Perseverance Rover lands on Mars [video]

Note: that's 290kg in NASA units

Great video! I am also surprised by the fact that they bring that much mass just to jettison. In theory they could mounted some of the useful mass on a slider/rail system to achieve the necessary adjustment to the mass distribution without dropping mass overall, but apparently it wasn't worth the complexity/volume cost.

I'm sort of surprised we don't yet have ML powered "de-accent-ization". His french accent isn't hard to understand at normal speed, but when I set it to 1.5x or 2x speed it becomes hard to decipher in a way native speakers usually are not. If there was just a button (for him or me) to hit to tweak the sounds a bit to reduce the accent, I bet this problem would go away.

I was hoping someone would link this video, it describes the various phases with a ton of details that.

Some of the other videos on this channel are just as in-depth: the ones about the plumes/exhaust of rocket engines as well as star occlusions are incredibly detailed.

Thanks for introducing me to the French Space Guy! I am hooked.

Just to set the record a bit straighter and ruin your joke, those pics of beats with weights were knockoff beats from the flea market not real.

We were doing that at Meraki back in the early 2010s (it turned out they were also useful as a heat sink and, because the metal was exposed to air, a radiator). Pretty sure Meraki got the idea from some Apple product or other.

What I'm getting from this, is that you can use weights to balance the mass of the spaceship during cruise conditions.

Got it. Fancy weights.

LIGO puts this shame with 10^11 better sensitivity.

NASA has experience in unit foul-ups. Mars Climate Orbiter is the $125M poster project reminding everyone of the importance in having consistency in units.

"At 09:00:46 UT Sept. 23, 1999, the orbiter began its Mars orbit insertion burn as planned. The spacecraft was scheduled to re-establish contact after passing behind Mars, but, unfortunately, no signals were received from the spacecraft.

An investigation indicated that the failure resulted from a navigational error due to commands from Earth being sent in English units (in this case, pound-seconds) without being converted into the metric standard (Newton-seconds).

The error caused the orbiter to miss its intended orbit (87 to 93 miles or 140 to 50 kilometers) and to fall into the Martian atmosphere at approximately 35 miles (57 kilometers) in altitude and to disintegrate due to atmospheric stresses."[0]

[0] https://solarsystem.nasa.gov/missions/mars-climate-orbiter/i...

Ever been on an airplane? Altitude was almost certainly measured in kilofeet.

As noted in other comments, NASA (like the rest of the United States [1]) does use the metric system.

But it doesn’t matter. Nothing about the metric system makes it uniquely suitable to landing on Mars. Or space travel in general. What matters is a consistent standard.

Internally NASA could use Armstrongs. Where 1 is the weight or height of Neil Armstrong at KSC on July 16, 1969 at 13:32:00 UTC. It doesn’t matter. As long as it is consistent.

[1]: https://en.m.wikipedia.org/wiki/Metrication_in_the_United_St...

Actually, NASA uses metric system internally. Imperial units are probably used for general public convenience.

As another commenter said, NASA uses metric.

During the stream, you can hear the various teams giving measurements in metric, whilst the media gave coverage in imperial.

It's a pretty interesting video from that perspective, as you can hear the two "realities" being translated for the intended audience.

Perseverance's Terrain Relative Navigation uses a camera system and generates a full 3D position fix, but the idea is similar.

Not at all.

I don't know in general, but JPL published a video [0] yesterday of three interviews. One of the systems engineers for the MOXIE (atmospheric oxygen separation) unit will wait several weeks after landing before their first experiment. Actually, scientific american has published a timeline that seems to corroborate that [1].

[0] https://youtu.be/TUd604rBR6I?t=643

[1] https://www.scientificamerican.com/article/the-first-100-day...

What is it about that that excites you so much?

Is it the idea that life could originate elsewhere and that there might really be aliens?

Or is it the idea that Mars could support some sort of colony?

Or the hope of completely novel microbiology?

Solar cells Would not handle a rud. But Just fill the entire thing with solar cells. If they want to produce methane and co2 on Mars they will need lots of power.

Soil? Though not sure it is prudent to potentially spread active biological material all over a pristine (eco)system.

Why not work on some very small machines that can mine and refine materials to make more of themselves?

Don’t litter Mars Elon. Stick your landing. LOL.

Bunch of 2x4s and screws/nails :D.

Water.

we playing factorio here?

A great video where the host visits the drone, interviews its makers, and goes over the cool technical aspects of it and its mission: https://m.youtube.com/watch?v=GhsZUZmJvaM

You may be interested in dragonfly then: https://www.nasa.gov/dragonfly

More about Ingenuity https://spectrum.ieee.org/automaton/aerospace/robotic-explor... and it's source code https://github.com/nasa/fprime

Today's images are from Sol 0. Zero-based counting rules.

