On rocket-based troop transports, I would say that parachutes on approach would be most essential. A hull washdown or icing system would probably be in order, you would think. And a Kevlar belt of some kind would definitely need to be in place.
Audio and visual signatures aside, anyone coming in hot (literally), all rockets blazing and hull still hot from reentry, will have the IR signature of a sun. Those pesky insurgents will have a turkey shoot from their rooftops. Bring your own Stingers and small arms. Not good at all.
Unless the transport makes a landing "in the rear, with the gear", frontline use is not a good idea. No sir'ee.
A combat assault landing from space requires the dropship to come in at speeds equal to "the ragged edge of burning up" while semi-random "drunkwalking" jinking to avoid defensive fire. And then firing retro rockets at minimum altitude/maximum burn to land in a controlled crash without killing the occupants.
Basically, think Glider Assault from WW2.
Complete with the desperate need for reinforcements.
The reality:
General Badass announces to a room full of special forces operators:
"We will stuff you in a spaceplane and shoot you across the sky at Mach 18. You will experience 6 g's at takeoff, and variable between 0 g's and 5 g's as you skip across the upper atmosphere. You will abandon the vehicle at 120,000 feet for a HALO jump into enemy territory while wearing an ill-fitting spacesuit made by the lowest bidder, breaking the speed of sound as you fall. You will land in a small compound with four of your fellows where you will rescue American captives from the stupid unteachable monsters who are currently holding them. You will then hold the compound from the onslaught of an expected 3,000 assailants for a minimum of five hours until conventional forces can be flown to support you. We can only send five of you at this time on this harrowing experience which chances are you will not survive. Who wants in?"
The news the following day says that the military had to deploy a combination of sleep gas and ED-209 droids to quell the riot as the operators started beating the hell out of each other for the chance to be first in line.
"This will harrow, yes, your very soul" is an *enticement* to exactly the sort of people we want to rocket across the planet to apply boot to ass for Uncle Sam.
Yup. SOCOM types are freaking adrenaline junkies, they'd volunteer to fly a Drop-rocket
for fun.
It doesn't matter what the launch vehicle is, flying a spacecraft into a war zone is not workable.
Not if you expect to fly it back out, no.
If it's explicitly a one-way trip with a separate system doing the pickup, it's closer to viable.
Again, you need it to come in as fast as the thermal management system can handle all the way down till it scrubs off most of the speed via retro-rocket burn at minimum altitude. Kinda like a Falcon Heavy 1st stage, but faster and with a "crash landing" acceptable.
Go ahead and use
a lot of crumple structures to dissipate impact forces, like how cars have crumple zones. Well, more like how race cars have the cockpit tub as the safety structure and everything else can break off to absorb energy instead of the driver.
"Any landing you can walk away from is a good landing."
Trick is dealing with the reentry heat.