[en] The PLASMAG-1 experiment on board the identical VEGA-1 and VEGA-2 space probes is described. The probes were launched to comet Halley with Venus flyby. The PLASMAG instruments were designed to explore the solar wind and the cometary plasma environment. This paper describes the main parts and sensors of PLASMAGs and their operating parameters. First experimental results are presented from the interplanetary space. From 1-6 April 1985, the probes crossed a high speed plasma stream of solar wind. The data observed are presented and some preliminary results of evaluation are given. The data are compared with the observations of the ICE space probe wich encountered the Giacobini-Zinner comet. (D.Gy.)