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+--- Thread: Curiosity Cracked Open a Rock on Mars And Discovered a Huge Surprise (/showthread.php?tid=2924)
Curiosity Cracked Open a Rock on Mars And Discovered a Huge Surprise - gortex - 07-12-2025
You can't make an omelette without breaking eggs but in Curiosity's case you can't find Elemental Sulfur without running over a rock , Curiosity rover's team took a look at the damaged rock and discovered their treasure.
![[Image: sulfur-mars.jpg]](https://www.sciencealert.com/images/2024/07/sulfur-mars.jpg)
Quote:When the rover rolled its 899-kilogram (1,982-pound) body over the fragile lump of mineral in May last year the deposit broke open, revealing yellow crystals of elemental sulfur: brimstone.
Although sulfates are fairly common on Mars, this represents the first time sulfur has been found on the red planet in its pure elemental form.
What's even more exciting is that the Gediz Vallis Channel, where Curiosity found the rock, is littered with objects that look suspiciously similar to the sulfur rock before it got fortuitously crushed – suggesting that, somehow, elemental sulfur may be abundant there in some places.
https://www.sciencealert.com/curiosity-cracked-open-a-rock-on-mars-and-discovered-a-huge-surprise
I think it safe to say the rover missions have found suitability for life occurring on Mars so time for NASA to send another mission to search for life , it's been decades since Viking found it.
RE: Curiosity Cracked Open a Rock on Mars And Discovered a Huge Surprise - Kenzo1 - 07-12-2025
I allways knew there was something rotten in Mars
RE: Curiosity Cracked Open a Rock on Mars And Discovered a Huge Surprise - FCD - 07-13-2025
I think the big surprise for me here is how much Curiosity weighs. I had no idea it weighed that much! Almost a ton. Although I never looked up that particular stat, I figured they weighed 200-300 lbs. max.
Now I'm even more impressed with the successful landing on the surface. Any landing on the Martian surface is a near super-human feat due to the really weird atmospheric conditions on descent. There's like no atmosphere at all on the way down initially, so no aerodynamic braking (parachutes don't work). And then you hit this thin atmosphere where you have to brake really hard, and really fast, to slow down enough to not destroy the vehicle you are trying to land. It's one of the most difficult landings in all of space travel so far. (by a pretty big margin too). We had plenty of experience landing things in no atmosphere (the Moon), or a really dense atmosphere (Earth), but Mars with its varied atmosphere presented challenges which were monumentally difficult to overcome. Especially for a vehicle which had to still be able to move around once it reached the surface.
I mean, just look at how many times the Russians tried landing on Mars and failed, before finally giving up. And we had a long string of failed (or semi-failed) landings too. I remember the first time I saw the math and some of the equations they were having to use, and I was like..."WOW! I had no idea it was THAT difficult!" Probably like a lot of other people, I was just thinking..."well, we've landed on the Moon countless times, so landing on Mars should be a slam dunk." Not even close!
Even if you think just a little bit about it, the true difficulty quickly comes into focus. Mars has a very thin atmosphere, but at the same time has very strong gravitational forces because of Mars' size and mass. More fuel for braking burns equals more mass (to slow down), and a bigger craft to carry the additional fuel. More mass requires exponentially larger parachutes to decelerate once inside the atmosphere. Considerably larger chutes, and in multiples, perform poorly and unreliably. Parachutes and rocket engines don't play nice in the sandbox together. Braking burns in no atmosphere are different engines than for braking burns inside the atmosphere (but multiple engine types equals even bigger craft, which is even more mass to slow down). And the list goes on. It's like this long list of changing variables you have to worry about at different altitudes and atmospheric densities. And then you can begin to understand all of the crazy different methods and types of craft they tried to land (i.e. bouncing beach balls, sky cranes, suspended payloads, multiple radically different combined technologies, etc.)
RE: Curiosity Cracked Open a Rock on Mars And Discovered a Huge Surprise - FCD - 07-13-2025
After I read the OP and made my response, I drifted off into "internet surf land' and came across a couple articles about the difficulties involved in landing on Mars. Looks like I remembered most of it pretty well (pretty good since it's been a while since I looked at any of that stuff). And, I also came across a really interesting video about the JPL's recent research designing parachutes which function properly when deployed above supersonic speeds. Pretty interesting stuff (I can post a link if anyone desires). Probably dry if you're not into that kind of stuff like I am (pretty much anything to do with aerodynamics and/or aviation/space travel I'm into...to the point of getting whacked over the head by my bride for not paying attention to whatever it is she's droning on about, erm, 'talking' about (which is clearly of utmost and critical importance for the continued survival of humanity! Ahem.)! LOL!
