Why not? Here's why not. Hypothetical scenario. Let's build one of these things, a photonic human, a high-speed-thought light-based soldier-human, a speedster, or whatever you want to call it. Let's tap into this hitherto-mythical "Ground Effect" and see what happens when we connect a real-life human to it. Let's follow this proposal through to its logical conclusion.
We can't control or guess at all the effects likely to come out of this. For one thing: if the man is capable at thinking at thousands or tens of thousands of times faster than a conventional human or his own pre-accelerated self then that is a function of his unaltered brain. There's an interface between the outside world as moves at the speed we're all to seeing it move and the accelerated human who exists in this dynamic pocket of accelerated spacetime. That interface, the envelope, is the key to the whole process, because it in and of itself does not move except in the figurative sense that a shadow moves. It is a function of the standing Ground Effect Field that is a natural property of all gravitationally-bound bodies, the result of channelled energy in that field, analogous with the intersection between two beams of light. As we know, by changing the angles of the light beams, the point of intersection can be made to move faster than light. This is an artifact of our tendency to call a point of intersection a physical thing when it is in fact ephemeral, made at any given instant from relativistic matter moving at or below the speed of light. Likewise a shadow can be cast and moved across a distant object at faster-than-light speeds. The user changes the point of intersection and a nearby area of the world opens up a little and the current area of the world closes down and you have moved. The point is, the Field Envelope does not move, so it does not need to be aerodynamic, or even round. It can be square, or act like armour surrounding the user. When he runs, spacetime opens up ahead of the user, and closes behind him, as if he were running through a series of stationary doors.
But what the envelope cannot do is enclose only a man's brain. Or his feet. There are vast, catastrophic biological effects which would arise out of that. The brain would start of oxygen in a minute or two-- or a microsecond from an external observer's perspective-- as blood seeped into it at such slow subjective speeds. You might as well amputate.
This isn't a thought experiment. I can show you footage of rats whose hind legs and tail are grey and moulding, dead, while the front half of the rat, still alive and in a great deal of pain, tows them around. Dying rats with living bodies, still beating hearts, but dead heads.
So what we must have is a man who is completely bound to this high-speed perspective. All or nothing. If the envelope is created, it must enclose him instantly or not at all. Second observation: he must be kept stationary and cordoned off, preferably with rebar! Nobody can be allowed to approach the field while it's active, in case some unlucky fool slips and falls into it while it's active and is dead from the waist up and decaying to a skeleton before he or she hits the floor. If the envelope is mobile, the subject cannot and must not touch another human being or living thing, in case they were only drawn partially into the envelope and the same thing happened again. He could kill anyone instantly just by dragging him or her into the field. The best we can say for this murder means is that it would be leave unmistakeable residue and would be easy to identify. "This man died from the Ground Effect..." You just gave them the power of life and death over the human race. You created a Person of Mass Destruction. What about accountability?
Let's say we make the field adhere to the skin, tightly enough to be worn, hermetically sealed. That means everything inside the shell is accelerated, and everything outside of it is not. How much air can one man carry? A few hours' worth? At accelerated speeds, he runs out in a second. By the time you get the suit shut down, he's dead.
Make the suit air-breathing. Now it's no longer sealed safely, which can be risky. You've exposed the mouth and nose. That's a raw acceleration interface. The amount of air being cycled through the accelerated lungs is thousands or millions of times more than a human's. You're in an enclosed space? Now it's full of carbon dioxide and you're choking to death. Your soldier's been dead on the floor for two weeks by the time you reach the door. You're outdoors? That's better. It's just equivalent to running a jet turbine next to your ear. Now, what about water? What about food? How long can the fellow go without needing to use a lavatory? A few seconds? You're talking about creating a mobile, self-contained life-support environment that can hold a human being for weeks at a time. That's submarine-complicated, Space Shuttle-complicated.
So you let the guy switch it off. When he needs to, he flattens down the accelerated envelope and does whatever needs doing: eats, spits, whatever.
How fast does spit come out of the field? Here's a plate of steel we tried that on. What about a punch? Here's another one. Notice the enormous hole. The tangled formations you see at the ragged edges of the hole? Those are stress marks from direct interaction with the envelope. Materials do frightening things.
He has no transport. If he wants to travel, he has to travel in a conventional car or train or bus or plane. But the field might accommodate a bicycle. And in theory he can run for as far as he likes. He can take a full night's sleep inside the envelope and be vulnerable only for a second. He can walk into a building and kill everybody inside it just by waving a finger through each throat, and be out of the building and a mile away before anybody can blink, leaving just shattered doors torn into pieces like this steel plate and a hundred people all falling and hitting the ground at once.
This is not a comic book. Somebody shoots a bullet at him? He just walks around it-- if he sees it coming. Someone sneaks up on him? As soon as he feels something touching the back of his head, an iron bar, let's say, he can go to high speed mode and duck or dodge it. A trip-wire? From his perspective, he runs into it at regular pace and hits the ground like any normal human. It's not fatal, he recovers in a second. An explosion? He walks away from it and watches it happen. We're at T plus ten minutes and democracy in this country is over.
A speedster with a brain? A human brain attached to a mature eigentechnology? You want to use that against another country? It's your worst nightmare.
Vulnerabilities? He has to eat, and the food has to be prepared in real time. If poisoned, there's nothing he can do to save himself. He can't use a book at high speed and he can't learn any more quickly than a normal human: a tough book remains a tough book even at accelerated brain-rates. He can't use a computer at high speed. Anything he can't do himself has to be done by someone else at regular speed - that opens up avenues of attack. He can jump high, and survive arbitrary falls, but he can't fly; the clue is in the title, "Ground Effect". He has to be physically in contact with Earth or some other body for the effects to persist correctly. He can theoretically be surprised and killed before he reacts. He can be killed slowly in a way he doesn't realise is happening until too late. He is human. He makes mistakes.
These aren't enough for us. There aren't enough outs here. Don't make a Ground Effect soldier. There are too many routes to catastrophe.
Try this instead.
The Ground Effect can be inverted. You can create a region of the world which moves slowly. In exchange for slower reactions or even a completely useless soldier, you have a lowered metabolism and total stasis. Move a troop or a set of troops from one part of the world to another in real time without needing to feed them. Install the whole system into a ship.
Install a full-fat positive Ground Effect in a ship and get an aircraft carrier capable of Mach 1 on the open ocean. Give us thirty years and that'll happen. Direct installation into a jet aeroplane or a space rocket are both no-gos. Again, see the title. But I showed you what happens when one spits out of the envelope? It was like a bullet. Can you imagine what happened when we fired a bullet out of the thing? Close to escape velocity. Are you getting it now? Shoot down a satellite from the ground with a conventional rocket launcher.
Got the electrical capacity? Got a fibre optic cable which can handle the bit-rate that'll come out of it? Got room in your installation? Wrap a computer in a Ground Effect Envelope and you have a supercomputer. What can you do with a thousand-fold supercomputation boost? Crack the entire encrypted world open? Simulate the future? These are just off the top of my head. Grow crops faster. Raise animals faster. Mature wine faster. Install the tech into a refrigerator and keep perishables for longer. I created this list in five minutes. Until I came into this meeting I didn't even know what Project Ground Effect was.
A human being? Draw up an international treaty outlawing that tosh. God help us, there isn't a worse idea in the world. We just created a brand new superpower and you're talking about bestowing it on a human being?