energetic they
are.
“You can have a million particles
with low energy or 10 particles with extremely high energy,” said RAD’s
principal investigator, Don Hassler of the Boulder, Colorado, office of the
Southwest Research Institute. “While MAVEN’s instruments are more sensitive to
lower-energy ones, RAD is the only instrument capable of seeing the high-energy
ones that make it through the atmosphere to the surface, where astronauts would
be.”
When MAVEN detects a big solar flare, the orbiter’s team lets the Curiosity
team know so they can watch for changes in RAD’s data. The two missions can
even assemble a time series measuring changes down to the half-second as
particles arrive at the Martian atmosphere, interact with it, and eventually
strike the surface.
The MAVEN mission also leads an
early warning system that lets other Mars spacecraft teams know when radiation
levels begin to rise. The heads-up enables missions to turn off instruments
that could be vulnerable to solar flares, which can interfere with electronics and radio communication.
Lost Water
Beyond helping to keep astronauts
and spacecraft safe, studying solar maximum could also lend insight into why
Mars changed from being a warm, wet Earth-like world billions of years ago to
the freezing desert it is today.
The planet is at a point in its
orbit when it’s closest to the Sun, which heats up the atmosphere. That can
cause billowing dust storms to blanket the surface. Sometimes the storms merge,
becoming global.
While there’s little water left on
Mars — mostly ice under the surface and at the poles — some still circulates as
vapor in the atmosphere. Scientists wonder whether global dust storms help to
eject this water vapor, lofting it high above the planet, where the atmosphere
gets stripped away during solar storms. One theory is that this process, repeated enough
times over eons, might explain how Mars went from having lakes and rivers to
virtually no water today.
If a global dust storm were to
occur at the same time as a solar storm, it would provide an opportunity to
test that theory. Scientists are especially excited because this particular
solar maximum is occurring at the start of the dustiest season on Mars, but
they also know that a global dust storm is a rare occurrence.
More About the
Missions
NASA’s Goddard Space Flight Center
in Greenbelt, Maryland, manages the MAVEN mission. Lockheed Martin Space built
the spacecraft and is responsible for mission operations. JPL provides
navigation and Deep Space Network support. The Laboratory for Atmospheric and
Space Physics at the University of Colorado Boulder is responsible for managing
science operations and public outreach and communications.
Curiosity was built by NASA’s Jet
Propulsion Laboratory, which is managed by Caltech in Pasadena, California. JPL
leads the mission on behalf of NASA’s Science Mission Directorate in
Washington. The RAD investigation is supported by NASA’s Heliophysics Division
as part of NASA’s Heliophysics System Observatory (HSO).
Additional information about the
missions can be found at: https://mars.nasa.gov/maven/
Source: NASA Scientists Gear Up for Solar Storms at Mars - NASA
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