This data set is a 20-min-resolution collection of solar wind plasma parameters from the interplanetary phases of the Soviet Vega 2 mission to Comet Halley. The data consist of proton flow speeds, densities and temperatures determined by fitting counts-vs-energy data measured on the sunward-looking electrostatic analyzer to a convecting Maxwellian. There are actually two sets of parameters, one ("linear") obtained by minimizing the sum of squares of measured and modelled counts and the other ("log") used logs of counts rather than counts themselves. Also included are numbers of energy intervals used in the linear and log determinations less than and greater than the spectral peaks. The data are at 20-min resolution because the during cruise phase only one or two 10-sec spectra were determined every 20 minutes. Further, the data have long gaps between the first and last days of coverage. The major data gaps are +---------------------------------------------------------------+ Vega 1: Vega 2: ----------------------------------------------------------------+ 85/04/20 - 85/07/23 85/04/16 - 85/07/24 85/12/21 - 86/01/05 85/09/27 - 85/11/27 86/04/29 - 86/08/04 85/12/03 - 86/02/20 86/02/23 - 86/03/06 +----------------------------------------------------------------+ Discussions of this investigation are found in Gringauz et al (Nature, v321, p282, 1986), Galeev et al (JGR, v93, p7527, 1988) and references therein.