NASA's Treasure Map for Water Ice on Mars

Re:NASA's Treasure Map for Water Ice on Mars by isolli on Thursday December 12, 2019 @10:07AM (#21772370)

Wow, I would have honestly thought that the Martian atmosphere was too thin for a helicopter to fly!

https://spaceflightnow.com/2018/05/14/helicopter-to-accompan...

> She said the size of the rotors was restricted to 1.2 meters by the space available on the Mars 2020 rover’s belly pan. In turn, the 1.2-meter rotor diameter limits the mass of the helicopter to 4 pounds — 1.8 kilograms — based on the rarefied density of the Martian atmosphere.

> “The biggest thing is the atmospheric density at Mars is very thin,” Aung said in an interview Friday. “It’s 1 percent of that at Earth. It’s equivalent to about 100,000 feet in altitude here on Earth. The other difference is the gravity at Mars is lower. It’s about 40 percent. That plays into how much we can lift.”

> The rotors on the Mars Helicopter will spin between 2,400 and 2,900 rpm, about 10 times faster than a helicopter flying in Earth’s atmosphere.

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Re:NASA's Treasure Map for Water Ice on Mars by jcims on Thursday December 12, 2019 @10:59AM (#21772917)

Yeah rotor tip speed is Mach .7 lol

Here it is running in test chamber at mars equivalent atmospheric density - https://www.youtube.com/watch?v=tMCJGfwj3rY

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Re:NASA's Treasure Map for Water Ice on Mars by JumpCrisscross on Thursday December 12, 2019 @12:14PM (#21773817)

> Yeah rotor tip speed is Mach .7

The thin atmosphere cuts both ways. It generates less lift. But it inflicts less drag.

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Re:NASA's Treasure Map for Water Ice on Mars by parsimo2010 on Thursday December 12, 2019 @01:02PM (#21774393)

It also lowers the speed of sound. This poses some design limitations and since traditionally designed rotors get less efficient near Mach 1- they still work, but not as well. So you have to spin the rotors fast to generate enough lift, but you want to keep them slow so the tips don't go supersonic. Helicopters/drones on Mars are a tough design problem in areas beyond just the atmospheric- you can't use a gas engine because you can't refuel it, recharging a battery with solar energy takes forever because there is less solar radiation. You can't replace the rotors if you crash, so you need to make it robust, but you can't make it too heavy. On and on...

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Re:NASA's Treasure Map for Water Ice on Mars by m_samuel_l on Thursday December 12, 2019 @05:03PM (#21777032)

Maybe a balloon to provide most of the lift, then attach a few electric props? And if you have access to ice, maybe we can use solar panel to electrolise it into fuel.

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Re:NASA's Treasure Map for Water Ice on Mars by winter_blue on Wednesday December 18, 2019 @02:19PM (#21828254)

What about solar-powered aircraft?

Would they work in Mars' atmosphere?

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Re:NASA's Treasure Map for Water Ice on Mars by Steel_Phoenix on Sunday December 15, 2019 @03:59PM (#21798934)

I'd like to see it tested in mars equivalent dust. I assume that the higher speed will correspond with more wear from sand blasting.

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Re:NASA's Treasure Map for Water Ice on Mars by ryanmercer on Thursday December 12, 2019 @12:50PM (#21774265)

The Planetary Society had a good interview with MiMi Aung on their podcast earlier this year, I think it is this episode https://www.planetary.org/multimedia/planetary-radio/show/20...

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