Turns out if you fire off a chute above Mach 2 it will pretty much self destruct instantly once it starts to collect air. Small drogue chutes are fine, but not parachutes in the 70+ feet in diameter range. JPL managed to find solutions for most of these issues in 2019, and now they have parachutes which can operate properly at 2x these velocities with 2x+ the design strength or any payload thought to be needed on Mars for the foreseeable future. A digression here, I suppose, but I thought it a little interesting factoid because it turns out that somewhere above Mach 1.5 is the sweet spot for where you want to deploy a large main chute on the descent to Mars.
That was really it, just thought I'd share.
RE: Curiosity Cracked Open a Rock on Mars And Discovered a Huge Surprise - Bally002 - 07-13-2025
(07-13-2025, 11:03 AM)FCD Wrote: Turns out if you fire off a chute above Mach 2 it will pretty much self destruct instantly once it starts to collect air. Small drogue chutes are fine, but not parachutes in the 70+ feet in diameter range. JPL managed to find solutions for most of these issues in 2019, and now they have parachutes which can operate properly at 2x these velocities with 2x+ the design strength or any payload thought to be needed on Mars for the foreseeable future. A digression here, I suppose, but I thought it a little interesting factoid because it turns out that somewhere above Mach 1.5 is the sweet spot for where you want to deploy a large main chute on the descent to Mars.
That was really it, just thought I'd share.
Great insight FCD. When talking about Mach figures, are they calculated at Mars speed of sound (about 540mph) or Earths (about 760mph). Mars atmosphere being thinner of course. Asking because I just don't know.
Kind regards,
Bally.
RE: Curiosity Cracked Open a Rock on Mars And Discovered a Huge Surprise - FCD - 07-13-2025
Bally - So, yours is an interesting question, and there's actually more than one answer. On Mars, the speed of sound is expressed in Martian values. And on Earth (obviously) Mach is calculated based on the speed of sound at atmospheric densities on Earth. So, then the question becomes, if "Mach" speeds are a concern, which value do you use to design a parachute which will be used on Mars, but has to be designed and constructed within the confines of Earth and it's atmosphere? So, it's an excellent question actually.
Turns out, "Mach" is just a reference point, a computed value based on air density (and to a certain extent, humidity values) with relation to Mean Sea Level here on Earth. You are correct, all these values change on Mars, for a whole variety of reasons. So, what values matter more and which ones matter less on Mars? It boils down to velocity versus air density, regardless of what 'Mach' value that velocity computes to in either Martian, or Earthly, terms (values). The actual speed of "sound" is irrelevant in these equations, so 'Mach' numbers don't really mean anything, in terms of parachute designs. In re-reading my earlier post, I see where I kind of inadvertently made a somewhat misleading statement. I should have said..."the ideal atmospheric reentry conditions on Mars equate to a main chute deployment above about 'Mach' 1.5...in Earth terms." (And that's just off the top of my head. I'd have to go back and check some of the math to see if that's more or less accurate, honestly. But I wanted to respond to your question, because it was a good one).
In all reality, I should have refrained from using 'Mach' terminology and values altogether when speaking to velocities of spacecraft during reentry on the planet Mars.
Edit - If a reader was concerned with attempting to calculate velocities (visually), Doppler effects, and various other things...while standing on the surface of Mars...then 'Mach' numbers would be relevant.
Edit II - Your question prompted another thought. I wonder what a 'Sonic Boom' really sounds like on Mars?? I never actually contemplated this question before now. My first reaction to this question is, a Sonic Boom would be far less prominent on Mars, compared to Earth. But, would it even be notable? (Don't know this answer, and may have to look into).
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(next post...reply...(hint, hint, hint, this is a PITA)
On just a side note, I became interested in Mars landing dynamics after doing a bunch of research into Venus and landing on Venus. Venus is yet another challenge. On Venus you have some things which are easier, and other considerations which are MUCH harder. If you can picture this, the conditions on the surface of Venus are extreme, to say the least. Temperatures at the surface often exceed 900F, and even worse the atmospheric pressure at the surface on Venus is equivalent to traveling 1,000 feet below Sea Level. Forgetting things like extreme sulfur and CO2 levels and other bad ju-ju in the 'air', the conditions on the surface are pretty dang hostile indeed. Much of the surface conditions have been known about in varying degrees since the many Russian missions to Venus in the 70's. But, the conditions between space and the surface were much less understood.
Turns out in the Venetian atmosphere there is a region / "zone" high above the surface which is surprisingly hospitable. Temperatures from 30-80F and pressures similar to that of Sea Level here on Earth (Okay, it drops to -226F at night, but we won't worry about that right now!)
Now, while keeping the landing dynamics of Mars in mind, consider the crazy atmospheric dynamics while trying to land in an apocalyptic and hostile environment like THIS one!
And just to put things in perspective, Russia managed to have a successful landing on Venus (Venera 9) where the craft continued to operate after landing. But imagine your liquid Oxygen cooled, titanium bodied, camera "melting' inside of 53 minutes after landing on the surface!!! THAT...is Venus...for anyone wondering why we don't go back very often.