2444: Ingenuity

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Plot twist: Thanks to [mumble mumble] second-order [mumble] Rayleigh-Taylor [mumble] turbulent [mumble] shear, it turns out powered flight is way EASIER on Mars!
Title text: Plot twist: Thanks to [mumble mumble] second-order [mumble] Rayleigh-Taylor [mumble] turbulent [mumble] shear, it turns out powered flight is way EASIER on Mars!


Ingenuity is a drone-like helicopter deployed to the surface of Mars. It rode on the underside of the Perseverance rover and at the time of publication its protective housing had been released from the rover and it was being prepared for a flight in early April. The helicopter is supposed to take off after the rover fully releases it and clears its takeoff trajectory.

The comic projects what might happen if the mission controllers activated the helicopter early. In this case, the process is approaching the point of detaching the part-deployed Ingenuity. Ponytail and Cueball are present in mission control when Cueball trips and hits a button that clearly triggers the Ingenuity drone to take off. Perseverance, still firmly above/attached is seen to easily ride atop it. The rover exclaims "Wheee!", presumably from excitement or happiness.

In the title text, some character discovers powered flight is easier on Mars, which contradicts our current understanding that powered flight is very difficult on Mars. Mars may have less gravity, but Mars's atmosphere is 1% the density of Earth's. It's so thin that you couldn't move a feather with a fan. This is why the character mumbles his explanation of the science, because they know any explanation doesn't actually make sense.

The total mass of the two vehicles is about 556 times that of the helicopter alone, meaning the unexpected lift effect 'described' would have to be several hundred times more effective than that anticipated, depending upon the factor of overdesign already built in to avoid an expensive marginal failure. It also seems to be trivially easy to balance the extremely top-heavy loading upon the small solar-panel that tops out the counter-rotating coaxial blades, which adds yet more questions of both the dynamic and structural performance, never mind questions about the available power to accomplish this and the later possibilities to recharge.

The Rayleigh–Taylor instability is a fluid instability that occurs at the interface between two fluids of different densities when the lighter fluid is supported by the denser fluid, leading to the mixing of the fluids due to the growth of perturbations at the interface.

It is not the first time that we have seen a Mars vehicle vastly exceed expectations in these pages.

It is also not the first time a character has caused an incident by tripping and hitting a control panel.


[Ingenuity/Perseverance is on the surface of Mars.]
Perseverance: Ingenuity helicopter has been lowered.
Perseverance: Preparing to release it onto the surface.
[A cut to mission control on Earth. Cueball trips and clicks on a key on his workstation, while Ponytail stands nearby.]
Cueball: Oops
Control panel: Click
[Back on Mars, Ingenuity's rotor blades start spinning.]
Ingenuity: Bzzzzzz
[Perseverance is being lifted into the air atop Ingenuity.]
Perseverance: Wheeee!
Ingenuity: Bzzzzzz

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Wow! I clicked open xkcd at 3:50 or so, I can't believe I was one of the first on the team!Hiihaveanaccount (talk) 20:58, 31 March 2021 (UTC)

Speaking as an Australian, I usually don't bother to check XKCD until well after the day after the post. It's 9am Thursday, and I'm surprised it's posted this early. Thisfox (talk) 21:56, 31 March 2021 (UTC)

Perseverance's maximum driving speed is only about 8 feet/minute (comparable to a baby's crawling speed). So Ingenuity wouldn't have to fly very fast to get it to say "Whee!". Barmar (talk) 21:40, 31 March 2021 (UTC)

Can we work in somehow that on the date of the comic, Ingenuity was in the middle of the multi-day deployment process? 23:07, 31 March 2021 (UTC)

I was thinking along those lines. I've made some edits that I think cover your suggestions, but obviously they're open to further refinement/expansion as anyone might desire to make. (The exact status of deployment, as of comic-posting, might be nice to know, but I don't currently believe it was so precisely timed to "the point they detached" or anything like that.) 01:22, 1 April 2021 (UTC)

I think the mumble mumble thing is a reference to the four fundamental forces comic 04:20, 1 April 2021 (UTC)

I think the title Text is a reference to the trope that nobody can really explain satisfactorily explain how flight works... On Mars or on earth. 06:07, 1 April 2021 (UTC)

Im probably wrong but the title text might be referencing the technobabble in various science fiction but i'm probably wrong -- 20:09, 1 April 2021 (UTC)
(^^Another corrected indenting...^^) Not really. Technobabble is usually very definite words (mis)used or (mis)constructed to 'explain' something, with the gap between canon and reality just hand-waved away. Mumbling over things is more a "I don't care enough even to try to make you understand, live with it" thing, in fiction as in reality. 21:05, 1 April 2021 (UTC)

Well, even if Ingenuity can't lift the rover, that setup would make a great Martian lawnmower...although...yeah...I know.  :-( SteveBaker (talk) 20:51, 1 April 2021 (UTC)

Edit: Deleted comment. Sorry for the accidental spam. {)|(}Quill{)|(} 18:17, 6 April 2021 (UTC)

Is it possible this comic is a reference to the Jerma985 video released just 10 days prior, where he performs this exact maneuver? https://www.youtube.com/watch?v=n5ZuHnpm7P8 I would like to believe that Randall is a Jerma fan, for all the implications that has 06:07, 1 May 2021 (UTC)