Curiosity selfie taken in Glen Torridon region.
Credit: NASA/JPL-Caltech/MSSS

 

 

 

In its on-the-ground Red Planet surveillance, NASA’s Curiosity Mars rover has catalogued a new set of large iron meteorites

The distributions and compositions of iron meteorites are of interest in part because they can constrain models of physiochemical weathering experienced since the space rocks came to full-stop on Mars.

These meteorites serve as “witness plate” rocks, reports Jeffrey Johnson, a planetary geologist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.

Curiosity Mastcam enhanced color images. Top image shows Island Davaar from 21 meters distance. Bottom photo captures Obar Dheathain at 31 meters distance. Note: greenish pixels represent saturation in the image.
Credit: J.R. Johnson, et al.

At a distance

In a paper to be presented at this year’s virtual Lunar and Planetary Science Conference, Johnson and colleagues report that on Sols 2958-2970, Curiosity identified a set of large iron meteorite candidates in November-December of last year.

As the robot meandered in the southern Glen Torridon region, it used a number of onboard tools to take a remote look at the meteorites. The rover acquired Mastcam multispectral images, along with the Chemistry and Camera (ChemCam) acquiring passive spectra of the objects supported by the Remote Micro-Imager (RMI).

Using those instruments, three candidate meteorites – Island Davaar, Obar Dheathain, and Eilean were remotely identified from as far as 410 feet (125 meters) distance. The tagging of them as meteorites is based on the targets’ textures, size, and relatively bluish color.

Portions of ChemCam RMI image mosaics of Eilean.
Credit: NASA/JPL-Caltech/LANL

Portions of ChemCam RMI image mosaics of Obar Dheathain.
Credit: NASA/JPL-Caltech/LANL

Size estimates

The trio of candidate meteorites are the largest seen since the discovery by Curiosity of the Littleton/Lebanon (formally Aeolis Palus 001, 002, 003) meteorites back on Sol 637.

Images from Curiosity’s Navcam stereo camera enabled size estimates of each meteorite: Island Davaar: roughly 0.75 x 1.0 meters; Obar Dheathain: approximately 1.5 x 0.3 meters; and Eilean: roughly 0.5 x 1 meters.

While no ChemCam laser-induced breakdown spectroscopy (LIBS) measurements were acquired of these rocks, Johnson and his co-authors note that the new reflectance data builds upon earlier discoveries of meteorites by Curiosity that used similar methods, as well as use of LIBS. Also used in the new work are previous observations of iron meteorites observed by NASA’s Opportunity Mars Exploration Rover.

Also, go to “Continued Use of Exogenic Materials found on Mars as Planetary Research Tools” submitted to the 2023-2032 Decadal Survey on Planetary Science and Astrobiology. The paper’s primary author is JPL’s James W. Ashley. This paper can be accessed at:

https://mepag.jpl.nasa.gov/reports/decadal2023-2032/AshleyJamesW.pdf

 

Leave a Reply