2865: The Wrong Stuff

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The Wrong Stuff
The phantom found Edward Everett Hale a century too early; by the time we invented satellites, the specifics of his 'brick moon' proposal were dismissed as science fiction.
Title text: The phantom found Edward Everett Hale a century too early; by the time we invented satellites, the specifics of his 'brick moon' proposal were dismissed as science fiction.


Multiple times in history, there have been incidents where companies, governments, and engineers have proposed or developed plans for large vehicles composed of unconventional materials. One example is Project Habakkuk (mentioned in the comic), an aircraft carrier which was to be composed of pykrete, a mixture of wood pulp and ice. The comic imagines that all of these proposals are linked together by a single "Material Phantom," a ghost which haunts engineers and convinces them to design giant vehicles made of impractical materials.

The three "wrong material vehicles" mentioned in the comic are:

  • The Spruce Goose - The largest flying boat ever made, in spite of its name, almost entirely out of birch wood. Most modern planes of that era were being constructed out of aluminum or some other metal/alloy. Due to wartime restrictions on aluminum usage, the use of birch wood was the next best option. The development of the aircraft was highly troubled due to various factors (including building in wood at an unprecedented scale), and the designers were accused of war-profiteering with an impossible design. The plane did make a single 26-second flight in 1947, well after the end of the war, but all it did was merely prove that the concept was possible. The plane is currently on display at the Evergreen Aviation & Space Museum in McMinnville, Oregon, United States. Other wooden aircraft of that era, such as the De Havilland Mosquito, were highly successful. Many early planes made use of wood in their construction, and the skills and knowledge to build an airframe of that kind were still readily available in that era, in a way that they might not be today.
  • Project Habakkuk - A proposed aircraft carrier whose hull was to be made out of pykrete (a mixture of wood pulp and ice). It would have been able to be easily camouflaged as an innocuous iceberg, and it was both stronger than steel (which the Mythbusters proved in a 2008 episode) and did not require voids between the structural elements in order to be buoyant (so could absorb a lot of damage and cannot spring leaks). Although the project excited great enthusiasm from Churchill, it quickly became clear that Pykrete did not scale well as a material, needing to be super-cooled to prevent creep, requiring a massive cooling system causing expense and engineering challenges to mount until it was concluded that it would cheaper to build traditional steel-alloy hulls, from which ships continue to be built today, given that large quantities of metal were pulled in to prevent the ship from warping under its own mass via extra cooling and structural support. There were also now airfields available to use in various Atlantic islands that could close the air-gap in coverage without having to (effectively) build their own floating island from scratch. The abandoned prototype lasted for several years before it finally melted.
  • Trojan Horse - A mythological, giant wooden horse, supposedly used by the Greeks to invade the city of Troy. Actual horses are composed, like any other animal, out of meat, bone, and other tissues and bodily fluids.[citation needed] In addition, the interior of the Trojan Horse was composed of Greek warriors rather than horse innards.

The title text references 19th-century author Edward Everett Hale and his science fiction novella The Brick Moon, the earliest known depiction of an artificial satellite and a scientifically-accurate GPS system in fiction. The satellite was made from brick as it is a refractory ceramic material capable of dealing with high heats. The novella is, of course, just a sci-fi story, but the title text states that Hale was actually approached by the Material Phantom, and the novella was a serious proposal for a moon made out of bricks. Ceramics are widely used in spacecraft today, largely as part of thermal protection systems, as they are lighter than most metals and able to withstand high temperatures.

The title "the Wrong Stuff" may be a play on The Right Stuff, a book/movie/TV series about the pilots engaged in U.S. postwar research with experimental rocket-powered, high-speed aircraft and the astronauts of Project Mercury. In that title, "the right stuff" refers to the figurative material that these men were made of which gave them the bravery to embark on these missions.


Ambox notice.png This transcript is incomplete. Please help editing it! Thanks.
[A ghost is approaching Cueball in a workshop. They are surrounded by shop equipment, such as a table with a press on it, and a small pile of what appears to be lumber. Cueball is backing away from the ghost, holding his hands up defensively.]
Ghost: oooOOOOOOoooo
[The "ooooo"s of the ghost are written in wavy letters of varying sizes]
Ghost: Build a spaceship out of bricks!
Ghost: oooooOOOOOOOOoo
Cueball: No! Go away!
[Caption below the panel:]
The Spruce Goose, the Project Habakkuk Ice Ship, and the Trojan Horse were all work of the Material Phantom, a ghost that wanders the Earth convincing engineers to make giant vehicles out of the wrong stuff.


This comic was uploaded with the "the" in "the Wrong Stuff" being entirely lowercase, breaking the normal title case used for XKCD comic titles. Possibly another word was initially intended to come before "the", in which case lowercasing "the" would be correct. xkcd displays lowercase letters in titles with small caps, making the lowercase "the" less obvious than it is in the true lowercase used on explainxkcd.

