The boring company goes to mars

[AudubonB]

So much goodness in this thread - from connecting Kimbal's work & Boring tunnels and Audie's new 'subareolian' terminology. Props to @sjoshuaj for starting it.

Why, thankee kindly for having noticed.
My first - okay, second after ornithology - desired course of study in undergraduate was in areology. Unfortunately, back in the lower Oligocene that was a field not available, so it was on to geochemistry and others.

In a neat twist, a still-fond former romantic attachment has become a Mars expert and, dear that she is, she gave me to hold one of those more-precious-than-diamonds "Mars Rocks", from one of the Antarctic Dry Valley meteorites.

So, while I've not been to Mars, Mars has been to me. How magnificent is that?!?!

 

[jkn]

It might make sense to go that deep if required to find solid material. Digging a tunnel in sand requires another material to make it rigid. Most options would require lots of energy. Once you dig the entrance, it doesn't make any difference how deep you are tunneling.

Thank you kindly.

About 5 m would give same radiation protection (= not perfect) as our atmosphere. In case of meteorite deeper would be better. Too deep is not good, because one day you'll find soft material squeezing into your tunnel with pressure of all weight above you.

Layer of sand would make very good meteorite protection.

 

[jkn]

2) Electric cars. They will work just fine on Mars.

Electric cars would work, with a problem: Weight is reduced to 37.8%, but mass is same as here. -> Acceleration time for 0 to 60 increases from 3s to 3/0.378 = 7.9 s. More serious problem: Braking distances do also increase by factor 2.64.

We should build moon base Alpha before going to Mars. But I have written about that many times....

 

[AudubonB]

Let me take your calculation to the absurd extreme, to see if it holds water...because to me, it doesn't make sense.

Let's take that EV to the "solid surface" portion of planet Jupiter, whose gravity is 2.4 times that here. According to what you wrote, our jovian vehicle's acceleration comes to: 3/2.4 = 1.25 seconds to get from 0 to 60! Beam me up, Scotty.....

I'm not convinced.

 

[Brass Guy]

jkn is referring to traction control. At times < 3 secs, you're near (or at) the traction limit the whole ride. On Mars the mass is the same, so inertia is the same (takes the same force to accelerate); but traction is less since the force between the tires and ground (weight) is less. With the thin atmosphere and lower rolling resistance you'd get further on a charge though.
On Jupiter, you wouldn't be nearly as traction limited but you would be power limited. You'd beat the Earth 0-60 but not by that much.

 

[jkn]

Let me take your calculation to the absurd extreme, to see if it holds water...because to me, it doesn't make sense.

Let's take that EV to the "solid surface" portion of planet Jupiter, whose gravity is 2.4 times that here. According to what you wrote, our jovian vehicle's acceleration comes to: 3/2.4 = 1.25 seconds to get from 0 to 60! Beam me up, Scotty.....

I'm not convinced.

Brass Guy already explained this. I add that on Jupiter you could accelerate 1.25 s from 0 to 60, if you have 2.4 times torque and power. On Mars you cannot accelerate much faster than 7.9 s, even if you have 10 times power and torque. I am assuming you don't glue your tires onto the road.

But stopping is the problem. Is CO2 ice slippery?

 

[AudubonB]

Ooh ooh ooh! Call on me call on me! I wanna answer!

Thank you.

The answer is NO. Carbon dioxide ice is not slippery.

The reason that we usually find water ice to be slippery is because under atmospheric pressure and most temperature conditions, the pressure exerted upon an icy surface melts a fine film of ice; that soild-liquid-object interface has only a minuscule coefficient of static or dynamic friction. Even on earth, when you get down to reallly cold temperatures, this no longer occurs. I've never gone iceskating at -40º but I believe that oft-reached number (around here) is sufficient for such slipperiness to disappear.

Regardless, CO2 does not have a liquid phase at what we and Martians would consider reasonable pressures. Rather, solid carbon dioxide sublimates directly to the gaseous state. Ergo, consider it sandpaper. Do not bring along your Flexible Flyers to Mars.

 

[ItsNotAboutTheMoney]

Ooh ooh ooh! Call on me call on me! I wanna answer!

Thank you.

The answer is NO. Carbon dioxide ice is not slippery.

