Main Engine Cut Off

Remains of ITS Composite Tank Spotted Back in Port

Our old friend u/Death_Cog_unit posted some photos over on r/spacex of the ITS composite tank back in port after its most recent test outing. This time, it came back in pieces:

This is what I saw when I was driving to work Wednesday morning. I was told that when the barge returned empty (Sometime last week?) the tank had exploded, and now here it is.

Supposedly when it went, it blew about 50 feet into the air and off the barge. Divers had to retrieve it. It is gone as of today.

We probably won’t get any detailed report from SpaceX on this. The big question is whether this failure met their expectations or was a surprise. Our old friend Lars Osborne shared some insight over in the comment thread:

Looks like it separated right along the seam.

I am going to interpret this as being a bad result for the test, since it failed in longitudinal stress, rather than hoop stress. A hoop stress failure will typically indicate that the vessel was efficiently designed, since longitudinal stresses are usually lower than hoop stresses. This is applicable to metallic pressure vessels, which is what my experience is in. It is also possible it was intended to fail a long the seam, but usually, a good seam/weld will be designed to be a little stronger than the bulk material.

Whatever the case, progress is being made.