Probe detects “unknown features” in Martian moon Phobos

What’s underneath?

New functions

The European Space Agency’s (ESA) Mars Express orbiter may be old — it launched in 2003 — but it’s still discovering new clues.

Equipped with a new software upgrade to its Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument, the veteran spacecraft now has a deeper look at Phobosone of the moons of Mars whose origin remains a mystery to astronomers.

“We are still at an early stage of our analysis,” Andrea Cicchetti, a MARSIS team member at the Italian National Institute of Astrophysics, said in a statement. press release. “But we’ve already seen possible signs of previously unknown features beneath the moon’s surface. We’re excited to see the role MARSIS could play in finally solving the mystery surrounding Phobos’ origin.”

Mysterious Moon

Phobos, along with Deimos, are the two small moons of Mars, ominously named after the Greek gods of fear and panic.

Neither, it’s worth noting, is particularly moon-like. They are both small, with Phobos less than 27 miles in diameter, and look more like lumpy asteroids than a spherical moon like Earth’s.

These strange but fascinating features, along with their suspected asteroid-like compositions, have long puzzled astronomers as to their origin.

“Whether Mars’ two small moons are trapped asteroids or made of material ripped from Mars during a collision is an open question,” Mars Express scientist Colin Wilson said in the release. “Their appearance suggests they were asteroids, but the way they orbit Mars suggests otherwise.”

moonlight

That’s where MARSIS comes in. With an antenna more than 30 meters long, MARSIS is able to pick up low-frequency radio waves that can penetrate deep into the core of Phobos. While many of the waves don’t make it past the surface, the ones that do bounce between the internal structures and boundaries of different materials within the mini-moon.

Examining these reflections, captured in a “radargram,” could give scientists a better idea of ​​Phobos’ underground structures, as well as its overall makeup. Bright lines in the radargram indicate more or less harmless surface reflections, but the scientists say there is evidence of fainter, “lower reflections” that could be signs of underground structures.

To unravel this mystery, ESA will work with the Japanese Space Agency to collect samples from the surface of Phobos in the Martian Moon Exploration (MMX) missioncurrently launching in 2024.

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