SpaceX Starship:Non-stop evolution of large Falcon rockets (2)
Author:Phillip Gaynor; Translator:21st Century Ayn Rand
Seventh Edition:interplanetary Transportation Systems – September 2016
In February 2016, SpaceX chose an MCT design of approximately 5,400 tons instead of the larger 7,000 tons, 88 m (288.7 ft) high and 14 m (45.9 ft) diameter design, which has three times the thrust of the Saturn V. One possible reason for this is that the company discovered that any design twice the weight of the Saturn V requires an impractical exclusion zone.
The company apparently quickly ignored this, because the subsequent Interplanetary Transportation System (ITS) announced in September 2016 that it would increase the total weight to a staggering 10,500 tons! If the launch is successful, the weight of the rocket will exceed the Tikonjaro-class cruiser and more than double the 4724-ton design of the previous year.
ITS The height is 122 m (400.3 ft) and is divided into two levels. Its 77.5 m (254.3 ft.) high first-stage booster can generate an astonishing 128,100 kN (13070 tons) thrust, which is equivalent to 85 Airbus A380s. This first stage booster weighing 6,975 tons and having a diameter of 12 meters (39.4 feet) is more than twice the total weight of the Saturn V. Above it is an ITS spacecraft with a large front window, 49.5 m (162.4 ft) high and 17 m (55.8 ft) in diameter.
Its thrust of 30,890 kN (3152 tons) will push this 2,100-ton spacecraft and up to 300 tons of cargo into LEO, where it can deploy an array of solar panels. With its three retractable landing pads, it can even project 450 tons of weight onto the surface of Mars. Its refueling spacecraft has a large fuel tank with a capacity of 2500 tons, and its dry weight is 40%less.
Raptor engine Its sea-level thrust increased from 1,961 kN (200 tons) to 3,050 kN (311 tons), an increase of 55.5%, and its sea-level specific impact increased by 3.9%(334 seconds vs. 321.4 seconds). It can even throttle 20-100%, and its 300 bar chamber pressure is the highest in rocket engine history. The vacuum version will have a higher thrust of 3,500 kN (357 tons) and a specific impulse of 382 seconds, which is the highest hydrocarbon impulse engine on record, thanks to the very large 200:1 expansion ratio nozzle.
As a comparison, the small amount of propellant (7%or 469 tons) required to recover the ITS booster to the launch site will exceed the weight of the early Falcon 9 (333 tons). It consumes more than three times the fuel load of the Statue of Liberty. Even its reusable payload is equivalent to the Boeing 777-300. What NSF experts worry about is that this design is too large to be safe, practical, and economical.
Eighth Edition:Big Falcon Rocket-September 2017
However, a few months later, SpaceX decided to adopt a smaller 9m ( 29.5 feet) diameter design to avoid the construction of a brand new factory. This will simplify production, but transportation and testing will become more complicated and expensive. The revised design will be called the”Big Falcon Rocket” (BFR).
When the 2017 BFR design was announced at the International Astronautical Congress, it was 106 m (347.8 ft.) high, weighed only 4,400 tons, and could deliver 150 tons of reusable payloads to earth orbit. . From October 2015 to September 2016, the design size more than doubled, and finally it was reduced to the smallest size.
The 58 m (190.3 ft) high BFR booster weighs 3065 tons and is powered by 31 Raptor engines to generate 52,700 kN (5378 tons) of thrust. This is”only” equivalent to 35 A380s. The length of the large Falcon spacecraft (BFS) has been shortened to 48 m (157.5 ft), with a pressurized cabin volume of 825 cubic meters and a total mass of 1185 tons. Its typical return load is up to 50 tons.
BFS to Four much smaller retractable landing legs replace three large retractable landing legs hidden in fins. It also had four vacuum-optimized Raptor Raptor engines arranged around two (later changed to three) Raptor landing engines. A pair of delta wings have been added to provide pitch and roll control. In turn, this will expand the flight range, allowing the BFS to land at various atmospheric densities. The large front window is divided into two rows of large windows. In the end, it also installed a solar storm shelter for residents in the 40 cockpits of the car, thereby solving the radiation problem.
