Air Transportation on Mars - Gravity's affect on Air travel on Mars

Palomar · 2003-09-12 10:18:20

What could be the effect of the dust in the atmosphere ? I've read that the dust is as small as cigarette smoke.

*May I ask a really quick question? Sorry to intrude, and I don't want to take this too much off-topic (little fear of that, since most of what you guys are talking about is beyond my ken):

Would Marsian dust/dirt/sand be suspended longer in the air because of the low gravity and thin atmosphere after an impact of a heavy object on its surface, as compared to here on Earth?

Any responses appreciated...

--Cindy

dickbill · 2003-09-12 10:40:57

Would Marsian dust/dirt/sand be suspended longer in the air because of the low gravity and thin atmosphere after an impact of a heavy object on its surface, as compared to here on Earth?

I think it's safe to say yes, the dust would stay longer than on earth. The only forces, that I see, that would take back the dust on the ground, would be the gravity and the electrostatic charge of the dust, while other forces, ascending air current and other dust devil, constantly resplenish the air in dust.

About the electrostatic charge of the dust versus the ground, I don't know how much it is an issue. Nobody has ever witnessed a lightning on Mars, to my knowledge.

Shaun Barrett · 2003-09-12 18:31:25

Hi Dicktice!
I haven't investigated in detail the actual physical mechanism by which a classical aerofoil shape causes lift. When I was in school, we were taught it was the Bernoulli Effect and since then I have most often heard it called the Venturi Effect.
My impression has always been that increasing the speed of the airflow over the wing causes a pressure reduction, though I am also familiar with the concept of redirecting a large mass of air in such a way as to give it a significant downward momentum vector, which must result in an equal and opposite upward force vector on the wing. (Newton and all that! )
Until now, I hadn't heard the name Coanda in relation to this topic. A regrettable display of ignorance on my part, no doubt!

But, whichever way you care to describe the mechanism of aerofoil lift, I hope it won't detract from the overall thrust of my argument, which was to reassure Dickbill that there is still hope for his winged re-entry vehicle.

In response to Cindy's question, I think the two major factors affecting the persistence of dust in the martian atmosphere are the size of the particles and the lack of rainfall, which 'washes' a lot of dust out of our air here at home.
If you remember the video clips of Apollo astronauts driving their cars on the Moon, you will recall how the dust thrown up by the wheels followed a long slow parabolic path back down to the surface. None of it remained in clouds in the air, as it would on Earth, because there's no air to support it. Gravity is only 1/6th of Earth's but that wasn't the main factor. It was the lack of air which mattered most.
For fine dust on Mars, there's enough air to keep it suspended for long periods regardless of the fact that gravity there is twice as strong as on the Moon. Again (at least for fine dust), gravity is of little consequence compared to atmospheric density.
With an atmosphere as dense as Earth's, we would be bedevilled with eternal dust in the air, and lots of it (! ), if not for the vast amounts of water vapour we have. The vapour tends to condense around fine dust particles and form water droplets, which ultimately become large enough to fall as rain.
On Mars, this 'washing' action doesn't happen, so we have the worst of all worlds in that the air's thick enough to support fine dust but too thin (and cold) to carry enough moisture to get rid of it!!

So you see, Mars is just too untidy with all that nasty dust everywhere. We really ought to get in there and terraform the place as soon as possible!!
:laugh:

Byron · 2003-09-13 04:17:50

On Mars, this 'washing' action doesn't happen, so we have the worst of all worlds in that the air's thick enough to support fine dust but too thin (and cold) to carry enough moisture to get rid of it!!
So you see, Mars is just too untidy with all that nasty dust everywhere. We really ought to get in there and terraform the place as soon as possible!!
:laugh:

---Coughs---As someone who has a low tolerance for dust, yes, I agree with you 100%... The terraforming process had better be well underway by the time I get there..lol.

In regards to your previous posts about Martian air pressure, here's an interesting little site: Calculating Air Pressure
It's about altitude sickness here on Earth, but you can enter whatever data you want (such as .38 for Martian gee and .007 for the air pressure) and see what the air pressure would be at different altitudes. You should try entering .16 gee (Lunar gravity) and a full Earth atmosphere (1 bar)...it's amazing at how "tall" the atmosphere would be there...even at 10,000 meters! (That is, if the Moon could ever be terraformed..lol.)

