Author Topic: Mars Airships  (Read 23550 times)

Offline Krevsin

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Mars Airships
« on: 11/30/2014 10:37 AM »
So I've been wondering about two things after watching the excellent Wanderers video (, thread to discuss the video here) and seeing the segment with an airship coming in for a landing on Mars.

1) Are airships on Mars actually possible?
2) Do they have any advantages over regular aircraft or suborbital cargo hoppers?

Offline Joel

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Re: Mars Airships
« Reply #1 on: 11/30/2014 11:09 AM »
Advantage: The fact that they could be made solar powered comes to mind. Hard to get a "regular aircraft" to fly without oxygen...

Offline Krevsin

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Re: Mars Airships
« Reply #2 on: 11/30/2014 12:33 PM »
Don't propeller aircraft simply require the presence of an atmosphere in order to generate thrust?

Offline TrueBlueWitt

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Re: Mars Airships
« Reply #3 on: 11/30/2014 12:40 PM »
Would it survive one of Mars infamous dust storms?
« Last Edit: 11/30/2014 12:40 PM by TrueBlueWitt »

Offline Krevsin

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Re: Mars Airships
« Reply #4 on: 11/30/2014 12:51 PM »
Would it survive one of Mars infamous dust storms?
Well, I would imagine it could, provided its outer shell is sturdy enough (think Kevlar or similar) and its thrusters powerful enough (think some sort of emergency gas thrusters to keep it steady next to ordinary propellers). I would imagine the SOP during a dust storm would be to keep the airships grounded, both to keep strong gusts of wind from destabilizing it and the dust off the solar panels.


Does anyone know any numbers about the buoyancy of helium in martian atmosphere?

edit: after doing some research, it would appear that martian atmosphere is thinner than even gaseous hydrogen. Does anyone have any alternate figures or are airships truly impossible on Mars?
Sources:
http://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html,
http://www.engineeringtoolbox.com/gas-density-d_158.html
« Last Edit: 11/30/2014 01:23 PM by Krevsin »

Offline eriblo

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Re: Mars Airships
« Reply #5 on: 11/30/2014 01:29 PM »
Possible - sure! The atmospheric pressure of Mars corresponds to about 31-34 km in Earths atmosphere which is comfortably within the capabilities of high altitude balloons (remember that Baumgartner and Eustace jumped from ~39 and 41 km respectively). Put a few solar panels and a propeller on the payload and you have an airship :)

Making an airship that has a useful payload and can actually move at a reasonable speed is however probably just beyond current material science; the current record on Earth seems to be slightly above 20 km (see for example this presentation on HiSetinel). The higher density of the Martian atmosphere (CO2 and colder temperature) helps somewhat, as does using hydrogen (not combustible so not dangerous) but it's still very hard:

The Hindenburg had a lifting volume of 200 000 m3 of hydrogen, which ideally would lift 237 tonnes at STP, and a structural mass of 118 tonnes. The atmospheric density on Mars is about 20 g/m3 (maximum I guess) and the density of hydrogen at 1 kPa and somewhat arbitrarily chosen 240 K is about 1 g/m3, giving 19 g/m3 of lift for a grand total of 3.8 tonnes. Even if Hindenburg was 1930s technology that will require quite a diet!

EDIT: Fixed links...
« Last Edit: 11/30/2014 01:40 PM by eriblo »

Offline eriblo

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Re: Mars Airships
« Reply #6 on: 11/30/2014 01:36 PM »
... after doing some research, it would appear that martian atmosphere is thinner than even gaseous hydrogen. Does anyone have any alternate figures or are airships truly impossible on Mars?
Sources:
http://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html,
http://www.engineeringtoolbox.com/gas-density-d_158.html

Not thinner than hydrogen at martian pressure ;)
« Last Edit: 11/30/2014 01:38 PM by eriblo »

Offline Krevsin

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Re: Mars Airships
« Reply #7 on: 11/30/2014 01:41 PM »
Thank you for your most educational response, eriblo!  ;D

So, despite being out of our current technological grasp, airships on Mars are in fact plausible (perhaps by using carbon-nanostuff or similar). Now the only question remains whether they are worth the investment.

... after doing some research, it would appear that martian atmosphere is thinner than even gaseous hydrogen. Does anyone have any alternate figures or are airships truly impossible on Mars?
Sources:
http://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html,
http://www.engineeringtoolbox.com/gas-density-d_158.html

Not thinner than hydrogen at martian pressure ;)
Oh right, my bad. Thanks! :D
« Last Edit: 11/30/2014 01:43 PM by Krevsin »

Offline JohnFornaro

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Re: Mars Airships
« Reply #8 on: 11/30/2014 03:11 PM »
They would have to be huge.
Sometimes I just flat out don't get it.

Offline pagheca

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Re: Mars Airships
« Reply #9 on: 11/30/2014 03:18 PM »
(1) maybe you forgot the gravity acceleration is lower?
(2) problem may be how to control their movement in very low air pressure.

http://www.spacedaily.com/news/mars-balloon-04a.html

Offline Krevsin

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Re: Mars Airships
« Reply #10 on: 11/30/2014 03:35 PM »
(1) maybe you forgot the gravity acceleration is lower?
(2) problem may be how to control their movement in very low air pressure.

http://www.spacedaily.com/news/mars-balloon-04a.html
1) yes, I kind of did. Likewise for air pressure.

