NSSDCA ID: 1975-054D-04
Mission Name: Venera 10 Descent CraftThe Nephelometer experiment measured the characteristics of the clouds and hazes in the Venus atmosphere as the lander descended. Measurements of the scattering properties gives information on the distribution of droplet sizes, droplet densities, and possible chemical composition. The experiment consisted of four nephelometer sensors and an infrared (0.92 micron) semi-conductor pulsed laser. The entire instrument was mounted outside the pressure hull. Three of the sensors were mounted as one unit, and the fourth sensor (the “backscatter sensor”) and the laser were mounted as another unit. The laser was aimed toward the first unit. The three sensors were mounted off the axis of the laser beam, pointed towards it at different orientations to measure the forward scattering from the particles at a range of angles. One was angled at 4 degrees to the laser axis, with an objective field of view (FOV) of 1.17 x 2.33 degrees. The second was at 15 degrees with a FOV of 2.33 x 4.83 degrees, the third at 45 degrees with FOV 6.33 x 6.33 degrees. The sensors had an operating spectral range of 0.8 to 1.0 micron.
The backscatter sensor pointed away (180 degrees) from the laser along the axis of the beam to detect any light reflected or scattered backwards from the particles. It was mounted 90 mm from the laser and had a FOV of about 7 x 7 degrees. The laser emitted light in rapid bursts at 160 – 400 Hz for the three small-angle forward scattering sensors, and 4000 Hz for the backscatter sensor.
Questions and comments about this experiment can be directed to: Dr. David R. Williams
Name | Role | Original Affiliation | |
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Prof. Mikhail Ya. Marov | Principal Investigator | Keldysh Institute of Applied Mathematics, Russia |