Don’t Add Mars to Your Bucket List

Unless you want to kick the bucket,
Mars is not a good place for humans,
or for anything alive

Mars is fascinating—from a distance. You wouldn’t want to go there. You could not live there. Our fascination with Mars ends at Earth’s magnetic field. From there on out, it’s a shooting gallery with biology as the target.

Radiation will be a real challenge for Mars colonists, powerful solar storm shows (Space.com, 13 June 2024). We’ve reported on the radiation problem on Mars since 2003, but now we have more data sent back by our rovers on the surface experiencing the current solar maximum. Meredith Garofalo includes some animated GIF images from the Curiosity Rover taken when radiation from a massive X12 solar flare hit Mars. Each flickering spot on the animation marks a pixel that got saturated by a charged particle from the solar wind. The radiation exposure to a human standing by the rover would have been like 30 chest X-rays, Garofalo says.

The impacts from this solar event provided quite an education for scientists watching everything unfold. Researchers with NASA’s MAVEN orbiter, 2001 Mars Odyssey orbiter, and Curiosity Mars rover each played key roles in capturing data from the event that will help us better understand our neighboring planet and plan for future crewed visits to it.

“We really got the full range of space weather at Mars from May 11-20, from large flares, CMEs and an extreme solar energetic particle burst, and we’ve only begun to scratch the surface analyzing the data. The May 14th flare really did deliver as expected,” Ed Thiemann, a heliophysicist at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado, Boulder, told Space.com in an email.

As for the notion we could “plan for future crewed visits” to Mars, only crude hopes can be imagined. The charged particles reach all the way to the surface, the article says, because Mars lacks a global magnetic field. Earth’s magnetic field shields life from the barrage, and the atmosphere shields the surface from the most harmful ultraviolet rays.

NASA Watches Mars Light Up During Epic Solar Storm (NASA, 10 June 2024). The animated GIF of particle hits seen by Curiosity is shown in this article, too, as well as another animation of auroras detected by the MAVEN orbiter. Without a magnetic field to deflect the particles to the poles (as on Earth), Mars gets auroras across the sun-facing hemisphere.

“This was the largest solar energetic particle event that MAVEN has ever seen,” said MAVEN Space Weather Lead, Christina Lee of the University of California, Berkeley’s Space Sciences Laboratory. “There have been several solar events in past weeks, so we were seeing wave after wave of particles hitting Mars.”

These were not the only instruments sensing the barrage. Nor was this the first year that major solar events have affected Mars.

Similarly, the star camera NASA’s 2001 Mars Odyssey orbiter uses for orientation was inundated with energy from solar particles, momentarily going out. (Odyssey has other ways to orient itself, and recovered the camera within an hour.) Even with the brief lapse in its star camera, the orbiter collected vital data on X-rays, gamma rays, and charged particles using its High-Energy Neutron Detector.

This wasn’t Odyssey’s first brush with a solar flare: In 2003, solar particles from a solar flare that was ultimately estimated to be an X45 fried Odyssey’s radiation detector, which was designed to measure such events.

A short video from JPL in the article illustrates these phenomena and how their intensity rises and falls in the 11-year solar cycle. (We are nearing Solar Max in the current cycle, which should peak between July 2024 and the end of 2025.) But even though activity rises and falls, it never stops completely. Mars is a radiation target all the time.

Will Humans Live and Work on Mars?

Both articles discuss future astronauts going to Mars. Curiosity’s RAD (radiation detector) measured the high-energy particles reaching the surface. “RAD’s data will help scientists plan for the highest level of radiation exposure that might be encountered by astronauts,” the NASA article says, adding that they “could use on the Martian landscape for protection.” Safe spaces on Mars would include cliffsides and lava tubes. But that’s only part of the danger in human flights to Mars. “In Mars orbit or deep space, the dose rate would be significantly more,” the principal investigator of RAD pointed out. Astronauts would be exposed to ionizing radiation for up to three years on a round trip mission. Even if a crew were not killed en route by a big solar event, they would be exposed to DNA damage and possible dementia from such long exposure in space. It is very difficult to shield them from solar rays and high-energy cosmic rays from outside the solar system.

Engineers are clever and may find ways to protect astronauts on missions to Mars. The Space.com article, however, mentions additional problems with planning long-term missions.

