SpaceX rendering of BFR
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| Function | Mars colonization, Earth–lunar transport, intercontinental transport, orbital launcher[1] |
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|---|---|---|---|---|
| Manufacturer | SpaceX | |||
| Country of origin | United States | |||
| Cost per launch | US$7 million (external estimate)[2] | |||
| Size | ||||
| Height | 106 m (348 ft)[1] | |||
| Diameter | 9 m (30 ft) | |||
| Mass | 4,400,000 kg (9,700,000 lb) | |||
| Stages | 2 | |||
| Capacity | ||||
| Payload to LEO | 250,000 kg (550,000 lb) expendable[3] 150,000 kg (330,000 lb) reusable[3] |
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| Payload to Earth (return) | 50,000 kg (110,000 lb)[1][3] | |||
| Launch history | ||||
| Status | In development | |||
| Launch sites |
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| First stage – Booster | ||||
| Length | 58 m (190 ft) [1] | |||
| Diameter | 9 m (30 ft) | |||
| Gross mass | 3,065,000 kg (6,757,000 lb) | |||
| Engines | 31 × Raptor | |||
| Thrust | 52.7 MN (11,800,000 lbf) sea level [1] | |||
| Specific impulse | 330 s (3.2 km/s) each engine, sea level | |||
| Fuel | Subcooled CH 4 / LOX | |||
| Second stage – Spaceship | |
|---|---|
| Length | 48 m (157 ft) [1] |
| Diameter | 9 m (30 ft) |
| Empty mass | 85,000 kg (187,000 lb) |
| Gross mass | 1,335,000 kg (2,943,000 lb) |
| Propellant mass | 240,000 kg (530,000 lb) CH 4 860,000 kg (1,900,000 lb) LOX |
| Engines | 7 × Raptor (4 × vacuum, 3 × sea level) [4] |
| Thrust | 12.7 MN (2,900,000 lbf) total |
| Specific impulse | 375 s (3.68 km/s) vacuum each, outer 4 engines 356 s (3.49 km/s) vacuum each, inner 3 engines 330 s (3.2 km/s) sea level [1] each, inner 3 engines |
| Fuel | Subcooled CH 4 / LOX |
BFR[1]:2:35 is SpaceX's privately funded next-generation launch vehicle and spacecraft announced by Elon Musk in September 2017.[5][6] It includes reusable launch vehicles and spacecraft that are intended by SpaceX to replace all of the company's existing hardware by the early 2020s, ground infrastructure for rapid launch and relaunch, and zero-gravity propellant transfer technology to be deployed in low Earth orbit (LEO). The new vehicles are much larger than the existing SpaceX fleet. The large payload to Earth orbit of up to 150,000 kg (330,000 lb) makes it a super heavy-lift launch vehicle.
The BFR system is planned to replace the Falcon 9 and Falcon Heavy launch vehicles, as well as the Dragon spacecraft, initially aiming at the Earth-orbit launch market, but explicitly adding substantial capability to support long-duration spaceflight in the cislunar and Mars mission environments.[1] SpaceX intends this approach to bring significant cost savings that will help the company justify the development expense of designing and building the BFR system.
