Leonard David's INSIDE OUTER SPACE

Remote viewing – image of low, sandy hills. There are higher hills in the horizon. This image was taken by Left Navigation Camera onboard NASA’s Mars rover Curiosity on Sol 3247 September 24, 2021.
Credit: NASA/JPL-Caltech

NASA’s Curiosity Mars rover at Gale Crater is now performing Sol 3251 duties.

Reports Michelle Minitti, a planetary geologist at Framework in Silver Spring, Maryland: “Solar conjunction is once again upon us – the time when the Sun comes between Mars and Earth in their orbital dances and precludes reliable communication between us and our robotic friends.”

Curiosity Front Hazard Avoidance Camera Left B image taken on Sol 3251, September 28, 2021.
Credit: NASA/JPL-Caltech

Since landing in August 2012, this will be the fifth conjunction Curiosity has experienced, “and such a regular, cosmic event like conjunction provides the perfect time to reflect,” Minitti adds, “where were we the last time Mars, Earth and the Sun aligned like this?”

Curiosity Right B Navigation Camera photo taken on Sol 3250, September 27, 2021.
Credit: NASA/JPL-Caltech

Scrapbook memories

Minitti says that looking back over what Curiosity researchers were up to around each conjunction “is very much like looking through a scrapbook of memories.”

Curiosity Left B Navigation Camera image acquired on Sol 3251, September 28, 2021.
Credit: NASA/JPL-Caltech

• First conjunction, starting on Sol 236 (April 2013), fresh off the excitement of finding evidence of a habitable environment in our first drill sample “John Klein,” and still feeling the relief of having survived a major fault with the A side computer. Curiosity runs on the B side computer to this day.
• Second conjunction, on Sol 1004 (May 2015), we had just passed the Sol 1000 milestone and had completed walkabout exploration (on our beat up wheels) of “Pahrump Hills,” the lowest exposed section of Mount Sharp. There we collected three samples of the mudstone-dominated Murray formation. We parked for conjunction at a contact between the Murray formation and another major formation, the Stimson, an aeolian sandstone deposit. Curiosity has continued to encounter variations of both formations throughout her exploration of Gale.
• Third conjunction started on Sol 1756 (July 2017), and we found ourselves sitting on the Murray formation just north of “Vera Rubin Ridge,” looking up at its enticing layering and color variations. Leading up to that point, we had sampled our way across the Stimson-capped “Naukluft Plateau,” maneuvered through the Stimson-capped “Murray Buttes,” and were systematically sampling the Murray formation when the drill fell out of commission. The loss of the ability to drill and deliver sample to the Chemistry & Mineralogy X-Ray Diffraction/X-Ray Fluorescence Instrument (CheMin) and the Sample Analysis at Mars (SAM) Instrument Suite was a blow, but the team, to borrow from our sister rover, persevered to continue building the story of the rocks of Gale with the rest of the payload.
• Fourth conjunction on Sol 2506 (August 2019), Mars investigators had made it up and down Vera Rubin Ridge multiple times and into the clay-bearing “Glen Torridon” region. Our multiple traverses across the ridge were not just for exploration. Since the previous conjunction, the engineers invented a new way to use the drill to once again allow us to collect samples. We revisited terrain to gather samples where it was not previously possible, and gratefully sampled our way into Glen Torridon, We acquired sample #22, the clay-bearing “Glen Etive” sample, right before conjunction. In the midst of all the exploration and sampling, Curiosity also survived a near-global dust storm!
• Fifth conjunction upcoming has the rover sitting just a few meters away from its 33rd drill hole, ”Maria Gordon,” in the shadow of the western side of the “Greenheugh Pediment.” We successfully “summited” the northern edge of the pediment since last conjunction, allowing us to cross over, sample, and analyze yet another (but higher!) Murray-Stimson contact.

Curiosity Right B Navigation Camera photo taken on Sol 3251, September 28, 2021.
Credit: NASA/JPL-Caltech

“We hope to climb up onto the pediment again as we make our way from the clay-rich rocks of the Glen Torridon region toward the anticipated sulfate-rich layers of Mount Sharp above,” Minitti notes. “But for the next few weeks, we will simply pause, look across the view…and appreciate how much we have done and how far we have come.”