After a rocky start, SpaceX has been nailing landing after landing with its reusable Falcon 9 rockets - and today it's hoping to stick the perfect take-off and descent for the fourth time in a row, after delivering not one, but two satellites into orbit. You can join us on the edge of our seats and watch the entire launch above, starting at 10.29am ET (00.29am AEST on Thursday).

Of course, as with any launch, there's the potential for bad weather to interfere. But, according to Florida Today, there's an 80 percent chance of favourable weather during the 44-minute launch window, so the odds are in our favour that we're going to see some action.

In this latest launch, the Falcon 9 will be blasting off from Cape Canaveral in Florida, and for the first time will be delivering two commercial satellites into orbit, around 36,000 km (22,000 miles) above Earth's surface.

The satellites will be dropped off 5 minutes apart, and one will provide Latin America with video, data, government, and mobile services, while the other will beam 'direct-to-home' mobile, TV, and maritime signals across the Eastern Hemisphere.

Once it's completed that ambitious mission, the SpaceX team will aim to land the booster for the fourth time in a row on a drone barge floating in the middle of the Atlantic Ocean… So, uh, just a regular Wednesday, then? 

As incredibly challenging as that is, SpaceX has been getting a lot better at the landing part lately, with the first successful on-land landing in December, and the first at-sea landing back in April. Last month, they completed two perfect landings just a few weeks apart. Here's hoping the fourth time's the charm.

The boosters used in the previous five successful landing have all since been retrieved and fixed up, and SpaceX CEO Elon Musk has tweeted that one of these (probably the April landing) could be used for a re-launch as early as September.

The reason this is so important is that reusing rockets could cut the cost of space flight by as much as 30 percent - something we really need to accomplish if we want to make any meaningful achievements in space travel and colonisation. 

After Wednesday, the next SpaceX launch will be in mid-July, when a Falcon 9 is scheduled to carry the 11th Dragon spacecraft to the International Space Station.

But if you're not around for today's launch, don't worry, because rival space company Blue Origin is going to have a crack at launching (and then crash landing) their reusable New Shepard rocket this Friday, too. And for the first time ever, they're going to be live streaming it - here's how to watch.

Speaking of, we're also going to be live snapchatting the SpaceX launch in person at Cape Canaveral - from 5am ET, science never sleeps! - so make sure you follow us (username: sciencealert) for lots of behind-the-scenes footage.

Happy viewing, space lovers!