Table: jet_engine_performance
Columns: engine_type
scenario
sfc_in_lb_lbf_h
sfc_in_g_kn_s
specific_impulse_s
effective_exhaust_velocity_m_s

Question: What engine type is used in a Space Shuttle Vacuum scenario?
SQL: SELECT "engine_type" FROM jet_engine_performance WHERE "scenario" = 'Space shuttle vacuum'

Question: What is the effective exhaust velocity in a Space Shuttle Vacuum?
SQL: SELECT COUNT("effective_exhaust_velocity_m_s") FROM jet_engine_performance WHERE "scenario" = 'Space shuttle vacuum'

Question: What is the maximum specific impulse with a 4423 m/s effective exhaust velocity?
SQL: SELECT MAX("specific_impulse_s") FROM jet_engine_performance WHERE "effective_exhaust_velocity_m_s" = 4423

Question: What is the SFC when the specific impulse is 453?
SQL: SELECT "sfc_in_g_kn_s" FROM jet_engine_performance WHERE "specific_impulse_s" = 453