NASA regains contact with mini-helicopter on Mars | Hacker News Reader

NASA regains contact with mini-helicopter on Mars

phys.org

407 pointsTommstein141 comments

On Jupiter Broadcasting there was a lot of interviews on how this was a Linux powered device and could be the first of many new Linux devices on Mars by JPL. If I remembered correctly they used a space hardened Power cpu with an ancient version of Yocto since the newer versions of it did not have working drivers. When the rover had an issue they actually used the helicoptor's userspace command line GNU utilities to debug and get logs from the rover to send to Earth.

Also, this makes Mars the second planet that uses Linux more than Windows as noted by the tweet in the linux below. :-)

https://www.theverge.com/2021/2/19/22291324/linux-perseveran...

> If I remembered correctly they used a space hardened Power cpu

If you're remembering correctly, then I'm misremembering in that this has essentially a Snapdragon chip and not a rad hardened CPU at all

Maybe I am misremembering the interview. Maybe the person said that they used to use a hardened IBM power chip?

This information is pretty widely available, e.g. on Wikipedia [1], no need to go off memory. Flight control is done by an FPGA, the main CPU is a Snapdragon 801 running Linux, and it uses Zigbee to communicate with the rover.

[1] https://en.wikipedia.org/wiki/Ingenuity_(helicopter)#Avionic...

At least they won't have any trouble finding a free channel.

They used the hardened PowerPC for the rover, similar to previous mars rovers and the Snapdragon chip for the helicopter.

The space-hardened POWER CPU was in Perseverance.

Some info from Wikipedia:

> The rover's computer uses the BAE Systems RAD750 radiation-hardened single board computer based on a ruggedized PowerPC G3 microprocessor (PowerPC 750). The computer contains 128 megabytes of volatile DRAM, and runs at 133 MHz. The flight software runs on the VxWorks operating system, is written in C and is able to access 4 gigabytes of NAND non-volatile memory on a separate card.

Fun fact - the cameras that captures Perseverance's landing are also Linux based and vim is installed - at least on the later model that I worked with.

Hopefully some engineer on the ground used Emacs to access the command line remotely, to run Vim, so that we are back on equal footing :D

What make & model of camera are these?

They're USB cameras. I don't know the vendor, but I worked with 4 cameras wired back to a small Linux computer.

FLIR Chameleon3 connected via USB to a Intel Atom Linux SBC running ffmpeg to encode the video.

See EDLCAM in https://link.springer.com/article/10.1007/s11214-020-00765-9

I am really surprised they are using essentially off-the-shelf USB cameras. I guess if it works, it works, but surprising that they didn't need to design circuitry to work in a space environment.

I am guessing the requirements for circuitry operating on Mars isn't quite as much as a spacecraft or satellite, but it is still getting hit with cosmic particles and solar radiation with no atmosphere.

Using it with a 20 minute delay between keystrokes and their results must be interesting

I'm sure they didn't connect to it via the internet to send keystrokes.

Huge delays between keypresses is what vi (and vim ofc) was designed for.

> When the rover had an issue they actually used the helicoptor's userspace command line GNU utilities to debug and get logs from the rover to send to Earth.

Wow, such a great testament to The Unix Philosophy of building small, modular, focused tools that can be combined together to do all sorts of interesting and more complex tasks. I'm sure no one imagined using these utilities from a helicopter to retrieve rover logs to aid in diagnostics, but here we are. What a cool story.

now if we just teach those tools to kids instead of turning them into spreadsheet office robots, that would be great.

I imagine NASA is built and operated on a foundation of thousands of spreadsheets

Spreadsheets are the best thing in computing since a Lisp REPL. Half of the startups today would be much better (in terms of utility, simplicity and ergonomics) for users and customers if they were served in form of a downloadable Excel sheet.

Almost agree, 'xcept for the "Excel" part, which I would switch against "spreadsheet".

For me, being listed as a contributor to Ingenuity is one of the highlights of my career in software development. I mean, I just fixed a bug in some python library, but that was enough to get the GitHub Ingenuity badge. And when ever I am asked for a fun fact about myself, I can answer: some of my code is flying on Mars :)

Ingenuity is running Python?

The vehicle itself is mostly C++ but there's lots of python in the ground station and data processing

Wow, I somehow never imagined that even NASA's technology choices would be influenced by "all the data stuff being for Python". But I guess if it's all sandboxed and any errors are reversible... then why not?

