I guess that means that thrust doesn't scale the same as conductive cooling with air density.

That's interesting, and surprizing. Since the rotors must produce comparable downward thrust on Mars as on Earth (to within an order of magnitude, anyway, considering the lower gravity), via a much greater rotor velocity, I might've guessed that the cooling effect of that air would be comparable too. I guess that means that thrust doesn't scale the same as conductive cooling with air density.

Thrust goes as rho * V squared. So for a given thrust and disk area, Martian density 50x less means the downwash has to be 7x faster

Power goes as rho * V cubed. So to generate that thrust we have to put 7x more power through the motor

But the heat transport goes as something like rho * V, so we have 7x less heat removal for a given temperature difference.


Now of course the disk loading of Ingenuity is a factor of a few less than typical small terrestrial drones, to make these effects a bit more manageable (and keep the rotor tips subsonic, etc.) but you can see the scaling really points to overheating being an issue for sustained operation at low density

The cameras can shoot at 10 fps and it would makes sense to have such a video.

I would imagine they have taken video of each phase of the deployment which would be show smooth rotation of the various components.

There are pyrotechnic devices being fired during these steps.

pyro involved.

One begins to expect Ingenuity to deploy something below itself as well...

Within a few days, Ingenuity will be on the surface of Mars. Until now it has been connected to the Perseverance rover, which allowed Ingenuity to charge its battery as well as use a thermostat-controlled heater powered by the rover. This heater keeps the interior at about 45 degrees F through the bitter cold of the Martian night, where temperatures can drop to as low as -130F. That comfortably protects key components such as the battery and some of the sensitive electronics from harm at very cold temperatures.
Before Ingenuity drops the last few inches onto its airfield, Perseverance will charge up the little helicopter's battery to a 100 percent state-of-charge. That's a good thing, because Ingenuity has to run its own heater from its own battery after the drop. No more free power from the rover!
But there is another free source of energy on Mars: the Sun! The Sun's energy is weaker at Mars-a little over half of what we would find here on Earth on a bright, sunny day. But it's enough for Ingenuity's high-tech solar panel to charge the battery. Of course, this means that the rover will drive away from Ingenuity after the drop so that we uncover the solar panel. This will occur as soon as possible after the drop.
Ingenuity can't afford to keep the temperature of its interior at a "balmy" 45F -that takes too much precious energy from the battery. Instead, when it wakes up on the surface after being dropped, it sets its thermostat to about 5F or lower. Then it's off to survive the first night on its own!
The Ingenuity team will be anxiously waiting to hear from the helicopter the next day. Did it make it through the night? Is the solar panel working as expected? The team will check the temperatures and the battery recharge performance over the next couple of days. If it all looks good, then it's onto the next steps: unlocking the rotor blades, and testing out all the motors and sensors.

Looking at the CAD file posted to https://rps.nasa.gov/3D-viewer/ it looks like there's definitely some involved in the chopper - shield deploy for sure, and at least some others around the interface to the rover.

Good drop! I read somewhere there was a contingency to try to use the robotic arm to right it, if it had toppled.

Click to view attachment

Assuming all goes well for the eventual lift-off, I wonder will the manoeuvre generate a dust cloud around it so as to obscure camera-recording of it by Percy?
Whatever occurs, it's still a great achievement...congrats to the team.
John

Assuming all goes well for the eventual lift-off, I wonder will the manoeuvre generate a dust cloud around it so as to obscure camera-recording of it by Percy?

Whatever occurs, it's still a great achievement...congrats to the team.

John

Assuming all goes well for the eventual lift-off, I wonder will the manoeuvre generate a dust cloud around it so as to obscure camera-recording of it by Percy?

Yikes. Do I see dust on the arrays already...?

Do I see dust on the arrays already...?

I couldn't find whether the navcam sensors include IR cutoff filters. There shouldn't be any real need to include them...

Each [Navcam] lens assembly contains six individual lens elements and a fused silica UV and IR blocking filter mounted between the powered elements and the detector.

Not sure where dust would have come from to have got to the top of Ingenuity.

https://bit.ly/PercyMAP has been updated to show the latest drives, Ingenuity at its current position but exercising its rotors 4m up in the air, a closer default view, and with more links from recent way points. Also, the 3d scene code was simplified a bit.

It is made using https://www.x3dom.org/ and a little javascript. One can zoom in (wheel or right mouse drag), pan (middle mouse drag) and re-center (double left click). The coordinates of the cross-hair are reported and left clicking adds the current position to a list, and calculates the distance from the last recorded point. For example, it turns out that the wind-carved walrus boulder (harbour seal) is about 12m away from the rover.