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When NASA’s InSight lander touched down on Mars in November 2018, it wasn’t there to roam the surface or search for signs of life. Its mission was more introspective: to listen to the planet’s heartbeat, measure its internal temperature, and study the soil beneath its feet. InSight was the first mission dedicated to exploring the deep interior of Mars—and what it uncovered has reshaped our understanding of the Red Planet.
A Different Kind of Explorer
Unlike rovers like Curiosity and Perseverance, which traverse the Martian landscape, InSight remained stationary. Its primary instruments included a seismometer (SEIS), a heat flow probe (HP3), and a suite of sensors to measure weather and magnetic activity. Together, these tools allowed scientists to peer beneath the surface and study Mars from the inside out.
The seismometer was the star of the show. Designed to detect tiny vibrations in the ground, it recorded hundreds of seismic events—known as marsquakes—over the course of its mission. These quakes revealed that Mars is still geologically active, with internal processes that continue to shape its crust.
Listening to Marsquakes
Marsquakes differ from earthquakes in both intensity and origin. Most are relatively mild, and many are caused by the cooling and contraction of the planet’s interior rather than tectonic plate movement. Still, some quakes were surprisingly strong, with one reaching magnitude 4.7—enough to rattle scientific expectations.
By analyzing the way seismic waves traveled through the Martian crust, mantle, and core, scientists were able to map the planet’s internal structure. They discovered that Mars has a thinner crust than Earth, a mantle rich in olivine, and a surprisingly large liquid core. These findings help explain why Mars lacks a global magnetic field and why its surface is so different from our own.
Soil Secrets and Thermal Mysteries
InSight also attempted to measure the heat flowing from Mars’s interior using a self-hammering probe nicknamed “the mole.” Unfortunately, the mole struggled to burrow into the unexpectedly dense and clumpy Martian soil. While it didn’t reach its intended depth, the experiment still provided valuable data about the soil’s thermal properties and mechanical behavior.
Understanding Martian soil is crucial for future missions. It affects everything from landing stability to habitat construction and resource extraction. InSight’s findings will help engineers design better tools and strategies for long-term exploration and colonization.
Weather and Magnetic Surprises
In addition to seismic and thermal studies, InSight monitored Martian weather. It recorded temperature fluctuations, wind patterns, and atmospheric pressure changes, offering insights into the planet’s daily and seasonal cycles. These observations are vital for planning future crewed missions, where environmental conditions could impact safety and operations.
One unexpected discovery was the detection of faint magnetic signals in the crust. Although Mars lacks a global magnetic field, remnants of ancient magnetism still linger in certain regions. This suggests that Mars may have once had a protective magnetic shield—similar to Earth’s—that faded over time.
NASA’s InSight mission may have ended, but its legacy is just beginning. By listening to Mars, scientists have gained a deeper understanding of its internal structure, geological activity, and environmental dynamics. These insights not only enrich our knowledge of Mars but also help us understand how rocky planets form and evolve.
InSight reminds us that exploration isn’t always about movement—it’s about attention, patience, and listening to the quiet signals beneath the surface. As we prepare for future missions to Mars, including potential human landings, the data from InSight will serve as a foundation for safer, smarter, and more ambitious exploration.
Mars has spoken—and thanks to InSight, we’re finally learning to understand its voice.