SpaceX had initially envisioned a larger design known as the ITS launch vehicle, which was presented in September 2016 as part of Musk's vision for an interplanetary transport system.[7] The ITS range of vehicles was designed with a 12-meter (39 ft) core diameter,[8] and the BFR design was scaled down to 9 meters (30 ft).[1] While the ITS had been solely aimed at Mars transit and other interplanetary uses, SpaceX pivoted in 2017 to a plan that would support all SpaceX launch service provider capabilities with a single range of vehicles: Earth-orbit, Lunar-orbit, interplanetary missions, and even intercontinental passenger transport on Earth.[1][9]
Development work began in 2012 on the Raptor rocket engines which are to be used for both stages of the BFR launch vehicle, and engine testing began in 2016. New rocket engine designs typically have longer lead times than other major parts of new launch vehicles and spacecraft. Tooling for the main tanks has been ordered and a facility to build the vehicles is under construction; construction of the first ship is scheduled to begin in the second quarter of 2018,[1] with first suborbital flights planned for 2019.[10] The company publicly stated an aspirational goal for initial Mars-bound cargo flights of BFR launching as early as 2022, followed by the first crewed flight to Mars one synodic period later, in 2024.[5]
History
As early as 2007, Elon Musk stated a personal goal of eventually enabling human exploration and settlement of Mars,[11][12] although his personal public interest in Mars goes back at least to 2001.[13] Bits of additional information about the mission architecture were released in 2011–2015, including a 2014 statement that initial colonists would arrive at Mars no earlier than the middle of the 2020s.[14] Company statements in 2016 indicated that SpaceX was "being intentionally fuzzy about the timeline ... We're going to try and make as much progress as we can with a very constrained budget."[15][16]Musk stated in a 2011 interview that he hoped to send humans to Mars's surface within 10–20 years,[12] and in late 2012 he stated that he envisioned a Mars colony of tens of thousands with the first colonists arriving no earlier than the middle of the 2020s.[14][17][18]
Early development
In March 2012, news accounts asserted that a Raptor upper-stage engine had begun development, although details were not released at that time.[19] In October 2012, 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 on which SpaceX had by then spent several billion US dollars.[20] This new vehicle was to be "an evolution of SpaceX's Falcon 9 booster ... 'much bigger'." But Musk indicated that SpaceX would not be speaking publicly about it until 2013.[14][21]In June 2013, Musk stated that he intended to hold off any potential initial public offering of SpaceX shares on the stock market until after the "Mars Colonial Transporter is flying regularly."[22][23]
In August 2014, media sources speculated that the initial flight test of the Raptor-driven super-heavy launch vehicle could occur as early as 2020, in order to fully test the engines under orbital spaceflight conditions; however, any colonization effort was reported to continue to be "deep into the future".[24][25]
In early 2015, Musk said that he hoped to release details in late 2015 of the "completely new architecture" for the system that would enable the colonization of Mars. Those plans were delayed,[26][27][28][16][29] and the name of the system architecture was changed to "Interplanetary Transport System" (ITS) in mid-September 2016.[7]
On 27 September 2016, at the 67th annual meeting of the International Astronautical Congress, Musk unveiled substantial details of the design for the transport vehicles. The details included the very large size (12 meters (39 ft) core diameter),[8] construction material, number and type of engines, thrust, cargo and passenger payload capabilities, in-orbit propellant-tanker refills, representative transit times, and portions of the Mars-side 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 the:[1]
- ITS booster, the first-stage of the launch vehicle
- ITS spaceship, a second-stage and long-duration in-space spacecraft
- ITS tanker, an alternative second-stage designed to carry more propellant for refueling other vehicles in space
In the November 2016 plan, SpaceX indicated it would fly its earliest research spacecraft missions to Mars using its Falcon Heavy launch vehicle and a specialized modified Dragon spacecraft, called "Red Dragon" prior to the completion, and first launch, of any ITS launch vehicle. Later Mars missions using ITS were slated at that time to begin no earlier than 2022.[32]
By February 2017, the earliest launch of any SpaceX mission to Mars was to be 2020, two years later than the previously mentioned 2018 Falcon Heavy/Dragon2 exploratory mission.[33] In July 2017, SpaceX announced it no longer plans to use a propulsively-landed Red Dragon spacecraft on the early missions, as had been previously announced.[34]
In July 2017, SpaceX made public its plan to build a much smaller launch vehicle and spacecraft before building the ITS launch vehicle that had been unveiled nine months earlier designed explicitly for the beyond-Earth-orbit (BEO) part of future SpaceX launch service offerings. Musk indicated that the architecture had "evolved quite a bit" since the November 2016 articulation of the comprehensive Mars architecture. A key driver of the new architecture was to be making the new system useful for substantial Earth-orbit and cislunar launches so that the new system might pay for itself, in part, through economic spaceflight activities in the near-Earth space zone.[35] ITS development was put on hold and "Serious development of BFR" began in 2017.[1]:15:22
Announcement of the BFR
BFR compared to other systems
On 29 September 2017 at the 68th annual meeting of the International Astronautical Congress in Adelaide, South Australia, SpaceX unveiled the new smaller vehicle architecture. Musk said "we are searching for the right name, but the code name, at least, is BFR."[1] The new launch vehicle system is a 9-meter (30 ft) diameter technology, using methalox-fueled Raptor rocket engine technology directed initially at the Earth-orbit and cislunar environment, later, being used for Mars missions.[1][5]
Aerodynamics of the BFR second stage changed from the 2016-design ITS launch vehicle. The new design is cylindrical with a small delta wing at the rear end which includes a split flap for pitch and roll control. The delta wing and split flaps are needed to expand the mission envelope to allow the ship to land in a variety of atmospheric densities (no, thin, or heavy atmosphere) with a wide range of payloads (small, heavy, or none) in the nose of the ship.[1]:18:05–19:25 The cylindrical shape is for mass optimization.
