A helium cooled balloon-borne infrared spectrometer was launched twice from Aire sur l'Adour (France; 44°N, 0°E) on 23 September 1983 and 4 May 1986. The experiment used the limb scan technique to measure mixing ratios of the stratospheric trace gases H 2 O, O 3 , N 2 O, NO 2 , CH 4 , HNO 3 and N 2 O 5 prior to, during, and after sunrise. The first flight was performed as part of the international MAP/Globus (Middle Atmosphere Program/Global Budget of Stratospheric Trace Constituents) campaign.The height profiles obtained during both flights are presented and compared here with data from other experiments. The ozone measurements are compared with in situ measurements taken by electrochemical Brewer/Mast sondes. N 2 O 5 mixing ratios were deduced from predawn measurements. A maximum value of 1.6 ppbv was obtained for a tangent height of 33.7 km. The N 2 O 5 height profile is found to be in good agreement with observations obtained by other experiments, indicating little latitudinal variation at sunrise. The height profile appears to be representative of an atmosphere with background aerosol levels.