Starship: SpaceX’s Eighteen-Wheeler to Space
By: Doug Holland
Tags: Spacex, Starship, Space, Technology, Elon Musk

Starship: SpaceX’s Eighteen-Wheeler to Space

SpaceX Starship at Starbase, Texas. Source: https://commons.wikimedia.org/wiki/File:Starship_SN9_Launch_Pad.jpg. Author: Jared Krahn, licensed under Creative Commons Attribution-Share Alike 4.0 International license.

The eyes of the world are on Boca Chica, and my eyes are included. In fact, I can’t take my eyes off of NASASpaceflight’s YouTube videos. I’m watching videos of a construction site. A construction site! That’s because it’s the most incredible construction site in the world. It’s where SpaceX is building spaceships! And my eyes are glued because SpaceX’s spaceship, Elon Musk’s dream, Starship, is going to change humanity forever.

I’m not exaggerating for clicks. I mean that Starship will change humanity forever. This is because Starship will be the first rocket that will enable humanity to take to space at a large scale. Elon Musk and SpaceX want to make humanity a multiplanetary species, and they plan to build a million-person city on Mars. That means that soon, you may be able to buy yourself a ticket and fly. It means that spaceflight is going to take off in ways that have yet to be imagined.

On the launch pad, Starship has a retro vibe. She’s shiny, as she’s made of stainless steel. With her fins, she looks like she came out of a Buck Rogers comic book. But Starship isn’t just a figment from the mind of a 1950’s science fiction author. Starship is real, and on the verge of making her first trip to space. SpaceX designed Starship to be reusable like an airliner. She’s planned to be capable of refueling in orbit and on Mars from local resources, giving her incredibly long legs. And she’s designed to be economical enough that ordinary people could afford to go to space.

Size

Starship is a monster and will be the most powerful launch vehicle in the world. When stacked, Starship and Superheavy are taller than the Saturn V, and her engines give her twice the thrust.

She comes in two parts: Starship and Superheavy (both the second stage and the complete rocket stack are named Starship.) Superheavy is the first stage, equipped with 33 Raptor engines to lift her off the pad and lob the second stage, Starship, out of the atmosphere. Then Starship lights her six Raptors and completes the trip to Earth orbit. She’s estimated to be capable of putting 150 tons of payload into orbit (source: Elon Musk, Twitter), while still being capable of reentry, landing, and reuse afterwards.

One of the reasons why NASA selected SpaceX to build HLS to bring astronauts to the moon is because its sheer size gives it capabilities that until now, NASA could only dream about. They asked for a subcompact to bring a pair of astronauts to the Moon, and SpaceX offered them a semi. HLS dwarfs the National Team’s and Dynetic’s offerings and enables Artemis astronauts to bring tons of cargo with them, such as habitats, rovers, and other gear.

Starship is big enough to bring dozens of settlers to Mars. She could perform Earth-to-Earth suborbital flights carrying hundreds of passengers. She could be left in orbit to be converted into a space station that’s bigger than the International Space Station. Or she could become an office-building-sized Moon or Mars base.

Engines

Raptor speaks! Source: Elon Musk, https://commons.wikimedia.org/wiki/File:Raptor-test-9-25-2016.jpg. Image is in the public domain.

To power such a beast of a rocket, SpaceX needs incredibly powerful engines, and they have built them. Raptor is the product of over a decade of development and has become the most technologically advanced rocket engine ever built.

The first thing that aerospace engineers will note about the Raptor is the words “full-flow staged combustion,” and those words make them drool. This design puts the fuel and oxygen through a pair of preburners that burn some of the propellants to spin the turbopumps that bring fuel into the engine. Compared to earlier gas-generator designs (that waste quite a bit of propellant), the full-flow staged-combustion design is far more efficient, can generate tremendous power, while being dependable enough for reuse. Admittedly, this design is complex, but SpaceX seems to have attacked this challenge head-on and won. For the curious, Tim Dodd explains Raptor and full-flow staged combustion in detail.

