I tried what you said in the most realistic simulator we have, Kerbal Space Program, assuming like you that a gentler approach would be better. And I learned that no, that most certainly is not better.
What you need to protect is on the inside of the heat shield. Heat conduction is based on temperature difference and time[1] and the conduction of the material[2]. Since the heat shield tiles have a very low thermal conductivity, it takes a long time for significant heat to pass through.
Yes a more aggressive approach will lead to a greater temperature, but it'll also provide significantly greater drag, thus the the extreme temperatures only exist for a relatively short amount of time, and thus it doesn't have time to pass through the tiles and heat up the inside.
A very shallow approach has significantly less drag, and you spend significantly longer slowing down. The temperatures might be a fair bit less, but the much longer time spent decelerating means it has a chance to make it through the heat shield tiles.
It's not entirely unlike iron meteorites which can still be cold when landing, as they only spend a brief time in the atmosphere[3] and thus don't have time to heat up.
You mean use fuel to remove all horizontal velocity? Yes, that works fine and puts much less stress on the exterior, but it's a gigantic amount of fuel, almost as much as it took to get into orbit in the first place.
Coriolis force. If a geostationary satellite was instantaneously accelerated straight down towards the Earth, its path (from Earth's perspective) would not be straight down as its original circumferential velocity at geostationary orbit (pi * geostationary orbit diameter * Earth radial velocity) would be "too high" when the altitude is lower.
To continue moving "straight down" its angular velocity would need to be constant, which means as its altitude decreases the circumferential velocity would need to decrease. But gravity only pulls down, there's no force to accelerate it in that direction. So therefore it appears to curve off to the side.
Keep in mind that the object orbiting is already falling. Orbiting earth is literally "falling around the earth", compared to "falling down to earth" which we are more familiar with from throwing rocks and whatnot.
So to go "straight down" either it would need to orbit the sun (instead of the earth) and have its orbit intersect that of the earth, like the meteors we're worried about, or it would need to do a very strong deceleration burn.
You still need to reduce your horizontal velocity. (For "geo-stationary", think "really high and really, really fast")
Either you do that with atmospheric drag, or a huge amount of fuel. The weight of heat protection is much lower and more efficient than the fuel option.
What you need to protect is on the inside of the heat shield. Heat conduction is based on temperature difference and time[1] and the conduction of the material[2]. Since the heat shield tiles have a very low thermal conductivity, it takes a long time for significant heat to pass through.
Yes a more aggressive approach will lead to a greater temperature, but it'll also provide significantly greater drag, thus the the extreme temperatures only exist for a relatively short amount of time, and thus it doesn't have time to pass through the tiles and heat up the inside.
A very shallow approach has significantly less drag, and you spend significantly longer slowing down. The temperatures might be a fair bit less, but the much longer time spent decelerating means it has a chance to make it through the heat shield tiles.
It's not entirely unlike iron meteorites which can still be cold when landing, as they only spend a brief time in the atmosphere[3] and thus don't have time to heat up.
[1]: https://en.wikipedia.org/wiki/Heat_equation#Interpretation
[2]: https://en.wikipedia.org/wiki/Thermal_conductivity_and_resis...
[3]: https://earthscience.stackexchange.com/questions/127/what-te...