Land for new apartments may be hard to come by in the city, but Elon Musk may soon have spots available — on Mars.

The visionary entrepreneur wants to colonize the red planet, and now his SpaceX company has set a date to send an unmanned craft there: 2018.

“Planning to send Dragon to Mars as soon as 2018,” the company tweeted Wednesday. “Details to come.”

Dragon, a craft far heavier than NASA’s unmanned rovers, will launch on SpaceX’s Falcon 9 Heavy rocket, later gently descending to Mars’ surface via thrusters.

Well, that’s the plan: SpaceX has yet to test either Falcon 9 Heavy or the landing system — and 2018 is just two years off.

And just getting anything to Mars is so difficult that few countries have tried it. Of 43 attempts, most were mere fly-bys, not landings. And most failed.

Kudos to Musk for daring to dream. And don’t count him out: SpaceX already made history with its vertical landings of rockets on Earth, on land and on sea platforms.

Musk’s 2018 Mars mission won’t get a dime from Uncle Sam, just some NASA technological help in return for sharing data.

SpaceX is one of several big-bucks private-sector firms taking over space exploration — and commerce. The trend vastly broadens the possibilities — and enormously boosts the chances of a permanent human presence off-Earth.

Fanciful as Musk’s colonize-Mars plan may sound, here’s hoping he keeps pursuing his dream. Who knows? As they say about city real estate: If you build it, they will come.