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Serial Number 7.2
SN7.2 test tank - photo by @bocachicagal
Also CalledSN7.2
Testing History
Cryo Test 1Complete
Cryo Test 2Complete

Serial Number 7.2 (SN7.2) is a Starship test article being tested in Boca Chica, Texas. SN7.2 is a small test tank constructed using 3mm stainless steel rings, with the purpose of evaluating and proving this reduction in thickness from the previous 4mm rings. If successful and carried over to Starship, this would represent a significant weight saving.


The first parts of SN7.2 to appear on site were the two domes which form the top and bottom of the tank. These domes appeared outside of the construction tents in November, and were likely intended to be utilised on a full Starship prototype, SN13, before this prototype was cancelled. The domes remained outside with no further progress until they were sleeved at the end of December. The forward dome was the first to be sleeved on December 27, receiving a single ring - serial 008. The thrust dome which forms the bottom of the tank was sleeved with a two-ring stack two days later, receiving rings 003 and 005.

The low serial numbers of the rings (other contemporary rings having serial numbers in the 700s) as well as the unusual sleevings soon lead to speculation about a new test tank being assembled. This speculation was fueled by "" being visible on one of the labels, and the particularly flimsy appearance of the rings.

A seperate two-ring test article soon followed, from which test samples were taken on January 6 to evaluate the dome-to-ring welds. This article was also marked "3mm dev", furthering the test tank theory. The same day, a pipe marked "Pad Kit SN7.2 Testing" was spotted, revealing the name of the test tank.

The two domes were joined on January 12, with stringers being added around the outside unpressurised skirt to provide sufficient strength to prevent collapse. The tank was moved to the launch site on the morning of January 20, being located on the same concrete pad that previously hosted SN7.1's burst test.


SN7.2's test campaign commenced with a cryogenic pressure test on the morning on January 26th. This test was terminated by the opening of one of the vent valves with a closed-valve duration of approximately 3 minutes and 30 seconds, and reported as a successful initial pressure test by Elon.[1]

The second pressure test occured on February 4th, with the result of two leaks that appeared to be on the ring weld line where the two sleeved dome sections were joined. As this weld was completed outside in the open, the weld could reasonably be expected to be of a lower quality than the other welds completed in the shelter of the tents.