How will we land the colony vab?

[SciMan]

Now now, that's no way to think of it. I've built landers that weigh thousands of tons without much issue, the main reason I'm able to do that is that I have engines which have sufficiently high Thrust and ISP, using a Dense fuel, to make that feasible. NSWR engines make great landing engines once you toss the whole concept of "radiation safety" out the window.

Heck if you want to go really crazy, it might actually be advantageous to use something like an Orion drive as a landing engine in certain situations.

Take a mining vessel for instance. You're only interested in the resource deposit, right? That's the reason you sent a mining vessel and not a science vessel.
Well, if you're trying to mine, nobody needs that dang overburden that's laying on top of the resource deposit your drills are trying to get to anyway.
So take a note from Project Plowshare and use the Orion drive to both do most of the landing burn, and simultaneously blast away most of that overburden while you're at it! The pusher plate should protect you from if not all of the vaporized debris, at least most of it, right? And you already factored in the radiation shielding needs when you built the thing with an Orion drive in the first place!

I see no downsides here, but there probably are downsides that I don't know of.

Seems no different to me than using a nuke in Factorio to clear the trees off of a resource deposit I want to plant mining drills on, just the whole process is faster.