Tag: Perseverance

Click for original image.

Even as the Perseverance science team prepares to cache the ten first core samples on the surface of Mars for later pickup by a future Mars helicopter for return to Earth, they have also released the planned route they intend to follow as they drive the rover up onto the delta that flowed into Jezero Crater in the distant past.

The black line on the map to the right shows that route, with the black dots indicating points in which further core samples will likely be taken. The red dot indicates Perseverance’s present position, with the white line indicating its past travels. The green dot marks Ingenuity’s present position.

The uncertainty of science: Though scientists had assumed the presence of an ancient delta that once flowed into Jezero Crater meant a lake once filled the crater, Perseverance data from its first year of roving has so far found no evidence that a lake every existed.

[A] summary of the first year of data from the rover, published in three different papers being released today, suggests that Perseverance has yet to stumble across any evidence of a watery paradise. Instead, all indications are that water exposure in the areas it explored was limited, and the waters were likely to be near freezing. While this doesn’t rule out that it will find lake deposits later, the environment might not have been as welcoming for life as “a lake in a crater” might have suggested.

Jezero Crater, like Gale Crater where Curiosity is roving, is located in the Martian dry equatorial regions. Though the data from Gale suggests a lake had once existed there, the data also suggests strongly that any water there acted more like water in cold climates like Iceland, existing mostly as glacial ice.

The jury is still out, but these results from Perseverance once again point to ice and glaciers as a possible explanation for many of the geological features on Mars that we on Earth automatically assume were caused by liquid water.

Click for full resolution. The original images can be found here and here.

Click for interactive map.

Cool image time! After spending several weeks at one location at the base of the delta that flowed into Jezero Crater eons ago, the science team today put the rover Perseverance into high gear, programming it to move 684 feet in one leap forward. The move worked, so that Perseverance has now climbed up onto a terrace of that delta so that it sits at the base of one of the hills that forms the delta’s head. The panorama above shows that hill. I estimate that hill is about thirty feet high, give or take 50%.

The blue dot on the map to the right shows the rover’s position. The yellow lines show the area viewed in the panorama above. The green dot shows the location of the helicopter Ingenuity.

It is almost certain that the science team will get another core sample from this location, as it is at least one layer higher on the delta, thus providing new geology for that core to document. I am guessing unfortunately. Unlike the Curiosity science team (which posts updates at least one to three times a week), the Perseverance science team posts updates at best only once a week, if that, and those posts have rarely provided information about the team’s future plans.

The panorama above is cool, but what prompted this post is the image below that the rover took after arriving at this location.
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Our second cool image takes us from grand galaxies, one of the universe’s largest coherent objects, to tiny cobbles on Mars. The picture to the right, taken by one of Perseverance’s close-up cameras on September 29, 2022, covers an area less than an inch across, making the largest rounded pebbles in this image only a few millimeters in size.

The rover presently sits on the floor of Jezero Crater, at the base of the delta that flowed into that crater eons ago. The data suggests that delta was created by flowing water entering a lake that filled the crater.

Did flowing water create these cobbles? These pebbles all have the look of the rounded cobble one finds either in river beds, or in glacial moraines. In both cases, the flow of the water or ice rolls the rocks along until they become rounded.

Two new papers (here and here), published last week in Science and using data obtained during Perseverance’s first year of roving on Mars, strongly suggest that the floor of Jezero Crater was first formed by lava flows, either from impact or later flows from eruptions, followed by a period where liquid water interacted with these igneous materials to produce the chemistry seen today. From the first paper:

After emplacement of the igneous rocks on the crater floor, multiple forms of aqueous interaction modified—but did not destroy—their igneous mineralogy, composition, and texture. Evidence for alteration includes the presence of carbonate in the Séítah abrasion patches, the iron oxides in the Máaz formation abrasion patches (which we presume are due to iron mobilization and precipitation), and the deposition of salts including sulfates and perchlorate. More broadly, the appearance of possible spheroidal weathering textures suggests that aqueous alteration played a role in rock disintegration.

