Author Topic: Retrieve the 2020 Samples with Helicopter instead of Rover?  (Read 9089 times)

Offline redliox

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Thought occurred to me when I thought of how drone copters here on Earth are being utilized for both recon and (especially if Amazon can have its way) transporting packages: what if the 2020 rover samples were retrieved by a copter instead of a rover?  Currently, the 2020 Mars rover will only have a tiny prototype flying for about a month, and plenty of scientists consider it more of a distraction than useful.  Given how rovers evolved from Sojourner to MER to Curiosity, could there be a parallel development with copter drones on Mars once the properties of Martian flight are understood?

More to the point, a drone might be smaller and able to cover ground faster than a rover and, here on Earth for certain, the devices are already being programmed to handle similar tasks to what MSR might need.  Any thoughts?
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Offline speedevil

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Quote from: redliox
More to the point, a drone might be smaller and able to cover ground faster than a rover and, here on Earth for certain, the devices are already being programmed to handle similar tasks to what MSR might need.  Any thoughts?

This is not in principle unreasonable.

However, while it is 'easy' to make 1-10kg class quadrotors or helicopters with near-off-the-shelf parts, going much heavier has issues.

Landing is very, very risky, as to fly on Mars, your blades have to be going most of the speed of sound.

You get with an architecture similar to the 2020 helicopter a minute or two of flight a day, in summer, whereas with a rover, you can trundle slowly along.

A likely near-term sweet spot as I see it would be a dozen or two helicopters per rover.
Various instruments on them, so you can take particular measurements of specific spots if desired, and perhaps even a tiny arm for 10g samples.

Then the rover trundles over a programmed and approved route mapped to milimeter resolution in 3d by the helicopters at 'high' speed for Mars to get to interesting samples that it can drill or use ground penetrating RADAR or other instruments the helicopters can't handle.

This would need better comms to earth.

Offline Blackstar

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Rovers work. Drones are unproven.

NASA will not spend billions of dollars and then rely upon something fragile and unproven.

Offline TrevorMonty

Nice idea but as others said risky, would need at least 2 very large drones to lift 10kg samples. The sample return rovers will simple and low cost, should be just as fast as drones as they will be travelling mapped routes.


Offline Zed_Noir

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Conventional helicopter drones might not be a good way to get around on Mars. As stated by @speedevil up thread.

However a helistat drone might work. Especially with a helium gasbag that could be heated to provide buoyancy. Think of a miniature semi-rigid blimp with multiple rotors from helicopter drones on outriggers.

There is the historical example of the ill-fated make shift Piasecki PA-97 test vehicle.


Offline speedevil

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Conventional helicopter drones might not be a good way to get around on Mars. As stated by @speedevil up thread.

However a helistat drone might work. Especially with a helium gasbag that could be heated to provide buoyancy. Think of a miniature semi-rigid blimp with multiple rotors from helicopter drones on outriggers.

There is the historical example of the ill-fated make shift Piasecki PA-97 test vehicle.

Blimp drones are problematic on earth.
They are almost ridiculous on Mars.

You need to go very large before the film gets thick enough to be anything you could touch with a finger without destroying it, never mind a rock.

To lift a kilo on Mars, you need around a hundred cubic meters of balloon, or around a 5m diameter sphere, or around a hundred square meters of material. A half kilo of plastic film of this area is around 5um thick.

It also has problems with being blown around in the wind.
Around a 3m/s wind will cause it to be blown sideways with a kilo of force.

1kg class quadcopters are somewhat problematic, but they are almost literally off the shelf - you can buy 90% of the parts you will need online for $200 or so, and they require very limited deployment.
10kg ones would be not off the shelf quite.

Balloon drones on the other hand are going to require complex deployment and be unreasonably fragile.

Offline hop

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More to the point, a drone might be smaller and able to cover ground faster than a rover and, here on Earth for certain, the devices are already being programmed to handle similar tasks to what MSR might need.  Any thoughts?
First thought: Why? What specific problem in the current architecture does this address?

Speed of getting the samples from the cache to the MAV is not likely to be a significant priority, while limiting the risk of losing the sample or needing to re-fly the fetch mission is a major concern.

Roving already known terrain is relatively quick and low risk (by mars rover standards).

Second thought:
Earth based delivery drones aren't directly applicable either in terms of technology or acceptable risk, so significant development would be required even if earth based systems with the same general capabilities were in widespread use.

