SpaceX Starship

Starship is a two-stage, fully reusable, super heavy-lift launch vehicle under development by American aerospace company SpaceX. Currently built and launched from Starbase in Texas, it is intended as the successor to the company's Falcon 9 and Falcon Heavy rockets, and is part of SpaceX's broader reusable launch system development program. If completed as designed, Starship would be the first fully reusable orbital rocket and have the highest payload capacity of any launch vehicle to date. As of October 13, 2025, Starship has launched 11 times, with 6 successful flights and 5 failures.

The vehicle consists of two stages: the Super Heavy booster and the Starship spacecraft, both powered by Raptor engines burning liquid methane (the main component of natural gas) and liquid oxygen. Both stages are intended to return to the launch site and land vertically at the launch tower for potential reuse. Once in space, the Starship upper stage is intended to function as a standalone spacecraft capable of carrying crew and cargo. Missions beyond low Earth orbit would require multiple in-orbit refueling flights. At the end of its mission, Starship reenters the atmosphere using heat shield tiles similar to those of the Space Shuttle. SpaceX states that its goal is to reduce launch costs by both reusing and mass producing both stages.

SpaceX has proposed a wide range of missions for Starship, such as deploying large satellites, space station modules, and space telescopes. A crewed variant, developed under contract with NASA, is called the Starship Human Landing System, which is scheduled to deliver astronauts to the Moon as part of the Artemis program, beginning with Artemis III currently scheduled for 2027. SpaceX has also expressed ambitions to use Starship for crewed missions to Mars.

SpaceX began developing concepts for a super heavy-lift reusable launch vehicle as early as 2005, with different names throughout the years. Starship's current design and name were introduced in 2018. Development has followed an iterative and incremental approach, involving a high number of test flights and prototype vehicles. The first launch of a full Starship vehicle occurred on April 20, 2023, and ended with the explosion of the rocket four minutes after liftoff. The program has failed to meet many of its optimistic schedule goals, with its development having had several setbacks, including the failure of the first four Block 2 upper stages in 2025.

Description

When stacked and fully fueled, Starship has a mass of approximately 5,300 t (11,700,000 lb), a diameter of 9 m (30 ft) and a height of 121.3 m (398 ft). The rocket has been designed with the goal of being fully reusable to reduce launch costs; it consists of the Super Heavy booster and the Starship upper stage which are powered by Raptor and Raptor Vacuum engines.

The bodies of both rocket stages are made from stainless steel and are manufactured by stacking and welding stainless steel cylinders. These cylinders have a height of 1.83 m (6 ft), and a thickness of 3.97 mm (0.156 in).

Domes inside the spacecraft separate the methane and oxygen tanks. SpaceX has stated that Starship, in its "baseline reusable design", will have a payload capacity of 100–150 t (220,000–331,000 lb) to low Earth orbit and 27 t (60,000 lb) to geostationary transfer orbit.

Super Heavy booster

Super Heavy was initially 71 m (233 ft) tall (in its Block 1 and Block 2 design, now retired), while Block 3 Super Heavy is 72.3 meters tall. It is 9 m (30 ft) wide, and is composed of four general sections, in ascending order: the engines, the oxygen tank, the fuel tank, and the interstage.

Tanks

The two cryogenic propellant tanks on Super Heavy are separated by a common bulkhead, a similar structural design to the S-II and S-IVB stages on the Saturn V rocket. After Starship's second flight test, the common dome's design was changed to be more elliptical, altering the propellant capacity of both tanks by a small amount. Each tank possesses roughly 74 stringers for structural reinforcement, attached to their interior walls. The booster's two tanks hold a combined 3,400 t (7,500,000 lb) of propellant: 2,700 t (6,000,000 lb) of liquid oxygen and 700 t (1,500,000 lb) of liquid methane. Fuel is fed to the engines via a single liquid funnel, and channeled into distribution manifolds of the engines. This system was upgraded on Block 3 boosters, featuring a substantially larger transfer tube connecting the engines and the methane tank. Block 1 and 2 boosters both have a single booster quick disconnect, along with multiple quick disconnects for the outer engines, while Block 3 boosters have two quick disconnects. One disconnect feeds liquid oxygen into the vehicle, the other feeds liquid methane.

The oxygen tank ends at the thrust structure of the vehicle. While the outer twenty engines are mounted to the walls of the aft bay, the inner thirteen are mounted onto the thrust puck, a part of the aft dome. Large steel structures are attached to the bottom of the dome, reinforcing the puck sufficiently to fully support the inner thirteen engines, and at the same time providing pathways for methane and oxygen into the engines. In addition, large filters were added in this region beginning on Booster 10. Liquid oxygen is supplied by a header tank during landing burn for the inner thirteen engines. On Booster 15, the header tank had at least nine additional tanks attached, increasing capacity for the landing burn. The added tanks may have been present on Boosters 12, 13, and 14, though this was unconfirmed as of February 2025. Booster 5 was the only 29-engine booster to receive a header tank, mounted to the side of the oxygen tank instead of being integrated with the thrust puck.

The methane funnel is partially contained within the header tank, as the methane sump is directly below it. On Booster 7 and all subsequent vehicles, four aerodynamic chines are located on the outside of the oxygen tank, providing aerodynamic lift during descent, as well as housing batteries, composite overwrapped pressure vessels (COPVs) for spin start, and CO₂ tanks for fire suppression. On vehicles with hydraulic power units (HPUs), COPVs dedicated to engine ignition, batteries, and communication antennae were located within the HPU cover instead of the chines.

Propulsion

Super Heavy is powered by 33 Raptor engines, which on Block 1 and 2 vehicles are housed within a dedicated shielding compartment. This compartment is not present before engine installation, thus boosters are roughly three meters shorter prior to engine installation. The outer 20 engines, arranged in a ring, are fixed in place. To save weight, the 20 engines are started using ground support equipment on the launch mount and cannot be reignited for subsequent burns. The inner thirteen engines are equipped with gimbal actuators and reignite for the boostback and landing burns. After Starship's first flight test, this gimbaling system was switched from a hydraulic system to an electric one, enabling the removal of the hydraulic power units. This change was made to the upper stage after the second flight test. During the ascent and boostback burns, the engines draw propellant from the main tanks, with the liquid oxygen being drawn from a dedicated header tank during the landing burn. Like the thrust vector control system, the engine shielding, which isolates individual engines in the event of a failure, was upgraded after Starship's first flight test, alongside the fire suppression system. The aft bay has eighteen vents visible on the outside of the booster, which are believed to be connected to the outer 20 engines, while the center engines vent directly below the launch pad.

The Raptor engine uses a full-flow staged combustion cycle with oxygen and methane-rich turbopumps. 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. To improve performance, the engines burn subcooled propellant; i.e. the propellants are cooled below their respective boiling points to further increase their density and the engine mass flow rates.

The Block 1 version of the booster (used through November 2024) produced a total of 73.5 MN (16,500,000 lb_f) just over twice that of the NASA Saturn V first stage, with this total being expected to increase to 80.8 MN (18,200,000 lb_f) for Block 3 boosters and later up to 98.1 MN (22,100,000 lb_f) with the Block 4 vehicle. The thirty three engines collectively produce large shock diamonds in the exhaust jet, visible during ascent and descent.

During unpowered flight in the upper atmosphere, control authority is provided by cold gas thrusters fed with residual ullage gas. Four perpendicular vents are located within the interstage. Additional vents are located just below the common dome, pointing down toward the engines at a slight angle.

The Block 3 booster contains an updated aft dome, with metallic heat shield tiles mounted upon it.