A tale of two rockets

It was the best of burn times; it was the worst of burn times…

For those of you familiar with Charles Dickens’ frothy novel of a similar title, set in Paris amid the French Revolution, telling the story of loss, reunion, and social justice, I promise this essay will be just as riveting and philosophically important… particularly if you are a true Space Nerd.

Now Dickens never wrote about rockets, but if he had, he would have reminded us that different vehicles are often built for different purposes. Just as his characters Lawyer Sydney Carton and French aristocrat Charles Darnay serve different purposes in his story, the same is true in space. Not all rockets are the same, and in today’s contested domain, choosing the right one for the right job is no longer only about efficiency — it’s also about national security.

As the Commander of U.S Space Command said recently, “Our government’s national security mission in space is to first deliver critical space services that our armed services rely on every day, and second to protect and defend our satellites against growing threats.”

Meeting those threats requires understanding of the tools and clear thinking. That starts with recognizing a simple truth: rockets are not interchangeable commodities. A Kenworth semi-truck and a Mini Cooper are both great vehicles, but you wouldn’t use one in place of the other. Rockets are no different. Like all complex machines, they are engineered for specific missions, and the mission dictates the design.

There are two basic categories: rockets optimized for Low Earth Orbit (LEO), and those built to go all the way to higher orbits like Geostationary (GEO). The design is driven by where the rocket’s job is done. While satellites dropped off in LEO sometimes lift themselves higher, the rocket’s architecture is driven by its drop-off point. Just like the Uber driver who doesn’t really care where you go after they drop you at the airport.

LEO is really close. It starts just a couple of hundred miles up and usually ends around 1,200 miles. That’s only the distance between LA and San Francisco and San Diego and Seattle, respectively. It only takes about 15 minutes for a rocket to get there, and even a long LEO mission rarely lasts more than 45 minutes.

GEO is very different. It is 22,000 miles high — a round-the-world trip — and a rocket must fly for seven to nine hours to get there and do its mission. Once in GEO, it performs a final burn to circularize the orbit before releasing its payload. Satellites placed there, near the equator, orbit the Earth every 24 hours, appearing to hover over a fixed spot. These are “high-energy” orbits, and they demand “high-energy” designed rockets.

This brings us to the “Rule of 10s.” A rocket optimized for GEO must endure ten times the mission duration, survive ten times the radiation exposure, and deliver ten times the orbital precision of a rocket designed for LEO.

That, in turn, drives the “Rule of 2s”: The High energy rocket must have double the burn time, double the altitude, and two to three times the booster velocity of a LEO rocket. These aren’t design preferences — they are mission imperatives.

The payoff for meeting these demands is significant. A rocket designed for high-energy orbits can deliver roughly twice the payload mass to GEO, all things being equal. And it can often do so at 20 to 30 percent lower cost.

But specialization always comes with tradeoffs. A high-energy rocket can’t practically return its first stage for reuse — at those altitudes and velocities, the propellant margin just isn’t there. Conversely, a LEO-optimized rocket will usually be 20 to 30 percent less expensive for missions in LEO. Using a GEO rocket for a LEO payload wastes capability and can be more expensive.

So, clearly different rockets do different things. You wouldn’t take a limousine off-roading in the Rockies, and you wouldn’t want a stripped-down rock climber for a cross-country road trip. Space is really big. Its regions are farther apart than the most remote places on Earth, and they demand different modes of transportation.

Why does this matter now?

Because space is now a contested environment — our adversaries are building anti-satellite weapons, cyber tools, and blurring the line between commercial and military space. In this contested domain, America Needs to have several tools, and to apply the right tool for each job. National Security Space Launch is a national imperative. Getting that balance right ensures resilience, preserves competition, and strengthens deterrence. Space is the ultimate high ground, and matching the right rocket to the right mission is one way that America keeps its edge.

Tory Bruno is president and CEO of United Launch Alliance.