I quite appreciate the visceral dislike that people have for Tesla. Given that we see their products directly in our everyday lives, I certainly don't blame people for reacting this way, and I'm happy to encourage this sort of scrutiny, especially over the longer term. I sometimes think, though, that the zeitgeist is missing some of the deeper damage that Musk's enterprises are inflicting. I don't think there's nearly enough journalism about the ongoing effects of DOGE cuts, for example.

And then there's SpaceX. In all the anger over the throttling of Starlink ("Starshield") for the defenders in Ukraine, I haven't seen a single note of awareness about Starlink and LEO satellite megaconstellations being inherently harmful (regardless of who launches them). Aside from the increased orbital collision risk, the atmospheric pollution, and the blinding of astronomical facilities (including asteroid defense), there's the threat to the ozone layer from all that reentering aluminum. All of which will only increase as lunatics continue to use near-orbital space as their dumping ground.

It's a powerful metaphor for our time. When it comes to Tesla, I think there's a good company in there, somewhere. And SpaceX absolutely employs some of the best aerospace talent on the planet, capable of advancing legitimate science and exploration in space. And yet, so many brilliant folk are caught up employing their skills in juvenile displays like flying car stunts and planet-encircling rings of disposable satellites.

I kind of preferred the version without ads (posted earlier today), but I'll comment here to highlight this decent infographic from JPL:

And destroyers.

Just a few months into its reign, the US regime intends to ruin decades of progress in science and space exploration:

On May 30, 2025, the White House Office of Management and Budget announced a plan to cancel no less than 41 space missions — including spacecraft already paid for, launched, and making discoveries — as part of a devastating 47% cut to the agency’s science program. If enacted, this plan would decimate NASA. It would fire a third of the agency’s staff, waste billions of taxpayer dollars, and turn off spacecraft that have been journeying through the Solar System for decades.

Shutting down a working, completely functional mission like New Horizons, in particular, that may just be on the cusp of a huge discovery - it has seen signs of a new, second "ring" to the Kuiper Belt - is the ultimate repudiation of the American self-image as explorers of the frontier. And all of this at a time when the Chinese are just about catching up to "the West" in space science prowess.

As a kid, I never understood what the Romans were trying to say with their Janus myth. Turns out that Orange Janus is simply the god of endings.

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.

Well. This is quite a pearl.

I don't have time to read a 16-page paper in detail, but I did want to know how the host star compares to everyone's favourite local solitary K-type dwarf, Epsilon Eridani. It's slightly less massive (~0.7 solar mass versus 0.8 for ε Eri) and quite a bit less bright (difference of about 0.1 solar luminosity), but I especially wanted to know about the age of the star. ε Eri is quite young and frothy, but the investigators here infer from the star's motion that it belongs to the thin disk, up to a whopping 10 billion years old.

So we are definitely not talking about an ε Eri-type system. So that should be mean no dust disks, no crazy activity from the star, and no newish planets still carving out their places through the system.

You've really got to wonder about such an old planet, however cold and quiescent it may be. The potential paths for climatic evolution on such a world boggle the mind, however cold it is. You could get an episodically or formerly active world like Mars, a beautifully unstable oscillatory world like Earth, or something completely different. Assuming any atmosphere, of course (safe assumption?). And that's without considering whether there are any other planets in the system.

I really wouldn't spend too much time thinking about this candidate detection, as we have literally seen just the one transit, and we will need to observe this fellow for a while to confirm the discovery, learn about other planets in the system, and so on. The investigators themselves note that the transit was shallow (meaning difficult to detect), but the good news is that the host star is fairly bright, well within reach of amateur equipment. I wonder if citizen scientists will be able to follow the transits.

Exciting times.

Some notes --

I have struggled to find earlier MastCam images of this difficult-to-reach part of Percy, but I will post updates if I find any. The science team doesn't image this part of the rover deck very often - at least not of late:

This location at the base of the rover's "neck" (mast) appears partly sheltered from the wind, which is interesting.

