I am a post-human adapted for permanent life in vacuum and micro-gravity. How might my physiology and biochemistry overcome the following challenges?

Please note I have a strong cultural aversion to augmenting my body in order to help me survive: i.e. enclosing myself in artificially-constructed protective shells, etc.

Current status

See Part 1 on radiation resistance

See Part 2 on temperature control

See Part 3 on metabolism

At this stage, I look similar to an enormous shining pangolin with interlocking plates of keratin-analogue that are alloyed with steel to protect against ionizing radiation. My radically engineered DNA and its unparalleled checksum and repair functions keep the doctor away. I can move these plates to help dissipate heat and - just like a Terran pangolin - curl up in a protective ball to shield my more sensitive parts. I have a reactive outercoating that allows me to alter my pigmentation (which I typically set to polished silver in order to minimise heat loss).

Space is a tough place to live and its very big, so you could say my metabolism has multiple redundancies. I can eat comets and asteroid material, using the spinneret on my tail to swaddle them in cocoons before supping on the extracted organics and minerals. I sift small concentrations of hydrogen from the interplanetary medium for use as a metabolic catalyst, and I'm a radiotroph, with the outer layer of my armoured plates coated in a melanin that helps me capture energetic rays to power my body. Stick me near a magnetic field and I'll even generate power like a dynamo.

Part 4: Movement

As mentioned, I look very similar to a pangolin. However, my prehensile limbs are much longer, identical, in that they are all hands, and there are five of them - I have a manipulator at the tip of my dextrous tail-limb.

In "artificial" environments such as the vacuum cities where I live, architecture helps me move primarily through the use of my limbs. I might use my tail-limb to stabilise me against a tether or outcrop while I work, or throw out some silk (similar to the stuff I use to cocoon comets) to reach locations or retrieve objects in the medium distance.

However, I'd also like to be able to move greater distances in a reasonable time, although I can ratchet down my metabolism to a somnolent hibernation for long journeys.

I'm wondering whether my body could incorporate a kind of chemical thruster, perhaps a nuclear salt-water rocket? As far as I understand, the NSWR reactions would occur outside of my body, presumably meaning that I wouldn't have to worry about heat so much. As I'm a radiotroph, I'm also wondering whether I could incorporate this into my metabolic pathways.

How might I move at reasonable speeds over medium to long distances within the system?

Note that I do not need to go interstellar (yet...)

See part 5 on senses

  • 1
    $\begingroup$ With locomotion you mean specifically short range movements, or both short and long range? $\endgroup$
    – L.Dutch
    Nov 7, 2018 at 10:23
  • 1
    $\begingroup$ Or only long range, as short range is covered under In "artificial" environments part? $\endgroup$
    – Mołot
    Nov 7, 2018 at 10:24
  • $\begingroup$ @L.Dutch edited for clarity, I am interested in traversing the system but also being able to move relatively short distances from A to B wherever my immediate surroundings lack surfaces to shoot silk at or propel myself from $\endgroup$ Nov 7, 2018 at 10:30

2 Answers 2


If you are isolated into the vacuum, with nothing to exert a force on, you have only two options:

  1. get pushed from the light, either coming from the central star or from an artificial source of light, like a laser: spread up your body as much as possible and let it act as a solar sail. Let the photons transfer momentum to you and move your body.

Yes, this is going to be pretty slow and not really versatile (how do you move toward the light source?). When you cannot use this method you can use

  1. Newton third law: you eject something, and that something will exert a force on your body allowing it to move. What can you eject? Let's go through a necessarily partial list:

    • gas: old school astronauts had small jets to assist their maneuvering in EVA. You can use something similar, or you can use PHART (PHysically Assisted Reliable Translation), relying on gaseous emission from your body.

    • liquid: like the above, but more effective thanks to the liquid higher density. You need proper training on how to control the abdominal muscles and the sphincter, but if Le Petomane could do it, you post human can surely achieve it.

    • solid: in this case you would need to throw something away, like some of the scales on your body.

Mind that in all the above cases you are expelling mass from your body. So you are bound to not overdo it, else you might be in obvious troubles. If you use the ejection method and you are in a somehow enclosed environment, you might even think of recovering part or all of the ejected material (mainly thinking of the scales, but also the other could do if needed)

  • $\begingroup$ Related: Can you tack against the sun using a solar sail? on Space sister site. $\endgroup$
    – Mołot
    Nov 7, 2018 at 13:36
  • $\begingroup$ Going toward the Sun with solar sails is easy. Just maximize the prograde component of the reflected photons. Send them retrograde to go away from the Sun. The one thing that you can't do is to precess your orbit forwards - but that doesn't even matter most of the time as it doesn't do anything to a circular orbit. $\endgroup$ Nov 9, 2018 at 15:25

Your a radiotrophic (you "eat" radiation) and also have a high immunity to it. As such, I would suggest constructing a small nuclear reactor (or perhaps a radioisotope thermoelectric generator) and then wrapping yourself in a big bag of water (this is your propellant) and then simply feeding the water past the reactor so that it heats up into steam which then propels you 'teakettle" style across the void. The advantages to this is that its quite simple and easy to construct, and you can steer it with your limbs, and the radiation can sustain your metabolism somewhat on the journey. However it would be a very, very long journey if you are planning on going far (say Earth to Mars) but if your living in say the Jovian or Saturnian system it can get your around quickly enough.

For more ideas and help calculating things like specific impulse and DeltaV I suggest the excellent Atomic Rockets website.


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