2423: Project Orion

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Project Orion
If you tune out again, when you tune back in you'll be hearing about dusty plasma fission fragment rockets.
Title text: If you tune out again, when you tune back in you'll be hearing about dusty plasma fission fragment rockets.


White Hat and Cueball are having a conversation. In the first panel, Cueball is telling White Hat about his gardening experiences. White Hat tunes out for the middle two panels, and when he starts paying attention again, Cueball is discussing Project Orion.

Project Orion was an ambitious idea, funded briefly by the US government in the 1960s, to launch enormous spaceships into orbit by detonating a series of nuclear bombs below them. The force from the explosions would be absorbed by a pusher plate on the bottom of the rocket, which is the detail Cueball is sharing when White Hat tunes back in. In Ad Astra, Roy McBride uses a similar mechanism to get from Neptune back to Earth. It was considered feasible for construction, but abandoned because of the 1963 Partial Test Ban Treaty as well as out of concerns for both cost and the idea of spaceships literally armed with atomic bombs. People probably daydream about this project because it seems like it could provide for rapid and massive entry into space, but it was halted due to the intense danger. We may have sufficient technology to somehow make this safe with extensive additional engineering, but the risk is still so large it has not been pursued.

The fact that physicists' conversations tend to converge towards Project Orion is similar to how Randall's conversations tend to converge towards carcinization in 2418: Metacarcinization. Cueball turned into a crab (i.e., he carcinized) when Megan first told him about carcinization in 2314: Carcinization; hopefully physicists don't do something analogous when discussing Project Orion.

The title text transitions to another cool nuclear rocket technology, dusty plasma fission fragment rockets, which also uses nuclear energy, and would fit well in the 2326: Five Word Jargon collection.

Project Orion has been mentioned before, in 786: Exoplanets, where Beret Guy sums it up as "nuke-riding city ships", and on what if?.


[Cueball is raising his arm, holding the hand tilted down with palm up towards White Hat. Above them is the words Cueball says (without a speech line showing this). The first three lines are in normal font, but then successive lines fade to lighter and lighter gray and finally in the fourth line, just above their heads, the text is almost white. The overall effect is that Cueball's words gradually become background noise to White Hat.]
Cueball: Our garden grew really well last year, so we think we might put a second raised bed along the garage, if we can find a...
[Only White Hat is shown, without text, as he stares away from where Cueball must be off the edge of the panel.]
[Only White Hat again, who now seems to look straight out of the panel.]
[Back to the original setting. Cueball has lifted both hands up in front of him. He once again has the attention of White Hat. The text above begins with a line half hidden under the top of the panel, almost white font, and then the text fades back to black font over the next three lines, with the next, and last, line in his first paragraph all in black. And then a small gap and connecting line between this and the last two lines of text in his second paragraph. This time there is also with a speech line down to Cueball. The text from "..." to the first comma is difficult to read as only bottom half is shown, and in very faded font.]
Cueball: ...thanks to X ray ablation, the pusher plate would absorb the nuclear blast, recoil, and then return to position for the next bomb.
Cueball: Such a wild idea! Probably good that it was abandoned.
[Caption below the panel:]
If you temporarily tune out while a physicist is talking, when you tune back in they'll be talking about Project Orion.

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If you read xkcd long enough, the comics always tend toward being about conversations tending toward something. (Okay, that’s not true; there’s one other comic like this and it was a conversation tending toward being about species tending toward being built like crabs. Still funny to think about, though.) 01:09, 11 February 2021 (UTC)

All xkcd comics eventually become conversations about conversations. Captain Video (talk) 01:15, 11 February 2021 (UTC)

Just wanted to point out that "dusty plasma fission fragment rockets" is a series of trochees. 05:45, 11 February 2021 (UTC)

TIL trochee means something different for English than for Greek, Latin, Hungarian etc. Torzsmokus (talk) 08:35, 11 February 2021 (UTC)
This also means that the first four words can be sung to the tune of Teenage Mutant Ninja Turtles 21:57, 16 February 2021 (UTC)

The current explanation mentions other examples of topics, specialists from different fields apparently tend to converge on. Can anyone confirm whether those are actually true, or at least commonly known stereotypes? I've never heard of any such claim. The claim being, that all conversations converge on these topics, not the topics themselves. Bischoff (talk) 13:35, 11 February 2021 (UTC)

Now I understand a bit better what may have influenced some plot elements of Neal Stephenson's book Anathem. 15:28, 11 February 2021 (UTC)

More specifically? It's not striking a chord for me. All Sci-Fi conversations eventually come around to multiverse phenomena? ProphetZarquon (talk) 20:12, 11 February 2021 (UTC)
Well, there definitely was an Orionesque system. With the pre-detection theorising by the core characters possibly being juxtaposed with more mundane gardening information within the Math/enclave. (Must re-read it!) 21:06, 11 February 2021 (UTC)

I don't think that modern engineering can make project Orion safe.[edit]

While modern engineering can perhaps make some forms of nuclear propulsion safe(ish) and I think that stuff like nuclear thermal rockets could be great in some roles, I don't think that we are close to being able to detonate nukes in Earths atmosphere safely. Safely enough for the people on the rocket, maybe, but not for the people eating their atomic dust. Like the plans for that giant hypersonic nuclear ramjet, it's awesome, and would likely work, but I don't see a way to clean up the emissions to anything like acceptable levels.

BlakeFelix (talk) 16:02, 13 February 2021 (UTC)