Channel electron multiplier operated on a sounding rocket without a cryogenic vacuum pump from 120 to 80Â km altitude

► CEM operation has been demonstrated on sounding rockets down to 80 km without cryopumping. ► The low pressure for CEM operation was provided by aerodynamics. ► DSMC simulations show sufficiently low pressure below aft facing surfaces on rockets. ► Aerodynamic pumping could simplify future flights of mass spectrometers.