It all makes rational sense. It just feels weird to think about Python running on Mars before there's even people there.

GP stated, that there is a lot of Python based stuff on the ground though, as I read it. Not necessarily on Mars.

Ah, I see. I read "ground station" as hardware on the ground on Mars, as opposed to on the helicopter itself.

We did recently (2 months ago...?) add a couple of Python scripts to the heli for the first time.

I contributed to `twbs/bootstrap` and got the badge too, lol.

This has "University: Stanford" and "Company: Apple, Role: Individual Investor" energy

(I'm kidding, the badging system is funny)

Speaking as someone some of whose code probably helped search for the fallen Malaysian Airlines Flight 370 a decade back, I gotta say, you have me beat by a country mile and deserve to be chuffed.

I don’t think you should be apologetic about the small scale of your contribution: the animating principle of open source is that the aggregation of small contributions like yours can create outcomes that rival those of even the wealthiest organizations in the world.

But usually it is a handful of really large contributors and more smaller ones. And that's fine, but I'm not aware of a project where the contribution graph is more or less flat. And more often than not those large contributors are paid by large companies to contribute.

I wonder which largish FOSS project has the flattest contribution graph?

That's a great question. Whichever project it turns out to be their governance and leadership will be well worth studying.

Didn't this use mostly off the shelf parts? If so, I wonder how this will impact costs on future missions. If they can do more with consumer hardware, they can save budget to apply toward more science.

Yes, it did. I like the sentiment but I wonder how much conflict of interest would undermine this idea. Imagine how many companies are involved in developing space grade one-off hardware! Also, why would a highly bureaucratic structure undercut the amount of money that they themselves are asking for (and receiving) out of a budget? Savings are not aligned with the interest of such structure. Its not that for the amount you have saved you can allocate rest of the funds for something else (usually this is how it works with publicly funded projects AFAIK)

Well maybe they could start doing bigger and better missions, if they can reliably pull it off.

This also drops the bar for other space agencies, from other countries and private alike. Getting cheaper hardware also means more launches and more testing. Instead of sendind a multi million project to space, you can send basically a smartphone (an epheumism, ofc) and some big antennas, and do it in bulk

Every bit of money and platform resources (rad hardened CPUs are giant, slow and power inefficient compared to even semi modern COTS) is money and resources that NASA can spend on scientific payload on the same platform.

NASA absolutely does have some incentive to find savings in control hardware and software.

Finally, while Ingenuity does use a non-hardened Snapdragon, many other of its critical electronics components are still rad-hardened. The FPGA and dual MCUs (that actually do the low level control and I/O I assume) are both rad hardened. In addition, the COTS components that were used where screened by NASA for their performance in radiation.

The Snapdragon is really just there to control the radio, and do image processing. Critically, these are functions that have -some leeway- for timing, giving the option to just restart the Snapdragon if a watch dog detects a problem.

All of this to say is that rad-hardening isn't going away, but will probably stick around in many critical niches. What Ingenuity absolutely do is validate that modern COTS processors have a role to play in radiation elevated environments, including in semi-critical applications.

This is a great and informative comment!

HN is dominantly a web/SW crowd plus some mobile frontend, and "it uses a Snapdragon" gives many a wrong idea. In embedded device projects a lot of time is spent planning and designing around a heavy compute element running Linux like this, especially if the device has a safety concept or other mixed criticality concerns. It will have a substantial moat around it.

On HN if you say "systems architecture" most folks go "Oh you mean like, whether we use microservices?". In embedded, while there is a lot of overlap and analogues, it's also all of the above, plus power state management and other aspects. It's not very shiny, but that profession makes all your cars, airplanes and alien planet multicopters.

"It's not very shiny, but that profession makes all your cars, airplanes and alien planet multicopters."

If you have a good head for it, it's a pretty darn good career. You might not make $500k/year like you would at google, but the money is still decent and reliable.

Plus, working on spacecraft is cool as hell.

The original Elon Musk biography describes how a legacy aerospace engineer joined spacex and was tasked with a part:

> He got a quote back for $120,000. “Elon laughed,” Davis said. “He said, 'That part is no more complicated than a garage door opener. Your budget is five thousand dollars. Go make it work.’”

This is a terrifying anecdote.

You're talking about the $120k price tag right? Considering the reliability of Falcon 9.

