First results of RASMUS: Source gases in the mesosphere

Abstract

We present the first results of project RASMUS ( R ocket-borne A ir S ampler for the M esosphere and U pper S tratosphere). Besides N 2O and CH 4, H 2, CO and CO 2, stable halogenated hydrocarbons such as CF 4, CHClF 2, CClF 2-CF 3 and CF 3-CF 3 have been measured for the first time at about 60 km altitude. RASMUS is a new LHe-cooled cryogenic whole-air sampler which allows collection of 4 samples of about 4 ℓ STP at freely programmable height levels between 65 and 40 km. The samples are collected at the apogee and during the descent phase, at subsonic velocity of the instrument. They are frozen out on gold plated cold fingers suspended in electropolished stainless steel containers with liftable sampler caps. After parachute-recovery they are analyzed using GC and GC-MS techniques. Results of the first RASMUS flight on May 6, 1987 from ESRANGE/Sweden are presented and discussed in the light of model predictions.