Helicopters for Mars exploration

http://www.cnet.com/news/nasa-propos...s-rover-scout/

A three minute flight of a 0.5 miles.

I wonder what it would take to build a very fine resolution image
of Mars for the upcoming 3D tech computers will soon have over the
course of the next 5 years? From orbit? And from these little machines?
It would be nice if it was good as being there on the surface at
least for a virtual walk about.


Mars in the 3D surface viewer..........................Trig

On Sunday, January 25, 2015 at 9:11:23 PM UTC+13, Posting into the ether wrote:
http://www.cnet.com/news/nasa-propos...s-rover-scout/

A three minute flight of a 0.5 miles.

I wonder what it would take to build a very fine resolution image
of Mars for the upcoming 3D tech computers will soon have over the
course of the next 5 years? From orbit? And from these little machines?
It would be nice if it was good as being there on the surface at
least for a virtual walk about.


Mars in the 3D surface viewer..........................Trig

More Here;



https://www.youtube.com/watch?v=vpBsFzjyRO8

Yes, SMALL SOLAR POWERED systems that fly are the way to go!

Especially since insect scale construction has now been achieved.

https://www.youtube.com/watch?v=C-Xi6DJAwbE

Here are other small autonomous agile systems

https://www.youtube.com/watch?v=YQIMGV5vtd4

The weight of the devices goes down with the cube of the dimension. The lift and solar power goes down as the square of the dimension.

Now, at 600 Pascal (0.087 psi) Mars' atmosphere has a density of 11.6 grams per cubic meter at 0C given that the gases on Mars average 43.34 grams/mol..

With Mars being 1.52366 AU from the Sun, and the Sun emitting 1368 W/m2 at 1.00000 AU then we can know that on Mars' surface the sun can be no more than 589.2 Watts/m2 normal to the Sun.

Mars surface gravity is 3.711 m/s2

Here's a calculator for RC-helicopters...

http://dhrc.rchomepage.com/calcAdvanced.htm


Here's a really cool paper about helicopter lift;

http://dspace.mit.edu/bitstream/hand...1/30057064.pdf

We have to figure out what it takes to lift a helicopter on Mars.

Thrust = mdot * w

Where Thrust is the force and mdot is the mass flow rate (change of momentum) and w is the velocity.

Power = Thrust * w

and Power for straight up lift is equal to Thrust times velocity.

Now mdot is related to the velocity of the air its density and so forth;

mdot = rho * A * w


Now, RC electric helicopters on Earth produce 10 m/sec exhaust speeds and have 0.35 m diameter blades. This is 0.0962 m2 area and rho=1.2 kg/m2 so;

mdot = 1.2 * 0.0962 * 10 = 1.154 kg/sec

Thrust = 1.154 * 10 = 11.54 N = 1.15 kilograms.

Power = 11.54 N * 10 m/sec = 115.4 Watts

On Mars this same rotor produces

mdot = 0.012 * 0.0962 * 10 = 0.0115 kg/sec

Thrust = 0.0115 * 10 = 0.115 N

Power = 0.115 * 10 m/sec = 1.15 W

With 3.711 m/sec2 acceleration this is capable of lifting up to;

0.115 /3.711 = 31 grams

At 40 m/sec exhaust speed and 0.70 m diameter this rises to;

mdot = 0.012 * 0.3848 * 40 = 0.1847 kg/sec

Thrust = 0.1847 * 40 = 7.389 N

Power = 7.389 * 40 m/sec = 295.6 W.

This is capable of lifting

7.389 / 3.711 = 1.991 kg

Now, a 350 mm diameter photocell that is 45% efficient produces 25.5 watts when normal to the sun. A MEMS based hexapod that attaches the photocell to the helicopter rotormast above the blade as shown in the video above, is capable of tracking the Sun through the Martian sky.

A Martian solar day is 24 hours 39 minutes 35 seconds. Collecting sunlight for 9 hours per day at 25.5 watt rate permits flying for 40 minutes a day given average battery efficiencies.

