Some red dwarfs are known to have very turbulent flare activity, so I'm not entirely surprised (although I don't know if this is the case for TRAPPIST-1).

Not trying to be a chauvinist here, but when it comes to understanding planets, astrophysics isn't the be-all and end-all, or planetary science wouldn't exist. Planetary atmospheres are very complex, even simple (and ephemeral) ones like Mercury's, for example.

>people are talking about making rocket fuel out of it

Fair point. It's actually the carbon (as CO2) that worries me in that case - hydrogen should be replenished (albeit very, very slowly), but the carbon is probably from comets, making it acutely precious on Luna. Some have been concerned with preserving the purity of the ice, but you may be right - we can't entirely bootstrap the exploration of the solar system with such a limited resource.

I commend you for trying, but I'm pretty sure you're never going to get through to people stuck in the Musk personality cult. A person who unironically says things like

> Human advancement requires sacrifices

after all the environmental degradation we've seen in the last 200 years of industrialization, and 50 years after "Tragedy of the Commons" was first published, can probably never be made whole. As for the callous and inhuman attitudes you find with Starlink fanatics, this is what I think of when they talk about what they call "human advancement".

Never before has a new industry worked so hard to destroy the very science that birthed it.

Somewhere, Robert Heinlein is smiling (you might really like The Moon is a Harsh Mistress).

Seriously though, who is going to be extracting the water just to remove it from Luna? I'm pretty sure that water/resource recycling is going to be a huge focus once the basic surface infrastructure is in place, more so than aboard the ISS. Even if one or two human crew operations are being stupid with it, there is a fair bit of the stuff (considering), it's not going to disappear that quickly.

Even by the very, very low standards of Canadian science reporting, this is a badly written article. Here's some actual, useful information about the mission:

• The rover would be the first to carry a neutron spectrometer to the south polar region, which will be able to detect hydrogen (in or out of water molecules) and do some basic mineralogy of the surface
• Hydrogen detection would be followed up with UV analysis (a first for a surface mission)
• Do some good old proper rock-sniffing (mineral detection) with a space Christmas tree array of coloured LEDs (sincere apologies to r/fuckyourheadlights)
• Work on its polar tan, Canadian-style (while keeping track of the radiation dose it receives from UV, cosmic rays and the like)
• The one instrument with a proper French name (LAFORGE) comes from... Maryland, namely the Pentagon's research arm Applied Physics Lab at Johns Hopkins. This will be a sort of thermal sensor that will give the rover night vision and allow it to determine the stability and consistency of the surfaces it will be driving on.

The last rover to land, Chang'e 4, carried a similar neutron spectrometer and radiation detector, but the other instruments are fairly new to Lunar surface science, and this mission could prove very useful if successful (the same set of instruments would work well on comets, or the poles of Mercury, for example).

Sure, chuckles, loss of data is no big deal. Especially when you know ahead of time that the transient object/behaviour you're looking for means that the light source has no guarantee of being at the same brightness or position next exposure.

Musk fanatics are forever betraying their ignorance of science. Bye-bye, troll.

What happens when the actual object you're trying to observe is blotted out with an adjacent satellite streak? Vera Rubin will be taking short exposures - lots of them. Wide-field surveys need the sky to be open because, you know, they're looking for unknown sources, or need to see if known sources are doing unexpected things. Why is that difficult to understand?

I'll leave it to the alert reader to actually read the quotes we both provided. The only thing I will say to you about your "in general minor" harms that have no potential for mitigation (and I have provided a source for that statement already):

If observatories are literally unable to carry out part or all the mission objectives for which they are designed (like searching for Atira-type asteroids, which must be searched for at twilight because they orbit the Sun closer than Earth does), you have an interesting definition of the word "minor".

EDITED TO ADD: This comment has been up for hours and stands at a mere minus-2. I'm disappointed in you Musk worshippers, you're off your game here. I suppose I could keep fielding clueless anti-science comments like dern_the_hermit's below all day, but I'm done with this thread. For people that actually want to understand science and the problems that satellite swarms present, please remember that observatories and photometers are not just taking one-off snapshots - they're often taking data over a certain period of time to build up a light curve (a graph of change in brightness versus time), to give just one example. Tearing out gaps in a curve means loss of data that can be irretrievable, especially when an object is doing something unexpected. You can't mathematically reconstruct something that is non-repeatable!

