As a part of SpaceX's Mars colonization program, the booster evolved into its current design over a decade.

[9] The propellant tanks on Super Heavy are separated by a common bulkhead, similar to the ones used on the S-II and S-IVB stages on the Saturn V rocket.

[16] It is unknown whether or not the top of this tank was ever completed, as a forward dome was never spotted during the assembly or scrapping of the vehicle.

[21] On vehicles with hydraulic power units, the COPV's dedicated to engine ignition, as well as the batteries, were located inside the HPU, instead of the chines.

[22] To save weight, these engines are started using ground support equipment on the launch mount and cannot be reignited for subsequent burns.

[27][28] Before 2014, only two full-flow staged-combustion rocket engine designs had advanced enough to undergo testing: the Soviet RD-270 project in the 1960s and the Aerojet Rocketdyne Integrated Powerhead Demonstrator in the mid-2000s.

The interstage is equipped with four electrically actuated grid fins made of stainless steel, each with a mass of roughly 3 t (6,600 lb).

[36] The fins remain extended during ascent to save weight,[9] though this results in mild warping during stage separation.

[37] The interstage also has protruding hardpoints, located between grid fins, allowing the booster to be lifted or caught by the launch tower.

[40]After the first Starship test flight, all boosters have an additional 1.8 m[41] tall vented interstage to enable hot staging.

[43] The vented interstage contains a dome to shield the top of Super Heavy from the second stage's engines.

[42][44] Elon Musk in 2023 claimed that this change might result in a 10% increase in the payload to low Earth orbit.

[44] Beginning with Booster 11, the vented interstage is jettisoned after completion of the boostback burn, to reduce mass during descent.

[47] Before assembly of the oxygen tank is finished, the methane downcomer is added, along with final stringers to the weld lines.

[13] In October 2012, the company made the first public articulation of plans to develop a fully reusable rocket system with substantially greater capabilities than SpaceX's existing Falcon 9.

[51] SpaceX COO Gwynne Shotwell gave a potential payload range between 150–200 tons to low Earth orbit for the planned rocket.

The concept, especially the technological feats required to make such a system possible and the funds needed, garnered substantial skepticism.

[55] In September 2017, at the 68th annual meeting of the International Astronautical Congress, Musk announced a new launch vehicle calling it the BFR, again changing the name, though stating that the name was temporary.

[61][5] In December 2018, the structural material was changed from carbon composites[55][54] to stainless steel,[62][63] marking the transition from early design concepts of the Starship.

[62][64][65] Musk cited numerous reasons for the design change; low cost and ease of manufacture, increased strength of stainless steel at cryogenic temperatures, as well as its ability to withstand high heat.

[71][72][73] In March 2021, SpaceX assembled the first Super Heavy prototype, BN1, a production pathfinder for future vehicles.

It was the first Super Heavy to be stacked with Starship,[80] and conducted multiple cryogenic tests before being retired in favor of Booster 7 and Ship 24.

[90] Ship 25 and Booster 9 were rolled to the suborbital and orbital launch sites in May to undergo multiple tests.

[94] Following separation, the Super Heavy booster completed its flip maneuver and initiated the boostback burn before exploding following multiple successive engine failures.

[94][95][96] Three and a half minutes into the flight at an altitude of ~90 km over the Gulf of Mexico, blockage in a liquid oxygen filter caused one of the engines to fail in a way that resulted in the destruction of the booster.

[97] IFT-3 launched from the SpaceX Starbase facility along the South Texas coast around 8:25 CDT on March 14, 2024, coincidentally the 22nd anniversary of its founding.

[100] B10 conducted a boostback burn, however, the planned landing in the Gulf of Mexico was not successful, as it exploded at 462 m (1,516 ft) above the surface.

[101] The fourth integrated flight test of the full Starship configuration launched on June 6, 2024, at 7:50 am CDT.

[43] The booster then rotates, before igniting ten additional engines for a "boostback burn"[94] which stops all forward velocity and reverses the trajectory towards the launch site.

After the boostback burn, the booster's engines shut off with Super Heavy on a trajectory for a controlled descent to the launch site using its grid fins for minor course corrections.