From some perspectives, yes. From others it's not so bad. I love having cover from the top to do engineering and qualification to have better solutions. Normally it's "we don't have time or resources to make it, get back to the spreadsheet mines".

For LEO you can scoot by pretty easily with non-hardened solutions and better systems engineering and software. For deep space you'll need to be more clever.

> It got there by challenging conventional wisdom, she adds. Most launchpad air conditioning systems, for instance, cost nearly half a million dollars, but SpaceX execs wondered why it cost so much more to cool an area the size of a conference room than the $75,000 it cost to cool their entire headquarters and manufacturing plant. The company brought the cost down to about $35,000, says Shotwell.

https://www.northwestern.edu/magazine/spring2012/feature/roc... (Page 3)

These are self-reported stories by one of the most extreme self-promoters in business. Let's not take it too seriously.

I wouldn’t take them seriously, except that SpaceX has a full decade of very reliable launch services at a fraction of the cost. You might ask how they did that, and SpaceX says “here are some examples”. It’s not just reusing rockets.

> You might ask how they did that, and SpaceX says “here are some examples”.

Right, but why would you believe what they say? I believe they know how to launch rockets, but that doesn't mean they are telling you the reason. They may not want it public, they may want to kiss someone's a-.

If there’s any company you should pay attention to when they report successful cost cutting, it's spacex. You can hate or love Musk but Gwynne Shotwell is the real deal there. Not sure how she keeps Elon from blowing the whole business up but somehow she does and quite successfully at that.

If she says you can keep cool whatever needs cooling for 10% of the Boeing price, you’d better believe it.

I'd better? Or else what?

That's not persuasive. People make things up all the time, especially stories that show how smart <powerful person> is.

Or else? I won’t ground you for a week for sure ;) Being wrong for the wrong reasons is good enough. You have proof their methods work in their launch manifest.

This isn't about their methods. You think Musk is honest because their launches are successful?

It is, but for different reasons to different people.

Consider how many governments signed 8+ figure contracts to develop apps. Why would this kind of waste be any different in other industries? It's humans all the way down ;)

Dude. It’s nowhere near just governments that sign comically inflated contracts.

Anyone dealing with oracle, ibm, sas, hp, Microsoft and hordes of others are not strangers to seeing a $500,000 bill for basically nothing in B2B.

We hear about the government ones cause duh.

$500k in government is chump change. As ridiculous as some of these business deals are, they are not even on the same planet as government contracts.

That depends on the validation and QC of their internal engineering. It is just as terrifying to spend USD120000 on a part that might be no better that what you can design&build in-house.

Here's the background:

  There were numerous ways in which SpaceX's strategies diverged from space industry norms, and almost all of them had direct implications for the cost of its launch systems. First, whereas most aerospace companies give their designs to myriad third-party contractors who create the hardware for them, SpaceX produced roughly 80% of its launch hardware inhouse. SpaceX builds its own motherboards and circuits, vibration sensors, radios and more. In most industries vertical integration increases the costs of firms by not enabling them to benefit from competitive bidding between efficient suppliers. In the aerospace industry, however, the entrenchment of norms around using parts specialized for the space industry ("space grade"), and the bureaucratic rules defined by government contractors, had kept supply costs high — very high. SpaceX decided instead to build many of its own parts, or to buy parts not considered "space grade" and modify them to achieve "space grade".For example, rather than paying $50,000 to $100,000 for an industrial-grade radio, SpaceX was able to build its own for $5,000, and shaved 20% of the weight off at the same time.