By adding a BFS cargo version with a huge payload bay and hinged door, BFR gained the ability to launch and recover satellites. Coupled with the smaller size, its commercial value is much better than ITS. SpaceX said that the design will be the successor to the Falcon 9 series. It also mentioned that in less than an hour, it is possible to carry out point-to-point travel, supply space stations and missions to the moon anywhere on the earth, which are other possibilities.
Ninth Edition:Big Falcon Rocket/Starship-September 2018
The next iteration of the design is a small step forward, and It debuted in September 2018 and also announced a mission to the moon involving Japanese billionaire Yusaku Maesawa. The length of the rocket has been increased from 12 m (39.4 ft) to 118 m (387.1 ft). The length of the BFR booster has been increased by 5 m (16.4 feet) to 63 m (206.7 feet).
The length of the BFS spacecraft has increased by 15%to 55 m (180.4 ft.), mainly due to the expansion of the pressurized cabin of approximately 1,100 cubic meters. Powering the BFS are seven sea-level optimized Raptor engines that produce 13,729 kN (1,400 tons) of thrust. This is equal to the thrust of nine A380s.
Help control The spacecraft has two actuated front rudders and a rear three-fin configuration. These three fins will also replace the previous wings and retractable landing legs. The new BFS will also reproduce the large front window that was last seen by the 2016 ITS spacecraft.
In addition, Musk hinted that it is possible to reintroduce the Raptor vacuum engine to Starship, but said:”As far as BFR and BFS’s extensive architectural decisions are concerned, I think this is the last iteration.” Then it was renamed in November 2018, BFS became an interstellar spacecraft, and BFR’s booster became super heavy.
Tenth Edition:Starship-March 2019
The tenth edition released in January 2019 mocked Musk’s previous”final iteration”statement. The construction of the carbon fiber”starship” has been lagging behind. The tenth edition was corrected by replacing the carbon fiber structure of the previous design with 301 stainless steel. The ablative PICA insulation panels used in all previous designs have been replaced by heat storage insulation panels. In it, the liquid methane will evaporate by heating and escape the hull through tiny holes. This will transfer heat away from the spacecraft, thereby protecting the atmosphere when it enters.
In an interview with”Popular Mechanics” editor chief Ryan D&39;Agostino on January 24, 2019, Musk pointed out that many factors have prompted the design change of 301 series stainless steel:Compared with carbon fiber, It handles structural stresses much better, has higher heat resistance (788 vs. 250 C), costs 3 US dollars per kilogram, and carbon fiber is US$ 135, has no carbon fiber’s 35%scrap rate, and is easier to process, compared to most steels. The difference is that it is still tough at low temperatures, and even its strength is increased by 50%, which reduces the difference in weight.
301 stainless steel is a high-strength steel alloy containing 16-18%chromium, 6-8%nickel and no more than 2%manganese, 1%silicon, 0.15%carbon, 0.045%Phosphorous, 0.03%sulfur and 0.1%manganese nitrogen. At room temperature, its minimum yield strength can reach 205 MPa (30,000 psi), and it can resist oxidation up to 788 degrees Celsius (1450 degrees Fahrenheit).
It has high yield strength, heat resistance and good corrosion resistance, making it a common alloy for aircraft structural components. It is also commonly used in household appliances, subways, sinks, clothes on the dining table, and even tableware used by many readers in the kitchen. 301 stainless steel is also an excellent material for cryogenic rocket propellant storage tanks. When cooled from room temperature to the supercooled liquid oxygen temperature of -196 degrees Celsius (-320 degrees Fahrenheit), its yield strength (310 to 517 MPa/45,000 to 75,000 psi) increased by approximately 67%.
Not surprisingly, stainless steel has a long history in rocket technology. People used stainless steel to make one of the earliest orbital vehicles, namely the SM-65 Atlas Intercontinental Ballistic Missile (ICBM). In order to save weight, the Atlas rocket uses a very thin stainless steel spherical propellant tank. Spherical storage tanks provide minimal structural support, so they must be pressurized to stay upright. Similarly, both”Starship” and”Super Heavy” will be equipped with some stainless steel spherical tanks. These structures will be sturdy enough for ground handling without stress, while also saving weight during flight.
