Presumably, if practical power armor was developed, a goal would be to fulfill applications which can not be satisfied with regular armored vehicles.
Imagine a criminal or insurgent hiding out deep within a building, armed with a pistol or rifle.
A tank can't fit through the doorway. A regular soldier is very vulnerable to bullets, even from the average civilian weapon or from a cheaply made AK-47 equivalent that takes little tech base for an enemy group without sophisticated industrial infrastructure to obtain.
But what if the equivalent of a Space Marine enters the building and searches it, in terms of someone in power armor such that shooting him with bullets from ordinary guns doesn't stop him?
Often anti-tank weapons may be far more difficult for a criminal or insurgent to acquire and conceal than regular guns. Also, there may be other disadvantages of trying to use anti-tank weapons to take out a power-armored infantryman in close combat. For example, if an insurgent fires a RPG indoors at someone in power armor in the same room, ten feet away, consider the effect of firing it so far under intended minimum range (or
minimum arming range), not only in regard to
backblast but also in regard to potentially (definitely?) lethal shrapnel from the rocket propelled grenade's shaped-charge explosive warhead detonating a few feet in front of the insurgent's face.
Factors having to be met for power armor to work well in the preceding situation include: (1) technology such that a suitable suit fits through doorways and (2) situational advantages over alternatives which may exist at the time such as robots. But, in some possible future scenarios, power armor may have applications.
The average building's structure would not collapse under the weight of a power-armored soldier several times the weight of a person.
When a 100-kg person jumps on a floor, they can be deaccelerating at several g's at the time of impact, temporarily exerting several hundred kg of force, but, as anyone knows from personal experience, someone can jump up and down without crashing through the average floor.
Even the average staircase can handle several people with a combined weight of a few hundred kilograms standing on it at once, even if on the same step.
With future technology possible within the laws of physics in a hard sci-fi scenario, there may be special capabilities possible with the extra weight of hardware able to be carried by power armor.
The folks at Vision Systems International of San Jose, California, who have designed advanced U.S. military helmets for the F-15, F-16, and F/A-18, make their living at the nexus between man and machine. VSI’s flagship program is the Joint Helmet Mounted Cueing System. It uses a magnetic field in the cockpit to sense the orientation of the helmet, then feeds information on the current line-of-sight to the aircraft’s flight computer. VSI’s helmet has an accuracy of about four milliradians, an angular measure commonly used in the world of shooting and targeting. One milliradian equates to one one-thousandth the distance to the target. So if the target is 1,000 feet away, you’d be accurate to within a foot.
From here
The above is tracking where the pilot looks as judged by their helmet orientation, but there is starting to be research on eyeball tracking, which may lead to weapons which aim as fast as the human eye rotates to focus.
Incorporating a future-tech equivalent of the above targeting system, there might be applications for partially computer controlled weapons where, once a physical safety is disengaged, a soldier can shoot an enemy at moderate range in less time than involved conventionally to aim and fire. Perhaps a soldier in suitable power armor
might shoot at the speed of thought rather than suffering from the delay it takes for nerve impulses going between the brain and hand, helping reduce
reaction time.
This is a bit reminiscent of SDN versus threads where someone with instant telekinesis at the speed of thought is imagined to potentially take out a regular soldier faster than they raise their rifle, aim, and fire ... yet done through hard sci-fi technology rather than imaginary powers.
Objections to such being the sole weaponry relied upon by the soldier can be less applicable if such is simply a supplement, as may be possible with the extra weight able to be carried with power armor. Currently, the majority of the
time, police miss their targets even at close range (in part due to the stress of combat), and no doubt military peacekeepers face complications too. Of course, good training is critical and may help, but technology might too, including the confidence provided by being bullet-resistant.
Power armor could allow carrying heavy weaponry, such as machineguns, semi-automatic grenade launchers, or the future equivalent, increasing the ability to hit targets hiding behind cover.
Another possible advantage might be being able to carry the extra weight of sophisticated sensors, such as possible future implementation of
terahertz imaging and seeing
through walls (plus through clothes concealing weapons). Imagine being able to see and shoot through a wall, to eliminate enemies setting up an ambush inside the next room of a building.
Over the past half century at least, there has been a trend towards more expensive military hardware and towards low-intensity conflicts like peacekeeping, where only a small number of troops may be involved relative to the total economy. Perhaps such may continue in the future, towards a point where the ratio of money to soldiers becomes far greater than now.
In WWII, the U.S. had peak military spending of $930 billion (converted
into about today's
dollars), while having
around 13 million total soldiers and personnel in the armed forces. Today, although a lesser percentage of the total economy due to growth in population and GDP per capita, military spending is
upwards of $500 billion, more than half as much, while the number of soldiers and personnel is vastly less than half as much, only 0.5 million total in the Army aside from more in the other branches. The ratio of money to soldiers has already increased a number of times. It already is the case that the military budget is upwards of $5 trillion a decade, while the number of combat troops is not more than hundreds of thousands.
The ratio is upwards of $10 million per decade per combat soldier, although, of course, the total military budget is divided between many purposes, from R&D and base maintenance to the Air Force, Navy, logistics, etc. Even with only a small portion of the total being conceivably allocated for infantry equipment alone, the potential ratio of affordable hardware cost to the number of troops is high.
Imagine if this ratio further increases in the future.
At some point, even if power armor suits did cost a million dollars each, equipping a portion of a future army with such in a small-scale conflict might be a small portion of the total military budget of the time.
For example, some soldiers being equipped with power armor might be advantageous in a peacekeeping mission facing technologically inferior opponents, conducting operations such as searching buildings.
Developing power armor isn't practical today, but future technology might make it sometimes worthwhile, in some decade or century, if its application niches aren't displaced by robots.
