Skip to main content

Rebooted Mars Express instrument peers inside martian moon Phobos

A nearly 20-year-old instrument on the European Space Agency (ESA)’s Mars Express orbiter recently received a software upgrade which has enabled it to study the martian moon Phobos in greater detail than ever before. The Mars Advanced Radar for Subsurface and Ionosphere Sounding or MARSIS instrument was originally designed to study the interior of Mars, but in a recent flyby, it was able to gather close-up data on one of Mars’s two moons.

MARSIS was updated from its Windows 98-based software earlier this summer, allowing it to collect and process data more efficiently. That let it take a deep look at Phobos. “We didn’t know if this was possible,” said ESA’s Simon Wood, who oversaw the upload of the new software, in a statement. “The team tested a few different variations of the software, with the final, successful tweaks uploaded to the spacecraft just hours before the flyby.”

Mars Express HRSC image of Phobos, taken on 7 March 2010.
Mars Express HRSC image of Phobos, taken on 7 March 2010. ESA/DLR/FU Berlin (G. Neukum)

Mars Express made its flyby of Phobos on 23 September, with the craft coming within around 50 miles of the moon. The MARSIS instrument was designed to operate from a much greater distance, as it typically passes over 150 miles from Mars.

“During this flyby, we used MARSIS to study Phobos from as close as 83 km,” said Andrea Cicchetti from the MARSIS team at the Italian National Institute for Astrophysics. “Getting closer allows us to study its structure in more detail and identify important features we would never have been able to see from further away. In future, we are confident we could use MARSIS from closer than 40 km. The orbit of Mars Express has been fine-tuned to get us as close to Phobos as possible during a handful of flybys between 2023 and 2025, which will give us great opportunities to try.”

The MARSIS instrument on ESA's Mars Express spacecraft uses its recently upgraded software to peer beneath the surface of the martian moon Phobos.
The MARSIS instrument on ESA’s Mars Express spacecraft uses its recently upgraded software to peer beneath the surface of the martian moon Phobos. INAF - Istituto Nazionale di Astrofisica

The data collected by MARSIS should help reveal the interior structure of Phobos. The researchers are still analyzing the data, but according to Cicchetti, they have already seen indications of previously unknown features beneath the surface. Understanding the moon’s structure can help to answer questions such as how Mars’s moon formed — whether they were asteroids which got too close to the planet and were captured by its gravity or chunks of the planet  blown off by an impact.

Editors' Recommendations

Georgina Torbet
Georgina is the Digital Trends space writer, covering human space exploration, planetary science, and cosmology. She…
How much fuel is left in this 20-year-old Mars orbiter?
NASA’s 2001 Mars Odyssey orbiter is depicted in this illustration. The mission team spent most of 2021 assessing how much propellant is left on the orbiter, concluding it has enough to stay active through at least 2025.

Designing, building, and launching a spacecraft is hugely expensive. That's why NASA missions to Mars are designed with the hope that they'll last as long as possible -- like the famous Opportunity rover which was supposed to last for 90 days and managed to keep going for 15 years. The longer a mission can keep running, the more data it can collect, and the more we can learn from it.

That's true for the orbiters which travel around Mars as well as the rovers which explore its surface, like the Mars Odyssey spacecraft which was launched in 2001 and has been in orbit around Mars for more than 20 years. But the orbiter can't keep going forever as it will eventually run out of fuel, so figuring out exactly how much fuel is left is important -- but it also turned out to be more complicated than the NASA engineers were expecting.

Read more
Rovers could explore lava tubes on Mars or the moon using breadcrumbs
In this artist's impression of the breadcrumb scenario, autonomous rovers can be seen exploring a lava tube after being deployed by a mother rover that remains at the entrance to maintain contact with an orbiter or a blimp.

When looking for safe places for astronauts to stay when they venture away from Earth to new moons and planets, one strong contender is that they should stay underground. Being underground means more protection from harmful space radiation and less exposure to weather events, and nature already creates environments that could be ideal bases in the form of lava tubes. Created when molten lava flows under the surface, lava tubes are thought to exist on both Mars and the moon, providing potential shelter for human explorers.

Now, new research from engineers at the University of Arizona proposes a method for using robots to scout out lava tubes for use as habitats ahead of the arrival of human astronauts. "Lava tubes and caves would make perfect habitats for astronauts because you don't have to build a structure; you are shielded from harmful cosmic radiation, so all you need to do is make it pretty and cozy," said lead author of the research, Wolfgang Fink, in a statement.

Read more
Mars Curiosity rover finds evidence of water where it was expected to be dry
Curiosity Rover

The key to understanding whether Mars was ever habitable is water. For life as we know it to thrive, liquid water needs to be present -- and we know that even though it is now dry, there was once liquid water on the surface of Mars. However, the history of water on Mars is complex, and scientists are still debating exactly how long water was present there and when the planet dried up.

And it's about to get more complex. Recently, the Curiosity rover has made an intriguing discovery suggesting that water was once present in an area that scientists had thought would be dry.

Read more