Expecting the launch of the most powerful rocket ever flown at 1345 today.

400ft tall Starship consists of two fully reusable parts.

The top section, also called Starship, has already performed several 'hops'. Today is the first time the fully stacked ship will (hopefully) fly.

Just under a year ago, 160ft Starship performed this magnificent flight propelled by its three Raptor engines.

Today with its super heavy booster attached, Starship has the power of thirty three extra engines.

^*almost two years ago - 5th May 2021.

Shows the extent to which the booster is a far more complex challenge. Getting this beast up into orbit is a monumental task.

Crucially, this is a system designed from the word go to get us to Mars - affordably.

120% more thrust than Saturn V.

An almost complete circumnavigation of the globe in orbit.

And two controlled splashdowns - of the booster and starship, gaining crucial data needed for controlled dry landings.

The goal today? Don't blow up.

One hour to go, now expecting lift off at 1420 BST.

SpaceX have compiled a new video of some of those early upper stage tests, many of which blew up.

It's worth remembering the way in which SpaceX innovates is unlike that of any other rocket company.

Others relentlessly test on computer models.

SpaceX tests prototypes in the real world, usually expecting them to fail - but learning an incredible amount from *how* they fail.