There are three versions of the ship: BFR crew, BFR tanker, BFR cargo. The cargo version can also be used to launch satellites to low Earth orbit.
After retanking in a high-elliptic Earth orbit the spaceship is being designed to be able to land on the Moon and return to Earth without further refueling.[1]:31:50 The most surprising announcement was to use BFR as a point-to-point transfer system for people on Earth. Musk expects ticket price to be on par with a full-fare economy plane ticket for the same distance.
As of September 2017, Raptor engines had been tested for a combined total of 1200 seconds of test firing time over 42 main engine tests. The longest test was 100 seconds, which is limited by the size of the propellant tanks at the SpaceX ground test facility. The test engine operates at 20 MPa (200 bar; 2,900 psi) pressure. The flight engine is aimed for 25 MPa (250 bar; 3,600 psi), and SpaceX expects to achieve 30 MPa (300 bar; 4,400 psi) in later iterations.[1]
Testing of the BFR vehicle is expected to begin with short suborbital hops of the full-scale ship, likely to be just a few hundred kilometers altitude and lateral distance.[36]
By September 2017, SpaceX had already started building launch vehicle components. "The tooling for the main tanks has been ordered, the facility is being built, we will start construction of the first ship [in the second quarter of 2018.]" Musk is hoping to be ready for an initial Mars launch in five years, in order to make the 2022 Mars conjunction window.[1] In November 2017, SpaceX president and COO Gwynne Shotwell indicated that approximately half of all current development work on BFR is on Raptor engine development.[37]
The aspirational goal is the first two cargo missions to Mars in 2022, with the goal to "confirm water resources and identify hazards" while putting "power, mining, and life support infrastructure" in place for future flights, followed by four ships in 2024, two crewed BFR spaceships plus two cargo-only ships bringing additional equipment and supplies with the goal of setting up the propellant production plant.[1]
Nomenclature
The descriptor for the large SpaceX Mars rocket has varied over the past five years that SpaceX has publicly-released information about the project. "BFR" is the current code name for SpaceX's privately funded launch vehicle announced by Elon Musk in September 2017.[1]:2:39[5][6][38][39][40] SpaceX President Gwynne Shotwell has stated the BFR code stands for "Big Falcon Rocket".[41] However, Elon Musk has explained that although this is the official name, he drew inspiration from the BFG weapon in the Doom video games.[42]From September 2016 through August 2017, the overall system was referred to by SpaceX as the Interplanetary Transport System and the launch vehicle itself as the ITS launch vehicle. Beginning in mid-2013, and prior to September 2016, SpaceX had referred to both the architecture and the vehicle as the Mars Colonial Transporter.
Scope of BFR missions
The BFR launch vehicle is planned to replace all existing SpaceX vehicles and spacecraft in the early 2020s. SpaceX cost estimation has led the company to conclude that BFR launches will be cheaper per launch than launches of the existing vehicles and even cheaper than launches of the retired Falcon 1. This is partly due to the full reusability of all parts of BFR, and partly due to precision landing of the booster on its launch mount and industry-leading launch operations. More specifically, both Falcon 9 and Falcon Heavy launch vehicles and the Dragon spacecraft flown in February 2018 will be replaced in the operational SpaceX fleet during the early 2020s.[43][1]:24:50–27:05Flight missions of BFR will thus aim at the:[43]
- legacy Earth-orbit market
- long-duration spaceflight missions in the cislunar region
- Mars missions, both as cargo ships as well as passenger-carrying transport
- long-distance commercial travel on Earth: the ability to transport people on point-to-point suborbital flights between two points on Earth in under one hour.[36][44] Musk refers to this as "Earth-to-Earth".[45]
Description
The BFR design combines several elements that, according to Musk, will make long-duration, beyond Earth orbit (BEO) spaceflights possible. They will reduce the per-ton cost of launches to low Earth orbit (LEO) and of transportation between BEO destinations. They will also serve all usage for the conventional LEO market. This will allow SpaceX to focus the majority of their development resources on the next-generation launch vehicle.[1][9][46]The fully-reusable super-heavy-lift BFR will consist of a:[1]
- "BFR booster": a reusable booster stage.