B

dicktice · 2003-09-13 13:26:31

Shaun: What a beaut bloke you are! (Did I get that right?) You're right, and Dickbill is a typical innovator: To hell with the extablishment, and full speed ahead! (A third Wright brother?)
Regarding Coanda, the internet tells all, including said controversy. All he needs to know, gutwise, is: Wing-lift through still air (of such-and-such density, etc.) under (whatever) gravitational conditions requires a (something)velocity vector in order to climb, glide or simply stay up. If then, you can picture the airflow (using one of the webpage demonstration animations to be found under: "aerodynamics), from there on, configuration is up to the clever innovator, whether it turns out to be hang-glider, parawing, or Wright Flyer knockoff--or flying saucer, for that matter! (Dickbill, please note!)

Regarding Mars (which is why I'm here), that suggestion of mine regarding catapulting a glider using a kilometre-high cliff to drop the weight of rocks from, actually might be a nice way to do local surveys, starting from (say) an altitude of a kilometre, and spiraling slowly down to land on skids back at base. Landing-out, as we say in gliding circles, need not be the death of you, either: Elastic catapult cable could be taken along, unhookable at the ground-end after overflying it. Your pressure-suit would be your (prone) "cabin," with another position alongside for rescues, etc.
Those Wright Bros. really "got it right" in my estimation: The canard lifting surface was designed to tilt from the leading edge, provide angle -of -attack control right down to stall-speed. The vertical rudder was integral with the wing-warping. Nice, but unnecessary and burdensome. I would eliminate the tail entirely, sweep back and stagger the wings to make it a flying-wing(s) biplane. Fixed end-plates on all four wingtips would prevent sideslipping while banking, to avoid spinning into the ground shile landing. Without a tail, the beaut could then be landed at zero airspeed by tilting it up fourty-five degrees just befor touching-down on skids, that which curl up in back as well as in front. And--oh I don't know--perhaps the wings could be transparent, with Solar-cells on the inside of the bottom surfaces, facing up, to power the craft, once catapulted--and, like that. Gosh, how I envy that kid, dickbill, his future. . . !

Shaun Barrett · 2003-09-14 02:39:22

Thanks for the compliment, Dicktice!
(Yes, 'beaut bloke' is the Australian vernacular for 'great guy'. Please don't ask me how the name 'bloke' originated as a name for males! I have no idea.)
By the way, one of your posts vanished again.
Also, I note your obvious interest in, and knowledge of, gliding. I've never tried it but I suppose it must be quite a rush (?).
I think your idea for 'potential energy launchers' for gliders on Mars is brilliant; I love it!

Thanks for that great little atmospheric pressure calculator, Byron. It kept me amused for ages! (Little things please little minds .. :laugh: )
I fed in the numbers for a 1 bar Earth-type atmosphere on Mars (i.e. molecular mass 29) at the altitude of the summit of Olympus Mons (27,000 metres). The pressure was still 250 millibars! You'd only need an oxygen mask.
If Mars had the same gravity as Earth, the pressure of Earth-type air on Olympus would only be 26 millibars! You'd need a full pressure suit.
Quite a difference.

dickbill · 2003-09-14 07:14:45

Regarding Mars (which is why I'm here), that suggestion of mine regarding catapulting a glider using a kilometre-high cliff to drop the weight of rocks from, actually might be a nice way to do local surveys, starting from (say) an altitude of a kilometre, and spiraling slowly down to land on skids back at base. Landing-out, as we say in gliding circles, need not be the death of you, either: Elastic catapult cable could be taken along, unhookable at the ground-end after overflying it. Your pressure-suit would be your (prone) "cabin," with another position alongside for rescues, etc.

Hi Dicktice,
catapulting, sure, but I think that with all the CO2/water available on Mars, a sabatier reactor plus an electrolyser would provide all the CH4/O2 necessary to make small disposable rocket boosters for take off. This maybe, would require less infrastructure than building a catapult.

