Categorising science fiction space travel ideas

Following on from my last post, I thought I would make a start at categorising science fiction ideas by putting together an overarching framework  for space travel. Below, with thanks to NASA for the pictures, is a start. I’m sure you can think of stories that has each of space travel methods mentioned.




This is only a start… I feel there must be loads more to put into this diagram. Also I’ve put the words in a colour code – green the physics is definitely feasible, orange for there are already hints that it might be possible and red for extremely unlikely, but you never know type. There are gaps in the diagram, probably more due to my lack of knowledge than anything else. Any hints as what might be included would be gratefully received… But even if I have missed some space travel ideas, the amount of white space in the diagram still has me puzzled… there shouldn’t be so much. Have science fiction writers of the past let us down? Have they just waved a magic wand and said hey presto we’ve moved from A to B. Come on, let’s see what we can do to fill this picture…

17 thoughts on “Categorising science fiction space travel ideas

  1. Hello James,
    Welcome to my blog. Thank you for the spot. I’ve added hyperspace into the chart.
    You’re right – there’s still a lot of untapped possibilities. It’s left me wondering where the heck they are and why they are missing. I’m sure some of it is due to my ignorance, but not this much!

  2. The most memorable, to me, intergalactic travel method was in Blish’s Cities in Flight, where the spindizzy drive was hooked up (among other things) to a whole planet, sent off in the direction of the Lesser Magellanic Cloud (and later turned around and brought back!). It may not be practical but wow is it captivating.

    1. Welcome Joseph,
      Thanks for the spot – I have edited it into the graphic.
      I also notice that the first in the ‘Cities in Flight’ series was originally entitled ‘Year 2018’. I wonder if they (the publishers) will bring out a special edition then?

    1. Yes – actually used in the Voyager 1 and 2 trajectories! Can’t remember any instances of it being used in science fiction though… do you have any pointers?

      1. I’m sure there must be stories with gravitational slingshots in (I’ve actually got one subbed at the moment with a conventional slingshot trajectory hidden away as mere background detail!) So I’ve added it in regardless. Disappointed nobody seems to have done a story with the modified Alcubierre drive (the feasible FTL drive for those not familiar with what we’re talking about!)

      1. Yo, Rosie, it’s me, Justine 😉 been off for a bit and quiet on the SF Forge. I really must change my WP user name!

      2. Hello Justine, I knew it was you… just some people are circumspect about giving their full name, so I tend to default to being circumspect. Been rather busy myself which is why I haven’t moseying around the SF Forge. Hopefully once this month ids over, things will settle down… but I keep saying that, don’t I?

  3. Gregory Benford has a gravitational slingshot in His novel, THE STARS IN SHROUD [1979] (revised version of DEEPER THAN THE DARKNESS [1970]). A binary star system, one component of which a neutron star, where interstellar ramjets are slingshot around the neutron star and then off into deep space. Part of a galactic empire that mixes both sublight travel (the interstellar ramjets) and FTL travel using a tachyon jump drive. Unfortunately, interstellar ramjets work better as magnetic braking systems than propulsion. Robert Bussard is usually credited with the interstellar ramjet concept, hence, they can be called Bussard ramjets. Recently it has been found that the Strugatsky brothers had a ramjet concept in their first SF novel, and proposed for interplanetary travel. Otherwise it sounds quite similar. Possibly this was original to the Strugatskys themselves or it may have been devised by a Russian scientist, perhaps published as speculation, and picked up by them for their story. Russian science is full of interesting and idiosyncratic concepts. Often beating Western scientists to the punch in important areas of research, but kept corralled by the Russian language. The Strugatsky novel was THE LAND OF CRIMSON CLOUDS, set on the planet Venus, written in 1957, and published in 1959. Robert Bussard published the interstellar ramjet idea in 1960. Unlikely that the two Strugatskys knew anything about Bussard’s speculative technology.

    1. Hello Jeff, Thanks for the history on the beyond Earth Bussard ramjet. It was enough to make me wonder why we haven’t seen these in recent science fiction stories – so I hopped over to wikipedia. It seems the interstellar hydrogen density was discovered to be much less than they originally thought, which makes the bussard ramjet all but useless for interstellar travel.
      The idea of the in-air ramjet dates back at least to 1913 when Rene Lorin obtained a patent. So I can well believe that the Strugatskys and Bussard could independently have extrapolated the ramjet idea into space. It’s no unheard of for totally independent inventors to come up with the same inventions – it boils down taking things a few steps further..

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