This is borderline Misinformation. You are attempting to create an impression that there is no problem, and that everything has been or will be mitigated. Some choice quotes, with sources:

From that totally disreputable, clickbait publication, Science.org:

> The Rubin Observatory, with an 8.4-meter mirror that will take pictures of the sky the size of 40 full Moons in 30-second exposures, "is the perfect machine for running into these satellites," Tyson says.

> He and his team conducted simulations that suggested the track of a satellite image across their camera would saturate each camera pixel as it passes, and cause leakage into neighboring ones. The resulting artifacts "cannot be removed in software. We have failed in doing that," Tyson says. The team looked at altering schedules to avoid satellite trails, but with such a wide field of view, avoiding thousands of satellites would end up as "a wild goose chase," he says.

Speaking of the Rubin Observatory:

> Simulations of the LSST observing cadence and the full 42,000 SpaceX satellite constellation show that as many as 30% of all LSST images would contain at least one satellite streak. With constellations of 400,000 LEOsats, most images will have very bright streaks.

> Due to its rapid cadence, LSST cannot usefully avoid tens of thousands of LEOsats.

> Darkening satellites to 7th magnitude would simplify removal of some artifacts in LSST images, but there is no guarantee most of the satellites will be limited in brightness to fainter than 7th magnitude.

> The bright main satellite trail would still be present, potentially creating bogus alerts and systematics at low surface brightness. This is a challenge for science data analysis, adding significant effort and potentially limiting discovery of the unexpected.

> However there is a larger challenge: because of the unprecedented large samples, LSST science will be limited by systematics rather than sample variance (area incompleteness). Of concern are various systematic effects that do not simply scale with the number of lost pixels—in other words, the residuals from these mitigation strategies on the science cases for which LSST was designed. For example, the LSST ability to detect asteroids approaching from directions interior to the Earth's orbit may be severely impacted because those directions are visible only during twilight when LEO satellites are brightest—nearly every LSST image taken at this time would be affected by at least one satellite trail. [My emphasis added]

TLDR: I could provide further quotes, especially about the harm to radio astronomy, but the point here is that software can't remove the streak when the CCD has been saturated - that would be like dumping thousands of identical lemons into a bin that initially contains only one or two, shaking the bin vigorously, and then trying to identify the original occupants. This isn't about amateur astrophotography - this is about trying to identify transient phenomena that are captured in single exposures. No software in the world can undo the harm if hardware and physics don't allow for it.

OP, it's nice to see someone thinking about the Galilean moons, and Callisto in particular. All of these worlds are interesting and they fly under the radar quite a bit, so I'm happy to see this post. There was even an announcement last week about Callisto seeing aurorae, which I never saw coming.

I want to first ask about your last point - what do you mean by "the future is in orbit around..."? I understood the second half of the sentence, but not the first.

Re: point #5: Mars is much closer than the Jovian system to the Main Belt, and the vast majority of known asteroids in the inner system. There are some interesting asteroid groups closer to Jupiter (e.g. the Hilda family, or the Trojan clouds that the Lucy mission will be investigating), but Mars has the advantage there in terms of proximity.

Re: point #2: Yes, Callisto is pretty undifferentiated, but not completely so - from what I understand (see papers like this or this) it does have some internal structure. I mention this because I don't think we know enough about weird objects like Callisto (or Ceres, to give the only other remotely comparable example I can think of) to speculate on the ease or difficulty of finding minerals in accessible quantity near the surface. All of our detailed geology experience is from well-structured/differentiated worlds (Earth/Luna/Mars), and we don't know that undifferentiated/messy mantles like Callisto's won't be worse at concentrating ores. I'd be speculating if you asked me about magmatic or hydrothermal processes in such places.

All of that being said, I would humbly like to add one point to your set of arguments: Callisto's location in the Jovian system seems like a huge advantage to me. Jupiter is a fantastic source of magnetic energy and light elements, and the other moons in the system are excellent targets for exploration, especially if you've a base camp on reasonably stable Callisto. Science aside, I wonder if there are resources available on the other Galileans that Callisto may lack, bolstering the overall case. I personally imagine Callisto would be part of a "second wave" of solar system bases/international scientific villages, but this is interesting to think about, for sure. Sign me up for the first expedition!