Those Wright Bros. really "got it right" in my estimation: The canard lifting surface was designed to tilt from the leading edge, provide angle -of -attack control right down to stall-speed. The vertical rudder was integral with the wing-warping. Nice, but unnecessary and burdensome. I would eliminate the tail entirely, sweep back and stagger the wings to make it a flying-wing(s) biplane. Fixed end-plates on all four wingtips would prevent sideslipping while banking, to avoid spinning into the ground shile landing. Without a tail, the beaut could then be landed at zero airspeed by tilting it up fourty-five degrees just befor touching-down on skids, that which curl up in back as well as in front.

would you really consider a glider without rudder and vertical fin ? flying a glider in the quasi martian vacuum is certainly not easy and without a rudder and fins, it would require other controls motor inside the wings and canard, making it even more difficult and complex. But, I agree that flexible adaptative (in shape, length) wings are not anymore an exotic complex and the technology could be developped for a robust martian glider.
But what you and Shaun said indicates that flying could be a major way of transportation and exploration on Mars.

dicktice · 2003-09-14 09:27:14

Shaun: I try to delete old stuff before it becomes obsolete. I blush to read some of my earliest posts, when I happen to stumble upon them.
Gliding (and motor gliding) is the only form of flying privately left to enjoy without harrassment by those who would protect us from ourselves. The medical physical here is a statement by you that you are fit enough to fly (solo, that is), and the license(s) no more restrictive than they need to be. You should look up the origination of modern hang gliding (not that I recommend it, because it's risky) since the A-frame which made it practical was first invented along your own South Shore. I'll look up the inventor's name, and post it asap. New Zealand is huge on soaring (which is what high performance sailplanes do).

Dickbill: The first airplane on Mars should be simple as possible, for lightness and zero-length runway, in view of all those rocks I expect you've noticed--calling for a catapult initiall--unless your landed happens to ground near a bulldozer leftover from a previous uncrewed capsule.
Regarding no vertical fin and/or rudder: They have no other function than (a) to correct for adverse yaw in turns, from the outside aileron's downward drag-prone position, and (b) to prevent sideslipping when the pilot fails to coordinate rudder and ailerons properly in turns. Adverse yaw becomes practically nonexistent, if you rig the outside trailing-edges to warp downwards less than the inside trailing-edges warp upwards--thus eliminating any need for a controllabe vertical surface. Fixed endplates at all four (or more?) wingtips then, would suffice to prevent spins resulting from inadvertant sideslips while banking in turns (see ultralight flying-wings). No problem though about its ability to fly controllably, once it gets off the ground. But the problems will start to multiply once you begin to add things that aren't necessary to flight, like engines and propellers and stuff! Leave all that for the 2nd expedition to help you sort out, when they arrive with all that hardware, eh?
Hope I'm not getting your goat: It's such a treat, to meet someone interested enough, and young enough to tackle something so farsightedly with some hope of success. Go for it!

sethmckiness · 2003-09-14 10:02:32

There is a couple of things I like to add about this discussion.

1.) The lack of Air density can be made up for by speed.

2.) A turbo fan setup could also be used, with the right fuel being used.(something that reacts to the martian atomsphere)

3.) Don't build anything like the U2. It is the least safe plane in the Military. It's a nightmare of a plane.

dicktice · 2003-09-14 10:24:27

Seth: Taking your points in reverse order--
(3) Yeah, but being a sailplane, the U2 can't be all bad. (Glider pilots are loyal to a fault, see?)
(2) Speed kills, especially when you land on rocks!
(1) Solar-cells in the wings to power electric motor-driven propeller(s) would be just the thing--since you can't burn anything in the air of Mars.

Spider-Man · 2003-09-14 12:18:55

Solar-cells in the wings to power electric motor-driven propeller(s) would be just the thing--since you can't burn anything in the air of Mars.

Ah, but you can! You can burn hydrogen in the Martian atmosphere, producing methane and water. Storing the hydrogen is a problem, though, because it evaporates and escapes quite easily, and is hard to come by on Mars.