Eleventh Edition:Starship-September 2019
The design of Starship was changed again in May 2019. The level is switched to three Raptor Raptor vacuum engines and three Raptor Raptor sea level engines.
The Starship Mark 1 exhibited at Boca Chica in September 2019 is the prototype of this version. At the time of the announcement, Musk announced further changes.
Starship The upper layer of the spacecraft will be shortened by 5 meters (16.4 feet) to 50 meters (164.0 feet) in length, and the three-fin layout will be abandoned and replaced by two fins to better maneuver in the atmosphere and reduce weight. It will also use ceramic tiles instead of thermal storage heat shields and use six landing legs instead of four.
The super heavy booster adds 6 Raptor engines, a total of 37, and the length has increased by 5 m (16.4 ft) to 68 m (223.1 ft.), replaced by six fixed fins Its three fixed landing posts were replaced with welded stainless steel mesh grids.
These changes modify or improve the design in many ways. By using six landing legs on the starship and six landing fins on the Super Heavy, the risk of failure of a single leg or fin as a whole can be reduced. Replacing the rear three-fin layout with rear wings can achieve better balance and better control during atmospheric manipulation. The addition of 6 Raptor engines will not only greatly increase the payload capacity of the starship, but also reduce the delta-v required for the starship class due to the reduction in gravity loss.
The advantage of switching to ceramic tiles is that it does not rely on cryogenic liquids, which may block the holes of the regenerative insulation board. The disadvantage is that the new heat shield design may require inspection and replacement of damaged tiles after each flight. This is achieved by using a longer atmospheric inlet, which will help the”spacecraft” stage to keep high temperatures below critical levels.
The final The starship/super heavy will have a take-off weight of 5,000 tons and a height of 118 m (387.1 feet). A starship carrying 1,200 tons of propellant and more than 100 tons of cargo and crew will be placed on it. The upper tier to choose from includes a cargo version that can hold 150 tons of cargo, and a refueling version with an extra-large fuel tank. The large overweight booster is located below and can hold 3,300 tons of propellant. It will enable 37 Raptor engines to generate 72,569 kN (7405 tons) of thrust to lift the rocket from the launch pad, which is equivalent to 48 A380s in one takeoff. And its propellant alone is equivalent to the weight of the entire Saturn V moon landing rocket.
Twelfth Edition:Starship-May 2020
The twelfth edition of the design adds another version of the interstellar spacecraft:A propellant warehouse ship. In Elon Musk (Elon Musk) on March 16, 2020 and later Twitter posts confirmed a series of designs After the change, the new version began to take shape.
These changes include the use of 304L low-carbon stainless steel structure, in which the length of the super-heavy booster is increased by 2 meters to 70 m (229.7 feet), and the overall length is 122 m (400.3 feet). The total mass of the agent was increased to 300 tons (661,400 lb), 6 (later changed to 9) Raptor engines were removed, new, higher-thrust Raptor engines were used, and new hexagons were added to the starship. The self-leveling retractable landing foot also includes other possible changes such as an embedded engine and a more effective tank curvature.
Improved fuel tanks and more effective tank curvatures will result in higher propellant quality and lower dry weight in the two stages. These changes will increase the effective to-rail load and may reduce the cost per kilogram of cargo and per passenger. The improved outriggers will increase the landing stability of the rocket and may increase the number of times the rocket is reused before an accident.
On April 30, 2020, SpaceX announced that it has won a $135 million NASA Artemis program contract, which is a lunar lander version of the spacecraft. It will make the Apollo LM lunar lander inferior. The height of 50 m (164.0 feet) is 7 times that of 7.0 m (22.9 feet), the crew capacity is 50 times (100 to 2), and the volume of the pressurized cabin is 150 times larger. Above (1000+ m3 to 6.65 m3). This type of spacecraft can carry 100 tons of cargo and eight times as many astronauts as the entire Apollo program.
SpaceX’s Artemis related plans call for LEO spacecraft flight, follow-up flight again, propellant transfer between interplanetary spacecraft and fuel tankers, longer-duration orbital interplanetary spacecraft missions and beyond LEO flight. All of these will be carried out before the unmanned moon landing demonstration mission in 2022.
