Dropping out something from the orbit of the ISS to Earth is not an easy task, as it might seem at first glance. The average speed of the ISS in orbit is 7.66 km/s with an average altitude of 408 km.
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At this speed, the station is in a state of constant free fall, at which it falls all the time to the Earth, but because of the high horizontal speed, it always misses the planet beyond the horizon.
Any object dropped from the ISS will have the same initial speed plus speed that will be given to it during the throw. If you drop the paper airplane in the direction opposite to the orbital motion of the ISS, its speed will slightly decrease.
With a decrease in speed, any object will go into a lower orbit. For a paper airplane with the ISS to fall to Earth, it is necessary to reduce its speed by 80-90 m/s, then it will sufficiently reduce its orbit and begin to rub against the upper atmosphere, reducing its speed, which will lead to a fall in a few months.
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In order for an airplane launched from the ISS to fall to the Earth within a few days, it is necessary to reduce its speed to about 7.5 km/s, that is, 160 m/s, then its orbit will go down to the denser upper atmosphere and it will quickly fall to The earth.
During the fall to the dense layers of the atmosphere, it will have time to lose another part of the speed due to friction against the rarefied air particles, but it will still remain too large. The specific value to which the airplane has time to slow down depends on many parameters, but in any case, the speed will be measured in Km/s. At such speeds, the friction against the atmosphere will be very strong and the airplane will burn at the entrance to the dense layers.
What if you drop something stronger: a plastic airplane, iron or ceramic? In fact, any object that can burn will inevitably catch fire when falling through the atmosphere, and objects that cannot burn will heat up and melt, scattering particles of its substance, which means that a plastic airplane will also burn, and an iron one will melt and atomize in the atmosphere in the form of tiny particles.
That is why the spacecraft lining is made of non-combustible refractory materials, usually these are certain types of ceramics. They have a low melting point and a very high specific heat of fusion.
A low melting point is necessary so that the spaceship does not heat up to a high temperature at which the devices inside fail and people inside can die, and refractoriness so that the ship does not have time to melt during a long passage through the atmosphere.
So if you make an airplane out of special ceramics, it will be able to safely pass through the atmosphere and fly to the Earth, but due to its enormous speed and relatively high mass, it will not be able to land smoothly and will crash at full speed when it hits the surface of the Earth.
