Mars looks very different today than it did billions of years ago. Scientists believe the planet once had flowing water, a thicker atmosphere, and a much warmer climate. Now the Red Planet is frigid, dry, and surrounded by only a thin layer of air.
Researchers think the biggest reason for this transformation is the solar wind. This steady stream of charged particles flowing outward from the Sun has gradually eroded Mars’ atmosphere over billions of years. As the atmosphere thinned, the planet cooled and much of its surface water disappeared.
NASA is now investigating this process with the ESCAPADE (Escape and Plasma Acceleration and Dynamics Explorers) mission, which launched on Nov. 13, 2025. The mission’s scientific instruments were activated and fully operational as of Feb. 25. These instruments will help scientists study how Mars lost so much of its atmosphere and how the Sun continues to shape the planet today. The spacecraft will also collect new information about space weather while traveling near Earth and during the journey to Mars.
Data gathered once the mission reaches Mars could also help NASA better protect astronauts who may one day explore the planet.
“The pioneering ESCAPADE duo will not only investigate the Sun’s role in transforming Mars into an uninhabitable planet, but also will help inform the development of space weather protocols for solar events directed at Mars during future human missions to the Red Planet,” said Joe Westlake, heliophysics division director at NASA Headquarters in Washington. “By joining the heliophysics fleet of missions across the solar system, ESCAPADE will be another weather station making humans and technology in space safer and more successful.”
A First-of-Its-Kind Mars Mission
ESCAPADE stands out because it uses two spacecraft working together in orbit around Mars. This coordinated approach allows scientists to observe the planet’s magnetic environment from two locations at once, providing insights that a single spacecraft cannot achieve.
The pair of spacecraft will track rapid changes in Mars’ magnetosphere, the region around the planet influenced by magnetic forces. By doing this, researchers hope to identify the processes that allow the Martian atmosphere to slowly leak into space.
“Having two spacecraft is going to help us understand cause and effect — how the solar wind, when it comes to Mars, interacts with the magnetic field,” said Michele Cash, ESCAPADE program scientist at NASA Headquarters.
Previous missions have studied Mars’ atmosphere using a single spacecraft. ESCAPADE builds on that work by giving scientists a simultaneous view from two different positions.
“The ESCAPADE mission is a game changer,” said Rob Lillis, the mission’s principal investigator at the University of California, Berkeley. “It gives us what you might call a stereo perspective — two different vantage points simultaneously.”
When the spacecraft arrive at Mars, they will initially travel along the same orbital path, passing over identical regions at slightly different times. This strategy will help scientists pinpoint when and where changes occur in the planet’s magnetic environment.
“When we have two spacecraft crossing those regions in quick succession, we can monitor how those regions vary on timescales as short as two minutes,” Lillis said. “This will allow us to make measurements we could never make before.”
After about six months, the spacecraft will move into separate orbits. One will remain closer to Mars, while the other will travel farther away. This five month phase will allow researchers to observe the solar wind approaching Mars while simultaneously studying the planet’s response within its magnetosphere.
“Prior spacecraft could either be in the upstream solar wind, or they could be close to the planet measuring its magnetosphere,” Lillis said, “but ESCAPADE allows us to be in two places at once and to simultaneously measure the cause and the effect.”
Preparing for Future Human Missions to Mars
Astronauts traveling to Mars will face much greater exposure to solar radiation than people on Earth.
Earth is protected by a strong global magnetic field that shields the planet from the Sun’s high energy particles. Mars once had a stronger magnetic field as well, but it weakened over time. Today, Mars has scattered regions of magnetism in its crust and a constantly shifting magnetic field created when solar wind interacts with charged particles in the planet’s upper atmosphere.
This unusual combination forms what scientists call a “hybrid” magnetosphere. Unfortunately, it provides limited protection from the solar wind, allowing energetic particles from the Sun to reach the surface more easily. Mars’ thin atmosphere adds to this vulnerability, creating a challenging environment for future explorers.
“Before we send humans to Mars, we need to understand what type of environment these astronauts are going to encounter,” Cash said.
ESCAPADE will also improve scientists’ understanding of Mars’ ionosphere. This region of the upper atmosphere is important because future astronauts will rely on it to transmit radio and navigation signals around the planet, much like communication systems on Earth.
“If we ever want GPS at Mars or long-distance communications, we need to understand the ionosphere,” Lillis said.
An Unusual Route to Mars
Most Mars missions launch during a narrow window when Earth and Mars align in their orbits, an event that occurs about every 26 months. ESCAPADE is testing a different strategy that could make missions to Mars more flexible in the future.
Instead of flying straight to Mars, the spacecraft are currently looping around a point in space about a million miles from Earth known as Lagrange point 2. When Earth and Mars align again in November 2026, the spacecraft will swing back past Earth and use the planet’s gravity to propel themselves toward Mars. The mission is expected to arrive in September 2027.
During this phase, the spacecraft will follow a large “loiter” orbit that stretches roughly 2 million miles from Earth. This path will carry them through an unexplored region of Earth’s distant magnetotail, the part of Earth’s magnetic environment that extends away from the Sun.
“We’re going to be doing some discovery science,” Lillis said. “No one has ever measured Earth’s tail this far away.”
Later, during the 10 month journey to Mars, the spacecraft will continue studying the solar wind and the magnetic conditions of interplanetary space. These are the same environments astronauts will eventually travel through on their way to the Red Planet.
The ESCAPADE mission is funded by NASA’s Heliophysics Division and is part of the NASA Small Innovative Missions for Planetary Exploration program. UC Berkeley’s Space Sciences Laboratory leads the mission with key partners Rocket Lab; NASA’s Goddard Space Flight Center in Greenbelt, Maryland; Embry-Riddle Aeronautical University; Advanced Space; and Blue Origin.