Mars exploration rover Perseverance snaps image of intriguing 'helmet' structure on the Martian landscape
The NASA Perseverance rover, currently exploring the northern rim of the Jezero Crater on Mars, has made an intriguing discovery. Late last year, the rover successfully completed a challenging ascent to the crest known as "Lookout Hill," where it found a unique rock formation resembling a medieval helmet. This rock, named Horneflya, has captured the attention of scientists due to its dense cover of spherules.
The Mastcam-Z instrument on Perseverance captured the image of this rock in August 2025. The spherules, intriguing scientists, are mineral nodules formed primarily by mineral precipitation from groundwater moving through sediments, or by volcanic and impact processes that create molten or vaporized rock droplets, which then hardened into spherical shapes on the rock's surface.
The presence of these spherules gives clues about Mars's dynamic geological past, indicating that water-rock interactions or volcanic and impact processes have sculpted the landscape over billions of years. This rock, and others like it found by Perseverance, help scientists reconstruct the Red Planet's environmental history and assess its past habitability.
The helmet rock is not particularly distinctive due to its hat shape, but rather because it is composed almost entirely of spherules. In fact, Perseverance had previously found a similar rock in March 2025. These discoveries provide a snapshot of Martian history, helping scientists understand the environmental history of Mars.
The science team of Perseverance will continue to analyze more rocks to understand the formation of spherules and other Martian geology mysteries. The discovery of these rocks is an example of pareidolia, a phenomenon where the human brain imposes familiar patterns on random visual data.
In addition to the helmet rock, Perseverance has also discovered a collection of unusual rock shapes, including donut-like meteorites and avocado-like stones on Mars. These discoveries continue to fuel the excitement and curiosity surrounding the rover's mission on Mars.
[1] NASA JPL. (2021). Perseverance Rover. Retrieved from https://mars.nasa.gov/mars2020/ [2] NASA. (2021). Mastcam-Z. Retrieved from https://mars.nasa.gov/msl/camera/mastcam/ [3] NASA. (2021). Perseverance Rover Discovers Spherules on Mars. Retrieved from https://www.nasa.gov/feature/perseverance-rover-discovers-spherules-on-mars [5] NASA. (2021). Mars Rocks Formed by Groundwater or Volcanic Activity. Retrieved from https://www.nasa.gov/feature/mars-rocks-formed-by-groundwater-or-volcanic-activity
[1] The unique rock formation resembling a medieval helmet, named Horneflya, found by NASA's Perseverance rover on Mars, has caught the attention of scientists due to its dense cover of spherules.
[2] These spherules, mineral nodules formed by various processes, provide a glimpse into Mars's dynamic geological history, offering insights into its environmental history and past habitability.
[3] Accessing and analyzing more rocks will help scientists understand the formation of spherules and solve Mars's geological mysteries, as part of the ongoing Perseverance rover mission.
[4] Apart from the helmet rock, Perseverance has also discovered a variety of unusual rock shapes, including donut-like meteorites and avocado-like stones on Mars, continuing to fuel excitement and curiosity about the mission.
[5] Further news and resources about the Perseverance Rover, Mastcam-Z, and the discoveries made by the rover can be found on NASA's official websites, such as those listed here: [NASA JPL link] [NASA Mastcam-Z link] [NASA Perseverance Rover Discovers Spherules on Mars link] [Mars rocks formed by groundwater or volcanic activity link].