Raptor uses a fuel that’s new to spaceflight, liquid methane. In other words, it’s refined natural gas. This fuel solves a lot of problems for SpaceX. First, it’s relatively cheap, especially when compared with the Space Shuttle’s fuel, liquid hydrogen. Methane is much easier to work with than hydrogen, which needs to be kept extremely cold, requires gigantic tanks because of its low density, tends to leak, and is highly explosive. While methane also has its hazards, it’s not nearly as difficult to handle as hydrogen, and can be handled with equipment that’s similar to that used with its oxidizer, liquid oxygen. It doesn’t have the propensity to leak like hydrogen or cause problems like hydrogen embrittlement, and it’s denser, meaning a lighter, smaller fuel tank can be used.

Methane also is nice because it burns cleanly, which makes full-flow staged combustion possible, unlike RP-1 (refined kerosene.) It also has a higher specific impulse (ISP) than RP-1, meaning it burns with more energy for its mass, giving Starship “great gas mileage.”

In-orbit and Martian Refueling

With the fuel it brings off the launch pad, Starship is capable of getting about 150 tons to low Earth orbit (LEO). Normally, this would make Starship almost as limited as the Shuttle, which was limited to LEO. However, Starship is capable of being refueled in orbit by another Starship, purpose-built as a tanker.

This is one of the key technologies that make Starship a far more capable spacecraft than its predecessors. Eight tanker refueling flights for an orbiting Starship can fully fill its tanks. Imagine a fully-fueled Starship, already in orbit, pressing the reset button on Tsiolkovsky’s rocket equation. This is what gives Starship the ability to carry large payloads to the Moon and Mars. It is what turns this spacecraft into a true deep space vessel. A Starship can take settlers and supplies to Mars, mine asteroids, or send space probes out of the Solar System.

Even better, Starship’s propellants, liquid methane and liquid oxygen, can be made on Mars from water and carbon dioxide found there using the Sabatier process. This solves one of the show-stopping problems with crewed Mars missions; how do the astronauts get back to Earth? With Starship, an expedition can go to Mars with a dozen people, plenty of supplies, and once they arrive, they can make the fuel to come home.

Reusability That Works

The Space Shuttle was the first, but it didn’t exactly fulfill the promise of reusability. The Shuttle was insanely expensive, needed enormous amounts of repair and refurbishment between flights, was only barely reusable, and was downright dangerous. But the Shuttle served for three decades, built the International Space Station, and launched so many other things like the Hubble Space Telescope. The Shuttle will always have a place in my heart, but when it comes to reusability, we can do so much better.

Fortunately, SpaceX is already the first company to make rocket reusability economical. They’re recovering and reusing Falcon 9 first stages and Dragon capsules, saving them millions of dollars. They’re doing it while maintaining a grueling launch cadence to serve commercial and government customers, and to launch thousands of Starlink satellites.

Starship is SpaceX’s second reusable launch vehicle, after Falcon 9. The first stage, Superheavy, will fly similarly to Falcon 9’s first stage. After separating from Starship, it turns around, boosts back, and uses its Raptors and grid fins to land at the launch site. But to save weight, rather than using landing legs, SpaceX is going to catch the booster using “Chopstick” arms on the launch and integration tower.

The second stage, Starship, continues to orbit using a combination of sea-level and vacuum Raptor engines. At the end of her flight, Starship reenters the atmosphere belly first, using its hexagonal heat-shield tiles to survive the plasma and heat of reentry. Her tiles are made of ceramic and are similar to the Shuttle’s. Also, Starship’s skin is made of stainless steel, which is very resilient to high temperatures.

In the stratosphere, Starship has already demonstrated the “Bellyflop”, where she uses her fins to control her descent, much like a skydiver. At the very end, Starship fires up her Raptors, swings to a vertical orientation, and comes to a gentle landing. Musk said he also plans to catch Starships with the “chopsticks” on the tower in the same way as they’d catch Superheavy.

SpaceX intends to make Starship work like an airliner. Elon Musk wants Starship to fly multiple times every day, with less than an hour of turnaround time between flights. In other words, Starship is to be a workhorse like a Boeing 737. This is because Elon Musk understands what needs to be done to bring costs down and make spaceflight economical.

