Artemis II is expected to reach about 25,000 mph (about 40,000 km/h) on the way back into Earth’s atmosphere, which is the mission’s peak human speed. During launch it also passes about 17,500 mph (about 28,160 km/h) after main engine cutoff, and NASA-linked coverage says it starts the flight already moving around 3,100 mph after booster separation.

Quick Scoop

  • Top speed: about 25,000 mph / 40,000 km/h at reentry.
  • After launch: about 17,500 mph / 28,160 km/h by main engine cutoff.
  • Early ascent: around 3,100 mph / 5,000 km/h after booster separation.

What that means

Artemis II will be one of the fastest crewed missions ever, mainly because Orion comes home from a lunar flyby at very high speed. That’s also why its heat shield and reentry profile are such a big deal for NASA.

If you want, I can also give you the speed in km/h, mph, or Mach in one neat line.