2) I assume some sort of compressed gas system could be utilized if propellers are inadequate.

Offline eriblo

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Re: Mars Airships
« Reply #11 on: 11/30/2014 04:23 PM »
(1) maybe you forgot the gravity acceleration is lower?
(2) problem may be how to control their movement in very low air pressure.

http://www.spacedaily.com/news/mars-balloon-04a.html
1) yes, I kind of did. Likewise for air pressure.

2) I assume some sort of compressed gas system could be utilized if propellers are inadequate.

1) Heh, so did I, although in retrospect I obviously meant 3.8 tonnes of lift (force) for a Martian Hindenburg  ;) Always dangerous to use oh-so-convenient gravitational metric units of force on other planets...

2) Is that a big problem though? I was thinking that drag, aerodynamic forces and vehicle mass/inertia to first order all scaled together with atmospheric density, compare with pictures of HiSentinel or other high altitude airships. The aerodynamic surfaces will have to be larger due to the larger inertia relative to the lifting force (see 1)) but that is a factor of three or so.

Online sanman

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Re: Mars Airships
« Reply #12 on: 11/30/2014 06:55 PM »
Regarding maneuvering -- does "ion wind" work in Martian CO2 atmosphere?
You know -- electrohydrodynamics.

If so, then a Martian airship could have a lot of surface area to create that effect for maneuvering purposes.
« Last Edit: 11/30/2014 06:56 PM by sanman »

Offline Nilof

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Re: Mars Airships
« Reply #13 on: 11/30/2014 07:47 PM »
A good rule of thumb for anything relating to the Martian atmosphere is that it is negligible at low speeds. Airplanes can work if they go fast enough. Anything that inherently has to fly in a low-speed regime on the other hand will usually not be practical.
« Last Edit: 11/30/2014 07:47 PM by Nilof »
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline pagheca

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Re: Mars Airships
« Reply #14 on: 11/30/2014 08:38 PM »
So, regarding your initial two  questions, Krevsin:

1) Are airships on Mars actually possible?
The 1997 JPL Mars Geoscience AeroBot project, was aiming to launch a superpressure balloon on Mars.

Here some parameters:

Spherical Superpressure Balloon
Volume = 10,500 m3
Diameter = 27.17 m
Balloon mass = 55 kg
Gas Mass= 12kg
Payload = 15-30 kg
Float altitude = 6.5-12 km
Daytime AP = 240 Pa
Nighttime AP = 20 Pa

This shows that your idea is at least theoretically feasible.

2) Do they have any advantages over regular aircraft or suborbital cargo hoppers

I guess that the main advantages for a mission on an unprepared region of the planet would be:

(a) much easier and safe take off (an aircraft/glider on Mars would need a very high take-off speed)
(b) no need for large amounts of propellants
(c) slow speed over the ground, aka more sensitive photogrammetry and remote sensing.
(d) long duration flights available
(e) easier control
(f) larger payload/(total mass landed on Mars) ratio for same coverage
« Last Edit: 11/30/2014 08:57 PM by pagheca »

Offline Vultur

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Re: Mars Airships
« Reply #15 on: 11/30/2014 11:25 PM »
JP Aerospace made a (very small and unmanned, admittedly) airship that flew up to 95085 feet (~28.8 km) which is not that far from Mars air density (It was basically two balloons connected by a stick with a motor & propeller attached.)

Offline ChrisWilson68

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Re: Mars Airships
« Reply #16 on: 12/01/2014 09:30 AM »
JP Aerospace made a (very small and unmanned, admittedly) airship that flew up to 95085 feet (~28.8 km) which is not that far from Mars air density (It was basically two balloons connected by a stick with a motor & propeller attached.)

I guess you missed upthread where someone pointed out that "Baumgartner and Eustace jumped from ~39 and 41 km respectively".

Offline Lampyridae

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Re: Mars Airships
« Reply #17 on: 12/01/2014 11:00 AM »
Martian atmospheric *density* is ~0.02kg/m^3, compared to 1.2kg/m^3 for sea level Earth. Pressure is lower because of Mars' gravity but the density is still manageable as far as aircraft are concerned. ARES developed the concept very well.

For transporting humans and cargo, you might find different solutions being used that take advantage of Mars' unique environment: upper-atmosphere or atmo-grazing skyhooks connected to asteroids in fairly low orbits (<Phobos). Solar concentrators focusing on aircraft solar arrays. High speed ground-effect aircraft (no cows!). etc.
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Online mmeijeri

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Re: Mars Airships
« Reply #18 on: 12/01/2014 11:32 AM »
1) Heh, so did I, although in retrospect I obviously meant 3.8 tonnes of lift (force) for a Martian Hindenburg  ;) Always dangerous to use oh-so-convenient gravitational metric units of force on other planets...

Surface gravity doesn't matter, does it? It affects weight and buoyancy equally.
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Offline Krevsin

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Re: Mars Airships
« Reply #19 on: 12/01/2014 12:13 PM »
(c) slow speed over the ground, aka more sensitive photogrammetry and remote sensing.
But does that not make them vulnerable to sudden gusts of wind?

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