In order to reduce Quality, Starship’s lunar lander version will not have an aerodynamic control surface or TPS, and will use a different final descent engine because the Raptor engine will kick out lunar debris. Six rendering thrusters appear above the side of the spacecraft, and their design is similar to the concept of NASA Langley Hercules. It will also have two fully redundant airlocks. However, when Japanese billionaire Yesaku Maezawa orbits the moon, it will be a regular interstellar spacecraft, not a lunar lander.
In a tweet on September 1, 2020, Musk pointed out further changes to the engine. Now, the super heavy will only use 28 Raptor engines, three fewer than before. The thrust of a conventional Raptor engine will increase by 5%from 200 tons to ~210 tons, while a new fixed-thrust version will produce 300 tons of thrust. Eight centrally mounted variable thrust gimbal Raptor engines will help Super Heavy control its direction. Twenty more powerful fixed-directional Raptor engines will provide most of the thrust.
Despite the reduction of three engines, the total thrust will increase from 72,569 kN (7405 tons) to 75,315 kN (7685 tons), an increase of 3.8%. This is equivalent to the thrust of at least 51 A380s.
Timeline of recent events
SpaceX announced on February 27, 2017 that Maesawa Tomomi was the predecessor of the moon flight. It is planned to use a super heavy rocket to carry the Dragon spacecraft to provide two paying passengers with a six-day flight around the moon. This plan was later shelved, and on September 17, 2018, SpaceX announced that Yusaku Maezawa and a team of six to eight artists would fly around the moon by the”Big Falcon” rocket by 2023. . For reference, the last time Apollo 17 orbited the moon was in December 1972.
SpaceX CEO Elon Musk (Elon Musk) said that the Japanese tycoon was once one of the potential customers of Falcon heavy rocket flight. However, he chose to upgrade from the Falcon Heavy to be able to attract more artists to participate in his voyage. Musk said in his”Dear Moon” speech that the cost of the entire BFR development is estimated to be about $5 billion. He added that Maesawa’s contribution to mission costs will have a substantial impact on the payment of BFR development costs.
On November 17, 2018, Elon Musk hinted that his rocket company will make more changes to the design and no longer replace the existing Falcon 9 rocket. Upgraded to be reusable. Instead, SpaceX is speeding up the development of the”Big Falcon” rocket, which will be fully reusable, so launch costs may be lower. Musk said on Twitter that the design has been modified in a way that is”different from intuition but pleasant.”
In a series of tweets on November 19, 2018, Elon Musk announced the fourth different name of the rocket. The second stage will be renamed”Starship” while the booster stage will be renamed”Super Heavy”. Musk had previously used this name before the first flight of Falcon Heavy in April 2018, when he mentioned the possibility of Falcon Super Heavy. This was originally a Falcon Heavy with two additional boosters. When Musk first discussed it in 2007, the original name of the rocket was Big Falcon Rocket. Musk later mentioned that part of the name was inspired by BFG in the Doom video game series.
SpaceX announced in April 2018 that it has been approved to develop BFR rockets and starships in the Port of Los Angeles. At this stage, about 40 people have designed and built a tent there, which is equipped with a large carbon fiber mold customized by SpaceX to build the BFR.
SpaceX’s plan calls for the launch vehicle to be assembled at the Port of Los Angeles and then transported to Florida by barge via the Panama Canal.Canaveral Corner’s launch pad. However, as Musk suddenly tweeted on December 8, 2018 that the design had been changed from all-carbon fiber to metal, these plans were questioned.
On December 22, 2018, Elon Musk confirmed in a NSF tweet that the completely redesigned engine will ignite next month. The next day, after visiting SpaceX’s Boca Chica launch site in Texas, Musk announced that the first test starship had been built here for several weeks.
He announced on the 24th that the interstellar spacecraft will be made of stainless steel. The rocket will use three of the seven planned Raptor engines to fly, and the first flight will be no earlier than March 2019. As of January 10, 2019, the main structure of the test prototype has been completed.
The reasons for the fundamental design changes include the mirror-like high heat reflectivity of stainless steel and its excellent ability to withstand extreme heat, which means that less insulation is ultimately required compared to carbon fiber. On January 23, the wind scratched the nose of the test prototype, and SpaceX decided not to replace it.
