JhonB: It was stacked and then quickly destacked. They were simply doing some fit tests as well as I think practicing the procedures for future stacking operations.

As was said of the F-4 Phantom II; ‘With enough thrust, anything can fly.’

I don’t think any of us thought this was the final design for production.

Diane Wilson wrote: “Noting that Starship has already been unstacked, I would not be surprised if Booster 4 is also unstacked, and both return to the build site for finishing work.”

Considering that the move to the launch site was immediately after the engines were installed, the only two things that SpaceX would reasonably be testing were either a static fire before doing too much additional construction or a fit check. Fit check it was.

In the second Everyday Astronaut video, Musk says, “A lot of parts have not been weighed.”

My first thought was that this is a terrible way to design a flight item, but on further thought I considered that they are not yet ready to design the operational versions. They are still trying to figure out how to get them to fly properly, and they will worry about optimizing mass at a later time. If the design can put 100 tons into orbit, then they have 100 tons of weight margin for these test units.

Mitch S. wrote: “Remember some of the snark when the Starship prototypes were blowing up, and Musk here says it’s better when they blow up because otherwise we have to store them somewhere.”

Well, that is a nice excuse from Musk, but they can always cut them up for scrap rather than store them. The important point is to find where the limits are so that they can back off from those limits and fly a safe craft. Right now, though, they seem to be trying to modify the designs so that the limits are farther than they are now.

There was an concerted effort at Kennedy a few years back where they were studying the regolith/blast interactions. I hope NASA can cough up the data and see if they can help Elon out.

I don’t expect anything more than what they have stated for this flight but even that would be incredible.

Just how much as a second stage could this first stage lift?

Starship booster replies: I have twice your thrust.

P.S. The Tim Dodd interview with Elon linked by Diane is absolute must viewing.

Noting that Starship has already been unstacked, I would not be surprised if Booster 4 is also unstacked, and both return to the build site for finishing work. But somewhere along the line, Booster 4 will be necessary for ongoing checking and finishing of the orbital launch platform, other ground support equipment, fueling tests, and more. I’ve also read that some of the 29 Raptors may not be flight models, so some engines may need to be replaced.

So they’ve done their photo op, but work continues. It would be nice to see it fly by the end of September, but no bets.

By the way, Everyday Astronaut (Tim Dodd) did a long interview with Elon Musk, and the first part is on Youtube. They’re taking a tour of the build site as they talk, and it’s really a must-watch video.
https://www.youtube.com/watch?v=t705r8ICkRw

What happened the autogenous pressurization? And self-start of the engines?

Clearly more work is in the works on the booster.