Curiosity applies color talents to ‘Vera Rubin Ridge’
The color-discerning abilities of NASA’s Curiosity Mars rover have proven particularly useful as the rover continues its climb of “Vera Rubin Ridge“. In addition to the thousands of full-color images that Curiosity takes every year, the rover can image the Martian surface using special filters that can aid in identifying some minerals – something it has used to scout the terrain it will soon cover.
Curiosity also has a spectrometer that sorts light into thousands of wavelengths, enabling the one-ton robot to “see” beyond visible-light colors into infrared and ultraviolet. The rover team uses these observations in determining where to drive and what target rocks to investigate.
One method for discerning colors uses Curiosity’s Mast Camera (MastCam). Each of the two camera systems that make up MastCam – one telephoto and one wider angle – has several science filters that can be changed from one image to the next to measure how brightly a rock reflects certain colors of light. Some of the filters are for diagnostic wavelengths that specific minerals absorb, rather than reflect. Hematite, an iron oxide mineral that is of particular interest as the rover studies Vera Rubin Ridge, is detectable by using MastCam’s science filters.
“We’re in an area where this capability of Curiosity has a chance to shine,” said Abigail Fraeman of NASA’s Jet Propulsion Laboratory, Pasadena, California, who leads planning for the mission’s investigation of Vera Rubin Ridge.
The Curiosity team had planned to visit Vera Rubin Ridge even before the rover landed on Mars five years ago (Curiosity touched down on the Martian surface in August of 2012). Hematite had been detected in the ridge by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on NASA’s Mars Reconnaissance Orbiter (MRO). Because most hematite forms in the presence of water, the ridge may provide clues about wet environments in Mar’s ancient past.
Curiosity’s ChemCam can also be used to discern colors in the Martian landscape. Although best know for zapping rocks with a laser to identify chemical elements within them, the instrument can also examine targets without firing the laser. It can do this by measuring sunlight reflected by the rocks in thousands of wavelengths. Patterns in this spectral data can be used to identify hematite and other minerals.
“The colors of the rocks on the ridge are more interesting and more variable than what we saw earlier in Curiosity’s traverse,” said science team member Jeffrey Johnson of the Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland. He uses both Mastcam and ChemCam data for analyzing rocks.
The rocks found at this part of Mars contain small grains of hematite which absorb some wavelengths of green light. This gives the hematite a purplish tint because more red and blue light are reflected than green wavelengths. The hematite appears even more clearly when using the color-discerning capabilities of Mastcam and ChemCam.
“We’re using these multi-spectral and hyper-spectral capabilities for examining rocks right in front of the rover and also for reconnaissance – looking ahead to help with choosing where to drive for closer inspection,” Johnson said.
About two weeks ago, Curiosity made an unplanned stop due to communication difficulties, insufficient arm heating, and a camera glitch. During the stop, Curiosity placed its drill on the ground for a test and dropped off a sample of “Ogunquit Beach” sand to the Sample Analysis at Mars (SAM) instrument suite for analysis. The Curiosity team planned to resume driving this week with a drive of about 25 meters (approximately 27 yards) scheduled for Thursday.
Jim Sharkey is a lab assistant, writer and general science enthusiast who grew up in Enid, Oklahoma, the hometown of Skylab and Shuttle astronaut Owen K. Garriott. As a young Star Trek fan he participated in the letter-writing campaign which resulted in the space shuttle prototype being named Enterprise. While his academic studies have ranged from psychology and archaeology to biology, he has never lost his passion for space exploration. Jim began blogging about science, science fiction and futurism in 2004. Jim resides in the San Francisco Bay area and has attended NASA Socials for the Mars Science Laboratory Curiosity rover landing and the NASA LADEE lunar orbiter launch.