In addition to the safety of humans on the Red Planet, scientists are also worried about agricultural development there. Powerful solar storms like the one last month could make it tougher to plant and grow enough food in the planet’s already challenging environment.

“Since growing plants requires sunlight, energy and lots of room, it will be difficult to grow enough food in lava tubes or caves, even if the colonists are able to supply enough artificial light to sustain their growth,” Skov said. “Unlike Earth, the atmosphere on Mars is so tenuous that energetic particles can penetrate all the way to the ground. This means radiation storms, of one form or another, are a continual problem there. They are like a light drizzle ceaselessly raining down onto the surface, all the time.”

As if these are not concerning enough, CEH has reported other hazards on Mars:

• The highest temperatures at summer noon might reach 70° F, but plunge to 100° below zero at night. Average temperature is -81° F at the equator. Constant energy production would be required to keep humans alive.
• There is no oxygen in its thin atmosphere, so all oxygen for astronauts would have to be supplied.
• Perchlorates are toxic chemicals found on much of the surface (8 May 2013).
• There is likely no water on Mars. How could any life survive without that? (26 Aug 2022).
• If water were found deep below the surface, it would quickly evaporate at the surface (11 Dec 2022).
• Any water under the surface is likely “an extremely cold, concentrated brine, which would be pretty challenging for life” (26 July 2018).
• Due to Mars dryness, the soil is permeated with static electricity that can make the soil cling to everything. Static charges could damage electrical components, especially when frequent dust devils race across the ground.
• Global dust storms occasionally blanket the entire planet for weeks at a time.
• Prolonged weightlessness would weaken astronauts’ muscles, bones and immune systems. Mars missions would last much longer than the longest space station missions, taking potentially irreversible tolls on human physiology.
• Because Mars is rapidly losing its atmosphere (20 July 2018), conditions will only get worse over time.

On top of these physical risks, psychological hazards to astronauts cannot be ruled out. These could include strife, homesickness, claustrophobia, depression over isolation from friends and loved ones, boredom, frustration with constantly having to wear a bulky spacesuit to survive outside, and worry that a malfunction in any life support system could mean instant death.

Impossible dream? The late Carl Sagan was a leading proponent of the search for life on Mars. Now Elon Musk believes migration to Mars is necessary to save humanity.

Remember that popular movies about life on Mars are made in Hollywood on the Earth’s surface where actors are well protected by our planet’s benevolent atmosphere and magnetic field. Even the more realistic movies like The Martian (2015), which illustrated a dust storm and the problem of obtaining food, were made by earthlings on Earth, and forgot to deal with the radiation problems. Our rovers and orbiters can operate for years, and have gathered valuable data, but we have zero experience so far with biology on Mars. One of the episodes in James Michener’s miniseries Space (1985) portrayed an astronaut desperately trying to reach the orbiter when warned that a solar flare was sending charged particles toward the moon. He launched his ascent module, bravely attempting to rendezvous with the orbiter, talking with the controllers in Houston as cheerfully as possible, his voice getting gradually weaker, until communication was lost. Fortunately, that didn’t really happen. But the tragic episode reminded viewers that outer space is dangerous.

Being cooped up for long periods puts severe strain on the human psyche. In the movie The Day After (1983) which portrays the aftermath of a global thermonuclear war, a young couple tries to survive on canned rations in a bomb shelter underground. After a period of time in such confinement, the lady cannot stand it any more, and against the protests and shrieks of her boyfriend, climbs outside and runs across the ground outside, trying to ignore the invisible radiation hazard that was threatening her life. He runs after her. Both die of radiation poisoning. Will the escape impulse be any different for Mars astronauts after months and years in a dark, cold Martian lava tube?

NASA and visionaries like Elon Musk tease youthful dreamers and unrealistic adults about being the first astronauts to Mars. Novels, movies and books make these futuristic hopes seem only a matter of time. But the best scientific findings from NASA have shown just how good we have it on Earth compared to every other place spacecraft have visited. Next time you admire Mars high in the night sky, think about our Privileged Planet.

Recommended Resources:

Spacecraft Earth: A Guide for Passengers by Richter and Coppedge. A calculation in chapter 1 gives reason to believe that Earth may be unique in the universe as a habitat for complex life.

Privileged Species (website) includes a short film illustrating some of the “cosmic coincidences” that made our planet ideal for life. The Books section includes five books by Michael Denton (see first five in the list) that delve into this subject in greater detail.