NASA’s largest interplanetary probe has successfully tested its ice-penetrating radar during a close flyby of Mars, confirming it is ready to hunt for hidden oceans on Jupiter’s moon Europa.
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Jupiter's largest moon, Europa, is thought to hide an ocean beneath its icy surface. To investigate, NASA’s Europa Clipper mission hopes to detect Europa's underground pockets of water, map out the ice, and study its geology using the REASON (Radar for Europa Assessment and Sounding: Ocean to Near-surface) instrument.
A low-frequency radar system, REASON is designed to send radio waves through ice and detect their echoes from below, creating a detailed profile of subsurface structures from the feedback. Two pairs of slender antennas, each stretching to 17.6 metres, will transmit and receive these signals to reveal Europa’s watery mysteries.
A Flyby Test
Having passed extensive grounds tests, Europa Clipper was launched and five months later on 1 March, passed another. Sweeping past Mars at tens of thousands of kilometers per hour, REASON was switched on. Gravity-assisted by the planet, the radar scanned the Martian surface and atmosphere, simulating the kinds of measurements it will make at Europa.
In just 40 minutes, the spacecraft recorded the timing, strength, and clarity of returning echoes to build radargrams, visual representations of the data. This helped verify signal transmission and noise suppression under these speedy spaceflight conditions.
Clear Signals From The Red Planet
The test returned 60 gigabytes of data, with crisp reflections from the Martian surface and even subtle topographic contours. These results confirmed the REASON’s ability to resolve fine details and demonstrated its capacity to probe Europa's surface.
The antennas were deployed correctly and stayed stable, signal quality remained high, and interference was minimal. Engineers compared the in-space results with preflight models, finding strong agreement. This success is a clear indication that the radar should perform as expected in Europa’s challenging environment.
In a press release, Don Blankenship, principal investigator of the radar instrument, said: “We got everything out of the flyby that we dreamed.”
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Ready For The Main Mission
This marks the first time REASON has been operated in space, and its success at Mars demonstrates it is ready for Europa’s complex surface and subsurface studies. When the spacecraft reaches Jupiter’s moon, the radar will help map ice thickness, locate liquid water reservoirs, and profile hidden structures. The data it obtains may reveal the potential for life on the moon.
Reference
Press Release. NASA. NASA’s Europa Clipper Radar Instrument Proves Itself at Mars. Accessed on 1st August 2025. http://nasa.gov/missions/europa-clipper/nasas-europa-clipper-radar-instrument-proves-itself-at-mars/