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1970-01-01

For perspective, its not as easy as you would think. The air is extremely thin. Flying near the surface on Mars is like flying @ 100,000 ft. on Earth.

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https://marsed.asu.edu/mep/atmosphere

from the website:

Relative to Earth, the air on Mars is extremely thin. Standard sea-level air pressure on Earth is 1,013 millibars. On Mars the surface pressure varies through the year, but it averages 6 to 7 millibars. That's less than one percent of sea level pressure here. To experience that pressure on Earth, you would need to go to an altitude of about 45 kilometers (28 miles). (Yes, you'll need a space suit to walk around on Mars.) The Martian surface pressure also varies due to elevation. For example, the lowest place on Mars lies in the Hellas impact basin, 7.2 km (4.4 mi) below "sea level." The pressure there averages about 14 millibars. But on top of Olympus Mons, 22 km (14 mi) high, the pressure is only 0.7 millibar.

A great video explaining how the helicopter works (and why it is indeed a feat of _ingenuity_).

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

It was a nice trick how they simulated Mars gravity.

Thankfully gravity is also lower.

I was thinking a crash might be less damaging, but just looked up the gravity at 3.721 m/s². That would hurt.

Given the blades are spinning at not too far off from the local speed of sound, the blades would explode if they hit the ground I imagine, similar to helicoptor crashes on Earth.

Wow! I just looked up the difference in pressure and found that the "air" pressure on the surface of Mars is 155 times less that of Earth (1013.25 mbar on Earth, 6.518 mbar on Mars).

Yeah, that was really not expected and only found via space probes. That's why you see gliders for landing in many of the early Mars mission concepts but not in the newer ones.

Actually the atmosphere is too thin for full gliding or parashute landing but too thick to ignore it like we can on the Moon.

Still twice the Moons gravity with no atmospheric breaking at all would also suck I guess.

Basically means you need a lot more delta v too slow down. Which means burning a lot more fuel to first get below escape velocity (5km/s) and then slow down all the way to zero. Escape velocity for Earth is 11km/s. ISS flies at about 7.6 km/s. A typical Mars approach and landing starts at about 20km/s. Most of that is Atmospheric braking. So yes, that would suck.

From what I remember of playing around with X-Plane's Mars atmosphere model, you can glide, but at very high speeds (for most planes close to the speed of sound), you can barely turn, and it's horribly easy to stall.

Doesn't paint a good future for large scale aeronautics on Mars - even if you somehow can sustain those speeds in an atmosphere where you cant burn stuff for propulsion, landing the thing, somehow, at the destination would be very hard - possibly harder than landing the F-104 Starfighter!;-)

That speed likely rules out any normal landing gear or runways, possibly with the exception of a maglev catcher cradle.

Most likely the "aircraft" would need some sort of a robust long duration vertical landing capability, likely rocket based.

No wonder you don't see any aircraft on Mars in The Expanse series - only hyperloop like pods on flimsy rails making use of both the low pressure and low gravity or full on spaceships or orbital shuttles.

We need to "inflate" the atmosphere. That means digging up nitrogen deep in the soil.

Yeah, the only real possibilities for landing on a runway are insanely long runways (dozens of miles!) or high-speed arrestor cables, like souped-up versions of those used on carriers. And even then, the super-wide maneuvering radius means flaring without stalling is practically impossible - you'd need to clear a long area in front of the runway so you can basically come in almost flat.

If anyone was a stupid as me in thinking "wow that's not that high up!" the "death zone" for humans is 26k feet, where if exposed long enough we will die[1]

[1] https://en.wikipedia.org/wiki/Death_zone

Space starts at the Kármán line at 330,000 feet, the ISS flies at about 1,300,000 ft (100km and 400km respectively).

Yes, and that altitude is right at the limit that helicopters on earth can achieve.

even 14k feet feels seriously noticeable and unsettling.

Another point of reference, 10,000 feet is the limit in aircraft. If pressurization is lost above that altitude, oxygen masks will drop and the pilots will make a quick dive to below 10,000 feet.

OTOH, La Paz, the/one capital of Bolivia, is at 11,942 feet.

https://the18.com/en/soccer-news/most-intimidating-soccer-st...

That tells you a lot about what can happen with slow adaptation / getting used to it as opposed to catastrophic fast change of the environment.

It's kinda true for climate change as well - just over much longer stretches of time.

The local native population does have genetic mutations adapting them to the altitude, as do of course Tibetans.

I've even heard anecdotes that they feel uncomfortable at sea level.

I'm pretty good up to around 10,000 feet these days due to where I live, but I felt like it took a few years.

but the gravity is less, so it surely isn't that bad?

38% of Earth's. Still difficult as the atmosphere is too thin.

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