What is the correct characterization of directed-energy weapons from Space Weapons, Earth Wars?

• A. They propagate energy at the speed of light, but the speed of effect will be slower.
• B. They propagate energy slowly and have limited output.
• C. They are illegal under the Outer Space Treaty.
• D. They have no practical use in space.

Answer: (A)

Directed-energy weapons deliver energy at the speed of light, so the beam reaches the target essentially instantly in space. But the damage they cause develops over time as the absorbed energy heats, melts, ablates material, or disrupts electronics. The rate at which those effects accumulate depends on the power of the beam and how long it is held on the target, so the observable impact can be slower than the beam’s travel time. That combination—energy moving at light speed with a slower, time-dependent effect—is the best way to describe these weapons. The alternative notions that energy travels slowly, or that there are universal legal prohibitions or no practical space use, don’t fit the physics and typical strategic context.