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In my world, a scientist and engineer by the name of Guoliang Guan successfully uproots and moves a quarter of a million tons of habitat, industry, miscellaneous chemicals, storage containers, rocketry, life-support, and scientific experiments from all across the western hemisphere of Mars - to the bottom of Valles Marineris in two months. This accomplished with a mixture of dug-out roads, gondola lifts, concrete shoots, and a bachelors degree in Engineering. Due to his extraordinary accomplishments, Diego promotes him to Chief Mover of Stuff ... Arbiter of Transportation.

Now, Guoliang is greatful for his promotion and all, but he considers it to be a real pain in the ass if he's gonna have to create new infrastructure every time he needs to move something from God-knows-where to Not-the-bottom-of-Valles-Marineris. So the thinks, "Why make infrasture at all?", and dabbles in a mobile, vehicle-based transportation system. He starts by thinking of the all-terrainiest vechicle of them all; an airship, and reasons out its practicality in a dome at the top of Marineris.

Requirement~

  • a useful lift capacity of 50 tons
  • Maximum speed of 180 mph
  • Operatable at 4 miles above the Martian surface level
  • All requirements must be fufilled in relation to Mars

My Question is:

What modifications in Size (dimensions and volume), Lift gas, Structure, and Propulsion to the design of a normal airship (for this question, consider that base to be the Zeppelin NT or LZ-130 Graf Zeppelin II) would be necessary to met Guan's requirements?

Points for factoring in the Martian Enviroment like sandstorms, air density, etc

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    $\begingroup$ Possible duplicate of Impracticalities of making a Vacuum Airship $\endgroup$
    – Braydon
    Commented Sep 3, 2017 at 0:44
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    $\begingroup$ Seriously, stop posting duplicates. $\endgroup$
    – Braydon
    Commented Sep 3, 2017 at 0:44
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    $\begingroup$ Seriously, read the questions you call duplicates before calling them duplicates. I change the question as instructed by the site. $\endgroup$
    – user15036
    Commented Sep 3, 2017 at 1:13
  • $\begingroup$ @Braydon While you're trying to be diligent, the OP is right. This question isn't about a vacuum airship. It's about a Marsworthy airship. Give the OP credit for trying to improve his question. If a question is called a duplicate I read it to make sure it is. $\endgroup$
    – a4android
    Commented Sep 3, 2017 at 4:39
  • $\begingroup$ Would Guan be up for moving approximately an Earth Atmosphere's worth of gasses onto mars? It doesn't seem completely outrageous given his other requirements and it would definitely make air flight a lot easier to manage. $\endgroup$
    – Kaosubaloo
    Commented May 10, 2018 at 19:25

2 Answers 2

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Requirement A) Useful Lift Capacity of  50 tons

Given the Atmosphere of Mars is 0.02 kg/m^3 , and the densities of hydrogen and helium being $0.0004\text{kg/m}^3$ and $0.0008\text{kg/m}^3$ respectively*, Helium should lift $25\space \text{kilos per Kg of gas} (1250 \text{m}^3)$ on Mars, and Hydrogen $50\space\text{kilos per kg of gas} (2500 \text{m}^3)$; making hydrogen the most practical choice (especially since helium is rare on Mars, whereas hydrogen can be extracted from water). This then gives us an airship of $2900000 \text{m}^3$ of hydrogen for it's 50 ton load, and using the proportions of the Zeppelin NT, one finds it need $3125000$ to carry it's own weight. This results in a diameter of $127.44$ meters and length of $675$ meters

Requirement B) Max Speed of 180 mph

Given the max speed of the Zeppelin NT being 77mph with a mass of 10 tons and three engines of around 170 kw each, it can be deconstructed that with its Maximum loaded mass being around 110 tons, the Martian Airship would need a total of 13,260 horsepower to met this requirement in Earth's atmosphere. However, since Mars' atmosphere is over 60 times less dense than Earth's, the total horsepower would need to be scaled up to $798,320$ total horse power to at 180 mph fully loaded through the Martian Air. This will require something on par with 3 OK-650 nuclear reactors.

 * The gas densities are given for STP on Mars ( -27° Celcius and 6.36 millibars )

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  • $\begingroup$ @ThroclesofSaturn; uhmm why are you scaling up power of engines compared with zeppelin's to compensate lower atmosphere density? You should scale up propellers, instead. Given lower density you'll have less drag (less power needed), but larger dimensions will partially counter this effect (square/cube law helps you, in this case!). In general I would expect less power requirements with larger propellers. $\endgroup$
    – ZioByte
    Commented Sep 3, 2017 at 8:38
  • $\begingroup$ @ZioByte How much larger than proportion would the propellers on an Airship need to be to make up for the difference? $\endgroup$
    – user15036
    Commented Sep 3, 2017 at 8:59
  • $\begingroup$ I would expect you need propeller surface to scale up to intercept (proximately) the same amount of gas, Then you should care for avoiding each blade to work in previous one turbulence as much as possible. I am stretching my knowledge, now, so please take this with a grain of salt as I'm not an avionics engineer (I'm a physicist). NASA seems to advise a three-blade design with relatively thin blades. $\endgroup$
    – ZioByte
    Commented Sep 3, 2017 at 9:37
  • $\begingroup$ Two large counterrotating propellors extending from the stern of the airship might do for forward propulsion, and secondary propellors along the sides can be used for thrust vectoring and fine movements. Alternatively, given the vast surface area of the airship, perhaps energizing the surface and using it as an MHD wind accelerator will do (and is more SFNal as well). $\endgroup$
    – Thucydides
    Commented Sep 4, 2017 at 0:26
  • $\begingroup$ By this calculations, since the atmosphere here on Earth is about 250 denser than Mars, you could lift 12,500 kg per kg of hydrogen or half as much with helium. If that were true, we would still be using zeppelins as freight carriers. Actually, given that Mars' gravity is 37% that of Earth, but its atmosphere is 250 times thinner I expect zeppelins to perform much worse than they do here. $\endgroup$
    – Rekesoft
    Commented Sep 4, 2017 at 10:22
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Since mars' atmosphere is thin enough to make a really good analog for hard vacuum in most laboratories here on earth, there isn't any way to get buoyancy for a zeppelin. .

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