On February 1, 2019, Musk showed the first full-size Raptor Raptor engine photo. He also pointed out that early test flights of the rocket’s super heavy booster may be equipped with fewer than 31 engines (later refined to about 20). The change can be made because the initial test flight does not require the full capacity of the design. This will have the additional advantage of reducing test costs.
SpaceX completed the construction of the Starhopper prototype in April 2019. It looks a bit like a flying water tank, made of stainless steel and equipped with a Raptor engine. It aims to test some elements of Starship’s design. The company conducted a two-second tethering test on April 3 and April 5. From May 6th to 7th, technicians installed an air-conditioned propulsion pod from Falcon 9 on Starhopper in preparation for an unfettered test flight. An unfettered jump test was conducted on July 25, 2019, when the Starhopper rose 18 m (59 ft) from the ground. On its last flight on August 27, it rose to 150 m (492 ft) and moved sideways to another landing site. Afterwards, Starhopper retired.
The rendering made by NASA’s Goddard Space Flight Center (GSFC) on April 11, 2019 shows that the cargo compartment of the Starship can carry two versions of the planned LUVOIR space telescope. This is One of the four succession plans of the James Webb Space Telescope. On the same day, it was announced that SpaceX is in another round of US$500 million in financing to fund SpaceX to simultaneously develop its Starlink satellite constellation and Starship/Super Heavy.
On May 14, NSF member Zpoxy discovered the second”starship” under construction in Cocoa, Florida. Soon thereafter, Elon Musk confirmed this, and he mentioned that two competing teams will be building prototype starships. They will share design details with each other, but do not have to follow another design, which may speed up the development of Starship and Super Heavy.
Each test starship will be equipped with three Raptor engines. Especially, it is built in the open air, which is different from almost all rocket construction. In the preliminary preparations for the launch of SpaceX on September 28, 2019, the construction of Starship Mark 1 (Texas) and Mark 2 (Florida) has made rapid progress. The nose cone and main cylinder of the Mark 2 prototype have been made, but not welded together. The nose cone of the Mark 1 prototype is mounted on the top of the main body.
The press conference on September 28, 2019 showed the 11th known version of the rocket. Elon Musk also announced that they hope to use a more advanced starship prototype to achieve orbital flight within six months. These prototypes will be equipped with a full six Raptor engines and single seam welding. Followed by the launch of a complete starship, the construction of its super heavy class will largely depend on the speed at which the Raptor engine is built.
After the conference, the long neck and wings of the Starship Mk 1 were dismantled and then reinstalled, while the lower part of the rocket was transported to the launch pad. More details about the launch pad were revealed, it will be able to support rocket launches with higher thrust than the LC-39A can support. Musk also mentioned that in future versions, the simplified Raptor engine with a fixed direction may generate 300 tons (2,942 kN) of thrust.
On November 20, 2019, the Starship Mark 1 (MK1) had a fuel storage tank rupture at its Boca Chica test site in southern Texas. During the test of the rocket’s fuel tank, the failure occurred while loading ultra-low temperature liquid nitrogen.
Part of the reason for the tank rupture was that the company’s test pressure was higher than normal. The prototype was originally planned for the first 20-kilometer test flight in the Starship Test. Although this failure slowed SpaceX’s test plan, the construction of Boca Chica’s Mark 3 prototype has proceeded smoothly.
On December 5, 2019, SpaceX announced that they are suspending most of the starship construction work at the Florida site. And the workers there will be transferred to the Boca Chica factory in Texas or SpaceX’s work location in Cape Canaveral.
On January 10, 2020, SpaceX experienced a liquid oxygen tank test failure. The test failed at 7.1 bar, which did not reach its goal of 8.5 bar. Subsequently, it successfully conducted a liquid nitrogen test on the roof fuel tank on January 24, 2020. On January 28, 2020, SpaceX tested the liquid oxygen tank again, and this time it succeeded. After passing the pressurized target, the storage tank was destroyed.
In January 2020, the Los Angeles Times learned that SpaceX was once again interested in building a Starship factory in the Port of Los Angeles. Followed by the news on February 6, 2020, a ship roof tank was tested to be pressurized to damage, but it passed the test pressure requirements. On February 26, 2020, the Los Angeles City Council approved SpaceX to use a 5.0 hectare (12.4 acre) site. A day later, SpaceX launched the third and first vertical Raptor engine test bed.
