Page 1 Validation by Balloons and Aircraft - ESRIN - 9–13 December 2002 Validation of MIPAS on ENVISAT by in situ instruments on the M55-Geophysica J. Heland, H. Schlager, C. Schiller, N. Sitnikov, A. Ulanovsky, F. Ravegnani, C. M. Volk, A. Werner, A. Petritoli, I. Kostadinov, F. Stroh, M. v. Hobe, C. Blom, and the Geophysica-Team - Motivation - M55-Geophysica In Situ Instrumentation - Internal Quality Checks - Comparison with MIPAS-E data - Conclusions