Design process
In March 2012, news reports claimed that an upper-stage Raptor engine had begun development, although details were not released at the time. In October 2012, Elon Musk publicly stated a high-level plan to build a second reusable rocket system with capabilities substantially beyond the Falcon 9/Falcon Heavy launch vehicles that SpaceX had spent several billion dollars on. This new vehicle was to be "an evolution." of SpaceX's Falcon 9 accelerator... 'much bigger'". But Musk indicated that SpaceX would not speak publicly about the issue until 2013.[36].
In June 2013, Musk stated that he intended to postpone any potential initial public offering of SpaceX shares on the stock market until after "the Mars Colonial Transporter is flying regularly".[37][38].
In August 2014, media sources speculated that the initial flight test of the Raptor-driven superheavy launch vehicle could occur as early as 2020, in order to fully test the engines under orbital spaceflight conditions; However, it was reported that any colonization efforts were "deep in the future".[39]
In early 2015, Musk said he hoped to release details in late 2015 of the "entirely new architecture" for the system that would enable colonization of Mars. Those plans were delayed,[40][41][42][43][44] after a launch failure in June 2015 until SpaceX returned to flight in late December 2015.[45].
In September 2016, at the 67th annual meeting of the International Astronautical Congress (IAC), Elon Musk released substantial details of the transport vehicle design. At the time, the system architecture was known as the "Interplanetary Transportation System" (ITS). Details announced at IAC included the very large size (12 meters core diameter), material of construction, number and type of engines, thrust, cargo and passenger capacity, in-orbit propellant tank refueling, representative transit times, and portions of the Mars- and Earth-side infrastructure that SpaceX intends to build to support a set of three flight vehicles. The three distinct vehicles that made up the ITS launch vehicle in the 2016 design were as follows:.
• - ITS booster, the first stage of the launch vehicle, which was responsible for placing the tanker freighters and manned ships into orbit.
• - ITS spacecraft, a second and long duration spacecraft in space.
• - ITS tanker, an alternative second stage designed to carry more propellant to refuel other vehicles in orbit.
Additionally, Musk spoke of a broader systemic vision, hoping that other stakeholders (whether companies, individuals, or governments) would use SpaceX's new, significantly cheaper transportation infrastructure to help build sustainable human development and civilization on Mars, thereby meeting the demand "Demand (economy)") that such a growing company could bring.[46][47].
In the 2016 plan, SpaceX attempted to fly its first spacecraft research missions to Mars using its Falcon Heavy launch vehicle and a modified Dragon spacecraft, called Red Dragon, prior to the completion and first launch of any ITS launch vehicle. Later, Mars missions using ITS were at that time scheduled to begin no earlier than 2022.[48] Those plans later changed, initially with a February 2017 announcement that no SpaceX Mars mission would occur before 2020, two years later than the aforementioned 2018/Dragon2 Falcon Heavy exploratory mission[49] and then, in July 2017, abandoning the plan to use a Red Dragon soft lander entirely.[50].
In July 2017, Musk indicated that the architecture had "evolved quite a bit" since articulating the Mars architecture in 2016. A key driver of the updated architecture was to make the system useful for substantial Earth-orbit and cislunar launches so that the system would pay for itself, in part, through economical spaceflight activities in the near-Earth space zone.
In September 2017, at the 68th annual meeting of the International Astronautical Congress, SpaceX unveiled the vehicle's updated architecture. Musk said "we're looking for the right name, but the codename, at least, is BFR." The 2017 design is a 9 meter diameter technology, using metalloxine-fueled Raptor rocket engine technology initially in Earth orbit and in the cislunar environment, later being used for flights to Mars.[52].
The aerodynamics of the BFR (Big Falcon Spaceship, or BFS) second stage changed from the 2016 design launch vehicle. The 2017 design is cylindrical with a small delta wing at the rear that includes a split fin" to control pitch and roll. The delta wing and split fins are necessary to expand the flight envelope and allow the craft to land at a variety of densities. atmospheric (no, thin or heavy) with a wide range of loads (small, heavy or none) on the nose of the ship.
There are three versions of the ship: BFS Cargo, BFS Tanker and BFS Crew. The cargo version will be used to launch satellites into low Earth orbit, delivering "significantly more satellites at once than anything ever done before," as well as for transporting cargo to the Moon and Mars. After resettling into a high-elliptical Earth orbit, the spacecraft is being designed to land on the Moon and return to Earth without refueling.
Additionally, the BFR system would have the ability to transport passengers and/or cargo in rapid Ground-to-Ground transport, delivering its payload anywhere on Earth within 90 minutes.
As of September 2017, Raptor engines were tested for a combined total of 1,200 seconds of test firing time in 42 main engine tests. The longest test was 100 seconds, which is limited by the size of the propellant tanks at SpaceX's ground test facility. The test engine operates at 20 MPa "Pascal (unit)") (200 bar "Bar (pressure unit)"), 2,900 psi) pressure. The flight engine targets 25 MPa (250 bar; 3,600 psi), and SpaceX hopes to reach 30 MPa (300 bar; 4,400 psi) in later iterations. In November 2017, SpaceX President and COO Gwynne Shotwell indicated that approximately half of all current development work on BFR is focused on the Raptor engine.[53].