> The present thinking is that the oxygen will come from ice in deep pockets in crater walls at the Lunar South Pole

Based on this related article from NASA, my understanding is that the oxygen will be extracted directly from the regolith.

Given that they're already going to be processing the stuff to obtain the metals in the first place, that makes more sense than drawing O2 from the ice, and can be done at any old site on Luna, which is not the case if you're dependent on polar ice.

I'm not sure that we know enough about Martian regolith to answer that yet. We really need those samples Perseverance is collecting back here in the lab...

Oxygen production is quite a bit easier on Mars, as it turns out. We've already produced O2 from the CO2 atmosphere. That's a lot easier than importing oxygen from Earth or extracting it from Lunar rock, as per this NASA proposal.

All true (though the proposal is for gaseous oxygen), which is why a long pipeline at the south polar site seems strange to me. Even if the O2 production must be done at a fair distance from the habitat, I'm wondering why it can't be buried in regolith over most of its length, which would partially mitigate some of the issues you mention, not to mention providing protection from meteorites.

OTOH, if you can learn to manage the issues you're identifying here at this site, you do open up a lot of the solar system (asteroids, moons of Mars, airless bodies generally)...

> Nasa’s current research efforts for in-situ oxygen extraction is focused on “bottling” the oxygen in compressed gas tanks or to liquefy and store it in dewars, which are insulated containers used for storing cryogens. Either approach requires moving tanks or dewars to various facilities for use. The process of moving this oxygen on rovers could be more energy intensive than the extraction process itself and could be the most expensive aspect of obtaining in-situ oxygen for use on the Moon.

> For this design study, Lunar Resources and Wood will do a system-level design study of LSPoP. They will explore the feasibility of building pipeline elements on the Moon with the metals found there, which will be extracted using a process called molten regolith electrolysis (MRE) [my emphasis added]. Lunar regolith is the unconsolidated sand-like debris on the surface of the Moon. Full scale test systems of this process on Earth have successfully extracted high-purity iron, aluminum and silicon.

> The starting concept is for a 3.1-mile (five kilometer) pipeline to transport oxygen gas from an oxygen production source to an oxygen storage/liquification plant near a lunar base.

It's not clear to me why you would build essential infrastructure like O2 production at any significant distance from a habitat. Perhaps "pipeline" is giving me the wrong impression here, but I do know this - the same regolith or sources you are processing to extract the metals also give you O2 - silicate rock is not exactly low in oxygen.

The article is fairly informative, but does contain this bit of silliness:

> Extracting oxygen ice and other lunar materials is one thing. Transporting it around a rock floating in space with no gravity or atmosphere is a much more complicated task.

No gravity, huh? I hope the people involved in the study are a little sharper than the author of this piece...

All emphasis added is mine:

> The new Perseverance research is detailed in three extensive studies published Wednesday, one in the journal Science and two in the journal Science Advances. The journal reports are highly technical and devoid of hype — daring to be dull as dirt — but the scientists involved translate them into a more exciting tale.

You mean, like nearly every other science paper ever published? I don't think Ken Farley and the rover team had WaPo reporters in mind when they write them, and I sure wasn't taught to think about that sort of person when writing up either.

> “It’s amazing. In pretty much every rock we’re finding organics,” said Abigail Allwood, a geologist at the NASA Jet Propulsion Laboratory in Pasadena, which operates the rover and the broader Mars Sample Return mission.

Not the first time we've discovered organic material on Mars - MSL/Curiosity has detected the same, and we know that plenty of meteorites have them too. This is still big, though.

> One of the studies concluded that the rocks in the crater experienced three different events in which they were exposed to water.

In other words, it's not as simple as "we found volcanic minerals, never was any water here" or "the floor of this crater is covered in limestone and coral!!!1!". It's something in between, or even something completely different. Sounds about right for Mars.

