On a private mailing list populated by my computer science friends,
We're going to define the "future" as the first time a real space pirate hijacks a spaceship in space. The question is, how far away are we from the future?
A rousing and deep discussion ensued. Guesses ranged from 50 to 500 years, with an average around 200.
I think we are already in the future and better off not having to worry about space piracy, but that's a separate discussion.
The following is my slightly edited response to a comment about space pirates launching ships from the surface of the Earth (or another planet).
Let's address just the issue of getting into space. There are four ways to escape a planetary gravity well: chemical fuels, atomic energy, a space elevator, and some unknown future technology.
I always find it comical when science fiction writers send a small handful of people into space on top of a rocket. With the earth's dwindling reserves of fossil fuels and the rising environmental costs of burning them, I think one would agree that chemically-powered space travel will be limited in the future and certainly out of the economic reach of a small band of space pirates.
Since the atomic golden age of the 1950s and 60s, we have learned that atomic energy is too dangerous for individual use due to the danger of accidents and atomic weapons. (Aside: Find one of Eisenhower's "civilian atomic energy" videos online. They're hilarious.) I don't see this danger dwindling except by the invention of force shields or other defensive systems. Atomic energy also has the same fuel discovery and transportation issues as chemical rockets.
The deeper problem with both chemical rockets and atomic energy is that the ship must lift both its own weight and the weight of its fuel. This inefficiency makes a space elevator a much more believable method of moving cargo into space. In that case, the energy source remains stationary and must lift only the weight of the payload.
Thus, a space elevator removes the need for surface-to-space ships that space pirates could board and loot. Criminals could certainly infiltrate the elevator "cars" and steal cargo, but as I have explained above, it is unlikely they could get the cargo into space without their own elevator. Furthermore, such a crime stretches the common definition of "piracy" in which criminals hijack an independent vessel in transit.
It is likely that future technologies will provide alternate energy sources or completely new ways of traveling from a planet's surface into space. However, there will always be a lower bound to how much energy is required to lift a certain amount of matter out of a planetary gravity well in a particular amount of time. This is a substantial amount of energy no matter where it comes from.
For these reasons, I don't expect that space pirates will launch from the ground to intercept interplanetary cargo shipments. Instead, if interplanetary commerce ever becomes widespread enough to support piracy, I would expect pirates to stay in space and smuggle stolen cargo through a space elevator or other public transport system.
We have deep discussions like this all the time.