Ashlee Vance

In a Twitter Spaces discussion with Vance, Musk says SpaceX is six weeks away from launching their second attempt to reach orbit with their Starship rocket. Despite implementing “well over a thousand” changes since the first attempt the launch will not go ahead unless the Federal Aviation Administration gives it clearance and signs off on the Starship’s self-destruct system which was slow to respond on the first attempt. During the Super Heavy’s maiden flight, a half-dozen engines shut down or never started and the Starship never separated from the Super Heavy first stage. The next test will use ‘hot staging’, which means that the Starship engines will ignite before separation.

We shut down most of the engines on the booster, leaving just a few running and then at the same time, start the engines on the ship, or upper stage

Musk says roughly 1,000 cubic meters of steel-reinforced high-strength concrete will be added to the launchpad to avoid damaging breakup.

On top of that, we have a sort of a steel sandwich, which is basically two thick plates of steel that are welded together with channels going through (with) perforations in the top so it will actually shoot a lot of water out. Think of it like a gigantic upside-down shower head. It’s going to basically blast water upwards while the rocket is over the pad to counteract the massive amount of heat from the booster. The booster is basically like the world’s biggest cutting torch with a massive amount of … heat, but also a massive amount of force.

Musk says the chance of the test getting to orbit is 60%:

I think the probability of this next flight working, getting to orbit, is much higher than the last one. Maybe it’s like 60%. It depends on how well we do at stage separation…In launching, what you’re doing is trying to resolve the unknowns which you cannot know before you launch, or at least we are not smart enough to know. So like I said, what appears to be the biggest risk right now is stage separation.