Ion engines are a non-chemical BTC travel technology that uses electricity to accelerate electrically charged atoms (ions) to much higher velocities than chemical rocket exhaust fumes. The acceleration is slow, but it lasts an amount of time equivalent of several Earth years, so the final velocity is many times higher. Altough chemical rockets would reach close destinations such as Luna much faster than ion engines, the ion engine would "win the race" to more distant destinations such as Jupiter. Plasma engines, described as "ion engines on steroids" have similar maximum velocity as ion engines but accelerate ten times faster. Neither does howewer give a sufficiently fast acceleration for launch from Earths surface, so they are only for travel between cosmic destinations.