This page no longer updated from 31 October 2001. Latest version can be found at www.astronautix.com
|Venus Multiprobe - |
Credit: NASA. 14,686 bytes. 340 x 279 pixels.
Class: Planetary. Type: Venus. Nation: United States. Agency: NASA, Ames Research Center. Manufacturer: Hughes.
The Pioneer Venus Multiprobe consisted of a bus which carried one large and three small atmospheric probes. . After release from the carrier vehicle, the probes entered the atmosphere at 41,600 km/hr, followed by the bus. The small probes were each targeted at different parts of the planet and were named accordingly. The North probe entered the atmosphere at about 60 degrees north latitude on the day side. The night probe entered on the night side. The day probe entered well into the day side, and was the only one of the four probes which continued to send radio signals back after impact, for 67 minutes. The carrier vehicle, not designed for atmospheric re-entry, followed the probes into the Venusian environment and relayed data about the characteristics of the extreme outer atmosphere until it was destroyed by atmospheric heating. Despite their drastically different roles, the Orbiter and Multiprobe were very similar in design. The use of identical systems (including flight hardware, flight software, and ground test equipment) and incorporation of existing designs from previous missions (including OSO and Intelsat) allowed the mission to meet its objectives at minimum cost.
- Multiprobe bus (Carrier vehicle) - With no heat shield or parachute, the bus survived and made measurements only to about 110 km altitude before burning up. The bus was a 2.5 m diameter cylinder weighing 290 kg. Spin stabilised. Body mounted solar panels provided 241 W. Payloads: Ion Mass Spectrometer (BIMS) - studied the composition of the upper atmosphere. Neutral Mass Spectrometer (BNMS) - studied the composition of the upper atmosphere.
- Large probe - Weighed 315 kg. Consisted of 3 parts: a forward heat shield, an aft protective cover and a spherical titanium pressure vessel (73 cm diameter). Total probe diameter was 1.5 m. After deceleration from initial atmospheric entry at about 11.5 km/s near the equator on the Venus night side, the heat shield and protective cover were jettisoned, and a parachute was deployed at 47 km altitude to further slow descent. After parachute deployment, the exposed pressure vessel and its instrument package descended for about 1 1/2 hour before impact. During descent, the instruments were powered by batteries. Nine observation windows (8 sapphire and 1 diamond) were provided for instrument observations.3 pressure vessel penetrations were also provided as inlets for direct atmospheric sampling. Payload: Atmospheric Structure (LAS). Nephelometer (LN) - studied cloud particles. Cloud Particle Size Spectrometer (LCPS) - measured particle size and shape. Gas Chromatograph (LGC) - studied atmospheric composition. Infrared Radiometer (LIR) - monitored the distribution of infrared radiation. Neutral Particle Mass Spectrometer (NPMS) - studied atmospheric composition. Solar Flux Radiometer (LSFR) - examined solar flux penetration into the atmosphere. Differential Long Base Line Interferometer (DLBI). Atmospheric Propagation (MPRO) - temperature, pressure, and acceleration measurements.
- Small probes - Each probe weighed 75 kg and was 0.8 m in diameter. Consisted of 3 parts: a forward heat shield, an aft protective cover and a spherical titanium pressure vessel. Unlike the large probe, the heat shield and protective cover remained attached to the pressure vessel, and no parachutes were deployed. Prior to atmospheric entry, each probe deployed a yo-yo despin device to reduce its spin rate from 48 to 15 rpm. Batteries provided power during descent (which lasted approx.75 minutes). Payload: Nephelometer. Temperature, pressure, and acceleration sensors. Net flux radiometer - mapped the distribution of sources and sinks of radiative energy in the atmosphere. Radio signals from all four probes were also used to characterise winds, turbulence, and propagation in the atmosphere.
Design Life: 4 months. Total Length: 2.9 m. Maximum Diameter: 2.5 m.
Pioneer 13 Chronology
08 August 1978
Pioneer Venus Probe 1 Program: Pioneer. Launch Site: Cape Canaveral . Launch Vehicle: Atlas Centaur SLV-3D. Mass: 315 kg.
- 2 - McDowell, Jonathan, The United Nations Registry of Space Objects, Harvard University, 1997. HTML when accessed: http://hea-www.harvard.edu/QEDT/jcm/space/un/un.html
- 6 - JPL Mission and Spacecraft Library, Jet Propulsion Laboratory, 1997. HTML when accessed: http://msl.jpl.nasa.gov/home.html
- 296 - National Space Science Center Planetary Page, As of 19 February 1999.. HTML when accessed: http://nssdc.gsfc.nasa.gov/planetary/planetary_home.html
Back to Index
Last update 12 March 2001.
Contact Mark Wade with any corrections or comments.
Conditions for use of drawings, pictures, or other materials from this site..
© Mark Wade, 2001 .