• 14 Posts
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Cake day: February 3rd, 2024

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  • Not onboard the rover, no - which is one of the reasons many hardcore types are obsessed with sample return, in spite of the cost and extreme technical difficulty.

    A number of age estimates for stuff in this area (the Jezero crater itself, the old mudstone down in the river delta we sampled last year, and so on) put them at easily 3.5 billion years plus - possibly older. That means the samples Perseverance already has in hand could be just as old as, or even older than, the most ancient sedimentary rock we’ve found on Earth. I get chills thinking about it.


  • Always so strange and wonderful to see how these objects, entirely free of atmosphere or storm, can have such a “soft” look - with craters seemingly buried under a layer of snow or paste, or something. I wonder if that would be that be due to the phenomenon of regolith moving via “seismic shaking”, which is supposed to partially bury smaller features in these asteroid landscapes. Even these preliminary images have enough detail and apparent features to beguile the eye.

    DJ definitely doesn’t appear as “soft” as Deimos or Atlas (out by Saturn), but those two moons are quite a bit larger than this inner main belt asteroid. A lovely reminder that there’s a lot to see in the Belt.


  • You’re not wrong about this thing being bombarded by tiny collisions, but we should note that the impacting bodies that made the craters visible in these images were a lot larger than dust or sand grains. It’s not surprising to see an object like this, within the asteroid belt, covered in simple bowl-shaped craters. From what the New Horizons probe to Pluto and the Kuiper Belt has seen, however, even dust grains are actually pretty sparse in the outer solar system. Even if there actually is a “second Kuiper Belt” as some of the NH team proposes, it isn’t that dusty. In interstellar space, I would expect dust grains to be even rarer, let alone sand or pebbles.

    That being said, interstellar probes will definitely need some form of protection from hypervelocity impacts, however rare they may be. That’s one good reason we should be looking seriously at more modest (and more feasible) proposals for spacecraft that will reach large but attainable distances beyond the heliosphere (say, 75 billion kilometres out from the Sun). The best way to verify the dustiness of nearby interstellar space is to measure it directly. Scouts have their value.


  • We do these abrasions on the rocks before we start analyzing them in detail with the science instruments.

    The geologists prefer not to analyze the raw, eroded outer surfaces of rocks - they tend to be covered in dust and sand, and they’ve been eaten away by the wind, or even (over long timescales) the minor amounts of humidity in the Martian atmosphere. By grinding away the outer surface, the fresh, unaltered interior of the rock is exposed.

    The instruments then let you learn what minerals and other materials are in the rock, hopefully allowing us to ID what we’re looking at. If the instruments turn up interesting results, the science team may decide to take a sample of the rock for eventual return to Earth.

    Hope this helps. Feel free to ask if I wasn’t clear about something.





  • It wasn’t even a trip into orbit. Their rather short voyage was a sub-orbital hop. A low orbit of Earth requires a speed on the order of 8 km per second - Blue Origin can make about Mach 3, from what I read, which is circa 1 km per second. You go up, you go down. That’s it. They don’t even go particularly high (~100 km), and the apogee doesn’t keep you “above the atmosphere” (LOL) for long. Given the risks, I’m not sure it’s worth it, personally.

    If we really want to inspire people by pointing out women’s accomplishments in spaceflight and space exploration, maybe we should be talking about people like Eileen Collins (astronaut on key shuttle/station missions), Lindy Elkin-Stanton (science lead for Psyche, the first to a metallic asteroid), Maria Zuber (lead the GRAIL mission to the Moon, co-discovered the rifts in the Ocean of Storms), or Mimi Aung (lead engineer for the Ingenuity 'copter on Mars 2020). And I’ve only mentioned a few Americans with recent work here; the rest of the world has plenty of enterprising female space scientists and aerospace engineers.

    I share the general distaste in this thread and on Lemmy generally for this sort of celebrity stunt, and I’m glad to see the criticism. I do sometimes think, however, that for a certain kind of person, Bezos and Musk are becoming associated or even synonymous with spaceflight/exploration generally, which is a dangerous association to make. People have many, diverse and very legitimate reasons for going to space - there’s a lot more going on than joyrides and ego trips.










  • AHHH the suspense! Come on relay network, send us the next ones ASAP! I know those sats are busy too, but this wait is killing me.

    I really wasn’t sure we’d abrade here. I mean, we skip past funky-looking darker caprock all the time (for months at a time when Ken Farley is in a hurry)! Even when the rover can physically reach it. Just look at this stuff, it’s craggy and lumpy as anything… but that flattish patch they’re grinding: yes.

    Even with all the evidence for volcanic deposits around here, I honestly wouldn’t guess what this abrasion patch might show us. Volcaniclastic rocks like tuff aren’t the hardest for sure, but this stuff forms the resistant layer here. We focus a lot on sampling with this mission, understandably, but I’d love to read more about the science team’s deliberations over whether we do (or don’t) stop and abrade stuff. We always abrade before we take a sample, so abrasions are just as important as samples in a lot of ways…

    Apologies for the word salad. Paul Hammond knows my pain.



  • In 2004, the Mars Exploration Rover Opportunity spotted so-called, “Martian Blueberries” at Meridiani Planum, and since then, the Curiosity rover has observed spherules in the rocks of Yellowknife Bay at Gale crater. Just a few months ago, Perseverance itself also spied popcorn-like textures in sedimentary rocks exposed in the Jezero crater inlet channel, Neretva Vallis. In each of these cases, the spherules were interpreted as concretions, features that formed by interaction with groundwater circulating through pore spaces in the rock. Not all spherules form this way, however. They also form on Earth by rapid cooling of molten rock droplets formed in a volcanic eruption, for instance, or by the condensation of rock vaporized by a meteorite impact.

    See also this recent Mars Guy episode.