However, it's worth noting that the comic title has since been changed to "The Wrong Stuff," with "the" capitalized as per standard title case.

Every September, Adult Fans of Lego who like spaceships have a month long build event called SHIPtember (SHIP stands for Seriously Huge Investment in Parts) where spaceships are actually built out of bricks: Lego bricks!

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So today is the day I learned about the Habakkuk Project. Cool, weird, crazy ideas - and built in Canada! 17:48, 11 December 2023 (UTC)

the design is very timeghost-esque 21:42, 8 December 2023 (UTC)Bumpf

It's probably worth a mention that the title is most likely a reference to "The Right Stuff" (film). 22:57, 8 December 2023 (UTC)

The title is probably a reference to "The Right Stuff" (TV Series) instead, since the title's unusual capitalization aligns with the series's title's font style but not the film's title font. 00:04, 9 December 2023 (UTC)

I don't understand why the Trojan Horse is considered an example of building something out of the wrong stuff. Within the legendary context of the Trojan War, the Trojan Horse succeeded at exactly what it was built to do, namely, transport the Greek warriors into Troy so they could sack the city. An actual horse made out of skin and muscle and bones would not have been able to fit the Greek warriors inside.[citation needed] That's like saying that Lunar Module Eagle from Apollo 11 was built of the wrong material because it didn't have feathers. -- 06:34, 9 December 2023 (UTC)

Humour comes in threes, perhaps Randall was struggling to come up with a third example (while saving the Brick Moon for the mouse over text)? :) NiceGuy1 (talk) 07:04, 9 December 2023 (UTC)
I built a horse out of Trojans. It's loud and covered in armor plating. How do I get rid of it? Psychoticpotato (talk) 21:07, 6 May 2024 (UTC)

What has happened to this wiki? It used to be when there were glitches and flubs, there would be evidence, screenshots, records for us to see, particularly for those of us who didn't see it before it was fixed. Now there's a passing mention in Trivia and for all we know someone could be mistaken or lying. Uhhh, we'd like to SEE this! I mean, when the anomaly is "It was posted super early/late", okay, not much to capture there, really, but a screenshot of the mis-capitalized title would have been easy! Every time the comic is uploaded 2x, a bot gives "here it is normal sized, which isn't special at all and you can see anyway because Randall fixed it by now". What happened to the recordkeeping here? (BTW, the text title here still says "the", not "The") NiceGuy1 (talk)

The mailing list email was sent out with the incorrect capitalization, which should provide some evidence. Unfortunately the RSS and Atom feeds have been corrected, so I'm not sure how someone could provide proof, since screenshots can be manipulated. Could someone publish the email headers to show that an email with that subject was sent by the mailing.xkcd.com servers? 12:47, 9 December 2023 (UTC)

The discrete would have worked. :-) What isn't mentioned was the successful (for a given definition of) we the reinforced concrete ships in WW2. Mostly mine sweepers. They could be repaired at sea! Possibly a precursor of GRP? Oh, BTW steel was thought to be a wrong material! RIIW - Ponder it (talk) 08:14, 9 December 2023 (UTC)

When I first read this comic, I was sure it meant LEGO bricks... -- 11:33, 9 December 2023 (UTC)

...which would naturally lead to the obvious reply: "That's no moon!" Ralfoide (talk) 18:48, 9 December 2023 (UTC)
Within the Long Earth series (Pratchett/Baxter, and I'm not quite sure whose imagination/knowledge was initially used in this case as they both have(/had) a lot of the necessary for this kind of thing) there's a "Brick Moon" in 'The Gap' (a place where there's not an Earth at all, in the place where one should be) that's built almost 'simply', given then ability to avoid the need to 'launch' hardware into space like you would to access space above the Earth(s) as we do here. The structural requirements and materials available (basically, anything so long as it wasn't iron) made bricks (or similarly trivial materials) the ideal bulk material to be 'stepped' over from adjacent Earths into the Earthlike 'solar orbit' where things would happily sit. And, by proxy, become a staging point to easily launch off the 'missing' Earth from which other steppings could also be made. With a few caveats, of course. 20:05, 9 December 2023 (UTC)
Look up SHIPtember!Chlang (talk) 12:08, 11 December 2023 (UTC)

My first association when I read what the ghost said: “The ships hung in the sky in much the same way that bricks don't.” – Douglas Adams, The Hitchhiker's Guide to the Galaxy -- 22:59, 12 December 2023 (UTC)

I had no idea who Edward Everett Hale was so I originally assumed Randall was talking about someone called 'Edward Everett', that the Material Phantom had visited *half*-a-century too early, and that the 'e' in 'Hale' was a typo. Probably just me tho. 02:33, 19 January 2024 (UTC)

personal similarity[edit]

NOTE: people are misleadingly adding comments below this lengthy topic. Looks like the interface is defaulting to that.