> “Crucially, conditions in the rock during each time that water migrated through it could have supported small communities of microorganisms,” lead author Michael Tice, a geologist at Texas A&M University, said in an email.

> Even finding organics — life-friendly molecules with combinations of carbon, hydrogen and oxygen — is a far cry from discovering life or even proof of its presence in the past. Such molecules can be either biological or nonbiological in origin.

> One of the new papers more closely examining Mars’s chemistry has delivered a surprise for geologists. They had assumed that they were going to dig up a bunch of sedimentary rocks. Instead the rocks are volcanic.

> The shallow crater clearly had water in it long ago. This could be determined from orbital images showing the remnants of a delta where a river flowed into the lake.

This is not in question, and hasn't been for years. The crater floor rocks are lower than the river delta sedimentary rocks, which are at or near the crater rim.

> Planetary geologists had assumed the floor of the crater was covered in sedimentary rock, formed from dirt and debris that slowly accumulated at the bottom of the lake.

> If such sedimentary rock was ever there, it’s gone now. It may have eroded away, Tice said. The lack of sedimentary rock could mean that the lake didn’t last very long, which would be disappointing for the astrobiologists.

I'm no astrobiologist, but I fully respect their work. Nonetheless, I have two words for everyone involved: Earth bias. In fact, we already know that at least some rock once found in the region has eroded away (there were volcanic layers atop the olivine rocks in the lower crater floor formation).

> The volcanic rocks are not a disappointment, though, because they preserve loads of information about the Martian past, including the presence of organic molecules, scientists said.

> Mars’s magnetic field died, and then it became a different kind of planet. It lost almost all of its atmosphere. It became a frigid desert world. How quickly that happened is unknown, but that’s something that might be revealed by the volcanic rocks in the crater.

> Magma contains some amount of iron, which is sensitive to a planet’s magnetism. As lava cools, it crystallizes into igneous rock, freezing electrons within iron-bearing minerals into patterns that could reveal a magnetic field’s traits, such as its orientation.

> Benjamin Weiss, a planetary scientist at MIT and co-author of two of the papers, said in an email, “On balance, we are actually super lucky that there are igneous rocks in the crater, and that we happened to land right on them, since they are ideal for determining ages and studying the past history of Mars’ magnetic field.”

Ding ding ding Credit to the reporter for getting this part right! So we didn't find a muddy lake bottom or the Great Barrier Reef on the floor of Jezero, but what we found will be super useful in dating the stuff that we know did form under large amounts of water.

> The presence of organic material on Mars had been confirmed in previous missions, but their precise nature and chemistry can’t be discerned through this kind of long-distance research and will require laboratory scrutiny on Earth, according to Bethany Ehlmann, a planetary scientist at Caltech and co-author of two of the new papers.

> “Are they merely organics that kind of washed into the system — maybe from meteoritic material that was just part of the water? That would be the least exciting. Or are they little niches of microbial life living in the cavities of these rocks? That would be the most exciting,” Ehlmann said.

> She added that the rover “is collecting an awesome set of samples to reveal Mars’s environmental history in all of its forms — the volcanic history, the history of water, the relationship of organics to those water-rich environments.”

All the planets from Venus to Neptune have wind, not to mention Titan, Triton and Pluto. There are only two necessary conditions: an atmosphere and a pressure difference between two locations. (Weather reports will talk about high and low pressure systems, yes? The stronger the pressure difference between high and low zones, the faster the wind moves.) Life is not a requirement. In the case of Earth and Mars, pressure differences are created daily by solar heating, so both pre-conditions are easily met.

I'm not entirely sure what you mean by "sustainable atmosphere", but Mars has more than enough to create some very - very - familiar phenomena.

It's not a matter of the absolute pressure/mass of a planet's atmosphere, it's the relative difference in pressure between two locations. The air molecules generally don't care how many other air molecules surround them - they care about moving from more pressure to less pressure. If by "sustainable" you mean "permanent", then Mars qualifies (although Pluto may not). If the air was so affected by the mass of the entire atmosphere, then Earth itself could barely be considered to have winds at all - the speed and motion you see in the atmospheres of Jupiter and Saturn make Earth hurricanes look like a light breeze by comparison.

EDITED to deal with Reddit's lousy formatting.