  SpaceX's willingness to produce their own parts came as a shock to suppliers. For example,Tom Mueller recounts a time when he asked a vendor for an estimate on a particular engine valve: "They came back [requesting] like a year and a half in development and hundreds of thousands of dollars. Just way out of whack. And we're like, 'No, we need it by this summer, for much, much less money.' They go, 'Good luck with that,' and kind of smirked and left." Mueller's team created the valve themselves, and by summer they had qualified it for use with cryogenic propellants. "That vendor, they iced us for a couple of months," Mueller said, "and then they called us back: 'Hey, we're willing to do that valve. You guys want to talk about it?' And we're like, 'No, we're done.' He goes, 'What do you mean you're done?' 'We qualified it. We're done.' And there was just silence at the end of the line. They were in shock." As noted, a big factor driving savings at SpaceX is that it often builds its components out of readily available consumer electronics rather than equipment alreadydeemed "space grade" by the rest of the industry. Twenty years ago "space grade" equipment would have had far superior performance characteristics compared to consumer electronics, but today that is no longer the case-standard electronics can now compete with more expensive, specialized gear. For example, at one point SpaceX needed an actuator that would steer the second stage of the Falcon 1. The job fell to engineer Steve Davis to find the important part, and since he had never built a part like that before he sought out suppliers who could make it for them. Their quoted price for the device was $120,000. As Davis recalls, "Elon laughed. He said, 'That part is no more complicated than a garage door opener. Your budget is five thousand dollars. Go make it work.'"20 Davis ended up designing an actuator that cost $3,900. Another example is provided by the computers that provide avionics for a rocket. Traditionally NASA's Jet Propulsion Laboratory bought expensive, specially toughened computers that cost over $10 million each to operate its rockets. Musk told engineer Kevin Watson that he wanted the bulk of the computer systems for Falcon 1 and Dragon to cost no more than $10,000. Watson was floored,noting, "In traditional aerospace, it would cost you more than ten thousand dollars just for the food at a meeting to discuss the cost of the avionics."21 Watson was inspired by the challenge, however, and ended up creating a fully redundant avionics platform that used a mix of off-the-shelf computer parts and in-house components for just over $10,000. That same system was then also adapted for use in the Falcon 9.

About the actuator:

  Steve Davis, the twenty second hire of SpaceX, needed an actuator that would trigger the gimbal action used to steer the upper stage of Falcon1. He went to find some suppliers and got a quote a $120,000. “Elon laughed”. Davis said. “He said, ‘That part is no more complicated than a garage door opener. Your budget is five thousand dollars. Go make it work.’” Davis spent nine months building the actuator and the final actuator approved by Musk ended up costing $3900.

Seems like they don't include the engineering time in the part cost calculations - so cheating a bit!

I've experienced building something in-house that is far better than what you could otherwise get. Back in the 00's I wrote a JavaScript framework because the existing ones were all crappy in a variety of ways. Even as a one-person effort (and I'm no 10x engineer) I could write something that was wayyy better in a bunch of important ways (albeit not pretty enough design). My work was engineered better than the open source and commercial frameworks that I evaluated/used. Better loading, better recovery from network and other errors, better memory behaviour, better size, better speed, better integration, better diagnostics, better browser support, better user interface, customised for our needs. It did exactly what we needed for our project and mostly worked flawlessly.

Not sure I understand your response. There is a tremendous amount of launch data from several years of launches (and landings) that demonstrate whatever approach to design and manufacture SpaceX is using results in incredibly robust and capable space systems. I think rather than fear, a better response is to see what can be learned from SpaceX and see if it can be applied elsewhere.

I'm sure Musk's biography says lots of things. Do you still take it a face value?

I see the results of spacex’s work. Are you blind?

That's got nothing to do with the story. Maybe people can have different perspectives than you.

It was a PoC, I assume mission critical hardware will go through the same vetting, hardening, etc processes that they currently do.

It does bode well for sending cheaper "nice to have" experiments on missions, though.

Applied Ion Systems is throwing these kind of rocks with small-scale electric space propulsion. It's interesting to see both the excitement and energy from eager researchers and hardcore hobbyists (cubesat folks), and the oftentimes rude and nasty pushback from industry.

"off the shelf" in aerospace means that you can buy it from an aerospace manufacturer, and don't have to build it in house. There's considerably more engineering behind these products than the equivalent consumer electronics

My understanding was they used actual consumer hardware for it. This was a big thing in the news when it landed.

edit: from another comment: https://news.ycombinator.com/item?id=39081718

It looks like it's just a couple of (important) components that can handle the quirks of not being radiation-hardened, but it's still significant.

There is a lot of cost savings in taking COTS parts and qualifying them for space vs. designing new space-qualified parts, we will see more of this in the future especially with expensive niche technologies with a lot of crossover such as optical communications.

I actually go to the gym with one of the guys who worked(s) on this copter/drone. Super cool guy

How much can he bench?

On Earth or Mars?

I don’t think you’re supposed to hold your breathe when lifting…

Just like your not supposed to puff your cheeks when playing an instrument, but that never stopped Dizzy Gillespie. More of a suggestion than a rule

Gillespie also exemplified why the rule against puffing your cheeks is more than just a suggestion.

Jokes aside, you absolutely are. Bracing properly is a critical skill in both olympic weightlifting and traditional strength training.

