Let’s say you want to create a powerful genetically engineered group of space marines. The main changes we’ll be making are, in order:

  • increased musculature
  • increased bone strength
  • Increased eyesight and hearing
  • Increased reflexes and reactiob time

Here’s one thing I was thinking about though: what would be the ideal size for a super soldier?

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    $\begingroup$ I would need to know more of their job description. At greater height there's more bone surface for muscles to attach, so you get stronger soldiers, but the possible need to infiltrate among regular people or even to be able to walk in regular houses puts different caps on height. $\endgroup$
    – KeizerHarm
    Jul 10, 2022 at 21:31
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    $\begingroup$ This is mission specific. This is dependant on the material properties of their bodies and the scaling and physics of their equipment. Tiny soldiers and equipment is best all things equal. But if they can't operate equipment effective for their objective then they need to be larger. $\endgroup$
    – DKNguyen
    Jul 10, 2022 at 23:52
  • $\begingroup$ @KeizerHarm Thwarting your space marines by building corridors only 4 or 5 feet tall. $\endgroup$
    – DKNguyen
    Jul 10, 2022 at 23:56
  • $\begingroup$ @DKNguyen Or thwarting everyone else with 3 ft. tall halls for your 2 ft. tall soldiers. dungeonsdragons.fandom.com/wiki/…. $\endgroup$
    – DWKraus
    Jul 11, 2022 at 0:11
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    $\begingroup$ Best and ideal are highly context dependent. You don't provide context so this question is 100% subjective and not a good question for this site. $\endgroup$
    – sphennings
    Jul 11, 2022 at 0:11

2 Answers 2


The same size as regular people.

When you think about all the formidable and terrifying implements of destruction an advanced-technology society might have at its disposal - nukes, bioweapons, lightning-fast tanks, rocket artillery, pocket-sized exploding spy drones, autonomous jet fighters, cyborgs with gatling gun arms - spending the extravagant amount it would take to genetically engineer supersoldiers just to get a result that's still fundamentally human is a bit underwhelming. Unless you take that liability and turn it into an asset.

There are two big advantages you can derive from the fact that your supersoldiers are human. One is that they're compatible with all of the infrastructure and technology you already made for regular soldiers. Need a super-tanker, super-pilot, or super-artillerist? You can, and without having to redesign your (fantastically expensive) materiel. Need to ship a unit of super troops to the front? Don't bother with the hassle and expense of setting up any specialist infrastructure (like you'd need with armored vehicles or aircraft), just drop them into the basic infantry barracks you already set up. Or do what regular troops do and "requisition" some handy civilian building.

When it comes to special operations, the advantages are even more profound. Partisans throughout history have found that one of their greatest advantages is to be able to take off their weapons and uniforms and blend with the civilian population. Unlike virtually any of your other advanced weapons, your supersoldiers could hide unnoticed in your enemy's population - or your own, if you found the need.

But, these advantages only apply to supersoldiers who are basically the same size as other soldiers. There's always a temptation to make your supersoldiers ten feet tall with refrigerators for torsos and giant ape arms, but when they can't drive a tank, hop a ride on an air cav helicopter, or even enter an apartment building without banging their head every five minutes, you'll see the disadvantages of that approach. Normal size is better.


Half an Inch

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Your soldiers are tiny so an entire army of them can be sent into space for thruppence of rocket fuel. You can store two thousand of them in deep cryo in a commercial freezer. When you are running out of soldiers just pull out a tray of them and leave it on the countertop to thaw overnight.

The tiny soldiers do most of their fighting inside vehicles and aircraft. The buttons and levers are tiny people sized and most of the vehicle is weapons and fuel.

Sometimes the vehicles are constructed out of materials found on site. It is much faster to build a tank than to grow a full grown human.

Oh did I mention they have no arms or legs? They wear biotic arms and legs custom for each job. I shall quote an earlier answer about fuel efficient ways to send people into space:

Nerve Ending Interface.

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The Beaners are suitable for space travel because the spaceships are custom built for them. They wear neural readers on each stump that are used to control things around the ship. They still need limbs to move around ala XCOM MEK troopers:


They save weight because they do not need limbs for every activity. The ship carries less than 4 limbs per person. And those limbs are lighter and stronger than meat limbs.


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