Expanse Delta-v Calculator
How long would it take to reach nearby stars with a drive similar to the Epstein Drive from The Expanse? Adjust your delta-v budget and pick a target star.
Mission Parameters
72,000 km/s = 24.02% of light speed
Journey Details
The Epstein Drive from The Expanse enables sustained thrust for months, giving ships a total Δv of ~72,000 km/s (24.0% c). This is far beyond any current propulsion technology.
At max Δv, most of the journey is spent coasting — the drive only burns during acceleration and deceleration phases.
All Routes at Δv 72,000 km/s
How It Works
This calculator models interstellar journeys using a fixed total delta-v (change in velocity) budget — inspired by the Epstein Drive from the science fiction series The Expanse.
Flight Profile
The ship splits its delta-v equally between acceleration and deceleration. It accelerates at ~1.4 m/s² until half its delta-v is spent, then coasts at maximum velocity for the majority of the journey, and finally decelerates to arrive at rest.
Relativistic Effects
When the maximum velocity approaches a significant fraction of light speed, relativistic time dilation is factored in. The ship's crew experiences less time than observers on Earth — though at typical Epstein Drive delta-v budgets (~24% c), the dilation is modest.
The Epstein Drive
In The Expanse, the Epstein Drive is a highly efficient fusion drive that enables sustained multi-g thrust for extended periods. Its canonical delta-v of ~72,000 km/s makes interplanetary travel practical but interstellar journeys still take lifetimes — unless you dramatically increase the delta-v budget.