The reason that we usually find water ice to be slippery is because under atmospheric pressure and most temperature conditions, the pressure exerted upon an icy surface melts a fine film of ice; that soild-liquid-object interface has only a minuscule coefficient of static or dynamic friction. Even on earth, when you get down to reallly cold temperatures, this no longer occurs. I've never gone iceskating at -40º but I believe that oft-reached number (around here) is sufficient for such slipperiness to disappear.

Regardless, CO2 does not have a liquid phase at what we and Martians would consider reasonable pressures. Rather, solid carbon dioxide sublimates directly to the gaseous state. Ergo, consider it sandpaper. Do not bring along your Flexible Flyers to Mars.

And, in a related note, this is why you know it's getting quite/very/extremely/unbelievably* cold once the snow starts squeaking.

* Circle appropriately according to climate.

 

[adiggs]

Ooh ooh ooh! Call on me call on me! I wanna answer!

Thank you.

The answer is NO. Carbon dioxide ice is not slippery.

The reason that we usually find water ice to be slippery is because under atmospheric pressure and most temperature conditions, the pressure exerted upon an icy surface melts a fine film of ice; that soild-liquid-object interface has only a minuscule coefficient of static or dynamic friction. Even on earth, when you get down to reallly cold temperatures, this no longer occurs. I've never gone iceskating at -40º but I believe that oft-reached number (around here) is sufficient for such slipperiness to disappear.

Regardless, CO2 does not have a liquid phase at what we and Martians would consider reasonable pressures. Rather, solid carbon dioxide sublimates directly to the gaseous state. Ergo, consider it sandpaper. Do not bring along your Flexible Flyers to Mars.

This is one reason I read TMC - I learn something new all the time, even if it's unlikely to ever be helpful

 

[Skotty]

While we are at it, send a vertical tunnel boring robot to Europa to find out what's really under the surface.

 

[N5329K]

And, in a related note, this is why you know it's getting quite/very/extremely/unbelievably* cold once the snow starts squeaking.

* Circle appropriately according to climate.

In Siberia, where it can still go to minus 60-70, they have an expression for the sound made when you exhale warm breath, the water instantly freezes dry, and falls to the snow. It's called "the whisper of stars."
Robin

 

[AudubonB]

This is one reason I read TMC - I learn something new all the time, even if it's unlikely to ever be helpful

I just can't understand why some people think advice not to bring their sleds to Mars isn't helpful.

 

[ICUDoc]

I just can't understand why some people think advice not to bring their sleds to Mars isn't helpful.

I agree, AudobonB- I'm picking up lots of tips I intend to apply sometime down the track....

 

[adiggs]

And here I was going to not take my sled with me to Mars, because the only pictures I ever see are of sand, not snow

 

[paretean]

Does anyone else think that really the ultimate goal of the boring company is to create the first long term habitable buildings on mars? [...]

My first thought as well. But it takes just a few meters (i.e. not 100 or even 27) of rock or water to shield from radiation to the same extent we are here on earth. Living spaces will be underground for sure, though I guess going above ground will be an everyday thing because radiation is not that bad on Mars, save those solar storms.

 

[Skotty]

And here I was going to not take my sled with me to Mars, because the only pictures I ever see are of sand, not snow

Actually, go ahead and bring the sled.

Sandboarding and Sand Sledding - Great Sand Dunes National Park & Preserve (U.S. National Park Service)

 

[TheTalkingMule]

Did I really write "propositioning"? I would like to propose a different gerund......

Yes, you also created a word that is essentially a synonym for under-boob.

Third, to the extent that subareolian (I really had to reach to create the Martian equivalent of "subterranean"!!!!)....

These should both be reported for moderation.

 

[AudubonB]

Uh huhhh....and inconceivable! can be taken out of context as well.....

 

[dhanson865]

Actually, go ahead and bring the sled.

Sandboarding and Sand Sledding - Great Sand Dunes National Park & Preserve (U.S. National Park Service)

From that page they say don't bring your snow sled.

What Works

• Yes: Sandboards and sand sleds are specifically made for sand, featuring a special design with extra slick bases and special wax; these work best for sliding in most conditions.
• No: Snow sleds, snowboards and skis only slide on very wet sand after rain or snow. The sand surface is usually dry.
• No: Cardboard, saucers, and soft plastic items don't slide on sand; they will dig into or drag on the sand.
• No: Rectangles of rigid, slick plastic or masonite might slide, but are not safe: there is no way to control or steer them, and their angled edges could cause injuries.

 

[ecarfan]

We've gone a long way from Mars in this thread...