With half the mass, 1 kg, equal to the best batteries, Lithium-ion Cobalt batteries, that have 167 Wh/kg

http://batteryuniversity.com/learn/a...er_lithium_ion

Permit collection of 6.55 hours per day and 34 minutes of flight per day.

Now, with a 2 kg system that produces 25.5 watts and consumes 295.6 Watts in flight, we can apply scaling laws as follows;


Power consumption scales as the cube of dimension.
Weight scales as the cube of dimension.
Power production scales as the square of dimension.

So, if we reduce our system by a factor of 10 - from 700 mm rotor diameter to 70 mm rotor diameter, our system mass falls from 2000 grams to 2 grams. Our power drops from 295.6 watts to 0.296 watts. Our power collection drops from 25.5 watts to 0.255 watts. We're nearly capable of continuous flight during daylight hours!

If we drop our size down to 35 mm rotor diameter, our system mass fall from 2 grams to 250 milligrams. Our power drops from 296 milliwatts to 0.3 milliwatts. Our rate of collection during daylight hours drops to 65 milliwatts. Over 20x the rate of consumption!

So, this shows how smaller systems have certain advantages over larger systems, if they can be built.

Of course we cannot fly at night since the specific density of Lithium-Cobalt batteries is only 167 Wh/kg no matter what the size. However, if we switch to hydrogen oxygen fuel cell with water - in a closed cycle system - our specific energy density rises to 4,376.5 Wh/kg. If half our weight is equipment to process the hydrogen and oxygen on board, and half our weight is water (hydrogen & oxygen) then this is still 2,188.3 Wh/kg. This means that 1 kg can operate the larger 2 kg system for 7.4 hours.

So, we can see that a 30 mm diameter rotor system masses

2 kg * (30/700)^3 = 157.4 milligrams - system weight
295.5 W * (30/700)^3 = 23.3 milliatts - power consumption
25.5 W * (30/700)^2 = 46.8 milliwatts - power production during flight

157.4/4 = 39.3 milligrams - water -- 4.3 mg H2, 35.0 mg O2.

173.2 milliwatt-hours of energy storage.

173.2 mwh / 23.3 mw = 7.40 hours battery powered flight.

Increasing from 39.3 grams to 64.6 grams of storage (of the 78.7 grams total allocated for power systems permits round the clock flight day and night.

History of Autogiro
https://www.youtube.com/watch?v=vFiPKUDCl58

Avro Autogiro
https://www.youtube.com/watch?v=3fG-j1YKxUQ
https://www.youtube.com/watch?v=IV-T7Ewqt_U

Avro merged with Hawker-Siddeley in 1963.

Hawker P-1127 Jet
https://www.youtube.com/watch?v=pdu0P6TM8qU

Hawker Kestrel
https://www.youtube.com/watch?v=4-h6A8x0ecg

Harrier
https://www.youtube.com/watch?v=D1i4ukSdqjc

Avro Arrow
https://www.youtube.com/watch?v=7sFRiacvNYo

Handley Page Vampire
http://www.britishpathe.com/video/du.../query/Vampire

The Vampire was equipped with a 'suction wing' surface to improve performance.

Avro VZ-9
https://www.youtube.com/watch?v=cjWHrPYvUo0
https://www.youtube.com/watch?v=a92BJ33AaXI

Avro Project Y
https://www.youtube.com/watch?v=OlZoFJ0qnr4

Avro Project 1794
http://www.laesieworks.com/ifo/lib/AVRO-Silverbug.html

McDonnell Little Henry - Ramjet Powered Helicopter
https://www.youtube.com/watch?v=qs7WlNrHRmA

Modern Autogiro
https://www.youtube.com/watch?v=G-4Y727dY4M
https://www.youtube.com/watch?v=LejOps-gHRU

http://www.cnet.com/news/nasa-propos...s-rover-scout/

A helicopter on Mars would have supersonic flow and therefore be
inefficient. Low payload, much complicated to operate. With the low
density of Mars the favor is on something else: A high tower with a
long lens camera system on top. Even at a Martian storm the wind
force on such a structure is low.

