Credit NASA



    The Pioneer Venus Mission consisted of two major parts: the Multiprobe and the Orbiter. The Multiprobe was composed of the carrier or Bus (290 kg), a large Sounder probe (315 kg), and 3 smaller probes (90 kg each). It was launched on August 8, 1978. the multiprobe reached Venus on December 9,1978 and the large probe was released on November 15.

    The Neutral Mass Spectrometer (LMNS) on the large probe measured the composition of Venus’ atmosphere from 60 km to the surface during which atmospheric pressure varied by 3 orders of magnitude, tabulating values from 15 to 208 amu based on scans every 64 sec. The Large Probe Atmospheric Structure Experiment (LAS) measured values for pressure, temperature, and density over the same range. Unfortunately, requirements for data archiving were limited and the LMNS results were submitted and stored at the NSSDCA as 29 pages of hard copy. The NSSDCA team used optical character recognition to extract data from these digitized scans, combined them with the interpolated LAS data, and output the results in a CSV table as the basis for the Gas Sampling Data Table in this archive.

    Reference
    Seiff, A., et al. (1980), Measurements of thermal structure and thermal contrasts in the atmosphere of Venus and related dynamical observations: Results from the four Pioneer Venus probes, J. Geophys. Res., 85, No. A13, 7903-7933, https://doi.org/10.1029/JA085iA13p07903.

    Hoffman, J. H., et al. (1980), Composition of the Venus lower atmosphere from the Pioneer Venus mass spectrometer, J. Geophys. Res., 85, No. A13, 7882-7890, doi:10.1029/JA085iA13p07882.

    Accessing the Data
    Citation
    PDS recommendations for citing data sets can be found here.

    Belkhodja, I., D. R. Williams, Hoffman, J. H., Hodges, R. R., and Seiff, A. (2025), Pioneer Venus Large Probe Neutral Mass Spectrometer Gas Sampling Data (1-15amu and 15-208amu) Bundle, NASA Planetary Data System, https://doi.org/10.17189/n23p-9r21.