Antimatter Development Program – Casey Handmer's blog

Skip to content

Search

Search for:

Printable PDF of this post.

“Space is big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.” Douglas Adams, The Hitchhiker’s Guide to the Galaxy

Our vision for the future has humans traveling between planets much faster than our ancestors sailed across oceans, but no existing rocket technology can achieve that. We’re going to need something significantly more energetic, and antimatter is the key.

In August 2024, I wrote a primer examining the merits of antimatter propulsion from first principles. In this post, I will lay out in some detail a specific plan for an antimatter “Manhattan Project”. If we don’t do it, someone will.

Credit: Avatar: The Way of Water. Canonically, these spaceships use antimatter fusion drives.

Why?

Chemical propulsion is the standard for launch today, while some satellites use electric propulsion for station keeping.

Credit: Trevor Mahlmann for SpaceNews

Starship is terrific but it’s not capable of flying to a nearby star at 30% of the speed of light and then landing. For that we’re going to need something far more energetic, and we are fortunate to have it.

Antimatter is powerful because its embodied energy gets to use the equation.

E = mc 2 .

c2 is a very large number, approximately 1017 = 100000000000000000. When antimatter encounters ordinary matter, it annihilates completely converting a tiny amount of mass into a huge amount of pure energy. This is 100-1000x more energy than even the most energetic nuclear fission reactions.

With rocket propulsion, the distance you can go is determined by the change in velocity, Δv (“delta vee”), you can achieve with all the fuel you brought. The Tsiokolsky rocket equation boils down to Δv ~ 2 ve, the exhaust velocity, while thrust is given by the mass flow times the exhaust velocity, T = ṁ ve. Exhaust velocity is usually expressed as specific impulse (Isp = ve/g) and measured in seconds. It is the amount of time a given propellant can generate 1g of thrust. A more powerful propellant can provide the thrust for longer.

This graph shows the rough domains of existing and hypothetical propulsion systems. Chemical can generate terrific thrust, but is limited by low specific impulse. Electric propulsion can achieve much higher specific impulse, but is plagued by low thrust. This applies also to nuclear electric propulsion systems, which enjoy all of the hassles of nuclear reactors and still don’t achieve the desired high thrust, high Isp, high power operating mode.

Credit: Adapted from graph by Frans Ebersohn.

An antimatter rocket cycle can bridge this gap. Like chemical propulsion, there’s no upper limit to thrust. And given that the default antimatter reaction product is hard gamma rays, there’s no real upper limit to Isp either. If humans ever find a way to cross the gulf between stars, it will be with antimatter powered propulsion.

How

I could spend another 10,000 words singing the praises of antimatter propulsion, but if you’re not bought in at this point, why bother? Let’s focus on the how.

Usually, when talk begins of exotic propulsion methods, discussion immediately centers on particle accelerators and superconduction magnets. Hold it right there! We’re trying to launch this on a rocket. Let’s conceptualize around a Starship upper stage, so we’re talking 1000 T of propellant, 100 T of structure, and 10 T of engine. Launch is a dynamic environment, which means everything needs to be able to withstand shock and vibration. I like particle accelerators as much as the next guy, but let’s begin by deleting as much complexity from the critical path as possible.

Let’s discuss the various parts of the antimatter problem that need to be solved: Production, storage, and use.

Production

The model for antimatter is that it is produced on Earth using the power and skill of our entire industrial base. Like aluminum, but to a far greater extent, it exists as an extremely condensed form of stored energy that can then be readily transported into space. We cannot easily lift the entire grid of the US into space, but its 1.3 TW capacity, run for an entire year, condensed into antimatter, would weigh just 227 kg (less than 500 lbs), which is well within our launch capacities. 227 kg of antimatter is also easily enough to launch hundreds of enormous spacecraft to nearby stars, so we will begin with a somewhat more modest quantity.

As of late 2025, humanity is able to produce antiprotons and antihydrogen in the thousands of atoms per day and millions in total. This is incredibly impressive even by the standards of a decade ago, but it’s roughly analogous to our plutonium production capacity in late 1940. We have a ways to go here.

Antimatter production is something like 0.000001% efficient. It requires quite large particle...