"Mission content: Penetrate the atmosphere to fight, land on the surface and arrive at the predetermined location. Pen & Fun & Pavilion www.biquge.info"

"Mission duration: 10 minutes."

"Target distance: 1500 km."

"Thickness of the atmosphere: about 1300 km."

Ground combat is more unfamiliar to prospective pilots than ship-to-ship. Although the Space Force does have such a project in its combat mission, the purpose of which is to occupy the planet's surface. However, since the launch of the "Dijing Counteroffensive" in SC0084, the Space Force of the New Asian Republic has never really carried out any ground operations, and the battle with the UAC Federation is still in a see-saw in space. There is no need to carry out ground warfare by retrieving a mineral star occasionally, because most of the mineral stars have no military power on the surface, not even living people, but purely automated mining.

Therefore, the pilots were mobile suit pilots in the Space Force before, and their combat environment was basically in a near-absolute vacuum of space. There is no gravity and no air resistance in space, so there will be no hindrance to mobile suits, and the degree of freedom is extremely high.

Surface warfare is first and foremost affected by gravity, and a significant portion of Mobile Suit's engine output must be used to fight gravity. What's even more terrifying is that when the pilot controls the mobile suit to make any acceleration, deceleration, or curved flight, it will produce a strong G-force due to centrifugal force.

The magnitude of the g-force is determined by the inertia generated by the change in the state of motion, and there is theoretically no upper limit. However, the body's tolerance is quite limited, and it fluctuates within 10 g depending on the constitution. If the g-force exceeds the individual's capacity, it will injure the inner abdomen and produce short-term adverse effects such as "red vision" due to excessive cerebral congestion or "black vision" due to cerebral ischemia.

On the other hand, the impact of air resistance on mobile suits cannot be ignored. Anyone who has seen a rocket launch knows how much the outer layer of a rocket launched at the first cosmic speed is affected by air resistance, and there must be a special thermal insulation layer that constantly peels itself off to take away the heat generated by friction, otherwise the rocket will burn out.

The design speed of the humanoid mobile suit is 110 km/s, which is more than ten times higher than the 7.9 km/s of the first universe that broke away from the earth. If you ignore the effects of gravity and fly in the atmosphere at full speed, you will melt yourself almost instantly. Of course, due to air resistance, it is impossible for mobile suits to reach their maximum value.

Another point is that neither the shape of the iron ball nor the humanoid mobile suit does not meet the aerodynamics required for high-speed combat in the atmosphere, and the flight agility is greatly restricted. In this regard, to be honest, Mobile Suits are really not as good as older fighters, and only a few high-end models have the ability to improve aerodynamics through external devices.

In general, if the day really comes when it is necessary to fight on the ground, the Space Force will also use a special airborne force as the main force, and the behavior of the iron ball unit to fill the hole is not done by a wise man. Therefore, the Space Force can not require iron ball pilots to master ground combat skills, but the requirements for pilots who are positioned as elite cannot be relaxed. Even if you don't have the opportunity for the time being, you must at least know what the ground war is all about and how to fight, so that you don't come to catch them when you need them.

At this time, Fengyu noticed that a thick layer of transparent gel was attached to his MA, which was a newly developed sublimation-type ablative material CJ (Carbonjelly) after mankind entered the cosmic age. CJ has an excellent thermal insulation effect, and after absorbing a certain amount of heat, it will sublimate and vaporize layer by layer, and the gas protective film formed by gasification will cover the surface of the body, which will greatly reduce the friction with the air.

The most important thing is that CJ is different from ordinary hard ablative materials, it is a flexible material, and after being coated on the surface of the mobile suit, it has the least impact on the movement of its limb joints, so that the mobile suit can have a considerable degree of combat ability even in the process of landing in the atmosphere, so that it will not be unable to move like a meteorite and fall straight to the ground, nor do you need to hang a deceleration parachute when approaching the surface and float slowly in the air to target ground firepower.

The ground mode narrows the scope of the battlefield, and compared to the vast expanse of space, and the thickness of the atmosphere is only more than 10,000 kilometers in diameter, the planet can only be regarded as a small stage. That being the case, the ground mode initially places the Quasi-Pilot close to the atmosphere, and there are no enemy mobile suits on the battlefield, instead assuming that the enemy Space Force has been completely defeated. All the prospective pilot had to do was brave the anti-aircraft fire blockade on the ground, force a landing on the surface and go to the assembly area.

Feng Yu controlled MA to do a few routine movements, in order to feel the extent of the impact of CJ coating on the body. Even though CJ is a flexible material, the blockage is clearly felt, and each movement takes nearly twice as long as usual, which means that he has to react faster than usual.

After getting a little familiar with the changes in the performance of the MA after attaching CJ to the atmosphere, Fengyu knew that he didn't have much time to waste, so he could only adapt to the changes while breaking into the atmosphere.