Manufacturability and Economics

Before SpaceX came along, the space launch industry was like the early automotive industry before Henry Ford and the assembly line. Cars were custom-made in small quantities, making them expensive. As a result, they were workhorses for a few large businesses that could afford them, and they were toys for the wealthy.

Then Ford came along with mass-production and the Model T. That is what Elon Musk is doing to the aerospace industry right now. Rockets until now have been mostly built on demand, bespoke for the customer, in low quantities, for the few entities capable of affording them. But Elon Musk cut his teeth on Ford’s industry, automobiles, at Tesla. He knows about mass-production. He knows about optimizing production processes, and he knows about value engineering. He knows how to get a product from concept to design to manufacture as efficiently as possible. In fact, he obsesses about that.

That’s why SpaceX abruptly switched from building what would become Starship with carbon fiber to stainless steel. Normally, carbon fiber is great for building rocket parts that are both light and strong. However, carbon fiber is both expensive and laborious to work with. Musk wants SpaceX to design and build with a rapid-iteration process, and carbon fiber was too slow. For the price of some mass, SpaceX built Starship with a material that was cheap, fast to work with, and resilient to the extreme temperatures of reentry and cryogenic propellants. Once the rapid iterations started, progress on Starship went amazingly fast.

Elon Musk isn’t just building a rocket. He’s building a rocket factory at Boca Chica. In an interview with Tim Dodd, the Everyday Astronaut (Part 1, Part 2, and Part 3,) Musk stated that 90% of the work was creating the production processes and systems that build the rocket, rather than designing and building the rocket itself. Much of Musk’s work is similar to what he was doing at Tesla: planning the production process, identifying bottlenecks, creating optimizations, and getting processes to run efficiently and smoothly.

Starship isn’t designed to be a one-off, occasionally manufactured artifact from the traditional cathedrals of old-space. Starship and Raptor are going to be built like cars are built: mass-produced, efficiently, with automation, optimized processes, and in large quantities. This enables individual Starships and individual Raptors to be built and run at a small fraction of the cost of previous rockets and engines. To build his city on Mars, Musk said he wants over a thousand Starships, and he’s building the facilities to make them.

SpaceX also plans to launch Starships from sites across the globe. They’re already constructing the launch and landing facilities at Starbase, Texas. They’re also planning to launch and recover Starships at Cape Canaveral, Florida. SpaceX has also acquired two former oil platforms, now dubbed Deimos and Phobos to launch Starships at sea. One of the plans is to position offshore launch platforms near coastal cities for passenger service. In short, SpaceX has plans for Starship on a scale far larger than has ever been seen in the industry before.

What Does This Mean?

When I was younger, I read a book by Jerry Pournelle and other authors (the book was Cities in Space, and I’m going from memory, so forgive me if I miss some details.) It had a great point I read as I was getting my first college degree. This was in the 90’s when the spaceflight world was in the doldrums. Cities In Space pointed out that people lost interest because all they were able to do was watch people on TV go to space. It’s not that people didn’t like space, but they wanted to personally go to space, rather than watch TV people do it. I’m the same way. I want to personally go to space.

Starship’s the key to making that happen. Starship could reduce costs to the point where ordinary people can buy a ticket and go to Mars. This could finally bring us to the day where we all can go to space.

That’s why I say this spacecraft will change humanity forever. Starship can bring ordinary people to space. It can bring heavy industry to space. It can bring unimaginable wealth back to Earth (check out the asteroid 16 Psyche and the dollar value of the precious metals there.) Starship will enable humanity to finally take real steps off this pale blue dot, so now’s the time to really dream. Jeff Bezos talked about Gerard O’Neill’s space colonies. Elon Musk wants a million-person city on Mars. But I’m dreaming a little further ahead.

Close your eyes, and imagine humanity, a few centuries from now, with a population of ten trillion (yes, trillion with a ‘T’), spread through the entire Solar System: Earth, Mars, countless habitats built all over the system, settlements on the outer moons and the Kuiper Belt, and more. Think of a humanity that’s grown a thousand-fold from today, thriving, with no limits in sight.

I don’t know about you, but I want this future. Starship can help make it happen. Starship will become humanity’s eighteen-wheeler to space. With it, humanity takes the Solar System.