How Fast Is Ion Thruster Exhaust?

Ion thrusters expel xenon ions at 30,000 m/s — 10× the exhaust speed of chemical rockets. The thrust is tiny — equivalent to the weight of a piece of paper — but they run continuously for years, ultimately reaching speeds chemical rockets cannot match.

Ion thrusters were first developed by NASA in the 1950s but weren't used in space until 1998. The Dawn spacecraft's ion drive ran for 5.9 years total — a record.

• 10× chemical rocket exhaust speed
• Thrust equivalent to a piece of paper