I made a post to the derelict cypherpunks list right before this about ghost visits. It’s notable because I used to post to the same derelict list about making a spaceship out of tissue paper, specifically pursuing the wrong materials in response to a ghostlike experience preventing me from effective work (which i now understand as a dissociative disorder).

Thu Dec 7 20:57:06 PST 2023

a ghost visits you

you: “oh! a ghost! are you a spirit of a person who is now dead?”

the ghost looks sheepish

ghost: “i am a psychological result of something you went through!”

the ghost grins, trying to put on a great-looking appearance

you: “awww frack”

the ghost stops grinning and looks crestfallen and depressed

ghost: “i want to repeat something that perturbed you from the thing you went through, over and over … would this be okay with you?” [translator may have taken liberties with this line]

you: “oh no that would um be really perterburing! um !!”

ghost [looking sheepish again]: “um !”

you and the ghost both put handkerchiefs over your mouths to represent politeness or something and you go for a walk down a lane in your town called “memory la—

Mon Jan 30 18:35:20 PST 2023

let’s reduce the tension and go back to a concept spammed to this list before

let’s make a space rocket out of tissue paper! or s9mething similarly incredibly flimsy like cobwebs or dustballs.

Mon Jan 30 18:36:19 PST 2023


- we can use an nlp bot to scrape the internet for materials properties and perform the rough design

- we can make bots that replicate like a reprap generator to collect the materials

Sun Sep 3 18:03:06 PDT 2023

Model Spaceship Made Of Snow

I'm guessing we can make it out of ice when it is really cold. We could press or melt the snow to make it into ice, and cast, cut, or assemble and fuse parts into a spaceship shape.

Rocket fuel could melt the ship when it burns, maybe need a way to cool it significantly, but with a model maybe it could hold compressed air somehow? it does seem hard

Sun Sep 3 18:23:54 PDT 2023

how to make spaceship out of ice?

so, ice is likely to melt when traveling at escape velocity, maybe imagining a huge buffer around the ship: like, design it to melt its exterior. big wide giant spaceship near ground, little tiny spaceship at edge of atmosphere

Tue Mar 8 17:35:33 PST 2022

The Questioning Spam

A worker was building a rocket ship out of grass.

Questioner: "Why don't you use, I dunno, like, steel and ceramic plates, to make your rocket ship, rather than grass?"

Worker: "It's just a hobby project."

Questioner: "Why don't you make it a serious proiject?"

Worker: "I really have more time than money, honestly." …

Fri Jan 7 03:23:38 PST 2022

[ot][spam][crazy] holding community goals

stone soup is kind of a puzzle, no? like building a spaceship out of wet noodles

Wed Dec 22 09:47:30 PST 2021

Making a Spaceship out of Wet Noodles in C

It's hard to make a C program that builds a spaceship out of wet noodles.

But, at the end of the day, it's down to your free time, experience+ingenuity, and the libraries you have available to call into.

Wed Dec 1 00:17:51 PST 2021

[spam][ot][rambling][crazy] Building a Spaceship Out Of Something Ridiculously Weak and Flimsy

I like to daydream around hard challenges.

I don't know how to build a spaceship. But maybe it would be fun to try.

To make it harder, let's make it out of only something ridiculously hard to do it with, like toilet paper, or leaves, or old newspapers.

I don't know what kinds of problems one runs into when building a spaceship, but when I start planning it I think the first problem will be getting something to go really, really far against gravity.

Another problem I hear about is burning up as you accelerate through the atmosphere.

I imagine aiming what direction you go in is pretty hard too.

I'm thinking I'm probably okay with there being some guidance computers and robotics on the craft, but that we would _mostly_ make it out of tissue paper or whatnot. Making computers out of tissue paper can be considered a separate problem, for now.

One way to make tissue paper move is to burn it. Could we use a tissue-paper-fueled rocket to accelerate the craft? Almost certainly not, but doing the calculations for this could inform what thing to consider next.

I have no idea how to make a rocket, or how rockets work, but I imagine that when you burn something, it turns into gas, and the expansion of the gas is much larger than the thing you burned, so if you direct this gas in some direction or another, it might push something further. I dunno. Like getting up from a chair because of a fire you sat in. Maybe? I dunno.

Maybe I'll briefly websearch for "solid fuel rocket" and see what I get.

… the post goes on and I then replied with more things for a few days. Rereading it turns out I was playing with my psychological triggers from social influence AI, and it’s hard to continue cause my amnesia and dissociation is kicking in (might try a different part not sure). I think of this xkcd as about me though! 21:48, 8 December 2023 (UTC)