Starship

The now retired Block 2 version of Starship was 52.1 m (171 ft) tall, 9 m (30 ft) wide, and was composed of four general sections: the engine bay, the oxygen tank, the fuel tank, and the payload bay. The retired Block 1 was constructed in a similar manner, though it was only 50.3 m (165 ft) tall. Elon Musk stated in 2021 that the vehicle had a dry mass of roughly 100 t (220,000 lb). The windward side is protected by a heat shield composed of eighteen thousand hexagonal black tiles that can withstand temperatures of 1,400 °C (2,600 °F). It is designed to protect the vehicle during atmospheric entry and is to be used multiple times with minimal maintenance between flights. The silica-based tiles are attached to Starship with pins, and had small gaps in between to allow for heat expansion. After flight test 4, SpaceX added a secondary ablative layer under the primary heat shield, though this was only added to the flaps of the flight test 6 vehicle. This ablative layer is likely composed of pyron, which is similar in composition to carbon composites. The total mass of the heat shield and ablative layer of a Block 1 ship is 10.5 t (23,000 lb). After flight test 10, SpaceX added a felt, called "crunch wrap," between the gaps in between the tiles to prevent heat seeping in.

The propellant tanks on Starship are separated by a common bulkhead, similar to the ones used on the S-II and S-IVB stages on the Saturn V rocket. While Block 2 vehicles use an elliptical dome, the common and forward domes of the Block 1 design were more conical. Block 1 vehicles only had 24 stringers within the oxygen tank, while Block 2 vehicles had these added to the methane tanks. The vehicle's tanks hold 1,500 t (3,300,000 lb) of propellant, consisting of 1,170 t (2,580,000 lb) of liquid oxygen and 330 t (730,000 lb) of liquid methane.

Fuel is fed to the engines via four downcomers, with three smaller downcomers feeding the Vacuum Raptors/RVacs and the central downcomer feeding the inner three engines. The central downcomer connects to a large sump, instead of directly to the methane tank. The original design had a single downcomer. The liquid oxygen (LOX) downcomer extends into the LOX tank, with a small expanded portion of unknown purpose. Two additional downcomers route methane and oxygen from the header tanks. …

The manufacturing process starts with rolls of 301 stainless steel, which are unrolled, cut, and welded along an edge to create a cylinder of 9 m (30 ft) diameter, 1.83 m (6.00 ft) tall, and 3.97 mm (0.156 in) thick, and approximately 1600 kg (3,600 lb) in mass. Twenty-one such rings are used in the Starship spacecraft.

These rings are stacked and robotically welded along their edges to form stacks of three to five rings in the Starfactory. Following this, the domes are installed within the forward, aft, and common ring stacks. Cutouts are made for the header tank downcomers in the forward dump, a sump is added to the common dome, and the aft dome is integrated with the thrust puck. Heat tile pins are added to the ring stacks, along with the secondary thermal protection system. Following this, the thermal protection system's tiles are attached.

The nosecone is assembled from two different segments. The header tanks are inserted into the tip of the nosecone, as well as the motors and structural frames for the forward flaps. Heat shield tiles are added at this stage.

The segments are stacked vertically, beginning with the nosecone being lowered onto the payload bay. This process continues until the vehicle is integrated with the aft barrel, completing the structure of the vehicle. Following this, the aft flaps are installed.

The vehicle is then rolled to the Massey's test site, where it is cryogenically tested. These tests fill both tanks with liquid nitrogen, which is nonflammable, while pressing on the thrust puck to simulate the raptor engines. After returning to the production site, the engines are installed. It is static fired at Massey's, and then is rolled to the launch site for flight.

For a non-Starlink satellite launch, Starship is planned to have a large cargo door that opens to release payloads, similar to NASA's Space Shuttle, and closes upon reentry instead of a jettisonable nosecone fairing. Instead of a cleanroom, payloads are integrated directly into Starship's payload bay, which requires purging the payload bay with temperature-controlled ISO class 8 clean air.

Crewed Starship vehicles would replace the cargo bay with a pressurized crew section and have a life-support system. For long-duration missions, such as crewed flights to Mars, SpaceX describes the interior as potentially including "private cabins, large communal areas, centralized storage, solar storm shelters, and a viewing gallery". Starship's life support system is expected to recycle resources such as air and water from waste.

Starship has been proposed to be able to refuel by docking with separately launched Starship propellant tanker spacecraft in orbit. If this concept proves successful, it could potentially increase the spacecraft's mass capacity, theoretically allowing it to reach higher-energy targets. As of 2025 this concept has not been demonstrated. Some proposed missions that would require this in-space refueling include: geosynchronous orbit, the Moon, and Mars. A Starship propellant depot orbiting Earth could cache methane and oxygen on-orbit and be used by Starship to replenish its fuel tanks.

Starship Human Landing System (HLS) is a crewed lunar lander variant of the Starship vehicle that would be modified for landing, operation, and takeoff from the lunar surface. It would have landing legs, a body-mounted solar array, a set of thrusters mounted mid-body to assist with final landing and takeoff, two airlocks, and an elevator to lower crew and cargo onto the lunar surface.

Varying estimates have been given about the number of tanker launches required to fully fuel HLS, ranging from between "four and eight" to a number "in the high teens". These launches will reportedly have to be in "rapid succession" in order to manage schedule constraints and cryogenic fuel boil-off. When fully fueled, Starship HLS is designed to land 100 t (220,000 lb) of payload on the Moon.

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. Later in 2012, the company first mentioned the Mars Colonial Transporter rocket concept in public. It was to be able to carry 100 people or 100 t (220,000 lb) of cargo to Mars and would be powered by methane-fueled Raptor engines. Musk referred to this new launch vehicle under the unspecified acronym "MCT", revealed to stand for "Mars Colonial Transporter" in 2013, which would serve as part of the company's Mars system architecture. SpaceX Chief Operating Officer Gwynne Shotwell gave a potential payload range between 150 and 200 tons to low Earth orbit for the planned rocket. According to SpaceX engine development head Tom Mueller, SpaceX could use nine Raptor engines on a single MCT booster or spacecraft. The preliminary design would be at least 10 meters (33 ft) in diameter, and was expected to have up to three cores totaling at least 27 booster engines.

In 2016, the name of the Mars Colonial Transporter system was changed to the Interplanetary Transport System (ITS), due to the vehicle being capable of other destinations. Additionally, Elon Musk provided more details about the space mission architecture, launch vehicle, spacecraft, and Raptor engines. The first test firing of a Raptor engine on a test stand took place in September 2016.

The ITS second stage was planned to be used for long-duration spaceflight, instead of solely being used for reaching orbit. The two proposed variants aimed to be reusable. Its maximum width would be 17 m (56 ft), with three sea level Raptor engines, and six optimized for vacuum firing. Total engine thrust in a vacuum was to be about 31 MN (7,000,000 lbf). It would have 1,950 tonnes (4,300,000 lb) of propellant, and a dry mass of 150 tonnes (330,000 lb).

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. …