Image sources:

Abrasion patch #2
Abrasion patch #18
"Bizarre" purple coating (left)
"Bizarre" purple coating (right)

my 250 million year old salt has expired

laughing in Martian

Yup, that's Earth alright. Rookie numbers, as usual.

well‐preserved, clay and carbonate‐bearing sedimentary fan deposit located on the western edge of the crater

This fan is estimated to have formed approximately 3.2–3.8 billion years ago when ancient streams flowed into the Jezero crater lake

Whether it's checking for sandworms or the Epstein files, I applaud the science team for this new, aggressive search tactic.

I wonder what would have happened if this imbecilic self-indulgence had come after China had successfully launched Chang'e 7. And by "wonder" I mean "dread".

Chang'e 7, whose launch has been delayed, is a highly ambitious and comprehensive (uncrewed) lunar mission incorporating four separate vehicles into a single launch and mission: orbiter, fixed lander, rover, and - an innovative "hopper", which has been previously implemented (by Japan) for landing on a small asteroid, but never a world as large as Luna, or as difficult to navigate.

This is definitely one of the most ambitious space probes ever to be assembled. One might even say the most ambitious, when you consider that the landing site is remarkably close to the South Pole - not the easier or safest region to visit, let alone properly explore. If this mission were going beyond Luna, I'd probably rank it in the same league as Viking or Cassini-Huygens - and in fact, depending on its longevity and science return, I ultimately might have to anyway.

Some have gone so far as to say that this mission represents the point where China's spaceflight abilities are challenging, or even exceeding, the USA's. I'll leave that debate to the side here while noting that the science return from Chang'e 7 looks to be phenomenal and possibly groundbreaking, if they can pull this off. This isn't a "flags and footprints" or purely nationalistic mission; China's already done those. From the science standpoint, this looks like the real thing.

Those who consider Lunar science a dead and settled issue have some shocks coming, both geopolitically - because of the potential for exploitation of Lunar resources and development of military applications) - and scientifically. The equatorial and mid-lat regions of Earth's Moon are not well-explored, despite what people think, with information about the origin and evolution of planets in general. And that's before you consider that the Lunar South Pole could be a repository for comet and asteroid debris that is second to none. Explore that properly, return those samples to your labs, and you could be gathering data on the ultimate development of the atmosphere and biology on Earth.

Lord Rayleigh disagrees, I'm afraid.

This is one of the best dust devil videos ever captured, IMO. Spirit used to catch whole packs of them roaming the great prairie-like floor of Gusev Crater (back when that rover was perched up in the Columbia Hills, I believe), but this devil in the foreground here shows a lot of detail, and is quite close to the camera, unlike those in old shots from Spirit. From what I recall, Percy has been able to capture some nearby dust devils in similar detail, which is unsurprising given that the Jezero region is supposed to be the windiest site we've visited on Mars... but awesome nonetheless.

Just looking at the shadows it casts is very revealing, and watching the thick white patches of the vortex really gives you an idea of the turbulence involved here. It's really cool that we can see the entire length of the shadows being cast; I wonder if this is one reason why these shots were taken near noon, rather than later in the afternoon, around the time of maximum daily heating.

For scale, the crater at the bottom left is 300 m across from left to right, so you can tell that the "foot" of the foreground devil is quite a bit bigger than Percy itself. So much to see here!

Sky colors are generally weather-dependent, even seasonal in nature. During dust storms (see, for example, the disastrous global storm of 2018) the sky gets darker and muddier. Cloudy days and evenings can add some different colors, and then of course there are the famous pale blue sunsets.

The question of whether Mars gets blue skies has been debated for decades. Personally, aside from the sunsets, I don't see what conditions could produce the blue skies you find on other worlds with much thicker atmospheres; the dust just never completely settles out enough to wash those reddish tones away altogether. The debate will continue, but there's probably only one to settle it - sending humans.

