During a pressurization test on November 20th, 2019, SpaceX's Starship MK1 prototype "popped" at the SpaceX facility in Boca Chica TX.

Starship pops

Do we know what caused this apparent failure? Some claim that this was intended to be a destructive over-pressure test while others claim this came as a surprise to SpaceX.


  • Was this test intended to be destructive in nature?
  • What exactly caused the failure?
  • 2
    $\begingroup$ This is the first I've heard mention of the possibility that it was intended...I find that extremely unlikely. If you want to execute a to-failure test, you'd test just the tank, not the whole vehicle. $\endgroup$ Nov 24, 2019 at 6:04
  • 1
    $\begingroup$ @ChrisB.Behrens To be fair, this wasn't anything close to the full vehicle. Sure, it had the aerodynamic fins on it, but it was missing engines, RCS, etc. $\endgroup$
    – ifconfig
    Nov 24, 2019 at 17:21

1 Answer 1


The most sensible and specific account I've come across is as follows:

RUPTURE UPDATE: Through back channels it has been revealed that MK1 suffered an accidental overpressure to failure. Fuel and oxidizer would typically be loaded to 3 Bar or 43.5 psi— for densification purposes and flightworthy tanks may be tested to 1.5-2x that value for single time structural proofing. In the case of what happened today the story is that communications errors between the pumps/sensors and remote controls allowed the tanks to be massively and erroneously overpressured to the point of failure. leading to catastrophic rupture.

According to this, I believe the answers to your questions are as follows:

  1. Most likely no. While they were likely testing the limits of their manufacturing techniques and trying to learn about their weaknesses, (pun intended) the actual overpressure event was itself unplanned.

  2. Support equipment failure. This was due to a failure in the pressure regulator control system, which accidentally let more pressure develop in the tank than was originally planned or desired.

  • $\begingroup$ That video claims that the failed test involved "liquid cooled oxygen". I certainly hope that isn't true and that it was nitrogen as stated elsewhere. $\endgroup$ Nov 24, 2019 at 14:05
  • $\begingroup$ @OrganicMarble why? $\endgroup$
    – BlueCoder
    Nov 24, 2019 at 15:21
  • $\begingroup$ It's a lot more dangerous. $\endgroup$ Nov 24, 2019 at 15:21
  • 2
    $\begingroup$ @ifconfig ars technica says it was N2. arstechnica.com/science/2019/11/… $\endgroup$ Nov 24, 2019 at 17:43
  • 1
    $\begingroup$ @ifconfig raptors use nitrogen as a purge gas so they likely have some anyway $\endgroup$
    – Stickyz
    Nov 25, 2019 at 14:39

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