Tuesday, April 2, 2019   |   Scientific Development

Insights into Martian Weather (And Beyond)

This mosaic “selfie” shows the deck of the Insight lander soon after landing, along with its temperature and wind sensors. Image credit: NASA/JPL-Caltech.

When the Mars Insight spacecraft landed on the red planet a few days after Thanksgiving in 2018, most of the scientific community’s attention focused on the geophysical aspects of the mission. The lander’s primary objective, after all, is to explore Martian seismology and geology at its landing site in a region called Elysium Planitia.

“Marsquakes” are the key to this mission, but meteorology is well-represented, even though Mars’ atmosphere is exceptionally thin—only 1% as dense as the Earth’s.

It wasn’t always that way. Four billion years ago, Mars was a warmer, wetter place, with standing water and flowing channels common on the surface. Over time, as the planet’s weak magnetic field allowed the sun to strip away its atmosphere, Mars became the dry, frigid desert we know today.

Much like the Curiosity rover currently roaming Gale Crater about 370 miles to the south, the Insight spacecraft carries a meteorology payload. The first instrument, named TWINS (Temperature and Wind for Insight), obtains near-daily measurements of temperature and wind speed/direction for transmission back to earth. Another science package designed to monitor air pressure has even been used to, in a sense, hear the wind on Mars. If you’re interested, NASA makes Martian weather reports available to the public; you can see them at the Mars Insight weather page.

 

As the sun begins to set at the Insight landing site, the evening temperatures rapidly drop. Image credit: NASA/JPL-Caltech.

Due to its thin atmosphere and relative distance from the sun, Mars is cold. Really cold. The highest temperature recorded by Insight so far has been a brisk 10° F. After sunset, temperatures have plunged as low as -161.1° F, as most remaining heat quickly dissipates into space. Like clockwork, surface pressure rises at night, dropping during the day. Winds remain light and calm at the landing site, commonly out of the southwest.

The wind isn’t incidental to a solar-powered mission like this one. Previous missions conducted by the Spirit and Opportunity rovers exceeded their design lifetimes many times thanks to seasonal winds and passing dust devils that cleaned dust from the rovers’ solar panels, providing the energy to survive and remain scientifically productive through several brutal Martian winters.

Mars Insight has a planned mission of at least one Martian year—that’s two full years on Earth—so it will be in place to help scientists document the weather, geology and seismology on Mars’ equatorial plains, contributing to humanity’s record of productive off-planet exploration.

 

Looking backward with its rear navigation camera, the Opportunity rover happened to capture this excellent shot of a passing dust devil. On Mars, dust devils are relatively common, and can occur even when the planet is at its greatest distance from the sun. Image credit: NASA/JPL-Caltech

A close-up of Jupiter’s Great Red Spot as seen by the Voyager 1 spacecraft. Image credit: NASA/JPL-Caltech.

 

And yet there’s much more to learn, even in our own solar system. Saturn’s moon Titan, with its methane rain and seas, can tell us much about the primitive history of our own planet. Closer to home, the overbearing temperatures and surface pressure of Venus show us a greenhouse effect gone wild. And then there are the outer gas giants like Jupiter, where a centuries-old storm the size of the earth dominates views of the planet.

In that context, planetary weather stations are just the beginning. Meteorologists are scientists. As our passion for earth-based meteorology drives us to learn more about our own atmosphere’s secrets, more mysteries above and beyond will remain, just out of easy reach. So when we delve into meteorology, whether here at home or millions of miles away, we are conducting an almost infinite science.