Two spacecraft catch giant plasma waves lifting Mars’s atmosphere into space

For decades, planetary scientists have known that Mars is still losing its atmosphere — a slow bleed of ions to space that, over billions of years, transformed the planet from a warmer, wetter world into the cold desert we know today. What has been harder to pin down is precisely how the solar wind converts its energy into that loss. A new study in Science Advances, led by Zhang and colleagues and based on coordinated observations from two spacecraft, identifies a mechanism that has probably been doing much of the work all along: enormous plasma waves that form at the edge of Mars’s upper atmosphere and drag ionized material away from the planet as they grow.

Kelvin–Helmholtz at planetary scales

The waves belong to a well-known family in fluid and plasma dynamics — Kelvin–Helmholtz instabilities that appear whenever two flows with different speeds share a boundary. On Mars, the two flows are the solar wind rushing past the planet and the sluggish, gravitationally bound upper atmosphere below. The interface behaves like the surface of a pond in a stiff wind: it ripples, then curls, and eventually breaks. Zhang’s team shows that when the waves grow large enough, their crests carry ionized material outward faster than the planet’s weak gravity can pull it back.

The coordinated measurements — one spacecraft sampling the incoming solar wind, another watching the atmospheric response — allowed the researchers to correlate specific changes in the solar wind with bursts of atmospheric escape, rather than settling for a statistical average. A representative event captured on July 31, 2023 shows a quasi-periodic plasma cloud emerging cleanly from the wave train.

One channel among several

Mars has no global magnetic field to shield its atmosphere, so several loss mechanisms operate at once: photochemical escape, ion pickup by the solar-wind magnetic field, sputtering after solar storms, and now this wave-driven channel. The Zhang result does not claim to fully account for the total loss — the exact fraction contributed by Kelvin–Helmholtz waves will require more observations and simulations, as the authors themselves note — but it adds a specific and probably substantial contributor to a puzzle that has long been dominated by indirect arguments.

From MAVEN to ESCAPADE

The paper draws on data taken during the operational lifetime of NASA’s MAVEN spacecraft, whose mission formally ended on June 3, 2026 after loss of contact the previous December. Continuity for this line of research now depends on ESCAPADE — NASA’s twin-spacecraft mission dedicated to solar-wind-driven atmospheric loss at Mars — which has already launched and will begin science operations after Mars orbit insertion. Kelvin–Helmholtz waves at planetary boundaries are precisely the kind of process ESCAPADE was designed to study with two spacecraft simultaneously, and its dataset should either confirm the picture drawn from MAVEN or complicate it in productive ways.

© 2026 Homer Dávila Gutiérrez, FRAS — SKYCR.ORG. All rights reserved. Publication: Zhang et al., Science Advances (2026). Complementary context: NASA MAVEN mission archive and ESCAPADE mission overview (NASA Heliophysics Division).