The graphic to the right, figure 6 in the first paper, shows two different models for the geological formation of the floor of Jezero Crater. “Basalt emplacement” are the lava flows.

According to the press release today [pdf], the first core samples that the rover gathered for later pickup and return to Earth will likely show the following:

The salts include sulfates, similar to Epsom salts, which are common on Mars. Most importantly, high levels of chlorine-containing salts are also present, such as chlorides (“table salt”) and perchlorates. These highly soluble salts reveal that the rocks were soaked in brines, and hence contain clear evidence of liquid water.

The on-going big geological mystery of Mars remains. The data suggests liquid water once existed as some form in Jezero Crater. Other data suggests liquid water existed elsewhere on Mars as well. Yet, no model exists that anyone accepts with any confidence that makes it possible for liquid water to exist on the Martian surface. Its atmosphere has always been either too cold or thin.

To underline this conundrum, note that in the graphic above, neither model includes a time period when liquid water sat on top of these layers. Though the evidence calls for liquid water at some time, the scientists do not feel confident enough to include it in these initial models.

One possible explanation that I sense some scientists are beginning to consider is the chemical interaction of melted ice at the base of past long gone ice glaciers. The ice would be frozen, but the glacier’s movement might create pockets of liquid water at its base, which over eons might result in these chemical reactions. If Jezero Crater had once been filled with glaciers, as many Martian craters in the mid-latitudes appear to be now, this could have provided the water necessary for the chemical modifications the scientists are finding.

This theory however is entirely speculative on my part, and has not yet been proposed by any scientists, though I have seen hints of it in a number of different research papers.

Click for full image.

Cool image time! The photo to the right, cropped, reduced, and enhanced to post here, was taken on August 17, 2022 by one of Perseverance’s high resolution camera. It shows the exposed layers of a nearby cliff face that comprises the end of the delta that once flowed into Jezero Crater in the distant Martian past.

My guess is that this cliff is about 20 feet high. The more massive, thicker and younger layers near the top, compared to the thinner and older layers below, suggest a major change in the cyclic events. The early cycles that lay down this delta were initially shorter and able to place less material with each cycle, while the last few cycles were longer, producing thicker layers.

The difference in layers also strongly suggests that all the blocks at the foot of the cliff fell from more massive layers at the top. Material that broke off from the lower thinner layers has likely long ago eroded away.

Click for full image.

Since August 5th, the Perseverance science team has been trying to figure out the origin as well as the consequences of “two string-like pieces” of foreign object debris (FOD as used by today’s acronym-happy scientists) that they have spotted next to one of the rover’s coring drill bits.

The photo to the right, cropped and reduced to post here, looks directly down at that core drill bit and shows one of those strings both to the side of the bit as well in full resolution in the inset. From today’s update:

Since first identified Aug. 5 in imagery of the rover’s sample collection system after a 12th rock core sample was taken, the FOD has been the focus of several methodical diagnostic activities in an attempt to better understand the nature of the debris.

We’ve commanded the rover to move, rotate, or vibrate components we think could harbor FOD. And we’ve obtained multiple sets of images of the components from different angles and in different lighting conditions from rover cameras: Mastcam-Z, Navcam, Hazcam, Supercam, and even the WATSON (Wide Angle Topographic Sensor for Operations and eNgineering) camera located on the rover’s turret. Finally, a thorough review of recent coring and bit-exchange activities confirm that they all executed nominally with no indication of interference from the FOD.

Analysis of the latest round of imaging, downlinked earlier today, indicates that while the two small pieces remain visible in the upper part of the drill chuck, no new FOD has been observed. In addition, imagery taken of the ground beneath the robotic arm and turret, as well as the rover deck, also showed no new FOD.

Because these strings do not appear to interfere in any way with the drill’s operation, the science team has decided neither is a cause for concern, and will therefore command the rover to leave this just-completed drill site and move on to the southwest to a location at the base of the delta the rover visited about three months ago.

The strings themselves are likely pieces from the equipment released during the rover’s landing, and might even have come from the tangled string the rover imaged on the nearby ground in July, and that was gone just four days later. The wind had blown it away, and may have even at that time blown pieces into the drill.