SpaceX is getting geared up to land its Falcon 9 rocket following a launch from Cape Canaveral in Florida, and we're either going to see one of its heaviest spacecraft stick the landing, or - the most likely alternative - crash violently into a ship. "A successful landing is not expected," the company announced earlier this week.
Regardless of the outcome, it's going to be spectacular to watch from start to finish. The mission is primarily to deliver a 5,000-kg (11,000-pound) telecommunications satellite into high orbit for global satellite operator, SES, and if they can safely return their massive spacecraft afterwards, SpaceX has had a very good day.
"The satellite is also one of the heaviest SpaceX has ever launched," Loren Grush explains at The Verge. "It's one of the reasons the company doesn't expect the rocket landing to succeed: the vehicle needs extra fuel to carry the satellite into space, leaving very little fuel for a return trip to Earth."
Whatever happens, let's all take a second to appreciate the name of the ship Falcon 9 will or won't fall apart on: Of Course I Still Love You. It's so lovely, our hearts hurt.
The launch window is expected to open at 6:46pm ET (10:46am AEST), and take-off will happen basically any time until about 8:16pm ET (12:16pm AEST), with a chance for unfavourable weather conditions to postpone the launch.
What happens if it crashes? Well, it'll probably end up something like this, when Falcon 9 landed, tipped, and exploded back in January. But that won't be so bad, because here in science, mistakes can often be just as valuable as success, and every crash just gives the SpaceX scientists and engineers more data to get to know their spacecraft better.
Watch the livestream below, and SpaceX, if everything ends up in a smoking mess, remember: of course we still love you.