A common trope in sci-fi is the idea of humans reverse engineering alien technology which results in breakthroughs in our own technology. My question is this: If a military/governmental organisation were to reverse engineer a new technology from captured alien machinery, how long is it likely to be before that technology becomes available to the public?

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    $\begingroup$ That would depend entirely on the potential applications (especially military applications) of said technology. $\endgroup$
    – Shadowzee
    Oct 29, 2018 at 22:39
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    $\begingroup$ Tough one to be accurate about. The Powers that be in whatever country you're refering to would consider social-stability, and their own hold on power. So........ Democracy? Totalitarian regime? Liberal republic? Benign dictatorship by Nepotism? What's your world? $\endgroup$ Oct 29, 2018 at 22:43
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    $\begingroup$ @Duckisaduckisaduck My world is an alternate history version of our own. The nation in question in the US, and the time period is late Cold War. $\endgroup$ Oct 29, 2018 at 22:50
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    $\begingroup$ Understood. Aneutronic - wow! Would that also be Neutrogenic or are you creating new non-terrestrial elements? Oops, no extented conversations.. etc.. $\endgroup$ Oct 29, 2018 at 22:59
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    $\begingroup$ @Arkenstein you need to be even more specific about technological applications. This Aneutronic Fusion may allow creation of only large scale power plants, or to put a small reactor on a cruise missile, or to turn this reactor into an easy to manufacture thermonuclear bomb. $\endgroup$
    – Alexander
    Oct 29, 2018 at 23:42

3 Answers 3


The answer depends upon the strategic value of the technology against likely threats. Stargate-like arguments that "our society is not ready" are purely fictional (they add drama and conflict to the story), and are not a real consideration.

  • Strategic value: Nuclear weapons, radar, stealth, etc. These mitigated (even sometimes obsoleted) whole classes of then-existing weapon systems. They gave their owners a powerful --though often temporary-- strategic advantage in both warfare and international influence. Technology is generally kept secret for as long as it provides that advantage. Example: When everybody had access to radar, there was no point keeping it secret anymore.

    Not all new-tech has strategic value: Zeppelins wound up having little strategic effect, and the marvel of encrypted-frequency-hopping radio has little offensive capability. The M16 assault rifle, while an incremental improvement, did not enhance anybody's international influence nor obsolete other types of hand weapons.

  • Likely threats: There are a whole spectrum of threats, from (fictional) super-powered Martian tripods with heat-rays to classic state-on-state military tank-and-helicopter-and-artillery to insurgents hiding among a population. Militaries pick the likeliest threats on the spectrum, and organize/equip/train to fight those. Against Martians, Bioweapons turn out to be very useful and it makes it makes sense to keep those secret. Against Independence-Day-type aliens, nuclear weapons are useless, so there's no point keeping them secret.

    There's one additional point here - likely threats often include nutters or disenchanted small groups. Keeping truly nasty stuff out of their hands is generally in everybody's best interest. So materiel like fissiles and poisons are controlled, and some key technologies (like complex detonators) remain secret.

Of course, there is also bureaucratic inertia. Folks often don't notice when a secret is not worth keeping anymore, or folks who know the secret might be too close to the problem. In the USA, this is addressed by automatically declassifying after 25-years (with exceptions).

  • $\begingroup$ Thanks for the answer. Are there any considerations made regarding what the potential civil benefit of said technology could be? For instance, if the technological breakthrough were a clean and abundant form of energy generation? $\endgroup$ Oct 30, 2018 at 1:11
  • $\begingroup$ I would say in a case like that, that there is actually more strategic value in the civilian application of cheap, clean energy. A military is only as strong as the economy behind it, and right now energy limitations are a pretty major bottleneck on the economies of developed nations. $\endgroup$
    – Ryan_L
    Oct 30, 2018 at 2:13
  • $\begingroup$ @Arkenstein what strategic value could clean-abundant-energy have to the military? Practically none - replacing many thousands of truck and aircraft and ship and generator motors seems to offer no game-changing advantage that obviates enemy formations, so there is no reason to keep such a device secret. If the device also rendered enemy weapons useless, that would be a game-changer, and the device would be kept secret...until the enemy eliminated the advantage by discovering a counter or obtaining their own devices. $\endgroup$
    – user535733
    Oct 30, 2018 at 3:58
  • $\begingroup$ @Ryan_L perhaps, but only if you are pursuing a high-cost strategy. Many western militaries tend to go this route for valid reasons, but it's not the only way. Poor countries have sometimes won wars against rich countries before. A smaller economy capable of supplying the actual materiel needs of the military will generally fare better than a larger economy that must import materiel. Example: There are many segments of the USA economy that are wartime essential, but offer no strategic value, no way to extend influence. Energy generation falls in this category. $\endgroup$
    – user535733
    Oct 30, 2018 at 4:08
  • $\begingroup$ This is the only answer so far which actually reflects (at least the US) de-classification considerations and procedures. $\endgroup$
    – LinkBerest
    Oct 30, 2018 at 11:37

Because of conspiracy theories, in the United States there is a law automatically declassifying information over 25 years old, unless the classifying agency makes a case for extension. https://www.justice.gov/open/declassification/declassification-faq

If a classifying agency does make a case to keep information classified, they can do so in blocks of time no longer than 10 year extensions. The classified information must be re-reviewed at that time. Also, it is possible for a classifying agency to specify an event that will make the information declassified.

  • $\begingroup$ Interesting. So at maximum, it'd be 25 years. How long has this particular legislation been in place? Would it have been already in effect during the 1980s? $\endgroup$ Oct 30, 2018 at 0:41
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    $\begingroup$ I don't see why @JamesMcLellan needs to do your Googling for you... $\endgroup$
    – user535733
    Oct 30, 2018 at 0:42
  • $\begingroup$ I'm pretty sure this law was just in the news because Donald Trump decided to release some portions of the JFK investigation and continue classifying others. $\endgroup$
    – ben
    Oct 30, 2018 at 0:50
  • $\begingroup$ @user535733 I was under the impression that the purpose of stackexchange was to ask questions. Apologies. $\endgroup$ Oct 30, 2018 at 1:16
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    $\begingroup$ The automatic declassification is by Executive Order, not legislation. The initial Order with the 25 year automatic declassification was signed n 1995 by President Bill Clinton. Both of his successors George Bush and Barack Obama added their own modifications through additional Orders. $\endgroup$ Oct 30, 2018 at 1:45

As Batman once asked Riddler: what riddle is not a riddle? The answer: The one that everyone know answer to. Your secret is a secret as long as you no one know about it's existence, power, effect and ways of use.
For example you do reverse engineering on energy source and put it into tank. Then you deploy that tank and it get stolen. Now your enemy can do exactly the same thing - reverse engineering.

In history Japan pilot was unable to destroy his ZERO plane so it was seized by USA and used to make Mustang planes better.

But WD40, for example, have a secret inside "not a secret". The formula is not patented so they don't need to enclose the composition.

You may want, and be able, to keep a secret for decades because no one actually really cares. But you may want to release some technology because you may then use the privately build infrastructure for your needs. For example fiber optics or communication sattelites.


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