You can see what this page looked like for Curiousity at https://mars.nasa.gov/msl/multimedia/images/?page=0&per_page...

Can't wait till they start posting raw images :)

Other posters have pointed out that it's the hazard avoidance camera, but they haven't said why the hazard avoidance camera is black and white.

When you do computer vision, the first step you do is convert your color image into a black and white image, and run your CV algorithms on the black and white image. This is because when you're looking at objects and shapes and stuff, it's contrast that tells you where the boundaries between things are. This is true even in a human world of human objects, which tend to be many colored. It's even more true on Mars where basically everything is varying shades of orange. So having color doesn't help a whole lot, and you also have to do the additional step of converting the color image to black and white, which takes CPU power and adds latency. Remember, the purpose is hazard avoidance- latency is bad.

Additionally, color camera sensors aren't actually color sensors. They're black and white sensors. In front of every pixel on the black and white sensor is a filter that is either red, green, or blue. Pixels are grouped into sets of four, and there are two pixels with green filters, one pixel with a blue filter, and one filter with a red filter. (sometimes one of the green filters is omitted, giving red, green, blue, and b&w, or sometimes one of the green filters is a filter that allows IR, or something like that.) So if you have a 16MP camera, the camera has 8M green, 4M red, and 4M blue pixels. This means two things; first of all, if you just wanted a black and white image in the first place, a color sensor gives less detail than the equivalent black and white sensor, and second, you need to do additional processing to convert the raw output from the sensor into an image that's usable for anything. The additional processing adds latency.

The world is a complicated place, Hobbes.[1]

The lower "HazCams" hazard avoidance cameras (which captured those initial photos) are there to detect hazards (rocks, trenches, etc.). They are stereoscopic, lightweight, and high resolution.

My guess is that using color sensors would have either increased the 3D mapping precision or added weight/power/bandwidth requirements, or otherwise been less robust in that environment.

Those cameras were also pre-deployed for the landing phase and likely transmit more quickly due to the lower data information. The other cameras were shielded for the landing phase.

The navigation and other cameras are in color, and I expect we'll be seeing better images shortly.

[1] This comes to mind whenever a question like that is asked: http://4.bp.blogspot.com/-CWM1zDcmWXs/TroD0VsX4WI/AAAAAAAAAV...

Just an enthusiast, no real answers, but here's a guess:

These are hazard cameras, designed to be inputs into the guidance algorithms on board. It might make sense for such a camera to be B/W to reduce on board processing required. There's also a glass cover on them, and a lot of dust from the landing, so that may be obscuring true color if the cameras do in fact take color images.

Also they may have just transmitted a lower quality B/W image to get something back to Earth quickly, since higher res images take longer to uplink.

It's from a hazard camera, which is not used for main photography. Better images will come soon.

My guess is lower image size, which means image can get transferred faster.

This was explained on the feed. It's from a lower-res safety camera mainly used for object avoidance on the ground. High definition images will be available later.

I heard on the live stream that it was taken by a camera that is used by the driving system.

Guessing its black and white/high contrast to help see rocks etc. And probably much lower res, smaller file size too for transferring.

Here's the answer from NASA: https://youtu.be/gm0b_ijaYMQ?t=6240

It's an "engineering cam" that's not really meant for taking nice pictures, more to see where the thing is going. There'll be some better Instagram selfies soon though.

I was still under the assumption of Curiosity's 7 minutes! Thanks for letting me know

what if those people were tested for covid and there was no risk?

I mean, I'd be pretty impressed if NASA managed to get Webex to run on a 133MHz PowerPC CPU and 128MB of RAM.

"Slack" is actually the answer to one of the questions I was going to ask, about internal communication!

Hmm, another: Given that it's roughly a decade since MSL Curiosity, what were y'all (Perseverance team members) doing when Curiosity launched and landed? How many of today's team were in school back then, or what's the generational turnover and overlap like?

What's everyone's "favorite" failed Mars mission that would've changed everything if it'd succeeded?

How much overlap is there now that two similar yet 10 years different rovers are in operation ? Is it possible to share some of the human/software/planning resources or are they basically two separate efforts by this points ?

Also, do the Rover Drivers still live on the Mars time that makes their working hours shift by 45 minutes every day, like in the good old MER days ? ;-)

Awesome achievement! What was the part of the mission you were most concerned about / most likely to go wrong?

Awesome stuff.

I couldn't help but wonder, while I watched the feed: What are the people in mission control doing during the landing?

Obviously they're monitoring telemetry - but what else? Presumably the time delay precludes them triggering anything critical manually, and making post-launch software changes would be frowned upon?

