SpaceX’s Journey to Mars: How Starship Will Use a Hohmann Orbital Transfer from Earth to Mars (And the Physics Behind It)

For centuries, Mars has captivated the human imagination — a mysterious red dot in the sky that beckons explorers, scientists, and dreamers alike. From ancient astronomers tracking its erratic orbit to modern engineers designing spacecraft to land on its dusty surface, Mars has always felt just out of reach. But that’s changing.”

SpaceX is pushing ahead with its most ambitious goal yet: sending humans to Mars. Elon Musk’s plan hinges on Starship—a fully reusable rocket system—and a classic orbital maneuver that’s been in the astronautics playbook since the 1920s: the Hohmann transfer orbit.

But how do you move a massive spacecraft across millions of kilometers with limited fuel and tight timing? That’s where orbital mechanics comes in—and understanding it helps explain why SpaceX is betting on this specific route to the Red Planet.

Why Planets Orbit in (Almost) the Same Plane—and Why It Matters

One reason the Hohmann transfer works is that planetary orbits aren’t scattered in 3D space. They’re mostly flat, sitting within what’s called the ecliptic plane. This isn’t random—it’s a remnant of how our solar system formed.

Roughly 4.5 billion years ago, a rotating cloud of gas and dust collapsed under its own gravity. As it spun faster, it flattened into a disk, similar to how pizza dough stretches when tossed. Planets formed within that disk and inherited its flat structure.

Most planets orbit within 7 degrees of this plane. Pluto is the oddball, tilted about 17°, likely due to gravitational nudges over time. But the relatively flat layout is a big win for spacecraft navigation—it keeps transfers between planets like Earth and Mars simpler and more fuel-efficient.

Observations of young star systems, like HL Tauri, show similar flat disk formations, confirming this isn’t a one-off—it’s how planetary systems typically evolve.

How the Hohmann Transfer Orbit Works

The Hohmann transfer orbit, first described by German engineer Walter Hohmann in 1925, is a fuel-saving way to get a spacecraft from one orbit to another. In the Earth-to-Mars case, you’re transferring from Earth’s orbit around the Sun to Mars’ orbit.

This method uses two engine burns: the first one pushes the spacecraft out of Earth’s orbit into an elongated elliptical orbit that intersects Mars’ path. The second burn happens near Mars, slowing the spacecraft down so it can match the planet’s speed and orbit.

Why use this method? Because it’s efficient. It takes longer—about nine months—but it uses less fuel, which is critical when you’re sending massive payloads across space.

In a video shared on X by Teslaconomics, Elon Musk explains just how big this journey is. “It’s roughly 1,000 times farther than going to the Moon,” he said. That kind of distance demands smart planning—and a whole lot of patience.

This is fuckin insane… this is how SpaceX will do orbital transfer from Earth to Mars. pic.twitter.com/TVKuZSPghF

— Teslaconomics (@Teslaconomics) May 29, 2025

Starship’s Role in All This

Starship isn’t just another rocket—it’s SpaceX’s ticket to long-distance space travel. It’s designed to be fully reusable and capable of carrying both cargo and crew to orbit, the Moon, and eventually Mars.

The system includes the Starship spacecraft itself and the Super Heavy booster, which together make up the tallest and most powerful rocket ever built. SpaceX has already demonstrated key milestones, like catching the Super Heavy booster mid-air—an early step toward quick turnaround and reusability.

The Hohmann transfer orbit fits neatly into Starship’s game plan. The first burn pushes it into the transfer trajectory. The second one, closer to Mars, helps it match the red planet’s orbit. By using the Sun’s gravity to coast most of the way, Starship can carry heavier payloads with less fuel.

It’s a method that space agencies have used for decades. Now SpaceX is scaling it up.

Timing Is Everything

There’s a catch: you can’t just launch to Mars anytime you want. Earth and Mars only line up for a Hohmann transfer every 26 months. These launch windows are brief, and missing one means waiting over two years for the next.

Musk points this out in the same video: “Every 26 months, their orbits align and a transit window opens.” That cycle drives SpaceX’s planning, as well as mission schedules for past NASA launches like Perseverance and Insight.

The Bigger Picture

SpaceX’s endgame isn’t just to land on Mars—it’s to build a permanent, self-sustaining colony. That vision has been baked into the company’s DNA since its early days. But getting there isn’t about a single launch—it’s about making round trips feasible, affordable, and repeatable.

The Hohmann transfer is a practical step in that direction. It’s predictable. It saves fuel. And it aligns well with how Starship is being engineered: big, reusable, and ready for deep space.

Reusable rockets like Falcon 9 have already shown that the cost of space access can be brought down dramatically. Starship aims to take that further by making interplanetary travel something we can do again and again, not just once for the history books.

What’s Still Ahead

Even with a solid transfer plan, Mars won’t be an easy ride. A nine-month trip in zero gravity means dealing with muscle loss, bone density issues, and exposure to cosmic radiation. There’s also no room for error—precision is key for orbital maneuvers and Mars landings.

But SpaceX is used to building in public, testing, failing, and iterating fast. That approach might give it the edge in tackling these challenges one by one.

If Starship pulls off a successful Hohmann transfer mission, it won’t just prove a concept—it’ll mark the beginning of a new phase in space travel. One where launches to Mars are routine, not rare.