Mars Helicopter (before it went to Mars)

Here's a really excellent video that answers all your questions: [VIDEO] TL;DW: Martian atmosphere is so sparse that it's equivalent to flying at 100,000 feet on Earth. (The altitude record on Earth is 85,000 feet, set by the SR-71.) In order to fly at all the blades have to spin at nearly the (Martian) speed of sound. The drone wouldn't fly on Earth because the atmosphere is so dense that the blades would never make it up to speed.

Totally agree. It's obviously a high risk portion of the mission but I'm glad someone had the guts to propose it. Derek from Veritasium did a nice little story on it last summer - [VIDEO]

Veritasium did an episode 'Mars Helicopter' containing some interesting discussions with the team that built it. [VIDEO] nm it was already linked elsewhere

A great video where the host visits the drone, interviews its makers, and goes over the cool technical aspects of it and its mission: [VIDEO]

You should watch Dr. Derek Muller of Veritasium, who did a video (2019) details of the Helicopter while it was being built. [VIDEO]

It's not just atmosphere and g-forces. The cold temperatures mean the helicopter spends 2/3 of its battery power keeping the batteries and electronics from freezing. Good rundown of how it was built: [VIDEO]

Veritasium has a great video on the helicopter. Early on in the video they explain that Mars’ atmosphere is equivalent in density to Earth’s atmosphere at 100,000 feet, and the record altitude for helicopters on earth is 40,000 feet. [VIDEO]

On top of what others have said, we need advancement it batteries that can withstand low temperatures. Lithium ion batteries generally need to be kept above freezing temps. There have been some advances in capacitors that operate down to -100C, but their energy density makes them a non-ideal option for weight limited applications. This video from Veritasium does a good job of covering the helicopter power system: [VIDEO]