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I've been really interested in NASA's Mars helicopter and have been reading bits of articles on that recently. But I have a few questions I hope people can help me understand — in this article, it says that the helicopter blades had to be more rigid than those on Earth, but it doesn't really provide an explanation why.

Also, I remember reading here that the weight of the helicopter has to be really light on Mars...

The reduced gravity on Mars (about 38 percent of Earth's gravity) will help JPL pack a few more components onto the Mars Helicopter. But even so, the entire vehicle must weigh less than 1.8 kilograms (4 lbs).

Why is this so? How does the reduced gravity allow them to pack more weight but why does it still need to weigh so little?

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    $\begingroup$ The extremely low air density makes it hard to generate much lift. $\endgroup$
    – Organic Marble
    Commented Oct 16, 2018 at 3:32
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    $\begingroup$ Here is a search on this site for things with the mars tag and contain the word "helicopter", you may find some of these interesting and/or helpful: space.stackexchange.com/search?q=%5Bmars%5D+helicopter $\endgroup$
    – uhoh
    Commented Oct 16, 2018 at 12:56
  • $\begingroup$ The explanation is there within that article, just read carefully 1. and 2. $\endgroup$
    – Uwe
    Commented Oct 16, 2018 at 17:57

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What is different for a helicopter on Mars compared to Earth?

There is less gravity, but there is also much less atmosphere.

The reduced gravity is good for a helicopter, but the thin atmosphere is very bad.

To produce enough lift force, the rotor of the helicopter has to move much more volume with more speed. A very large and fast rotating rotor is needed. But thee centrifugal forces to the blades increase with diameter as well as speed.

The blades should be very strong but lightweight.

The record for the highest takeoff for a helicopter from Earth is 8,848 m (Everest), but the pressure there is still much higher than that of Mars.

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  • $\begingroup$ Got a link for that record take-off? I find this link: en.wikipedia.org/wiki/Flight_altitude_record#Rotorcraft (which isn't the record take-off, but the record height before a flame-out 12,440 m). $\endgroup$
    – Magic Octopus Urn
    Commented Oct 17, 2018 at 21:11
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    $\begingroup$ @MagicOctopusUrn helicopter takeoff record info here en.wikipedia.org/wiki/Didier_Delsalle $\endgroup$
    – Organic Marble
    Commented Oct 25, 2018 at 0:27
  • $\begingroup$ @Uwe I’m just a little confused though bc my physics teacher always says centrifugal force is not a force...? $\endgroup$
    – space
    Commented Oct 26, 2018 at 9:52
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    $\begingroup$ @jjhh: Your physics teacher should do a ride at the 20 G centrifuge. After experiencing about 10 G for some minutes he should explain why he could not lift an arm or leg. $\endgroup$
    – Uwe
    Commented Oct 26, 2018 at 10:05
  • $\begingroup$ @Uwe — so is he wrong...? $\endgroup$
    – space
    Commented Oct 26, 2018 at 15:40

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