Offline deruch

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More to the point, a drone might be smaller and able to cover ground faster than a rover and, here on Earth for certain, the devices are already being programmed to handle similar tasks to what MSR might need.  Any thoughts?
First thought: Why? What specific problem in the current architecture does this address?
Firstly, this obviously isn't something that could or would ever be considered for 2020 as the planning for that is mostly set already (Right?).  But as an option for some future sample return mission after much development has taken place and many things have been proven out: 

Could use the drone to eliminate the need for a pick-up/retrieval arm on the MAV delivery vehicle.  Drone picks up sample, flies to MAV (possibly/probably in stages).  Lowers/drops sample into catchment funnel which slides it down into the ERV payload container.  Or same but the sample ends up in a staging location near the ERV and a much smaller arm moves it into the payload container.  But the drone would work sort of like a helicopter crane. 
« Last Edit: 12/02/2018 07:01 am by deruch »
Shouldn't reality posts be in "Advanced concepts"?  --Nomadd

Offline Zed_Noir

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Conventional helicopter drones might not be a good way to get around on Mars. As stated by @speedevil up thread.

However a helistat drone might work. Especially with a helium gasbag that could be heated to provide buoyancy. Think of a miniature semi-rigid blimp with multiple rotors from helicopter drones on outriggers.

There is the historical example of the ill-fated make shift Piasecki PA-97 test vehicle.

Blimp drones are problematic on earth.
They are almost ridiculous on Mars.

You need to go very large before the film gets thick enough to be anything you could touch with a finger without destroying it, never mind a rock.

To lift a kilo on Mars, you need around a hundred cubic meters of balloon, or around a 5m diameter sphere, or around a hundred square meters of material. A half kilo of plastic film of this area is around 5um thick.

It also has problems with being blown around in the wind.
Around a 3m/s wind will cause it to be blown sideways with a kilo of force.

1kg class quadcopters are somewhat problematic, but they are almost literally off the shelf - you can buy 90% of the parts you will need online for $200 or so, and they require very limited deployment.
10kg ones would be not off the shelf quite.

Balloon drones on the other hand are going to require complex deployment and be unreasonably fragile.

Are we discussing the same thing? A helistat does not have negative buoyancy and semi-rigid means there is a partial airframe.

Doubt that commercial drones can operate effectively in the thin Martian atmosphere with average air pressure of 0.6 kPa. The same low atmospheric that will not generate that much wind force to affect any flying drones on Mars most of the time.

Then there is the issue of no real time operation for any type of drones on Mars. So any micro flying machine on Mars have to be autonomous with the ability to take off and optionally landed by itself.

Offline speedevil

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Are we discussing the same thing? A helistat does not have negative buoyancy and semi-rigid means there is a partial airframe.
The volume is still unfortunately large, with all the concommitant issues.
Quote
Doubt that commercial drones can operate effectively in the thin Martian atmosphere with average air pressure of 0.6 kPa. The same low atmospheric that will not generate that much wind force to affect any flying drones on Mars most of the time.
Commercial drones will not work off the shelf.
However, commercial drone components are almost entirely adequate to do so.

A commercial 30" diameter prop weighs ~80g per, because it's designed for 15kg of thrust force -  on mars it will produce 150g at nominal RPM.

Even this is within shouting range of working, though the margins are closer than you would like - the above quad would have 600g lift, and the props eat up 120g of it.

Using earth masses for the moment, we'd like to build a quad that has a maximum mass of 1kg, so as to have a 1.5:1 thrust ratio.
The props eat up 320g of that.
To run the props at 4800RPM or so and 100W per prop needs around another 400g of motor, gearbox, and ESC.
Battery is another hundred grams for two minute flights.
Controller another 100.

This is a grand total of - before structure and instruments beyond a mobile phone class camera - 900g.

A couple of carbon fibre spars with small box in the middle, and wire legs will pretty much get you something that will fly with stock parts on Mars for a couple of minutes, for around $600 per or so, and packs into a 1.5m*10cm*10cm box.

With better parts picking - not for example going for the prop based on tabs I already had open - you can get something which performs moderately better.
Actually making a custom prop, rather than using a ridiculously overspecced earth one would give enough margin to make an insulated electronics box and add a solar panel.

https://forum.nasaspaceflight.com/index.php?topic=45676 - this is the original thread on the Mars Helicopter.

If you dig down and find the PDF describing it in detail, you will find that other than the complex fragile coaxial blades, it is remarkably pedestrian, and pretty much the only 'aerospace' bit of tech on it is the multiply redundant controller and aerogel box. The redundant controller is not required if you are willing to accept some risk /send backup vehicles.

'Hobby' drones have really, really pushed the envelope in this area, maturing the technology to the point it is quite adequate for Mars. (apart from props).

 

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