Think about a low weight inflatable / extendable / (printed ?) structure.
Not an easy task to develop. But such a camera could scan a large area
in high resolution. It would be close to a CPU for preprocessing. There
are algorithms able to find fossils. And of course movements like from
dust devils or water eruptions. Selected images would be send to Earth
and the rest stored for some time. The bottleneck for any such Mars
mission is the limited transmission capacity to Earth, not the camera
capacity. Some of the Curiosity descend camera high res images are still
on Mars.


## CrossPoint v3.12d R ##

Far better to use a spy sat looking at mars from orbit. Far more stable, well understood, and might even be better resolution than a helicopter.

On Friday, January 30, 2015 at 2:52:26 PM UTC-8, bob haller wrote:
Far better to use a spy sat looking at mars from orbit. Far more stable, well understood, and might even be better resolution than a helicopter.

Microassay as payload? Didn't someone propose part balloon copter to
increase sensor and travel properties?

Remote assay? How possible?

"bob haller" wrote in message
...

Far better to use a spy sat looking at mars from orbit. Far more stable,
well understood, and might even be better resolution than a helicopter.


Tell you what Bob, you figure out the size of a mirror needed on a spy
satellite to get the same or better resolution than an airborne camera on
Mars.

I'm ready to be convinced if you can show the math.


--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

On Sunday, February 1, 2015 at 2:43:54 PM UTC-5, Greg (Strider) Moore wrote:
"bob haller" wrote in message
...

Far better to use a spy sat looking at mars from orbit. Far more stable,
well understood, and might even be better resolution than a helicopter.


Tell you what Bob, you figure out the size of a mirror needed on a spy
satellite to get the same or better resolution than an airborne camera on
Mars.

I'm ready to be convinced if you can show the math.


--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

I have read the latest spy sats resolve to around 2 inches. Isnt that enough?

obviously areas of interest from spy sats or helicopters would be checked closer by rovers.....

On Sunday, February 1, 2015 at 3:35:56 PM UTC-8, bob haller wrote:
On Sunday, February 1, 2015 at 2:43:54 PM UTC-5, Greg (Strider) Moore wrote:
"bob haller" wrote in message
...

Far better to use a spy sat looking at mars from orbit. Far more stable,
well understood, and might even be better resolution than a helicopter.


Tell you what Bob, you figure out the size of a mirror needed on a spy
satellite to get the same or better resolution than an airborne camera on
Mars.

I'm ready to be convinced if you can show the math.


--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

I have read the latest spy sats resolve to around 2 inches. Isnt that enough?

obviously areas of interest from spy sats or helicopters would be checked closer by rovers.....

I won't think so. Ask a field geologist, they carries some pretty strong
magnifying pieces. if we want to know what's there, the questions are about
rock chemistry, rock crystals, water, ore perhaps and micro fossils
maybe.

Now you want look for crashed ancient spacecraft 2 inches should
do it................................................ .....Trig

"bob haller" wrote in message
...

On Sunday, February 1, 2015 at 2:43:54 PM UTC-5, Greg (Strider) Moore
wrote:
"bob haller" wrote in message
...

Far better to use a spy sat looking at mars from orbit. Far more stable,
well understood, and might even be better resolution than a helicopter.


Tell you what Bob, you figure out the size of a mirror needed on a spy
satellite to get the same or better resolution than an airborne camera on
Mars.

I'm ready to be convinced if you can show the math.


--
Greg D. Moore
http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

I have read the latest spy sats resolve to around 2 inches. Isnt that
enough?


Again, please, do the math. Don't trust what you've read. The math isn't
that hard. Make some effort here.

obviously areas of interest from spy sats or helicopters would be checked
closer by rovers.....

Obviously... because ewe have so many rovers just ready to go.

Seriously, just do the math. It's not hard and it would be a useful
exercise.



--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net