The goal is to send the first two cargo missions to Mars in 2022, with the goal of "confirming water resources and identifying hazards" and launching "energy, mining and life support infrastructure" for future flights, followed by four spacecraft in 2024, two crewed BFR spacecraft plus two cargo-only spacecraft bringing additional equipment and supplies with the goal of establishing the propellant production plant.
At an announcement held at SpaceX headquarters in Hawthorne in September 2018, Elon Musk showed off a redesign of the BFS with additional wings and canard fins. The new BFR concept has seven Raptor engines of the same size in the second stage. The second stage also has two small drive fins near the nose of the craft, and three large fins at the base, two of which act, and all three double as landing legs.[54]
As of 2018, a new production facility to build the vehicles is under construction at the Port of Los Angeles. Manufacturing of the first spacecraft was underway in March 2018 with the first suborbital test flights planned for 2019. The company publicly stated an ambitious goal for initial BFR cargo flights on Mars launching BFR as early as 2022, followed by the first crewed flight to Mars a synodic period later in 2024. Additionally, the BFR will be used for the SpaceX lunar tourism mission, a proposed private mission to fly space tourists around the Moon, crewed by Yusaku Maezawa along with some artists from different artistic backgrounds.[55].
In January 2019, Elon Musk announced that the spacecraft would no longer be built from carbon fiber and would instead use stainless steel. Musk cited several reasons, including cost, strength, and ease of production, to justify the change.[56].
In May 2019, the spacecraft design changed to just six Raptor engines, with three optimized for sea level and three optimized for vacuum. As of late May 2019, the first prototype, Starhopper, was being prepared for untethered flight testing in South Texas, while two orbital prototypes were under construction, one in South Texas starting in March and the other on Florida's Space Coast starting before May. It is anticipated that construction of the first Super Heavy booster stage could begin in September.[57] At that time, neither of the two orbital prototypes yet had aerodynamic control surfaces or landing legs added to the tank structures under construction, and Musk indicated that the design for both would be changing once again.[58] On September 21, 2019, "moving fins" visible from the outside[59] began to be added to the prototype. Mk1, giving a glimpse of the promised mid-2019 redesign of the aerodynamic control surfaces for the test vehicles.[60][61].
In June 2019, SpaceX publicly announced that talks had begun with three telecommunications companies to use Starship, instead of Falcon 9, to launch commercial satellites for paying customers in 2021. No specific companies or launch contracts were announced at the time.[62].
In July 2019, Starhopper performed its initial flight test, a "jump" of around 20 m altitude,[63] and a second and final "jump" in August, reaching an altitude of around 150 m[64] and landing about 100 m from the launch pad.
SpaceX completed most of the Boca Chica prototype, the Starship Mk1, in time for Musk's next public update in September 2019. Watching construction in progress ahead of the event, online observers circulated photos and speculated about the most visible change, a switch to two tail fins from the previous three. During the event, Musk added that landing would now be achieved on six dedicated landing legs, following re-entry protected by glass thermal tiles. Updated specifications were provided: when optimized, Starship is expected to be able to accumulate 120,000 kg empty and could initially carry a payload of 100,000 kg with the goal of increasing that to 150,000 kg over time. Musk suggested that orbital flight could be achieved for the fourth or fifth test prototype in 2020, using a superheavy booster in a two-stage launch vehicle configuration to orbit,[66][67] and emphasis was placed on the possible future of lunar missions.[68].
In September 2019, Elon Musk unveiled Starship Mk1.[69][70].
In November 2019, the Mk1 test prototype broke up in a tank pressure test, and SpaceX stated that they would move on to work on the Mk3 prototype. A few weeks later, work on the vehicles in Florida slowed substantially, with some assemblies that had been built in Florida for those vehicles being transported to the Texas assembly location and a reported 80 percent reduction in the workforce at the Florida assembly location as SpaceX paused activities there.[71].
After the Mk prototype accidents, SpaceX made a design change. The stainless steel rings were made up of a single higher plate, the engine bay was reinforced, a new provisional landing gear was designed for the suborbital prototypes and all the cables for the electrical systems were placed on the back of the rocket. Starting in the middle of the year, the rocket had a redesign of the wings, which began to have a more squared design and were controlled by electric motors. Additionally, the oxygen and methane landing tanks were redesigned and relocated for greater stability during the descent of the suborbital prototypes.
The Boca Chica, Texas assembly site was gaining buildings and hangars throughout the year. The launch site was expanded with a second prototype stand and the Super Heavy launch pad began to be built.
As already planned, the suborbital prototypes would change over time. After the Starship SN8 accident caused by a lack of fuel supply at the time of landing, SpaceX decided to add a gas to pressurize the tanks and solve this problem. After the SN9 accident, it was decided to change the landing maneuver.
Despite there being no announcement in 2021, official images of the future DearMoon mission showed a redesign of the window, as well as a new landing gear, a reduction in the number of covers compared to the 2019 design and an increase in the percentage of the fuselage occupied by the heat shield.
With the assembly of the Starship S20 another redesign could be observed: both the upper and lower fins had reduced their size and the structure that supports the skirt changed shape.
Another redesign was announced in the summer: the front fins would be located more towards the exposed part of the fuselage, at a distance of 120° between them, to improve the aerodynamics of the ship in atmospheric descent. In addition, the valve system for recharging both the booster and the ship will be changed to a more classic way to load the Super Heavy with a retractable arm and do orbital refueling with a new method.