It could descend to groundbreaking.
The term of art you're looking for is ... Lithobraking.
You use the lithosphere to decelerate ...
And a
Thoroughly Satisfying Kaboom™ was had by all ...
Why are Traveller ships reversing course halfway when they can just aerobreak when they get to a World?
Because Traveller craft are capable of 1G+ continuous acceleration during an entire transit, which can last for days/weeks of time.
TL=6 chemical rocketry doesn't have the "power density" to sustain 1G+ acceleration for more than an hour of operation (in most configurations).
TL=7 ionic propulsion is capable of vanishingly small accelerations over LONG durations (months or more), but that's a different use case (typically robotic, rather than manned). Low acceleration over longer time frames is "more efficient" (in a variety of ways) for orbital maneuvering than using high acceleration for short bursts with long inertial coast phases between acceleration burns.
Furthermore, aerobraking requires a streamlined hull ... and not every craft that can be built in Traveller has a streamlined hull (for reasons various and sundry).
Can we playtest aerobreaking?
To my knowledge, aerobraking already existed in LBB2.77 and LBB2.81.
LBB2.77, p35:
Atmospheric Braking: Ships passing very close to the surface of a world with a standard or dense atmosphere may slow their speed through atmospheric braking. lf any portion of a ship’s vector passes within 1/4 inch of a world’s surface, that vector is reduced by 1/4 inch in length.
LBB2.81, p34:
Atmospheric Braking: Ships passing very close to the surface of a world with a standard or dense atmosphere may slow their speed through atmospheric braking. If any portion of a ship's vector passes within 10 mm of a world's surface, that vector is reduced by 10 mm in length.
So aerobraking has existed in Traveller from the beginning.
I was reading an article, wish I could remember where, about the planned Mars mission.
They were talking about aerobreaking at Mars.
What they mentioned was hitting the atmosphere of Mars 130 times in order to break the ship.
The problem with Mars is the low atmospheric pressure.
In Traveller terms, it would be a Code: 2 (very thin, tainted) atmosphere.
Ask any engineers designing craft that need to descend to the planetary surface of Mars and they'll tell you that the atmosphere is BOTH "too thick" as well as "not thick enough" at the same time.
It's "too thick" in the sense that ... you HAVE TO DEAL WITH IT in order to descend to the surface.
It's "not thick enough" in the sense that there's a limit to how much deceleration you can do using atmospheric drag with parachutes
... so you need to use SOMETHING ELSE in order to get your velocity close enough to zero that you don't "break things" on contact with the lithosphere.
There's basically 2 ways (at TL=6) to do this ... all of which involve a combination of aerobraking, parachute breaking, active rocket thrust and ...
additional engineering ... to deliver undamaged payloads to the surface of Mars.
Delivering DAMAGED payloads to Mars is EASY (and has been done multiple times already!).
At this point, I'll get out of the way and let the professionals explain the Rube Goldberg™ contraptions they've needed to devise in order to reach the surface of Mars, from orbit ... because ...
pictures vs millions of words.
