Pioneer Venus Spacecraft Design And Operation

• Published in: IEEE transactions on geoscience and remote sensing Vol. GE-18; no. 1; pp. 5 - 10
• Main Author: Nothwang, George J.
• Format: Journal Article
• Language: English
• Published: IEEE 01.01.1980
• Subjects: Antenna measurements; Atmosphere; Atmospheric measurements; Extraterrestrial measurements; Frequency; Probes; Propellants; Space vehicles; Transmitting antennas; Venus
• ISSN: 0196-2892; 1558-0644
• DOI: 10.1109/TGRS.1980.350251

The Pioneer Venus Orbiter and Multiprobe spacecraft design and operation enabled both remote and in-situ measurements of the Venusian environment from the outermost fringes of the atmosphere all the way to the surface. Both spacecraft were spin-stabilized and solar-cell powered from launch to Venus. Since orbit insertion, the Orbiter has been transmitting measurements from a highly elliptical 24-h orbit with periapsis altitudes down to about 150 km. Data rates up to 2048 bits/s have been utilized through a despun high-gain antenna transmitting at S-band frequency. Spacecraft attitudes, orbit periods, and periapsis altitudes are being maintained as required with a hydrazine propulsion system. The Multiprobe spacecraft (Bus with all four Probes attached) perfomed the necessary Probe checkouts and deployed the Probes to achieve the desired Probe and Bus targeting. Silver-zinc batteries provided the necessary power on each of the four Probes from separation from the Bus through the entry/descent sequence. Data rates of 256 and 128 bits/s on the Large Probe were maintained with 40-W radiated power, and 64 and 16 bits/s on the Small Probes were maintained with 10-W radiated power, through omni antennas directly to Earth-based stations. Each Probe's entry/descent sequence was controlled with a hardwired entry sequence programmer to achieve the desired scientific and spacecraft operations.