Ah, shows how much I know about lifting... in general I've always been reminded to keep breathing when exercising.

It's the same if you measure in lb

is this a joke about America?

It's a joke about mass vs weight, since the imperial "pound" is unspecific as to being pound-_mass_ or pound-_force_, the latter being based on Earth's standard gravitional field.

The conversion of kilograms, mass, to pound-force, weight, relies explicitly on the given acceleration of Earth's gravity, ~9.8 m/s².

Since Mars has a gravity with acceleration ~3.7 m/s², for two things that weight the same on Earth and Mars the latter would need to be larger in mass to weigh the same in pound-force.

The biggest issue though, and something I will say even having been through multiple physics courses myself I don't recall having had literally explained, is that even though "pounds" can refer to force and not mass, they are not equivalent. 1 pound-mass ≠ 1 pound-force.

It is actually converted using the Earth's standard gravitional field's force, so 1 pound-mass ≈ 9.8 pound-force.

Thus, the amount on bench's is the pound-mass amount, say 66 kg or 145 pounds-mass, which is not 145 pounds-force but actually *1421*.

It's also true even that the gravitional force can change up to as much as 0.5% depending on where on Earth you are due to the shape of the Planet.

While the joke made _me_ laugh, but it seems as you dig further there isn't often reference to pounds as a force as much as I had thought, so I even learned something from it too!

Lots more information on Wikipedia[0] around these that is particularly useful if you for any reason want to know more:

0: https://en.m.wikipedia.org/wiki/Pound_(force)

Excellent explanation! Although 1 lb * 32.2 ft/sec^2 = 32.2lbf.

It's still 145 lbf and 145 lb mass. Under Earth's gravity the numbers are identical. (That is, a mass of 1 lb has a weight of 1 lbf).

The 10x difference comes in with metric units (kg and N).

Edit: might as well mention the rocketry connection... Probably the most well-known use of pounds-force is when discussing thrust of rocket engines (and other means of jet propulsion).

He's an older dude. I see him working with like 135-155 but never seen him max

It was probably just stuck in a tree.

Or a Martian canal.

I'm curious how long they expected it to remain in working condition. NASA has a habit of underestimating lifespans by a comical amount. It will be like "we expected the rover to operate for 10 weeks and that was 6 years ago". I think the most extreme example is Voyager 1, which was on a 5-year mission that reached nearly 50 years.

“We need the rover to operate for 10 weeks and will be discredited as an organization if it fails at 9” is what causes that. It's not necessarily a bad thing.

They planned for three 90 second flights prior to launch. After those worked they transitioned over to longer "operations demo" flights and those were extended tentatively out to 12 flights. After the 21st flight they just stopped manually allocating labor and funding to the project for a set number of flights and instead gave them a running budget for indefinite continued operations.

So while "strictly speaking" they planned for three 90 second flights. There was the unstated assumption that it'd be used for much more than that as long as it actually worked effectively.

It sounds as though mission life has as much to do with funding for ground staff (not something I ever considered) at least as much as it has to do with the life expectancy of deployed hardware.

Yep. For example, Spirit and Opportunity were part of the Mars Exploration Rovers mission. 2/3 of that mission's total cost was the development, manufacture, and launch of the rovers themselves. Which more or less "per unit" works to 1/3 of the total mission cost per rover. The other third of that mission cost was staffing for the (15 year) ongoing mission from when it passed the initial mission parameters to when opportunity finally was deemed dead in 2018.

https://www.planetary.org/space-policy/cost-of-the-mars-expl...

I always feel like NASA has mastered the basic "under promise, over deliver" philosophy that keeps the lights on and the next missions funded. I'd love to be a fly on the wall at who they get to tap dance in front of the congressional committee or how they schmooze the decadal people to rise above the rest.

We will use more helicopters instead of rovers for new missions ? Or larger crafts would be much harder or riskier to use ?

Or maybe have a helicopter that can move the rover with the equipment to different locations.

The existing helicopter is extremely small and light, IIRC. less than one kg. So it definitely won't be picking up a 900kg rover, even if you tried to scale it up somehow. The atmosphere is just too thin to support anything but a minimal payload.

But yeah having more helicopters might be feasible - for surveying the surface.

Is there a problem of scaling this up to say a 20kg payload?