Therefore, internal combustion engines using methane and oxygen, produced in-situ from the Martian atmosphere, would be most effective on Mars, as Dr. Zubrin puts forth.

dickbill · 2003-09-14 19:08:31

(2) Speed kills, especially when you land on rocks!

well, I really expect to land the glider on ski-like plates on the flanks of O. Mons. How ? you said it Dicktice: approach for landing with a quasi-null speed and then turn the canard 45 degres upward for the final "fall" ( a fall is slow anyway on Mars) on the ground. With a slow horizontal speed, the destructive effects of hiting big stones are reduced. Their is plenty of dust and sands area of Mars that an experienced pilot could target.
In addition, satellites like MGS can spot in advance these relatively smooth areas.
I am not a glider pilot myself but I have enjoyed a flight with an instructor: we landed, like in emergency because we had no speed left and no ascending warm air current available, in a grass field, luckily relatively flat. I guess that we were either lucky, or the pilot was experimented and knew enough the region to know in advance where were the safe areas to land.

Also, following your ideas Dicktice, I think to supress the rudder and vertical fins. And thanks for all the constructive comments from all.

RobS · 2003-09-14 23:27:16

I once thought hydrogen burns in carbon dioxide, but it turns out it does not; the reaction is mildly endothermic. But Silane (SiH4) burns in CO2, producing SiO2 and CH4. Zubrin discusses it in The Case for Mars. Designing engines to use it will be tricky because the silica byproduct is a solid.

-- RobS

dickbill · 2003-09-15 07:25:07

here is a preview of my glider reshaped:
biplan + canard
I have to finish the texturing before I post a definitive picture.
comments welcome.
http://www.renderosity.com/viewed.....New=Yes

sethmckiness · 2003-10-09 23:52:00

I once thought hydrogen burns in carbon dioxide, but it turns out it does not; the reaction is mildly endothermic. But Silane (SiH4) burns in CO2, producing SiO2 and CH4. Zubrin discusses it in The Case for Mars. Designing engines to use it will be tricky because the silica byproduct is a solid.

Depending on the engine style, it may not be, is Silane a liquid or a gas, also, if you use a standard combustion engine and used oil injection would that help carry out the burned Silicon-Dioxide?

RobS · 2003-10-12 21:44:38

Here are my notes about silane:

Silane SiH4 burns in CO2 to make SiO2, 2C, and 2 H2O at a specific impulse of 280 seconds. But the silane is only 27% of the total weight. The rest of the mass is CO2. This is an excellent candidate for fuel for a Martian airplane. It also burns in terrestrial air with a specific impulse of 345 seconds. Density as liquid is 0.68; melting point, -185C; boiling point, -111.9C. Silane also burns in liquid oxygen with a much better specific impulse.

I got some of this from The Case for Mars and some by googlating on "silane." Zubrin says you can make it from sand; Mars has plenty of that.

RobS

rgcarnes · 2003-10-13 13:32:41

By the way, the silica you see as a trace ingredient in many powdered food and drink mixes (to keep them flowing as a powdered material and prevent clumping) is probably the product of burning silane and is called fumed silica. The particles are very small and light\fluffy.

Trivia, I know, but for what it's worth...

SpaceNut · 2015-08-03 18:48:25

RobertDyck wrote:

RobS
Lift is a function of the density of the air, not its pressure.
Density is directly calculated from pressure. For example, one mole of carbon dioxide gas is 22.256 litres at 0ºC and 1 atmosphere pressure. The term mole is a number of molecules = 6.02*10^23. One mole of carbon dioxide masses 44.0098 grams. The ideal gas law states that PV=nRT, where P is pressure, V is volume, n is the number of moles, T is temperature, and R is a constant. R=0.0821 litre atm / K mol. Here atm is the contraction for pressure in atmospheres, K is the temperature in Kelvin, mol is the contraction for mole. This means the density of carbon dioxide at 0.7% atm pressure and 0ºC will be 0.007 * 44.0098 / 22.256 = 0.01384 grams/litre. The bottom line is you factored gravity in twice. Using your numbers that means Martian wings do have to be 55 times as much area.
soph
if a plane developed its own thrust ... then air density should not be a problem
If a plane is supported by wings, then wing area is calculated by air density, speed of flight, and weight of the aircraft. Thrust will increase speed, but it won't help with lift unless you are building a helicopter or other form of vertical thrust craft.