- a reusable, integrated second-stage-with-spaceship, which will be built in at least three versions:
- "BFR spaceship": a large, long-duration spaceship capable of carrying passengers or cargo to interplanetary destinations, to LEO, or between destinations on Earth.
- "BFR tanker": an Earth-orbit, cargo-only propellant tanker to support the refilling of propellants in orbit. The tanker will enable a long-duration spaceship to serve as the second stage of the launch vehicle while expending almost all of its propellant to reach LEO. After refilling in orbit, the spaceship will provide a significant amount of the energy needed to put it onto an interplanetary trajectory.
- "BFR satellite delivery spacecraft": will have a large cargo bay door that can open in space to facilitate the placement of large and small spacecraft into orbit.
The BFR spaceship, the BFR tanker, and the BFR satellite delivery spacecraft will have the same outer mold line. The second-stage-spaceship will be capable of returning to the launch location. While returning, it will be able to tolerate multiple engine-out events and land successfully with just one operating engine.[1]
The functioning of the system during BEO launches to Mars will include propellant production on the Mars surface. This is necessary for the return trip and to reuse the spaceship at a minimal cost. Lunar destinations will be possible without Lunar-propellant depots, so long as the spaceship is refueled in a high-elliptical orbit before the Lunar transit begins.[1]
The major characteristics of the launch vehicle will include the following.[1][47][3]
- Both stages will be completely reusable.
- The booster will return to land on the launch mount. The second-stage/spaceship will have the ability to return to near the launch mount. Both will use retropropulsive landing and the reusable LV technologies developed earlier by SpaceX.
- The expected landing reliability will be on a par with major airliners.
- Rendezvous and docking will be automated.
- There will be on-orbit propellant transfers from BFR tankers to BFR spaceships.
- A spaceship and its payload will be able to transit to the Moon or fly to Mars after an on-orbit propellant loading.
- Heat-shields will be reusable.
- The BFR spaceship will have a pressurized volume of 825 m3 (29,100 cu ft), with up to 40 cabins, large common areas, central storage, a galley, and a solar storm shelter for Mars missions.
Component
Attribute |
Complete | BFR booster | BFR spaceship/tanker/ sat-delivery vehicle |
|---|---|---|---|
| LEO Payload | 150,000 kg (330,000 lb)[3] | ||
| Return Payload | 50,000 kg (110,000 lb)[3] | ||
| Cargo Volume | 825 m3 (29,100 cu ft)[3] | N/A | 825 m3 (29,100 cu ft)[3] (spaceship) |
| Diameter | 9 m (30 ft)[3] | ||
| Length | 106 m (348 ft) | 58 m (190 ft) | 48 m (157 ft)[3] |
| Maximum weight | 4,400,000 kg (9,700,000 lb)[3] | 1,335,000 kg (2,943,000 lb) | |
| Propellant Capacity | CH 4 – 240,000 kg (530,000 lb) |
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| O 2 – 860,000 kg (1,900,000 lb) |
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| Empty weight | 85,000 kg (187,000 lb)[3] | ||
| Engines | 31 × SL Raptors | 3 × SL + 4 × vacuum Raptors[4] | |
| Thrust | 52.7 MN (11,800,000 lbf) | 12.7 MN (2,900,000 lbf) total | |
The Raptor engine will operate at 25 MPa (250 bar; 3,600 psi) of chamber pressure and achieve 30 MPa (300 bar; 4,400 psi) in later iterations. The engine will be designed with an extreme focus on reliability.[1][47]