Any idea on the timeframe for unfurling the robotic arm? And doing the test drive?

Thanks for your efforts towards the fantastic result today.

I just want to thank you all for the wonderful time tonight, we’ve been watching with the family. Amazing accomplishment!

Sick!

Will this rover make contact with its forebears at some point?

thats Mars 'tonight', of course

How are they getting audio without an atmosphere?

Thanks!! Also wanted to mention, NASA is separate from JPL for the most part as far as web services go.

All hail the shining twin gods, Advancement and Progress.

It's funny that they never say. (My mother-in-law asked if it would go back to orbit, too.) Saying "it flies far enough away to be sure it won't hit the lander when it crashes" would sound funny. They never seem to drive over to check it out, either, AFAIK.

It started with ~800 lbs of hydrazine fuel on board that had to slow tons moving at 200 mph to a dead stop, and then hover for 10+ seconds while the lander spun down; and then boost away and crash. ("Crash-land" sounds like entirely more control than what really happened.)

The skycrane system is just SO COOL. It's also one of those things that is super easy to explain but incredibly difficult to actually construct, let alone have it work well after flying all the way to Mars.

> (The altitude record on Earth is 85,000 feet, set by the SR-71.)

The A-12 Arkangel flew higher (95,000 feet) and faster, but was short-lived and so highly classified that it doesn't hold any "official" records.

And a MiG pilot flew up to 123,000 feet, but only on a ballistic trajectory, it wasn't a sustainable altitude.

They can't exactly procure a bunch of parts and then call it a day. Lots of the cost is tied to the verification and validation. Then there's the system design, requirements engineering, trade studies, system integration, engineering models, simulation, software, environmental testing, launch costs, ground command and data systems, interfacing with the rover, etc. Paying engineers to do all that is what makes it so expensive.

If we go by MER Opportunity standards (surviving 55x times its design timespan) we might go up to 275 flights! :D

It's powered by plutonium.

Rovers with solar panels deal with the dust by waiting for a storm to blow it away.

These live streams are anxiety inducing for us, I can only imagine how they must feel!

I guess technically it's on an 11 minute delay for the whole planet.

You are correct, I did. Thank you. That's just amazing!

> also there are no absolute reference frames.

"Well, officer, perhaps to you it seemed like I was speeding there..."

Actually, Percy has her own Mars-to-Earth radio. It's that the high bandwidth is UHF to MRO, MRO to Earth usually (as I understand it). My guess is they probably could manage a few FPS at low resolution directly from Percy - but probably wouldn't do that for power reasons. https://mars.nasa.gov/mars2020/spacecraft/rover/communicatio...

It was already communicating with DSN the whole way down, via one of the orbiters, and "send a pic" was apparently a pre-programmed command not requiring Earth initiation.

We actually got a picture like 3 minutes after landing. (Okay, a picture from shortly after landing.)

> Earth Receive Time

Ah great, that's a great phrase to make everything clear and provide a kind of "frame of reference" to think & communicate in. Always need these abstractions.

The local Czech stream (20k viewers!) I watched went over the events in real time and then commented how events were happening as signals were received on Earth - with the final confirmation of successful landing coming first via Twitter, no less! :)

Still a very nice yet nerve wrecking idea to do it like this - you know the lander is on Mars now. But is it safely on the ground or is there a third Shapirelli crater now ? You don't know! A huge relief in the end. :)

But aren’t those two events essentially simultaneous in the relativistic sense? That is by some definitions of “simultaneous”?

Simultaneity is at least as well defined as clock time. Both clock time and the velocity of your reference frame can have arbitrary constants added to them to yield equally valid coordinate systems. So "it's not really simultaneous" is analogous to "it's not really 6:30 PM."

Depends what type of physicist you ask.

According to the energy-time uncertainty principle we don't even know when exactly the RF waves that transmitted information hit the receiver on Earth either.

In the absence of a physicist, I suppose that a software engineer in the room might do. After all, the counterintuitive consequences of relativity have their counterparts in counterintuitive effects in distributed systems and concurrent programming. In both cases, the core issue that misleads our intuition is the lack of a shared global clock that would impose a total ordering [1] on events/reads/writes/etc. Instead, events in both situations are only ordered partially [2]. In relativity the ordering is determined by the speed of light, in distributed systems the ordering is determined by what messages have been exchanged by two nodes and in concurrent programming reads and writes are ordered by synchronization actions such as lock acquisition and release, memory barriers etc (c.f. the happens-before relationship in JMM [3] and other memory models).

See for example [4] and [5].

