NASA astronaut Christina Koch exits the vacuum test chamber for the Interaction Heating Facility (IHF) of the Ames Arc Jet Complex, N238, following Victor J. Glover, left. During a test, a TPS test sample is suspended in the hypersonic flow produced by IHF’s arc heater. The shock heating produced by the interaction between the hypersonic flow and the stationary test sample simulates the heating and other forces the spacecraft will encounter during atmospheric hypersonic entry.