A full-scale 16-story Starship prototype has yet to fly, though a previous and shorter version of the rocket — known as Starhopper — successfully launched 500 feet high and landed in 2019.

Since then, more advanced yet still early iterations of Starship prototypes have failed and were obliterated during testing, typically when engineers filled the rockets with inert liquid nitrogen to test the limits of their integrity.

During a test-firing of recent Starship prototype called SN4 in Boca Chica on May 29, the vehicle spectacularly exploded. The failure happened the day before the astronauts Bob Behnken and Doug Hurley rode the company’s Crew Dragon spaceship to the International Space Station with the help of a different SpaceX rocket, Falcon 9. (That launcher successfully flew 85 missions before sending Behnken and Hurley into space.)

Such a string of failures, however, is anything but unexpected, as SpaceX saw with the development of core technologies for its Falcon 9 system. Musk has also said the company may need to build about 20 large Starship prototypes before SpaceX can attempt to launch one into orbit.

Musk confirmed on June 4 that he still hoped to launch the first crew to Mars in a Starship vehicle in mid-2024 — ostensibly as the start of an effort to populate the red planet.

Though SpaceX is licensed to launch suborbital rockets from Boca Chica, the Border Report recently revealed that the company would face a new environmental analysis with the FAA before flying prototypes to orbit.

Business Insider requested details about the nature and timing of that assessment from the FAA on July 9, and an agency representative acknowledged receipt of our questions. The FAA, however, has yet to provide answers to the inquiries.

This story has been updated.