Sampling here wouldn’t surprise me, given the mission’s pace of late, although there’s a lot more outcrop to study just downhill, which makes me wonder if they’re going to be careful and selective. If the long-term plan really is to drive Percy back to the crater floor some time from now, they don’t need to be quite so cautious about preserving tubes as they have been, you’d think…

Close-up, sol 1360, taken in the early afternoon

Close-up, sol 1360, taken in the evening (illuminated by LED)

This stuff doesn’t superficially resemble any of the prior patches closely; this should be fun to dig into!

EDIT: fixed broken link

Why wouldn’t there be avalanches on Mars? It’s a rocky planet, and gravity doesn’t function any differently there. Same goes for Earth’s Moon. Satellites orbiting Mars have managed to catch them in progress, and that I believe was even before the InSight lander proved there are fairly strong groundquakes, which would trigger even more. And this is a planet known for its deep canyons…

Hmm. Well, infrared (from the Sun) and other sources of heat definitely eat away at ice, but that’s more of a thing near the south pole, where the CO2 ice goes away every spring. Rocks have been known to crack due to repeated heating and cooling, yes, so you’ve got the first part of erosion, the breaking part. Moving/transporting broken fragments is another matter, though.

Cosmic rays do cause damage to rocks, but on a much finer scale than the cracking referred to above - you’re not going to get big chunks of the rock to break off as a result. Meteorites and Lunar samples definitely show tiny streaks (“cosmic ray tracks”) when viewed under the microscope, and I’m sure fresh Mars samples will show them as well, but it’s not the kind of thing a rover (or human) would see in the field.

a day of on duststorm days?

Ha, I wish it was just a day.

Adding to what Paul Hammond wrote, Perseverance, the rover itself, has not been forced to stop yet for bad visibility. The storms have never gotten that bad here in Jezero since this mission started 2+ Martian years ago, and we haven’t seen a really bad “global” storm since that 2018 one. Unfortunately, even smaller Martian storms can lift the dust so damned high in the atmosphere that it takes weeks or even months to fall out, and the winter season is known to be dusty, so… we’re stuck with this scenery-killing haze for a while.

Right, the layering/bedding. I see why you’d define those as grooves. Generally speaking, for sedimentary rocks (which these are), some layers “stand out” because they’re more resistant, and some get eroded more easily, making little ridges, which creates the contrast you’re seeing.

I’ve never thought of them as soothing before - but yes, the more rounded ones remind me of underwater sand ripples you’d see in a river or large body of water, which is pretty calming, isn’t it? And since there was so much water in Gale Crater, once upon a time…

EDITED TO ADD: On Earth the “stair-step” pattern that comes to mind for that is shale, but there are plenty of examples!

Paul, let me thank you again for all that you do to keep this community going. I know this question is kind of detailed, but I’d be happy if you could steer me even a little here.

I have some confused impressions about Ingenuity’s last several flights. I seem to remember the flight team (or someone at JPL) mentioning that the drone’s navigation software was having trouble orienting itself above mega-ripples and ripple fields, like the one occupying the Neretva channel, though Ginny had crossed plenty of ripple fields elsewhere in Jezero. If those fields were that disorienting, why was the team determined to fly the drone along that terrain, rather than directly across? (You can see that in flights 68-70, they didn’t take the short way across the ripples, as they did in flights 36-40!) Some stretches of the Neretva channel do have steep sides, admittedly, especially as one moves in the upstream direction. I can imagine that they wanted Ginny to avoid that sloping terrain - well and good; why not follow the edge of the upper fan, then, alongside the channel, as Percy did? I do remember that the terrain was very blocky, and that it was slow going for the rover, but Ginny had navigated such terrain before itself, simply keeping up with the rover. They could have flown Ginny across the same relatively narrow and unrippled reach of Neretva that the rover took on the way to Bright Angel.

For me, the irony of Ingenuity’s loss is that it did not occur in flying over all the variegated terrain of the crater floor - confusing even to geologists - or the steep cliffs of the delta front, or the weird surface of the upper fan… but in a ripple field. On a vertical hop, no less, when no lateral motion was planned. Geoscience me thinks, probably naïvely, that moderately-sized ripple fields like the one in Neretva are among the most organized and benign terrains the landscape offers in this part of Mars. They’re not featureless like the smooth slopes of the crater rim - ripple crests are readily identifiable in Ginny NavCam images as sequential, distinct and curvilinear, forming high-contrast boundaries in most, if not all, cases. So you… land between them, where slopes are gentlest (and the drone didn’t even seem to need the flattest slopes available!) I’m not a coder or engineer by any means, and I’m not trying to say that any of this is easy, but… if ripple fields are disorienting to the point where you must fly over them high and fast, shouldn’t we have avoided them as much as possible?

I’m not sure what you mean by “erosion patterns”. Are you referring to the layers (parallel and mostly curving lines) in some of the boulders?