[1]: https://en.wikipedia.org/wiki/Total_order

[2]: https://en.wikipedia.org/wiki/Partially_ordered_set

[3]: https://en.wikipedia.org/wiki/Java_memory_model

[4]: https://www.youtube.com/watch?v=UYZIHP120go

[5]: https://www.microsoft.com/en-us/research/publication/time-cl...

S/he already did. We just don't know yet.

> simultaneity

not in the true accurate to the picosecond sense of the word, no, but the exact word simultaneity is used when discussing number and density of satellites about a given latitude/longitude in the starlink beta program. Since they're LEO and orbiting at only 550 km, the satellites above a given spot on the ground vary greatly in the not-yet-complete sparse network.

Usually related to discussions of whether a beta test customer terminal will briefly hiccup and lose connection to its default gateway, or if somebody is at a sufficiently high latitude that they can have full coverage for all 86400 seconds in a day.

https://satellitemap.space/ has a good animated visualization of this.

Came here to suggest The Order of Time by C Rovelli, which explains this in such a captivating way.

Oh but there is. Just not in the same frame of reference.

NASA has a good breakdown of their expected miletones at 'earth receive time' - https://www.nasa.gov/feature/jpl/nasa-s-next-mars-rover-is-r...

Apparently the latency time is currently 11 mins 22 seconds -- which is somewhere near the average. It goes from under 4 mins to over 22mins depending on distance.

Relative time (in five minutes) without relativistic speeds is actually uniform. The is no observable difference to either participant.

And there is no concept of now in a significantly distant location. Related video: https://youtu.be/pTn6Ewhb27k

There's a lag time in communication due to distance. I don't see what that has to do with relativity.

PBS Space Time recently explained what the present time means within general relativity[1]. As I understand it... it matters in this context.

[1]: https://www.youtube.com/watch?v=EagNUvNfsUI

Yes, yes, you have shown you know what relativity is. But the relative velocity of earth and mars — which I can't convince Wolfram Alpha to tell me, but it's got to be on the order of their orbital velocity so let's say 5x10^4 mph — is a tiny tiny fraction of c so their inertial reference frames are essentially identical. So sitting in our reference frame, we can make inferences about what's happening "now" on mars,such that these inferences are consistent (to within that tiny fraction of c) with all of our current and future observations in this reference frame; i.e., consistent with a classical(+ finite speed of light) model of the universe. Which is why I left this out of my question and only asked about the consequences of a finite speed of light.

Put another way, simultaneity is perfectly well defined in a single inertial reference frame, and for purposes of my question, earth and mars can be considered to be relatively motionless.

I'm not saying anything bad about the landing. It was a great feat. I just find the chanting often done in US videos disgusting.

why not

You have it exactly backwards. Risk tolerance is higher for the government. Fox example, SpaceX would never just send a rocket to mars just to do science which would bring it zero profits. It won't take risk funding something where the science may or may not bear any fruit.

Also, SpaceX IS mostly funded by NASA anyway as a government contractor. SpaceX exists because the government wanted to create a private space market. Strangely thank George Bush for it. https://www.fool.com/investing/2017/02/05/how-profitable-is-...

As you can see, SpaceX was so cash strapped in 2017 it obviously didn't go to mars in 2018 as they wanted. Also notice Elon didn't fund that trip (otherwise it would have happened). There is no way he would risk HIS own money on that.

.

In fairness to the parent comment: those weren’t the first try.

Mars Observer is mad that you forgot to mention it! https://en.m.wikipedia.org/wiki/Mars_Observer

Actually it is not mad - becase it exploded into millions of pieces due to the leaky fuel system...

I'll just leave Thunderf00t's latest video here: https://www.youtube.com/watch?v=4TxkE_oYrjU

Let's not diminish ether's breakthroughs, but financial isn't one of SpaceX's.

How could you know? SpaceX never landed or sent a craft on a foreign body.

The Mars atmosphere is at a tricky spot where you can't ignore it like when landing on the Moon (also Mars gravity is higher than on the Moon) yet it's not thick enough for survivable landing with parachutes or wings (as envisioned in the earliest Mars mission plans) only.

That's why you always see parachutes + something else for Mars EDL - parachutes + rockets, parachutes + airbags, parachutes + skycranes. And in Starship case, high speed glide and speed shedding with propulsive landing at the end.

I'm not commenting on the rest of your post but the "dominating the commercial sector" just so you don't think I'm badmouthing SpaceX. Just wanted to add that if you sell X pounds of cargo to the commercial sector but sell the same capacity to the military for X times 3 then your are not dominating but are subsidized by the state and in a position to undercut the commercial competition. It's not just for PR that SpaceX competitors, both foreign and nationally, are saying SpaceX is propped up by the state.