2427: Perseverance Microphones

Explain xkcd: It's 'cause you're dumb.
Revision as of 17:22, 23 February 2021 by (talk) (Added reference to Samples from Mars)
Jump to: navigation, search
Perseverance Microphones
If the first audio they downlink is from the descent, we probably won't be able to hear anything over the sound of the rover screaming.
Title text: If the first audio they downlink is from the descent, we probably won't be able to hear anything over the sound of the rover screaming.


Ambox notice.png This explanation may be incomplete or incorrect: Created by a MUSICAL ROVER. An explanation of the title text is missing. Do NOT delete this tag too soon.
If you can address this issue, please edit the page! Thanks.

This comic is a play on dual meanings of the word "sample". The day before this comic was published, NASA successfully landed a new rover, Perseverance, on Mars; part of its mission is to drill and scoop Martian rock and dust from the surface, store it in tubes, and leave them on the surface for collection by a future mission which will return them to Earth. If successful, this would be the "first Mars sample return" in history.

Samples” can also refer to short snippets of recorded sound used in music. Perseverance is the first Mars mission to land on Mars with microphones too, so it would be possible to use audio samples from those microphones musically, e.g. using a looper pedal, which lets a musician play short samples of music and then repeats them back live as if it were another musician. Using a loop pedal would make sense if the sample includes a tune that repeats throughout the song—or that could repeat throughout the song. This is similar to 411: Techno. The joke is that these audio samples, as opposed to rock samples, would be "the first Mars sample return." Additionally, the comic might be a reference to Samples from Mars, a company that sells sampled audio from older instruments for digital music production.

The title text anthropomorphises the rover, suggesting that the drop to the surface was so frightening for it that it was screaming as it descends.

The period between entry into the Martian atmosphere and touchdown on its surface has been dubbed the "Seven Minutes Of Terror", mainly for the terror felt by the mission controllers on Earth, rather than the lander, as they are unable to make any useful corrections to a craft that is hundreds of millions of miles/kilometres away. The round-trip communication delay significantly exceeds the whole of the passage through the thin atmosphere, so they have to rely on whatever pre-arranged autonomy they engineered and programmed into their craft beforehand, and hope they anticipated all eventualities.

You can view the landing here.

The landing was the topic of the next comic 2428: Mars Landing Video.


[Megan is sitting in an office chair at a desk, typing on her laptop. The laptop is connected to an audio mixer box on the floor. The box has several buttons and indicators etc. Cueball is standing on the other side of the box, holding an electric guitar ready to play. The guitar is plugged into the box. From the box there is also a wire going to a small pedal on the floor. Cueball has one foot on top of this pedal.]
Megan: Perseverance's microphones are active! Downlinking audio!
Cueball: I'm ready with the looper pedal.
[Caption below the panel:]
The first Mars sample return

comment.png add a comment! ⋅ comment.png add a topic (use sparingly)! ⋅ Icons-mini-action refresh blue.gif refresh comments!


Thank you, Galaktos, for the explanation. I knew all the events and words already, but you put them together for me so that Randall's intent became clearer to me. Kudos. JohnB (talk) 22:26, 19 February 2021 (UTC)

I mean, I just thought I’d write a first version and later someone would rewrite it, but apparently it’s been good enough so far :D --Galaktos (talk) 22:48, 19 February 2021 (UTC)
I read it through several times utterly happy with how I found it, but decided to add a little bit about the actual Terror. It ended up less snappy, unfortunately. Hope it doesn't smother the rest. 00:24, 20 February 2021 (UTC)
I've added a little bit about the audio. I'm not sure there's much more to add to this, given it's a (well-executed) one shot joke and there's content elsewhere about Mars Rovers etc?

None of the explanations for screaming look very believable to me, yet we made up a lot of them. There are other explanations where, if you have the relevant experience, it's very obvious that the explainer made their explanation up. I wonder if it would be good to have a way to indicate in-article that a part of the joke didn't actually strike home for any of the editors so far, and there might be a domain of expertise missing in the authorship. 21:29, 20 February 2021 (UTC)

Yeah, I don't think the electric guitar/feedback explanation is right. "Squealing" or "squawking" are the normal terms, not screaming. I read the title text as being analogous to someone screaming on a roller coaster. This would be the rover's first ever descent, it would be scary, it would scream. Stevage (talk) 09:21, 21 February 2021 (UTC)
A NASA lady speaking to BBC radio said that they do have audio of the probe "screaming" down to the ground, so either this simply is what happens, or she reads this comic - and maybe even these words? Hi, ma'am! Congratulations on hitting the ground not too hard! Robert Carnegie [email protected] 09:57, 23 February 2021 (UTC)

"The round-trip communication delay significantly exceeds" ... The descend took 7 minutes, the delay was 11 minutes (would be 22 in both directions). Not THAT much exceeding ... of course, not usable for steering. -- Hkmaly (talk) 01:27, 21 February 2021 (UTC)

If it takes three times the time to react to something than the whole duration of the something one might wish to react to, I say that's significantly exceeding. (More so given it's probably the later minutes or even the last few seconds where intervention might have been most needed. Though wasn't.)
It also makes you wonder if manned descents will ever be as with Armstrong in the Eagle or just "spam in a can" where the human payload is told to stay hands off whatever controls they think they can use. I really doubt (unlike in Ad Astra) it'll ever be more practical to have a piloted entry. Not in a tail-first-with-suicide-burn landing, anyway. A 'descent-plane' maybe, with Shuttle-like glider/semi-glider landing, but even then the Russians had a 100% record (one of one!) landing Buran without a pilot, and martian flight is obviously a trickier thing to train for. (Maybe design for... Ingenuity is yet to do its own thing for real..) 16:14, 21 February 2021 (UTC)

The intro refers to a play on words on "sample" and "return". Now, "sample" is covered (a specimen of soil/rock vs a short clip of music). What are the two meanings of "return"? Stevage (talk) 09:22, 21 February 2021 (UTC)

FIFY 11:35, 22 February 2021 (UTC)

Here's some more information about Perserverance's Microphones and here is a link to some of the sound recordings that are available. --WhiteDragon (talk) 16:30, 22 February 2021 (UTC)

Has anyone actually done this yet?

I was surprised to find that the discussion didn't include any links to any actual techno music that fans have made using the audio from the rover. --WhiteDragon (talk) 16:30, 22 February 2021 (UTC)