Worth noting that we’ve traversed about 3.5 km and climbed 400 m since the beginning of the “Crater Rim” campaign, c. sol 1245. This rover really has traveled.

After 8 years of ascending the mountain, this is what it’s come to. As this episode documents very nicely, the rover’s brush tool has been working perfectly all this time… until now. After stumbling over all that raw sulfur and being forced to backtrack over all this rocky terrain - he’s faulty, malfunctioning. Kept babbling on about his mission.

To quote Mars Guy:

that post, spinning at a few hundred RPM, appears to have been jammed into the rock, which was soft enough to result in a shallow hole. Now the remaining question is, after hundreds of uses without jamming the post - what went wrong this time?

These astro-droids are getting quite out of hand. Even I can’t understand their logic at times.

Moderators, would it be possible to add a pinned post or two, with some resources to give people an overview of what Percy has done so far? The mission website outlines things to an extent, but I’d be happy to add some explanatory material. I’m thinking, to give one example, of a post that shows all the abrasion patches Percy has made to date. IRL I get a lot of blank reactions when I try to show people photos of geological materials on a screen, or comments like, “It’s just a rock. So what?” Seeing all of the holes/patches in a montage would be very illuminating, however.

If a pinned post isn’t the best way, I’ll go ahead with making a new post each time we get suitable images from a new patch, but it might be difficult to find in a search. I look forward to your feedback.

Are we really passing up all those tasty-textured boulders on the hill??

Come on, rover team! If you won’t give Percy the pleasure, send me! I’ll core those rocks for free. We really need astrogeologist boots on the ground…

Thanks for posting these. Do you prefer this JPL version of the overhead view to the contour-lined ESA one?

You mean you didn’t manage to get all your wheels dragged through slippery mud, or get sand sliding up and down your back for months at a time?

…

No wonder Percy hasn’t proven the case for biology yet. It’s too damned organic and sexy as it is. No witness tube can help the rover escape its own hot signal. That bot is living its best life!

You mean “notional path to the SSW”, Paul, no?

STOP STOP I’M GETTING A NOSEBLEED

(OK, I know Opportunity was a lot higher up in elevation. But that’s not a fair comparison - “Oppy” was born lucky and everybody knows it. The wind was always at that rover’s back and it never had to land in a 1500 km-wide hole punched out of the highlands…)

Don’t be all proud of yourself. The rover drivers will be given control of the death ray (sorry, the “breakdown laser spectrometer”) when they summit the rim as a reward for their hard work. They’ll be carving out the words, “We Persevered, ******s” into the finest basement rock any rover has ever tasted.

Beat that.

Oy. Less than 5 vertical m cleared after a whole week of short slippy drives. I’m not sure what I was expecting to find on this rim, but this terrain wasn’t it.

EDITED TO ADD: I meant - only 5 m on this drive, after a whole week of slippy drives, with less than 10 vertical m cleared on any one drive. And this is hardly the softest-looking crater rim we’ve seen on Mars…

While I’m being chatty, I’d like to ask you if you have any suggestions re: contributions to this community or instance or whatever we call it. I often see things in the raw images that I feel like pointing out here. In reading social media since this mission started, though, I see vast knowledge gaps in people’s understanding of basic geology (or “earth sciences”, if we can use that term for Mars - maybe “environmental sciences” is a better term), and I sometimes feel I should try to shine a light in those gaps. I’ve thought about breaking down some of the big science papers/results from this mission here, but I wanted to ask you about this first, as I think you have a better feel than I for what people might be interested in actually reading.

You’re talking sense, Paul. As you say, opinions certainly differ, especially among people of different scientific disciplines (e.g. meterology vs. geology), and that even extends to the mission PIs. Steve Squyres was certainly driven and focused in achieving his science goals, which meant that the MER missions drove hard as well. John Grotzinger was criticized for not connecting the dots and “lacking focus” on a big flagship rover. From everything I’ve seen and heard, Ken Farley is being more careful in balancing priorities (and I’d say his job is a lot harder here, considering the needs of sample return!) All that being said, even pure geologists will certainly disagree amongst themselves, though we don’t see that here as interested members of the public.

I’m not privy to the inner workings on this project by any means - certainly not directly. Having observed prior missions from a somewhat closer perspective, however, I see Mars 2020 as very, very driven by the work of other missions and a surprisingly broad community. Orbital spectroscopy and geologic mapping has guided this rover in detail from the very start, to a degree greater than I remember even for MSL, and I’m not aware of much debate about the rover’s planned route at any point since before landing. I was personally quite surprised by the short amount of time that Percy spent in Neretva Vallis (amazing place!), to say nothing of acquiring only one sample. Yes, there aren’t many spots as interesting as Bright Angel along the traverse path, but I still don’t agree that one sample was enough, and I somehow doubt that I’m alone in that opinion.