I’m not an aeronautical engineer, so I guess what I’m asking is if there is some problem scaling up flying machines in an extremely thin atmosphere?

In a thin atmosphere, lifting a heavier payload needs bigger rotors or increased RPM, which increases power demands and structural stress. The challenge is to keep the vehicle light enough to fly while also making it sturdy enough to carry the payload and survive environments.

Ok - this makes sense to me. Also taken into account the context that anything going to space needs to be light at this point in time. Hopefully we don’t have that restriction forever :)

Why can’t “more rotors” be another solution?

This is what I'm thinking too. A number of posts above talked about physical limits based on speed of sound and rotor length. Cool, so add two rotors, or four.

For sure, that’s another way to decompose “bigger rotors”. It would probably be appropriate to dive into a conversation about Ingenuity’s design goals, requirements, and the trades performed to end up with what they got.

It scales up to 20kg, yes.

One issue might be rotor span. Ingenuity has pretty big rotors to counter the thin atmosphere (about 4 feet top-to-tip).

On earth rotor sizes are limited by the speed at the wing-tip. Once you make the rotor too long the tips start approaching supersonic speeds, giving you all kinds of weird mach effects. To make matters worse, the speed of sound is about 30% lower on Mars compared to near earth's surface.

Oh interesting! I can see how that would be a harder problem (although not insurmountable since some planes on earth have supersonic propellers).

Just a quick edit - wow, u didn’t realize the span was already 4ft! Anything much larger could definitely be hard to pack inside a fairing!

Yea good point. Apparently the blade tip speed on Ingenuity is Mach 0.6-0.7!

Interesting note about this: the speed of sound on Mars is only ~70% of that on Earth, due to less atmospheric density. Might change your Mach numbers!

It's not due to less density, but rather a different gas composition (CO2 vs. N2+O2).

Let's run the numbers!

The speed of sound in an ideal (calorically perfect) gas is given by

  a = sqrt( gamma * R * T )

where gamma is the ratio of specific heats (thermodynamic property of a gas, which may vary with temperature), R is the individual gas constant, and T the temperature of the fluid. All of these are going to be different on Mars versus on Earth:

  Earth:
  R = R_atm = 287 J / (kg * K)
  gamma = 1.44
  T = 293 K (taking room temperature as an average temperature)

  Mars:
  R = R_CO2 = 188 J / (kg * K)
  gamma = 1.37
  T = 210 K (from a quick google, about -60 deg C)

If the Martian and Earth atmospheres were at the same temperature, then the speed of sound on Mars would be 80% that of the speed of sound on Earth. Given the temperature difference, the speeds of sound are

  a_mars = 232 m/s
  a_earth = 347 m/s

So yes, much of the difference is due to the composition: the Martian atmosphere has a higher atomic weight, which leads to a lower individual gas constant, and decreases the speed of sound. However, a substantial amount of the difference is simply due to the different temperatures on the surfaces of the two planets.

I included it

What about multiple smaller rotors? Or would that cause weird turbulence effects? Could we use some kind of jet engine?

I don't know the answer to your question, but for context here are the weights of Mars rovers:

Sojourner (1997): 11 kg

Spirit & Opportunity (2004): 185 kg

Curiosity (2011): 899 kg

Perseverance (2020): 1,025 kg

I know these are much larger - I’m just really curious about the dynamics of scaling up rotorcraft & why it is problematic. ie - do rotor physics become impracticality large or fast at some point for materials science, or is it purely a space problem for rocket launches.

Oh for sure, it's a great question.

I have led efforts building Chinook style tandem rotors with 2 sets of blades from a size like the Trex 800, powered by a 2 stroke engine, as well as 40kg max takeoff quad-planes with both electric quadrotor and 2 stroke engine (for forward motion).

But because I was the main lead and pushing the pace so fast, I wished I did it with a more rigorous aero-engineering to it. I started both projects with barely any experience developing aircraft.

Thinking about your question, here are my 2 cents:

The biggest thing I stugged with is how the vibrations and the accompanying harmonics on the sytem as the rotors spin up and down. I could see it on the logs as the rotors spin through certain Hz, there's would spikes in virbational ampiltudes at predictable frequencies. As the blades get bigger the forces (probably) goes up. Sometimes, these frequecies (especially the lower ones) are at the range where its very hard to find the right materials to damp it out of the control and sensing electronics. Ingenuity probably deals with a virbration range that well into the hundreds/thousand of Hz and I do remember that renge is not a difficult range to damp out, vis a vis the low tens of hertz.

