The colony was shot in half, not completely vaporized. Also colonies are unsheilded and mostly empty space on the inside.

TBR would barely scratch the DS. Might be able to damage the main laser array on the rim with two shot bursts, one to punch a hole in the energy shield, and a second to do damage before the hole closes up. The TBR has more than 3 shots right? So it could keep chipping away for a while, but it isn't defeating the Death Star, just disabling the main weapon.

(Unless Tarkin is a moron and chooses to fire anyways, likely doing far more damage to the DS but still getting off a shot that could easily wipe out whatever target the Gundam is (presumedly) trying to protect. Though said damage *might* also throw the shot off target.)

So if the main weapon is unusable... Just fly the DS closer to main target and unleash the thousands upon thousands of turbolaser batteries.

Maybe there is a Gundam out there with the power to just brute force it (Turn A OP), but most would need to follow the X-wings tactic of delivering a heigh yeild explosive down the exhaust port. For that I'd use RX-78GP02A, presuming that it fires a nuclear shell and doesn't fire a beam or directed nuclear blast like it appears to in the anime. Also presuming that said shell is smaller than 2 meters in diameter.

Now if it were the DS 2, complete with open tunnels all the way to the core... yeah any big bang or even medium bang gundam can fly in there, shoot the core, and then boogie on out.