I should add that there are plenty of shots with the horizon included from every landed mission, in case you're curious.

I'm sensing jest here, but for those not in the know, the rover makes these patches with its Rock Abrasion Tool:

https://www.youtube.com/watch?v=INlSAGD01q8

The purpose of the abrasion is to grind awway the outer rind of material on the surface of the rock. We do that because that outer "skin" has been eroded by sand, wind and even moisture for up to billions of years. Geologists would like to see the fresh, untouched interior of the rock, so Percy abrades the outer few millimetres. In the case of this abrasion, we got a truly glorious result in doing so.

I need to write up a FAQ for the whole process and science of abrasions that this rover makes, but I'm a little delayed right now by all the amazing stuff this mission keeps throwing at us...

😃 I hope some rover drivers get to see this question - it's a very good one, just funny if you've seen the whole mission.

In the past - before Curiosity landed - NASA definitely chose rover landing sites based in part on their (presumed) smoothness and traversability (e.g. Opportunity). This was also true for the first Chinese lander.

In the case of Perseverance, the "rockiness" in this region actually varies quite a bit over fairly short distances. The terrain we've been exploring since late 2024 was chosen for two reasons: ease of traversal (when we were climbing out of the Jezero Crater) and science (our current location, Witch Hazel Hill). When we were down on the old river delta last year, though, the rover drivers had a very difficult time with terrain like this and this.

Witch Hazel Hill is smooth in part because the bedrock here is soft and easily eroded. Quite a bit of it has significant clay content, like you'd find in Earth soils, due to heavy interaction with water in the geologic past. Down on the crater floor where we landed, where the terrain is made of volcanic rocks, there are scenes like this. In the end, the rover drivers are pretty protective of their vehicle, so we tend to prefer smooth stretches for driving.

In the USA we wasted time, money, and media resources going to the moon while black people were treated as less than citizens and millions were living in abject poverty. Not much has changed on that front for the countries entire history. What good did the moon landing do for the average man?

I'm sincerely wondering if you'd like an answer to your question. I can provide you the science perspective, if you like, not to mention a political one. Not interested in an emotional debate here, you're entitled to your point of view and your polemic, if that's all you prefer.

Everyone in this thread is approaching the question from the perspective of the passive resident role, and not the traveling science minstrel role.

Given that I am definitely more inclined toward the latter - which apparently makes me a tiny minority, even in this thread - I feel confident saying that I would have far more to fear from all of you than the reverse.

You may all point and laugh now.

In the last 48 h the JPL website has had trouble serving up the raw images page, which is pretty frustrating when you're working on any projects associated with this mission. Percy has already seen and done a lot in ~4 Earth years, so there is one hell of a lot to review if you're trying to be thorough...

You mean the objective of the abrasion? The point is to remove the outer surface of the rock.

As you can see, the abraded part (inside the circle) is very different from the unabraded/natural part (outside the circle). The natural surfaces of these rocks have been sitting out in the weather for billions of years - they've been worn down by endless wind, sandblasting, radiation and even the tiny bits of moisture that the Martian atmosphere still has to offer. The geologists generally want to analyze the original, "fresh" parts of the rock which haven't been exposed to weathering, which you can get by drilling into the inside.

Hope this is clear enough. Feel free to ask if you've further questions.

It's a small boulder, comparable in length to the diameter of Percy's wheels, I'd estimate - so the long dimension is roughly 50 cm. Here's one of the HazCam shots that Paul Hammond assembled, from sol 1642:

Please keep the questions coming, everyone - they're helping me put together my link dump reference list! (I'm not promising a FAQ any time soon, but that's the way this really should go, ultimately...)

Those four selfies that Paul links to above all represent significant mission milestones - the deployment of Ingenuity, our first sampling attempt, our finding of a "potential biosignature" down in the valley, and the rover at the sample depot.

Perhaps this latest one can be labeled "Perseverance's Pre-Budget Cut Selfie".