SpaceX chief Elon Musk showed news from the Starship spacecraft project this weekend. The concept was introduced for the first time a year ago. But since then it has “matured” a lot – and changed its appearance completely.
The presentation with which the SpaceX chief spoke on the night of September 28 – 29 of our time showed how the project underwent a fundamental transformation.
Instead of carbon composites, it uses stainless steel, has a different number and layout of Raptor engines and also has differently designed aerodynamic control surfaces. During the presentation, Musk explained the benefits of steel, showing new images of the final form of the Starship and the Super Heavy carrier, which has new landing legs. And he also outlined an aggressive plan to produce more Starship specimens and test flights.
Back to the crime scene
The lecture was held in Boca Chica, Texas, exactly 11 years after SpaceX’s first successful orbital launch on September 29, 2008, with Falcon 1. Starship.
During the presentation, Musk reiterated that the most important feature of the new missile is its full reusability. The price for a single start should be very low because with a high number of missions, production and operating costs are spread out and the most expensive item is fuel.
SpaceX has been striving for reusability right from the start. So the presentation of the first Falcon 1 stage was parachuted. Laughing, Musk remembered that he had blamed the parachute maker for landing failure. Only then came to the conclusion that rescue missiles using parachutes is an inappropriate solution.
The dimensions of the Starship have changed slightly since last year’s presentation when the rocket was still called BFR. The ship is still 9 meters in diameter, but is 50 meters tall, five meters less than before. The Super Heavy to launch Starship into space is 68 meters higher than last year’s BFR. With a total height of 118 meters, Starship surpasses the legendary Saturn V, making it the largest rocket in history. In low Earth orbit, Starship can carry up to 150 tons of cargo at full reusability.
The first prototype ship called the Mk1 (Mark 1) has a dry weight of 200 tons, but other specimens will be lighter. The fourth or fifth piece should only have about 120 tons. Later, the weight could drop to 110 tons or less. Weight reduction is possible thanks to “exponential improvements” in production and construction.
For example, the hull of the ship currently consists of steel rings, which are welded from smaller parts. In the future, however, these rings will be thinner and lighter and will be made of one piece of steel with only one weld. Parts corresponding to this description have been seen for some time at the Florida Cocoa site, where the second prototype Starship is currently being produced. It was believed that these new rings were designed for the first Super Heavy carrier, but are likely to be used for the next prototype.
Designed Starship with basic parameters (length 50 meters, diameter …
Design of Starship with basic parameters (length 50 meters, diameter 9 meters, empty weight 120 tons (repair is in the original presentation), fuel weight 1 200 tons, cargo 150 tons, typical cargo return 50 tons).
Both Starship and Super Heavy are made of 301 types of stainless steel, which, according to Elon Musk, has a number of advantages. For example, it is much cheaper than originally planned carbon composites. A tonne of composites costs $ 130,000, while a ton of stainless steel costs $ 2,500.
In a new interview with CNN,
Musk said it would greatly reduce the cost of developing a Starship rocket to about $ 2-3 billion. Last year, when considering the use of carbon composites, the cost of development was estimated at up to 10 billion. Switching to stainless steel is, according to Musk, the best development decision he has ever made, and if he could return the time, he would have chosen the steel from the beginning.
Compare the size of a man and several SpaceX carriers (plus a fictional ship …
A comparison of the size of a human and several SpaceX carriers (plus the fictional Millennium Falcon that we skip). Starhopper is a trial and development prototype for the Starship program. Starship Mk1 is the first pre-series, basically a verification piece. On the right is the expected form of Starship in the starting configuration. The heat resistance is also a big advantage: its melting point is 1500 ° C. Falcon’s originally planned carbon composites and aluminum-lithium aluminum alloy are lighter but have a melting point of about 300-400 ° C. As a result, Starship does not need thermal protection at all on the “leeward” side (the side that is exposed to less thermal stress when returning). Even the more stressed “windward” side, which gets hot when returning to the atmosphere, suffices with a relatively thin heat shield. Precisely because the steel below it can withstand high temperatures.
Starship returning to the atmosphere. The heat shield is to be …
Starship returning to the atmosphere. The heat shield should be made of reusable ceramic tiles. However, it should be relatively thin because the stainless steel hull can withstand high thermal stress.
With tiles and without “breathing”
Concerning the heat shield, Musk explained before the presentation that the originally planned transpiration cooling would not be used in the end. SpaceX had developed cheap reusable tiles instead. Also, he said during the presentation that these are lightweight ceramic tiles that are resistant to cracks. As a result, the combination of stainless steel and a relatively thin-tile heat shield represents a reusable architecture with the lowest possible weight. Although steel itself is heavier than other alternatives.
When returning from orbit, the Starship will enter the atmosphere at a 60 ° angle, with four self-tilting aerodynamic surfaces to steer. Two smaller ones are located at the tip and two large ones at the rear. The surfaces create a little buoyancy, which is important in the high atmosphere, where the ship needs to stay as long as possible and to aerodynamically brake.
Before landing, the ship is then turned vertically using Raptor engines and nitrogen correction nozzles. According to Musk, this is not an ideal solution; the Raptor engines are too powerful, so the ship will turn too much, which they must equalize again.
Therefore, the ship gets more powerful methane maneuvering nozzles. These will have a specific pulse of 300-350 seconds and fuel will be injected into them only by pressure from the tanks. Current compressed nitrogen nozzles have a specific pulse of only about 60 seconds. The more powerful methane jets will allow the boat to turn more smoothly before landing, without having to rely on the engines.
So far we’ve only been talking about Starship, but as Musk confirmed during the presentation, the ship will need a giant Super Heavy carrier to travel to Earth’s orbit. It has also undergone several changes since the last presentation. The most obvious difference is the six landing legs.
The number and placement of Raptor engines on the Super Heavy is also different. According to new data, the engines should be up to 37, but Musk admits that the figure is not final. However, he said the Super Heavy will probably have at least 24 Raptor engines.
The deployment of 37 engines also confirms earlier information from Musk. According to them, the engines protrude slightly at the edge, they will not lean and they will be firmly connected by jets. And when the rocket has all 37 engines, six of them will be placed under the aerodynamic landing gear covers.
Elon Musk also spoke about the sequence of ignition that Super Heavy will perform when returning to Earth after separation from the Starship. The all seven central engines, which should be able to tilt by 15 degrees and used for steering, will be used for reverse ignition. In addition, the carrier will have grate rudders, like Falcon rockets. However, they will have a different shape for Super Heavy.
Musk said he hoped they could design the carrier so durable that they could survive their return to the atmosphere. Maybe even without performing the retardation ignition that Falcon rockets performed when entering the atmosphere. This would mean that the Super Heavy only needs the last landing spark and will require less fuel to land.
… the melting point is 1500 °…
The heat resistance is also a big advantage: its melting point is 1500 ° C. The originally planned carbon composites and the aluminum-lithium aluminum alloy used by Falcone are lighter. But have a melting point of about 300-400 ° C. As a result, Starship does not need thermal protection at all on the “leeward” side. Even the more stressed “windward” side, which gets hot when returning to the atmosphere, suffices with a relatively thin heat shield. Precisely because the steel below it can withstand high temperatures.