03/01/2014 05:54 GMT | Updated 23/01/2014 08:17 GMT

US Army To Have 'Nano' Insect Drones By 2030s, Internal Roadmap Reveals

The US Department of Defense has released its 'roadmap' for bringing new and ever-more-subjectively-terrifying robots to the battlefield.

The 'Unmanned Systems Roadmap' document actually addresses overall cuts to the budget for drones, down to $4.1 billion ($3.7 billion of which is for aircraft).

But the document still marks out several milestones which will see the US armed forces increasingly reliant on autonomous systems in the coming decades, until at least 2038.

They include new and improved unmanned aircraft, as well as new ground-based robots.

While drones in the air are more familiar, ground-based robots too "have proven their worth in Iraq and Afghanistan across a spectrum of mission areas" the report says.

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The document projects wide improvements to drones of all kinds, with the principal aim to increase their range and affordability.

Looking further ahead, the document also references 'nano'-style drones, very small (insect-sized) devices designed for land and air that could be in use as soon as 2018 (though more likely around 2035 for the smallest classes of drones), as well as "robotic wingmen" which could provide unmanned help to ground-based infantry:

The report also includes an intriguing roadmap for water-based drones, used for both mine-hunting and maritime security:

The report does not specifically address the morality of armed unmanned systems - particularly the the prospect of autonomous killer drones, against which a large-scale campaign was launched in 2013.

But it does lay out new strategies for more designing cheaper and more effective weapons specifically for drones, and hints at new strategies or arenas in which they could be used.

Other details in the report include the fact that the army currently has 10,964 drones in use (as of July 2013), most of which are Raven, Wasp and Puma-class aerial drones.