The simulated battlefield used for Earth combat is a terrestrial planet with an atmospheric structure similar to that of Earth, the home planet of mankind. Looking down from space, the atmosphere is divided into the fugitive layer, the ionosphere, the mesosphere, the stratosphere, and the troposphere.

The uppermost fugitive layer, also known as the outer layer, is extremely thin in the air at about 1 billionth of a billion at sea level, but the temperature is several thousand degrees Celsius, the warmest in the entire atmosphere. However, the fugitive layer has little effect on flying objects entering from space, mainly because the air here is too thin to produce much friction. And the air is thin, and the heat conduction is naturally poor. Therefore, although the thickness of the fugitive layer reaches tens of thousands of kilometers, it does not have the value of simulation assessment, and the simulator directly puts the MA of Fengyu at the bottom of the fugitive layer, close to the ionosphere.

The lower four layers, including the ionosphere, are collectively called the inner layer, that is, the atmosphere in a narrow sense, and the thickness of the atmosphere displayed on the main control screen refers to the thickness of the inner layer.

The temperature of the inner atmosphere varies greatly, and the ionosphere that the wind first touches is also called the warm layer or thermosphere, the temperature is second only to the fugitive layer, but it is the cemetery of all the flying objects that enter the atmosphere, because the density of the atmosphere here is by no means comparable to the outer layer, and the high-speed flying objects pass through the ionosphere at different speeds, which will produce a high temperature of thousands to tens of thousands of degrees, even higher than the surface temperature of ordinary stars, and most meteorites are burned in this layer.

As soon as MA entered this layer, Feng Yu immediately felt the difference, and the vision of all the optical sensing devices in the body was a fiery red and hazy, which was the CJ coating on the surface of the body that was constantly vaporizing, peeling off and burning. If you look up from the ground, MA is now like a burning meteor, piercing the sky and piercing the earth. At the same time, Feng Yu also felt that the whole MA was constantly vibrating, making people worry that the body would fall apart at any time, and he couldn't help but sigh that the air that he couldn't usually touch or touch would show such power.

The ionosphere is an excellent protective layer for the planet's surface, ordinary kinetic weapons are basically unable to penetrate this layer and will be burned, and particle beam weapons will also be affected by ionization interference, resulting in severe refraction and attenuation. It's just that this protection is relative, and while the surface is protected, Fengyu's MA is in turn not afraid of threats from the surface.

At this time, Fengyu only needs to pay attention to the consumption degree of CJ coating. Of course, since it was a pilot assessment, he could not be allowed to play soy sauce so easily, and when the MA reached the bottom of the ionosphere, the first wave of sniping from the ground came as scheduled.

It was two anti-aircraft missiles, one on the left and one on the right. Seeing these two missiles flying slowly at the first cosmic speed, looking like the end of a strong crossbow, Feng Yu was not worried, first raised the 40mm particle beam rifle to shoot two bursts, and found that the interference of the ionosphere was too strong to hit the target at all, and then replaced it with an alloy saber, activated the vector nozzle, and came to the side of one of the missiles in a flash, and cut it off with a knife, cutting it in two.

Zou Ji outside the court watched him play handsome, and couldn't help showing a mocking look.

I saw that the missile was detonated in advance, turning into a huge fireball, and the blast wave blasted Fengyu's MA out.

The simulation cabin immediately rolled up, turning the wind in the cabin into a veil. He also finally realized the difference between fighting in the atmosphere and in space, and the effect of the G-force really worked on him. Not only that, but a report of damage to the aircraft also popped up on the main control screen, showing that the MA shell was damaged by missile fragments.

It's just that Feng Yu has no time to take care of him, and while enduring the discomfort caused by the G-force, he controls Ma to return to his normal posture.

Fortunately, the other missile lost its target due to the explosion interference and continued to fly high in the ionosphere, where it was eventually burned.

By the time the MA stopped rolling, it had left the ionosphere and came to the mesosphere. The temperature of the mesosphere drops dramatically from 500 degrees Celsius in the transition zone between the two layers to about minus 80 degrees Celsius. Fengyu could see the flames on the exterior of the MA extinguish and turn into a white mist. At this point, as long as he doesn't let MA accelerate, CJ's protective layer is basically useless.

The CJ coating had been damaged in many places by the missile fragments, and if it hadn't been just about to leave the ionosphere, the heat would have invaded the MA through these breaches, turning the body into an oven and burning the pilot inside. Only then did Feng Yu realize how stupid it was for him to fight with missiles before, and it was the right choice to avoid it honestly.

Entering the middle layer, the attack from the ground can be regarded as the official beginning, and the fire net formed by particle beams and high-power electromagnetic cannons envelops the path of MA's fall.

Feng Yu dodged and complained, "Why didn't the ionosphere burn CJ more just now, it's a hindrance thing." "At this point, there is still about a third of the CJ coating, and although it is not as big as before, the movement of the MA will still be 10% slower than normal. Intuitively, Feng Yu felt as if he was driving back to the iron ball.

Conducting the pilot assessment at the speed of an iron ball is not a matter for Fengyu. But now he's in big trouble.