A multicoloured 5.6-gigapixel map of Mars is about to provide scientists with a new perspective on the planet. The map, which covers 86 percent of Mars’ surface, reveals the distribution of dozens of key minerals. Scientists can better understand Mars’ watery past and prioritise which regions need more research by looking at mineral distribution.
NASA’s Planetary Data System released the first sections of this map. More will be released over the next six months, completing one of the most detailed surveys of the Martian surface ever made.
For the past 16 years, NASA’s Mars Reconnaissance Orbiter, or MRO, has been mapping minerals on Mars with its Compact Reconnaissance Imaging Spectrometer for Mars, or CRISM.
The CRISM team has previously produced high-resolution mineral maps that provide a record of the formation of the Martian crust and where and how it was altered by water using detectors that see visible and infrared wavelengths. These maps have been instrumental in assisting scientists in understanding how lakes, streams, and groundwater shaped the planet billions of years ago. NASA has also used CRISM maps to select landing sites for other spacecraft, such as the Perseverance rover, which is exploring an ancient river delta in Jezero Crater.
The first section of this new map contains 51,000 images, each representing a “strip” 336 miles (540 kilometres) long by 6 miles (10 kilometres) wide captured as MRO passed overhead. Because the data was acquired with the instrument looking straight down, a different imaging strategy designed to cover much more of the planet, the resolution is lower than CRISM maps made from targeted observations.
CRISM collected data using two spectrometers, one of which was outfitted with three cryocoolers to keep temperatures low enough to detect the longest wavelengths of reflected solar infrared light. The last of these cryocoolers finished its lifecycle in 2017, limiting the instrument’s ability to view visible wavelengths. As a result, this will be CRISM’s final map covering the entire wavelength range of the instrument. The instrument is now in standby mode and may record data a few more times before being decommissioned in the coming months.
One final map, covering visible wavelengths and focusing solely on iron-bearing minerals, will be released within the year, with twice the spatial resolution of the most recent map.
“One of the crown jewels of NASA’s MRO mission has been the CRISM investigation,” said Richard Zurek, the mission’s project scientist at NASA’s Jet Propulsion Laboratory in Southern California. “For many years to come, analyses based on these final maps will provide new insights into the history of Mars.”
