I remember a story where two people are trapped on a space ship and the only way out for them is that one of them sacrifices himself.

The ship uses some sort of propulsion system that needs some chemical component in the human bones (perhaps Calcium??) and the only way to get enough to escape is for one of them to sacrifice himself.

One of them knocks the other unconscious and sacrifices himself so the other can escape.

The story could be German and is probably older than 2 years.

  • Hi, welcome to SF&F. When did you read this? This sounds like a short story, or is it a part of a longer work? If it's a short story, did you read it in an anthology, a magazine, online...
    – DavidW
    Jun 2, 2021 at 15:05
  • 1
    Unfortunately I don't remember. I don't think it was a short story though. It may be part of a bigger series but I am not sure
    – Cookie04
    Jun 2, 2021 at 15:07

1 Answer 1


It sounds like an adventure of Hamilton's Captain Future.

I preface that I haven't read the book, but I remember a very similar scene from the anime that was derived from the books (to my shock, there is no Wikipedia page in English about this amazing anime, so I have linked the German page).

Reading the episodes’ plots, the scene seems to come from Captain Future #13 The Face of the Deep

The plot (in the cartoon), according to my memories, is about Captain Future together with some of his friends shipwrecking on a lost planet together with some dangerous criminals. They have to become ally and try to "reinvent" everything to build a spaceship from scrap in order to escape the planet and come back to the civilization.

In the end, they discover that there is no calcium on the planet, but this element is needed for the atomic engines of the starship to function. So, one of the group must decide to sacrifice himself in order to provide the calcium from his bones and allow the other companions to leave the planet.

In the French Wikipedia, there is the plot of the cartoon (you can read it in case it rings any bells).

In particular, from that page (automatically translated):

Volcanic explosions take place, showing that the planet does not have very long to exist. Or Captain Flam and P r Simon have a technical problem: While their spacecraft is completed, it takes a few tens of grams of calcium to operate the cyclotron without exploding. However, it was impossible to find any on the planet. How to do ? A handful of prisoners, led by Molémos, decide to seize the ship and operate the cyclotron without calcium: one of the two engines explodes, killing these prisoners. Captain Flam and the surviving prisoners are working day and night to repair the ship, but the calcium problem remains.

and (emphasis mine)

The castaways of space finally discover who claims to be "master of the planet": it is a living and thinking being located inside the immense cactus, located in the middle of the camp. They fight against the telepathic powers of this alien and cut down the cactus, revealing its brain. This one reveals to Flam that there is no calcium on this planet! But the volcanic explosions multiply and faced with the urgency of the situation, the captain orders everyone to board the makeshift vessel. He orders Crag, the ship's pilot-helmsman, to launch the machines exactly ten minutes later and leave the planet. He then makes a speech to his companions which is akin to a farewell speech, before heading to the engine room in order to get inside the cyclotron so that the calcium from his bones serves to channel the energy of the cyclotron and therefore to allow the propulsion of the vessel. But one of the machinists, Maclinton (one of the crew present in theBalcan since his departure from Earth and who escaped the murders committed by the mutineers), had the same idea as the captain. He knocks the latter down and enters the cyclotron. At the appointed time, Crag turns on the engine and takes off the ship. Calcium from Maclinton's bones allows the craft to function normally and propel itself into space.

  • 1
    Yes it seems to be the right one. Weird... I don't remember ever watching or reading Captain Future or any anime for that matter. But I guess human memory isn't very reliable...
    – Cookie04
    Jun 2, 2021 at 17:27
  • 7
    Why not use the dead prisoners? Why does it need a living sacrifice? And if it only needs a few 10s of grams, why not just have 2 or 3 crew members each give up a leg?
    – DavidW
    Jun 2, 2021 at 17:44
  • 2
    @DavidW If they give up a leg, they will look like fricking space pirates! In any case, according to this table about 7 promille of the universe's atoms are Calcium at the present time, so not finding just about anywhere is unlikely. Aluminum is lower at 5 promille and you have whole Moons of that stuff floating around. Jun 2, 2021 at 21:34
  • Anyway, that was a good story. Jun 2, 2021 at 21:34

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