Tuesday, August 2, 2022

A Couple of Good Days to Watch Starbase

We seem to be coming up on a couple of good days to keep an eye on the goings on at SpaceX's Starbase Boca Chica.  

The week started out with talk about possible road closures from 10AM to 10PM Monday through Thursday.  So far, Monday and Tuesday have gone by with no road closures and continued work on the infrastructure.  We know that a warning to mariners about possible over pressure events, or other things to be avoided was issued for the four days, and there have been rampant rumors that Ship 24 will be static fired this week.  I think they won't issue notices like that without knowing some probability exists they'll get to the test, but I don't know what the chance is.  

Still, if it's going to be this week, it's either Wednesday or Thursday.  

There still have been tests and things going on at Starbase, even though it hasn't been involving long pillars of fire.  While last week was quiet, they did rather substantial testing on the tank built to test all their changes to the way tanks are built, with a test tank called B7.1, because it's built identically to Booster 7, B7.  It appears every test was passed with no issues.  

The company began testing B7 months before B7.1, subjecting the full-size booster to multiple cryogenic proof tests and Raptor thrust simulation testing to qualify its new thrust ‘puck’ and several other structural changes. SpaceX began testing B7.1 in late June, shortly before Super Heavy Booster 7 was damaged by an unplanned explosion that halted its first Raptor engine test campaign. B7.1 testing then restarted in mid-July and was completed by the end of the month.

For unknown reasons, SpaceX’s decision to build and test Booster 7 before B7.1 meant that any significant issues discovered during subsequent B7.1 testing could disqualify the booster for flight testing, potentially wasting the months of work and tens of millions of dollars already invested in the prototype. Ultimately, though, B7.1 appeared to sail through multiple cryogenic proofs and crush tests without any catastrophic issues. Only on the last crush test did any part of the test tank finally give way, and the resulting damage was minor.

Photo by Mary, Boca Chica Gal from NASASpaceflight.com.  

Test tank B7.1 is seen in the center here, with vertical straps from the test system called the "Can Crusher" arrayed around its circumference.  During the test, when the tank contains the desired amount of liquid nitrogen those black straps are pulled downwards putting tremendous crushing forces on the tank. 

It's believed that the test is aimed at replicating as much of the thermal and mechanical stresses of the real cryogenic fuel/oxygen tanks and the weight of the vehicle above this point in the tank as it can simulate.  While the straps are being pulled down, additional rams installed under B7.1 push up to simulate the thrust of 13 central Raptor engines, so that the test item is subjected to crushing loads from both directions.  The real load a booster will face the from the weight of a fully-fueled Starship sitting on top of it is ~1350 tons or ~3 Million lb.s pushing down.  The thrust of 13 Raptor engines pushing up is ~6.5 Million lb.s.

While it appears it's a good idea to keep an eye on your favorite way to watch things (I tend to watch Lab Padre's Rover 2.0 camera to start), of course I have no way of knowing if they actually plan to run a static fire test.  For what it's worth, I'll have a browser tab open on it all day tomorrow. 

UPDATE 080322 3:23PM.  All road closures have been cancelled for this week.  So much for a static firing. 



  1. I love watching this stuff happen.

    1. WHEN it happens, absolutely. Waiting is the hardest part.
      It'll happen when it'll happen.