Launch of SpaceX Falcon 9

The first-ever test flight for SpaceX's monstrous new rocket is almost here.
It's called Falcon Heavy, and if it launches as planned Tuesday, it'll become the most powerful rocket in use.

The rocket is poised for its first test at Kennedy Space Center in Florida. Takeoff is slated to happen Tuesday between 1:30 pm ET and 4 pm ET.

"People [came] from all around the world to see what will either be a great rocket launch or the best fireworks display they've ever seen," Elon Musk said in an interview with CNN's Rachel Crane.

If Tuesday doesn't work out, due to weather or some other delay, there's a backup launch window on Wednesday.

Why all the buzz for this launch?

For one, this rocket is built by SpaceX, the game-changing company helmed by billionaire Tesla (TSLA) CEO Elon Musk.

Related: Bezos says he's rooting for SpaceX

SpaceX has shaken up the rocket industry by becoming the first company to successfully reuse rocket boosters in order bring down the cost of space flight. To do that, it guides the rockets back to Earth for a safe landing after they send their payloads into orbit.

So far, SpaceX has safely recaptured first-stage boosters after 21 of its 40-plus Falcon 9 launches.

The Falcon Heavy rocket is essentially three Falcon 9s strapped together, which means there are three first-stage rocket boosters.

SpaceX will try to guide all three of those boosters back to Earth after launch. Two will attempt a synchronized landing back at Kennedy Space Center, and the third will land on a droneship.

It should also be noted that two of those rocket boosters are actually used Falcon 9 boosters that have flown on previous missions.

Related: SpaceX Falcon Heavy launch: What happens if it fails?

And Musk has thrown in a branding stunt with this launch.

Most first-time rocket test flights have a dummy payload on board. But instead of a hunk of metal, Musk has opted to send his personal Tesla (TSLA) roadster to space with this launch.

The plan is to send the car into an orbit around the Sun that will, at times, be as far away from the Sun as Mars. Musk says the car will play an endless loop of David Bowie's "Space Oddity."

Of course, there's a chance this rocket doesn't make it to orbit. Because of its design, it's extremely difficult to test this rocket on the ground. So SpaceX says putting it on a launch pad and seeing if it flies is the next step in the design process.

SpaceX has taken a long time preparing for this test launch. The company said back in 2011 that the rocket would be ready in 2013. That target eventually moved to November 2017, then December.

But now, with a firm launch date in place, it's clear the company is dead set on getting this rocket in the air.