Also, the harmonics is related to ground resonance. I had built my tandem with "skids" that are rigidly attached to the rest of the frame. When the system made contact with the ground on just one skid, that one skid becomes a pivot, the vibration has no where to go and I witnessed first hand, first time, what ground resonance can do to mechanical systems. I can never forget seeing M4 through to M8 hex holt beads being sheared clean off after the resonance event. Only later did I find out that in full scale systems, they have dampeners between the main body and the skids of the aircraft. See https://m.youtube.com/watch?v=IIC-oBzLYhQ ;

Staying in flight is not as hard. But getting the ssytem to land and spin down proerly was big pain without understanding ground resonance and its effect on mechanical design. When I saw the little puny legs of Ingenuity, this experience of mine came into mind and I was glad they had legs like to damp out vibrations as it came down to land.

Then there is the relation between the mechanical vibration regimes of the system, the polilng rates of the foundational flight sensors and the freqency of the main flight stability and movement control loop itself.

With bigger systems, the cables (for signal and power) could run longer too (becoming long long antennas), which means you can run into problems with noise of various origins. If I'd do it again, something like CAN bus would probably be something I look at seriously. Bigger systems also draws more power, and that can have an impact on how much management is needed for noise. Bigger power draw usually also means heavy power store & delivery system, which affects CG management, when then means you can't move things around to management noise. At some point, I felt like I was doing dancing a multi-factorial show.

I wished I could be clearer. Perhaps someone more qualified can chime in.

These must be the masses of the Mars rovers, the weights would be measured in newtons (or pounds in the USA) and would differ between mars and earth.

Here's a paper that describes what the next gen could/should be. The lead author is the head of Mars heli, IIRC.

https://ieeexplore.ieee.org/abstract/document/9843501

In short: 30kg heli, 5kg payloads. Other designs by collaborators are closer to 20kg. It's probably possible to transport a few of these on the existing lander technology, which would be awesome.

The scholar.google.com keywords you want are "Mars Science Helicopter" and a good touchpoint author is T. Tzanetos or S. Withrow-Maser

Ames and JPL were still collaborating on this when I worked there.

I was surprised to learn that it’s actually a fair bit heavier. I was lucky enough to get to attend a talk by the head of the Ingenuity program, and he mentioned how the mass ballooned a bit to something under 5 pounds.

(Listed as 4 pounds on this official fact sheet) https://mars.nasa.gov/files/mars2020/MarsHelicopterIngenuity...

That's the goal, yes. Depending on the destination, naturally. Here's what's planned for Titan: https://en.wikipedia.org/wiki/Dragonfly_(spacecraft)

Was going to post this.

Titan is such a wonderful place for a nuclear powered helicopter. Much better than rover/submarines/floaters, IMHO. A balloon would also have been excellent, but the extra mobility from helis is going to be amazing.

Ingenuity was just a technology demonstrator. I think it demonstrated the technology splendidly, so we are likely to see more helicopters on Mars in the future.

Not sure if Nasa has said yet which roles they see for future Mars helicopters. The initial idea behind Ingenuity was to use them as scouting vehicles for rovers. Of course rovers improved a lot too, with better autonomous driving. But with a Mars rover driving about 100 meters/yards per day scouting helicopters are still useful.

Maybe we will also see Helicopters carrying more instruments themselves. But I imagine in the beginning that's mostly better imaging instruments. Weight is still an issue for flying things, no matter the planet. But maybe we will see some future missions that instead of a car-sized rover and one tiny helicopter have a fleet of helicopters with a small support-rover for exploring wider areas.

I think the current plan is that helicopters will be very light with minimal instrumentation and will be used mostly to scout ahead for rovers. The rovers will be much heavier and include many instruments.

(Of course, all of NASA's long-term plans for Mars would be completely disrupted if Starship lowers the cost-per-kg of delivering equipment by two orders of magnitude, which arguably is likely.)

Making it more economical to escape Earth's gravity well isn't going to alter the physics of the Martian atmosphere or the relative utility of copters vs rovers for Martian exploration. Which is to say, even if you stationed humans on Mars, they'd still be exploring remotely via copter/rover pairs, just no longer with a human-to-robot latency measured in tens of minutes.

