Super Heavy Lift

Vol. 1, No. 4 — On November 18, the most powerful rocket ever constructed was launched from a sleepy peninsula on the US/Mexico border in southern Texas. By one calculation, it produced over 40 million horsepower during the first second of full burn, enough to raise the 11,000,000 lb vehicle about 25 feet off the ground.

After clearing the launch tower, it accelerated to nearly 15,000 mph and reached an altitude of 485,000 feet in just over eight minutes. A few seconds later, its control systems decided to self-destruct the vehicle after guidance failures.

This is only the second flight for SpaceX’s full Starship design and it bested the first flight’s performance in every aspect. But, predictably, headlines about the event were decidedly negative: Musk’s rocket blows up again.

Let’s take a look at SpaceX’s progress with a bit of context. We should be jazzed about how quickly space travel and transport are becoming a reality.

Ten years ago, all rockets were single-use. “Rockets are impossible to land” was the generally accepted opinion. Makes sense too: how do you even go about landing a wingless silo tumbling back from the edge of space? Turns out, it was unthinkable before computers caught up to the task. The calculations and sensors involved have so many different variables to consider, that it was impossible to design a solution in advance. It had to be honed by an artificial intelligence.

In 2015, after many attempts and several near successes, SpaceX successfully landed their Falcon 9 booster. They managed to stall the 135 ft long rocket and flip it around 330,000 ft above the Earth, then power it back to the launch site. It comes in pretty hot, about 5,000 mph. So it fires again to scrub down to subsonic speeds. And then again, at the very last second to land the 50,000 lb vehicle undamaged and upright. The ultimate egg drop test. Oh, and this is done with such accuracy that the rocket legs don’t deviate more than 30 ft from their intended target. That’s quite the trick. A trick they’ve now pulled off nearly 250 times. So often, it’s old hat.

Now the Falcon 9 is not a “super heavy lift” launch vehicle. It can only put 41,000 lbs into orbit. A super heavy distinction means at least 110,000 lbs. The Saturn V which took us to the moon could heave 311,000 lbs into orbit. This was the most powerful rocket ever flown and held that title for over 50 years. Until Starship. Starship is rated to carry over 440,000 lbs into orbit on crewed missions and over 660,000 lbs when operating autonomously.

Did SpaceX just strap a bunch of Falcon 9s together to achieve this? No, but they did try that too. It’s called the Falcon Heavy, uses three boosters, and still only reaches 141,000 lbs to orbit. So how did they now nearly 5x that result? SpaceX started from scratch on Starship. They threw away their workhorse and designed a new system from the ground up.

Starship is 400 ft tall and 30 ft wide, nearly three times as large across both dimensions compared to the Falcon 9. Its body is made of cheaper stainless steel instead of a complex aluminum alloy. And perhaps most importantly, it uses a brand new engine, the Raptor, moving away from the ultra-reliable Merlin engine used in Falcon 9.

The Raptor is an engineering marvel. It produces twice as much thrust as the Merlin. Its chamber pressure is a record-setting 5,100 psi, blowing away Merlin’s 1,400 psi. Now maybe those numbers don’t mean much to everyone but here is one that should: how many engines does each vehicle use? The Falcon 9 uses, unsurprisingly, nine Merlins. Starship has 33 Raptors. Thirty-three engines, each of which weighs 3,500 lbs. A total beast.

What is this beast for, though? Well, it has one metric that hardly any other super-heavy launch vehicle has: payload capacity to Mars orbit. Starship wasn’t designed to just slingshot satellites into orbit. It was designed to deliver heavy payloads to Mars and the Moon. It was designed to allow us to build infrastructure on other heavenly bodies and do so with full reuse like the Falcon 9 so these missions are affordable.

So important was this objective for the design that the new engine burns a completely different fuel as well. It uses liquid methane and liquid oxygen also known as methalox instead of the more traditional RP-1 fuel used on the Saturn V and Falcon. Why? Methane and oxygen are much easier to produce on Mars than highly refined kerosene, the basis of RP-1. Some say that travel to Mars will be a one-way trip, either due to danger or expense. Could be. But it definitely will be if we can’t make any fuel once we’re there. Same goes for the choice to use stainless steel. Much easier to produce.

Seeing all 33 engines light up on Starship and rocket away from Earth last week was a huge moment for me personally. I herded my four-year-old, Nikola into the living room to watch it. I’d imagine, by the time he’s fortysomething like me, all of it will seem quite quaint. We’ll nearly certainly have a Moon base and a Mars base. But will we already have a hotel up there somewhere? I’m already saving my pennies to take a trip. Forget the retirement Winnebago, let’s check out the neighborhood!