Mars Helicopter (before it went to Mars)

Here's a really excellent video that answers all your questions: ▶ this 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.

Saw this Veritasium youtube video a year ago and the technical complexity required to fly on Mars was shocking to me. Since the air density is super low the blades need to spin at a speed which nears the speed of sound at the blade tips. Crossing the speed of sound causes mini sonic booms which could disrupt the flight entirely. Kudos to NASA scientists for this technological breakthrough! Sharing the video: ▶ this 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. ▶ this 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: ▶ this video

Video from Veritasium about the helicopter that talk with the team about this. He mentions that 2/3rds of the daily energy gathered is used for the purpose[1] Other information about the tech; camera & landing, energy use for heating, flight in low pressure atmosphere, the system to actually land the thing, is also really interesting. ▶ this video

This video ▶ this video explains it: they can change the attack angle of rotor blades for different positions, which produces a torque, though you have to compensate for the gyroscopic effect, which lags behind. Humans cannot fly this, but computers can. The video also explains why the chose two contra-rotating rotors instead of a quad-copter design.

Veritasium did an episode 'Mars Helicopter' containing some interesting discussions with the team that built it. ▶ this 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: ▶ this video

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

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 - ▶ this video

They briefly talk about it in this Veritasium Video at around the 9 minute mark ▶ this video He says, unlike in the movies, it is not really an issue. With 1% earth’s atmosphere there is very little matter actually hitting you.