SpaceX’s Starship rocket is mostly silver instead of the conventional white.
The silver color comes from the non-corrosive stainless steel SpaceX used to build the rocket.
The spaceship is also studded with black hex tiles to protect it upon re-entering the atmosphere.
Located at the southern tip of Texas near the tiny village of Boca Chica sits a not-so-small space rocket: SpaceX’s Starship mega-rocket.
Not only is Starship the largest and most powerful rocket in the world, it also looks unlike anything SpaceX has ever built. In fact, it looks like no other rocket in the world.
As shown below, the mega rocket consists of two stages. The first stage rocket, called Super Heavy (far left), is all silver, while the second stage spacecraft, dubbed Starship, is half silver and half black.
This black-and-silver color scheme is a big change from SpaceX’s white Falcon 9 rockets or NASA’s orange and white Space Launch System.
So why the flashy specs, SpaceX?
SpaceX’s silver rocket made of steel
Starship’s mostly silvery look comes from a type of non-corrosive alloy called 300-series stainless steel. It’s the first time since the 1950s that anyone has made a rocket ship out of this material.
The reason most rocket companies shy away from steel is because it’s heavy, and the heavier your actual rocket, the less payload you can carry into space on the same fuel tanks.
Instead, the outer frame of most rockets is constructed of durable yet lightweight metals such as aluminum and titanium. Titanium is great for keeping a rocket light, but can cost 15 to 20 times more than steel.
That’s why, in 2019, SpaceX replaced the titanium grid fins of its Falcon 9 rockets with welded steel fins. However, cost isn’t the only reason SpaceX now prefers steel over titanium in its rockets.
According to materials science experts, steel performs better in extreme temperatures than titanium. This means both in extremely hot conditions, such as during atmospheric launch and re-entry, but also in extremely cold conditions, such as in deep space.
And that’s important since Starship’s mission is to eventually get humans to the Moon and Mars by exposing the spacecraft to temperatures as low as -455 degrees Fahrenheit (-270 degrees Celsius), which could make most of the rocket material weak, brittle and prone to cracking. or it breaks.
Stainless steel, on the other hand, actually increases in strength at these cryogenic temperatures, making it ideal for deep space travel.
Additionally, Mike Gruntman, a professor of astronautics at the University of Southern California, told Insider, “It is essential to use stainless steel to prevent corrosion. The skin of the vehicle is subjected to dynamic loads during electrical ascent through the atmosphere, so the structural strength of the materials is also important. In addition, the price also plays an important role.”
SpaceX’s black-encrusted Starship spacecraft
The spacecraft has a black underbelly, similar to NASA’s Space Shuttles, and for similar reasons too.
Black is a series of silica heat-resistant hexagonal tiles designed to protect the spacecraft from scorching temperatures as it reenters Earth’s atmosphere.
You can see a close-up of these tiles in action from multiple flamethrowers in this video SpaceX founder and CEO Elon Musk posted to Twitter in March 2019:
One difference between the Starship tiles and the Space Shuttle tiles is their hexagonal shape. Shuttle tiles were square.
When a Twitter user asked about the unusual shape of the tile, Musk he answered that the hexagonal-shaped tiles leave “no straight path for the hot gas to accelerate through the gaps”.
In other words, it is an additional measure to prevent the spacecraft from overheating and exploding upon re-entry.
Why are most rockets white?
The reason is simple: the cost.
White absorbs the least amount of heat of all the colors in the visible spectrum, which helps keep the rocket as cool as possible. And that’s important since rocket fuel typically needs to be kept at temperatures between -297 degrees Fahrenheit and -432 degrees Fahrenheit.
So if your rocket is baking in the bright sun on the launch pad for hours or days, it will be cheaper to keep it fresh if it’s white. That could also be true for silver, according to research that found silver cars had cooler cabins than black cars.
SpaceX wouldn’t comment on whether or not that’s the reasoning for their silver Starship rocket. But it makes sense that if they don’t have to paint the rocket white and keep its natural steel color, they not only save money on paint, but also end up with a lighter rocket, since paint is heavy.
“Absorbent and emissive properties, including color, will always play a role for passive thermal control,” Gruntman said. Although when it comes to heat management, white is even better than silver.
Despite a neat explanation from SpaceX for Starship’s silver-and-black face, it’s likely keeping the rocket light and safe, and it’s not just for show.
Recently, during a conference in Washington, DC, SpaceX president and COO Gwynne Shotwell said, “The real goal is not to blow up the launch pad. That’s success.”
Read the original article on Business Insider