In addition to producing auroras, a recent extreme storm has provided more details about the amount of radiation future astronauts might encounter on the Red Planet.
Mars scientists have been expecting epic solar storms since the sun entered a period of peak activity called solar maximum earlier this year. Over the past month, NASA’s Mars rovers and orbiters have provided researchers with front-row seats to a series of solar flares and coronal mass ejections that have hit Mars — and in some cases even created auroras on Mars.
This scientific bonanza has provided an unprecedented opportunity to study how such events unfold in deep space, and how much radiation exposure the first astronauts on Mars might encounter.
The largest event occurred on May 20, with a solar flare later estimated at an X12 – class and NASA. The outburst emitted X-rays and gamma rays at the Red Planet, while a subsequent coronal mass ejection launched charged particles. Moving at the speed of light, the solar flare’s X-rays and gamma rays arrived first, while the charged particles lagged slightly behind, reaching Mars in just tens of minutes.
The unfolding space weather was closely monitored by analysts at the Moon to Mars Space Weather Analysis Office at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, which flagged the possibility of incoming charged particles following the coronal mass ejection.
If astronauts had stood next to NASA’s Curiosity Mars rover at the time, they would have received a radiation dose of 8,100 microgray, which is equivalent to 30 chest X-rays. Although not fatal, it was the largest increase measured by Curiosity’s Radiation Assessment Detector RAD, since the rover landed twelve years ago.
The data from RAD will help scientists plan for the highest level of radiation exposure that could be encountered by astronauts, who could use the Martian landscape for protection.
“Cliffs or lava tubes would provide an astronaut with additional protection against such an event. In orbit around Mars or in deep space, the dose rate would be significantly higher,” said RAD’s principal investigator, Don Hassler of the Solar System Science and Exploration Division of the Southwest Research Institute in Boulder, Colorado. “I wouldn’t be surprised if this active region of the Sun continues to erupt, meaning more solar storms on both Earth and Mars in the coming weeks.”
During the May 20 event, so much of the storm’s energy hit the surface that black-and-white images from Curiosity’s navigation cameras danced with “snow”: white streaks and dots caused by charged particles hitting the cameras.
Similarly, the star camera that NASA’s 2001 Mars Odyssey orbiter used for orientation was flooded with energy from solar particles, temporarily failing. (Odyssey has other means of orienting itself and recovered the camera within an hour.) Even with the brief interruption in its star camera, the orbiter collected vital data on X-rays, gamma rays and charged particles using its high-energy neutrons. Detector.
This wasn’t Odyssey’s first brush with a solar flare: In 2003, solar particles from a solar flare, eventually estimated to be an X45, broke off Odyssey’s radiation detector, which was designed to measure such events.
High above Curiosity, NASA’s MAVEN (Mars Atmosphere and Volatile EvolutioN) orbiter captured another effect of recent solar activity: glowing auroras above the planet. The way these auroras form is different from those on Earth.
Our home planet is protected from charged particles by a robust magnetic field, which normally limits aurora to areas near the poles. (Solar maximum is the reason behind the recent aurorae seen as far south as Alabama.) Mars lost its internally generated magnetic field in the distant past, so there’s no protection from the barrage of energetic particles. When charged particles hit Mars’ atmosphere, it results in auroras that engulf the entire planet.
During solar events, the sun releases a wide range of energetic particles. Only the most energetic can reach the surface to be measured by RAD. Slightly less energetic particles, which cause aurorae, are observed by MAVEN’s Solar Energetic Particle instrument.
Scientists can use the data from that instrument to rebuild a timeline of each minute as the solar particles screamed by, minutely piecing together how the event unfolded.
“This was the largest solar energetic particle event MAVEN has ever seen,” said Christina Lee, head of MAVEN Space Weather at the University of California, Berkeley’s Space Sciences Laboratory. “There have been several solar events in recent weeks, so we saw wave after wave of particles hitting Mars.”
The data coming in from NASA’s spacecraft won’t just help future planetary missions to the Red Planet. It adds to a wealth of information collected by the agency’s other heliophysics missions, including Voyager, Parker Solar Probe and the upcoming ESCAPADE (Escape and Plasma Acceleration and Dynamics Explorers) mission.
Aiming for a late 2024 launch, ESCAPADE’s two small satellites will orbit Mars and observe space weather from a unique dual perspective that is more detailed than what MAVEN can currently measure alone.
Curiosity was built by NASA’s Jet Propulsion Laboratory, which is operated by Caltech in Pasadena, California. JPL is leading the mission on behalf of NASA’s Science Mission Directorate in Washington.
MAVEN’s principal investigator is based at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder. LASP is also responsible for managing scientific activities, public outreach and communications. 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. NASA’s Jet Propulsion Laboratory in Southern California provides navigation and Deep Space Network support. The MAVEN team is preparing to celebrate the spacecraft’s 10th year on Mars in September 2024.
For more information about these missions, visit:
http://mars.nasa.gov/msl
http://mars.nasa.gov/maven
Andreas Good
Jet Propulsion Laboratory, Pasadena, California.
818-393-2433
andrew.c.good@jpl.nasa.gov
Karen Fox/Charles Blue
NASA Headquarters, Washington
202-358-1600 / 202-802-5345
karen.c.fox@nasa.gov / charles.e.blue@nasa.gov
2024-080