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Comment by JoeAltmaier | Hacker News Reader

Lots in here, taking me time to unpack.

Kind of blue-sky - 30kG is heavy, so maybe its all moot - who's going to dedicate that much mass to this project.

Any geology it does, will be contaminated by rotor wash scrubbing the surface material when it lands. Is that an issue? Maybe its a benefit.

Can it really react to sample inaccessible places? What is the response time between capturing an image of a face, and getting a response from Earth saying "take a sample!"? Is it even within the battery life/flight time?

Can it range outside the rover line of sight? What about radio relay to the orbiter? Surely it can't track that itself, especially in flight. That level of independence may be a pipe dream.

I'm in favor of a drone element to the next mission, as long as it doesn't instantly get lost or broken.

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I interviewed Bob and wrote this article, so I can answer a few of these.

I think JPL's idea is that MSH would be a dedicated helicopter mission, rather than piggybacking on some other mission, so it wouldn't be eating up the mass budget of another lander or rover.

Similar to Ingenuity, the flights would be autonomous but the science wouldn't be. MSH would fly up to a cliff face (or whatever), take pictures, land, ask Earth where to sample, and then make a second flight to do the sampling.

MSH would be able to communicate with orbit directly and would not need rover or lander support.

The rotors would have to be massive to lift 30kg, that may be a stumbling block as it’ll require folding and so on. Seems like it would need a lander at least for recharging right?

You can see how the whole thing would fold up in the linked article, there's an image from the white paper that shows MSH fitting into the same size aeroshell Mars Pathfinder used. It would run on solar power and recharge itself, just like Ingenuity.

Thanks, for some reason I had a brain fart and thought it’s one giant rotor.

Also, the rotors would blow away dust on the landing site, which may be a problem if you want to research dust, but may be an opportunity if you want to see what's beneath it.

If you're interested in the details of what goes in to developing rotors for a helicopter for an atmosphere we've never built in before you should check out this talk: https://doi.org/10.52843/47ly7q

Thanks! In scaling up the fragility of the material seems very likely to be a big factor, cube-square law and so on. I wonder if there’ll be physical testing of proposed designs, are there even near-vacuum wind tunnels?

A lot of that talk compares theoretical results with experiments in a low-pressure wind tunnel (see e.g., the slide at this point https://cassyni.com/events/6GYLBKG5pBd4su8dm9A9FB?t=255.0s for a reference).

It's quite a simplistic (2d) setup however. I'm not aware of any more complex experiments.

> MSH would be able to communicate with orbit directly and would not need rover or lander support.

Does that mean it wouldn't be powered by an RTG like the last few missions? Or do you just mean that the MSH will have its own comms independent of a supporting rover/lander?

JPL has run the numbers on this as part of the engineering study. The solar panel shown in the concept image (in the center) charges a battery that gives MSH a 10km range or 5 minutes of hover time after charging for a day. It would have its own comms that could reach orbit.

Ooof that's hard to swallow :(. Would the MSH be so productive that it makes up for the limited operating time? Is mission planning so meticulous that it would be a bottle neck anyway? What about winter?

Whats the power budget for instruments during/after flight?

This is all the next step. If they end up putting together an actual mission proposal, they can factor in power budgets for specific science instruments, sun angles and seasonality at the landing site, etc, but they're not quite there yet.

Not sure what you mean by limited operating time, though- if you mean that MSH has to spend 50% of its time charging, that's true, but relative to a rover, it can travel so much farther and faster that JPL is arguing it more than makes up for it.

For reference the rovers can do 100 meters a day. 10km in one day is huge.

Yeah I was going to post this too: the range of a helicopter like that is massive. Well into the "find an interesting feature and follow it" range.

Hopefully by the time this thing is ready to be built SpaceX have the Starship flying. Getting payload to Mars is going to get a lot cheaper if they hit even half their goals (even if we're just launching the rocket that goes to Mars on top of a Starship).

Imagine deploying 100 of these helicopters deployed from a single Starship.

>Kind of blue-sky - 30kG is heavy, so maybe its all moot - who's going to dedicate that much mass to this project.

if it is delivered by Starship - and timeframe wise i guess it will be so - then there can be tens of those delivered while not being an even the main mission payload.

I’m looking forward to the swarm robotics Starship could enable. If we really get to the point where we are sending thousands of tons of payload to Mars (building a city) then we could have lots of cheap rovers instead of one big one. I designed a 3D printed plastic rover and I’m super curious how it would behave in Mars. An aluminum framed version with injection molded gears would be much more robust while staying low cost. And it can drive over very large obstacles:

https://youtu.be/gqLQ5Ht8YE0

significant share, by mass, of the parts of such cheap simple rovers would probably be 3D printable - say using something like sand, clay or regolith laser sintering - right there on Mars. Basically one of the most important things to be solved on Mars would be to substitute as much as possible with locally produced components (kind of like Russia after international sanctions in 2014 :) That in particular means that the original designs should be very robust and simple in order to be amenable to such a local production. Kind of like do we want to bring rubber wheels all the way from Earth or may be we can locally produce something which would most probably be worse than rubber and thus the original design should account for increased vibration and roughness of the resulting ride.

Yes local materials production on Mars will be important. But I think there will be a period before that is running where we could still send like ten simple rovers and that would be an interesting mission compared to how we have been doing it.

One thing of note, it’s too cold on Mars for rubber (as far as I can tell). The tires are one part of my robot that wouldn’t work. NASA developed some elastic-mode Nitinol tires that would do the trick.

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