The Starship Mark 3 prototype was renamed SN1, and was subsequently destroyed in a pressure test on February 28, 2020. When pressurized with cryogenic liquid nitrogen, the liquid nitrogen leaked violently and it suffered catastrophic structural failure. The reason for the error was an improperly designed scaler, where the three engines installed at the bottom of the liquefied methane tank are located. In Boca Chica, a test fuel tank was built using a newly designed scaler, named SN2. It passed a key tank pressurization test on March 8, 2020.
On March 16, 2020, Elon Musk confirmed that the design of the starship has undergone further changes, resulting in the 12th design version. The company suffered another failure on April 3, 2020, when the SN3 prototype suffered a severe failure in the stress test, which led to its destruction. The data indicates that this is a test configuration issue. Due to the failure of SN3 and the struggle of the United States in the new crown pandemic, SpaceX’s aggressive testing schedule was forced to postpone.
The SN4 prototype is equipped with one of the Raptor engines that was supposed to be installed in the SN3. The first Raptor engine ignition of the SN4 prototype was subsequently carried out on May 5, 2020. SN4 didn’t survive long, until May 29, 2020, it was destroyed shortly after the fifth engine test. At that time a large amount of propellant overflowed due to a malfunction and the rocket was ignited. The problem is caused by a malfunction of the ground support equipment (GSE) quick disconnect system, not by a starship design issue as before. While repairing the damage, the Los Angeles Times reported on June 8 that SpaceX will once again abandon the Port of Los Angeles as the location of Starship’s factory. At the same time, the expansion of the Boca Chica base continues.
The prototype SN7 test tank was tested to burst on June 23, 2020. It is a new and more ductile test bench for stainless steel alloy 304L, which has better ductility (more ductility) at ultra-low temperatures, thereby reducing severe structural failures.
SpaceX conducted a liquid nitrogen pressure test on its next prototype SN5 on June 30, 2020. SN5 successfully performed its first 150 m (492 ft) jump flight on August 4, 2020. After that, SN6 conducted the same jump test on September 3, 2020. At the same time, SpaceX continues to make rapid progress in SN7.1 (a 304L stainless steel test tank), SN8 (to be equipped with 3 Raptor engines, front nose cone and air surface), SN9 and SN10 prototypes. It also began preparations for the construction of the first super heavy rocket booster in the new high steel building.
The Starship project is unique and one of the most ambitious projects in rocket history. Now, the design has gone through at least twelve versions and four different names!
Its first version was a single-core or tri-core rocket design launched in 2013, and it has now evolved into a single-core stainless steel starship design under construction. Even if the size of the design changes greatly, its tasks and functions are indeed increased.
< p>It was originally designed to colonize Mars, but is now conceived as a replacement for the full-featured launch vehicle of the Falcon 9 rocket family. In addition to its initial role as a Martian colonizer, it is expected to launch satellites into earth orbit, carry out point-to-point manned flights on the earth, and carry cargo and people to and from the moon.
Since the decision to abandon the all-carbon fiber design in 2018, the rocket has made rapid progress with the goal of space flight. Despite the setback of the Starship Mark 1, the rupture of SN1 and SN3 storage tanks, and the accident of SN4 ground support equipment, further rapid development can be expected. Of course, the financial pressure facing development will always exist.
The combination of stainless steel structure, A/B rotation prototyping and iterative testing can speed up the development progress. Although the starship is larger and has a short development period, it is still possible to defeat several rival rockets to enter orbit first. The starship is based on Wernher von Braun’s Mars plan to colonize Mars after World War II.
If this kind of aircraft does bring an era of rapidly reusable rockets, then a new era of spaceflight may dawn. Perhaps the most encouraging fact is that it all started with the dream of a little boy in South Africa.
Special thanks to the NSF design team for helping the author write this article. I would also like to thank the NSF community members Bocachicagal and Nomadd for their unremitting efforts, which greatly helped our understanding of the evolution of Starship design.
— Welcome to pay attention to the headline number:21st Century Onland