SpaceNut · 2015-08-03 19:04:16

Another shifting thread fixed before making a post to its topic...

We have meantion a helo ride aong as a possibility but a full sized unit...

Nasa developing space exploration drones

Nasa engineers are developing a Martian quadcopter designed to fly in the Red Planet’s thin atmosphere and gather samples from sites inaccessible to rovers.
The Martian drone, under development under the Extreme Access Flyers programme, would use a lander as a base to refuel and re-charge its batteries between missions.
In addition to Mars, it could work on asteroids and the Moon or other celestial bodies lacking atmosphere.
The engineers envision the drones would be fuelled by propellants made of locally available resources and would be delivered to the target planet or asteroid aboard a lander. Ideally, multiple drones would be delivered at the same time, so that they could be easily replaced if any single one broke down.
Unlike Earth-bound quadcopters, the Martian one would not use rotors to keep itself in the air but cold-gas jets using oxygen or steam water vapour. Moreover, it would require an autonomous navigation system, as there are no GPS signals available on Mars.
The Nasa team has so far experimented with a program that would enable the drone to recognise landmarks in the terrain and guide itself to areas based on ground controllers’ commands.
The team is currently testing prototypes of several sizes and shapes to refine the design of the final vehicle.

Insitu use and exploration.....

RobertDyck · 2015-08-03 20:15:26

Sounds like a great idea. Can I make technical comments? Why 8 thrusters? The blue thrusters in the body appear to be mini jet engines; based on length of duct. But thrusters on the booms appear to be electric ducted fans. Why? It appears redundant. Unable to quickly throttle the jet engines for control? There are designs with thrust vector nozzles to balance thrust without changing engine speed. Or veins in the exhaust stream. This design appears dependant on jet engines for thrust, but electric for control. That requires two energy sources: fuel and batteries. Mini jet engines do not have a generator. Are the electric ducted fans really simpler than steerable veins in jet engine exhaust? And if the goal is to manoeuvre into tight spaces, then eliminating the 4 booms would allow flight into tighter confines.

Last edited by RobertDyck (2015-08-04 15:05:49)

SpaceNut · 2015-08-04 19:13:15

The 4 blue appear to be verticle motion control while the 4 at the end of the arms are for tilt and rotation from what I can see. Hopefully more details will be made soon....

Tom Kalbfus · 2015-09-01 14:21:19

-pnibizworldview09072.jpg20140904.jpg
Would this work on Mars?
http://www.azcentral.com/story/money/bu … /15218367/
Seems to me that if it could take tourists to the edge of space, it might also work in Mars' atmosphere but at a much lower altitude perhaps.

elderflower · 2016-10-10 04:24:52

I've been tinkering with numbers to see if we could make helicopters work on Mars. Conclusion- only just! It might be doable in the depths of Hellas as the increased atmospheric pressure there would nearly double the mass flow through the rotor disk.
Does anyone have any ideas about supersonic helicopter blades. If these are possible a Mars copter becomes practicable.

Last edited by elderflower (2016-10-10 04:26:21)

SpaceNut · 2016-10-10 09:53:50

Tom Kalbfus your posted image looks like an ultra light craft which is one of the ways to overcome lift....

elderflower, Nasa was to try a ride along helicopter as a means to get more science but have not heard any more about it.
Mars supersonic is part of te EDL plans for using this Looking to land humans on Mars by 2030, NASA will test this latest space capsule from the 50th state.

The saucer will be taken to Hawaii and then lofted up to an altitude of 120,000 feet (37 kilometers) on a high-altitude balloon. It'll fire a rocket engine to rise even higher, to 180,000 feet (55 kilometers). And then it'll start falling.
During its Mach 3.5 descent, it will inflate like a pufferfish to increase atmospheric drag, slowing its speed to about twice the speed of sound. That will trigger the deployment of a super-strong 100-foot-wide (33.5-meter-wide) parachute, which should slow down the test vehicle enough for a gentle splashdown.

GW Johnson · 2016-10-10 17:13:54

Supersonic propellers were tried about 1945. They made a lot more noise than thrust, by far. Did not pan out as practical for aircraft propulsion.

That bodes very ill for the concept of a supersonic-rotor helicopter on Mars.

GW

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