However we might be willing to drive a lot more agressively if we know we can get a mechanic out to a stuck rover. Similarly, cheaper delivery might make a large number of smaller more disposable vehicles more appealing for many missions, just like what happened to satellites in the last decade.

If you increase the mass and/or number of vehicles by 100x, a bajillion things will change.

A heli that can move a rover is basically worse than a heli that has rover instruments and a few wheels. You have extra weight and parts and complexity for hitching and carrying that you can just avoid by giving a small rover flying ability.

Even the combo is probably too much complexity. A heli with good imagers, spectrometers, and the ability to cart soil samples would be fantastic.

Surfacing a comment: Here's a paper that describes what the next gen could/should be. The lead author is the head of Mars heli, IIRC.

https://ieeexplore.ieee.org/abstract/document/9843501

In short, future designs target ~30kg heli, 5kg payloads. Other designs by collaborators are closer to 20kg. It's probably possible to transport a few of these on the existing lander technology, which would be awesome.

The scholar.google.com keywords you want are "Mars Science Helicopter" and a good touchpoint author is T. Tzanetos or S. Withrow-Maser

> Other designs by collaborators are closer to 20kg. It's probably possible to transport a few of these on the existing lander technology, which would be awesome.

Actually it could be like 50 of them. Plus some ground robots to put together solar farm. And wooh... we get the first extra terrestrial permanent base

Well size is the limiting factor for fliers, since they like to have broad surfaces with low weight. But I think you're referring to some, ahem,

untested possible landing vehicles ...

in which case, yeah, you have a lot of robots.

For the solar farm assembly case, It's actually a lot easier to have a teleoperated robot doing the work, a few astronauts in orbit doing the operation / construction. In the case of building things, you want as much space / weight landed to be the thing being built, not the builders, per se.

Non-paywalled article about the concept, including renderings of the hexacopter design:

https://spectrum.ieee.org/the-next-mars-helicopter

Why not some helium balloon type craft that could float along with low power for longer periods of times? Could cover vast distances? Descend into fertile plains looking for samples?

Helium's lifting capability is proportional to the density of the atmosphere, which is very low on Mars.

Is it viable to use vacuum instead of helium?

Wouldn't you need something with some amount of pressure to stop the "shell" you plan to float from collapsing?

What if we use hydrogen, which is halfway between helium and vacuum?

Hydrogen it is.

Hydrogen leaks.

Minimizing moving parts, so much as possible, when dealing with hardware tens of millions of miles away, let alone with a 13 minute delay in 1-way messaging, is generally smart. And Mars' atmosphere is so thin that these rovers will never be moving any meaningful payload, so their only real use case is as a scouting type system. But they also add very little value there given the existence of orbiting satellites. Even the Mars Recon Orbiter (from 2005) captures images in the < 1m resolution range.

IMO NASA wanted to try to deal with the sort of 'oh boy... another rover' fatigue and saw the drone as a way to spice things up with some passable science arguments behind it, and a relatively minimal cost. Further supporting this is that the helicopter wasn't an initial part of the plan - it was strapped on at the 'last minute', speaking in government time. In any case, I would comfortably wager against us seeing more drones in future missions, at least to Mars.

In the shorter term, I see the helicopter as making the rover more capable, by finding routes and destinations of interest. And the rover makes the helicopter more capable by providing a recharging station. So they're both at their best when working as a system. Maybe a rover can support multiple choppers.

> the rover makes the helicopter more capable by providing a recharging station

Does it? I thought the helicopter was just solar powered.

That's cool. Thinking about it, there must be a tradeoff. The rover could support more massive batteries, but then "docking" between the two machines would have to be utterly reliable.

IIRC as a result of Ingenuity's success, one of the proposals for the Mars sample return mission architecture involved several helicopters to retrieve Perseverance's sample canisters (it drops them as it goes along, so that there's no worry about how to get the samples out of the rover in the future).

I should add though that the prospects of the parasites in Congress properly funding such a complex mission seem pretty low for now.

> "Good news today," NASA's Jet Propulsion Laboratory (JPL) wrote on X, formerly Twitter, late Saturday.

I heard this line in my mind with Professor Fansworth's voice.

So did it crash, or freeze?

Yeah! Let's go NASA, Godspeed! USA, USA, USA!!! Not only has it already exceeded its objectives, but now it may generate even more useful data for new objectives...does anyone know if NASA maintains any kind of engineering blog or stream where we can learn more details about what went wrong and how they reconnected?

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