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Radar Mapper (ORAD)

NSSDCA ID: 1978-051A-02

Mission Name: Pioneer Venus Orbiter
Principal Investigator:Dr. Gordon H. Pettengill

Description

The Pioneer Venus Orbiter radar altimeter (ORAD) was used to obtain information on the orbiter altitude, planetary surface temperature, and radar scattering properties in order to infer the surface topography, geology, and the thermal and mechanical properties of the interior of Venus. From observations of the radar echo, surface heights along the suborbital trajectory can be estimated to an accuracy of 150 m. Surface electrical conductivity and meter-scale roughness can also be derived. The measurements are made whenever the spacecraft is below 4700 km. A low power (20 W peak pulse power), S-band (1.757 GHz) pulse is transmitted to the surface, and the echoes are recieved and processed on-board. The antenna is mechanically moved in a plane containing the spacecrafts spin axis to view the suborbital point on the planet's surface once during each roll of the spacecraft. The radar observations occupy about 1 sec out of each 12 second spacecraft rotation period. The surface resolution at periapsis is 23 km along track and 7 km across track. Relatively long pulses are used to obtain a good signal-to-noise ratio from each pulse.

Alternate Names

  • ORAD
  • PioneerVenusOrbiter/ORAD

Facts in Brief

Mass: 9.7 kg
Power (avg): 18 W

Funding Agency

  • NASA-Office of Space Science (United States)

Discipline

  • Planetary Science: Geology and Geophysics

Additional Information

Questions and comments about this experiment can be directed to: Dr. David R. Williams

 

Personnel

NameRoleOriginal AffiliationE-mail
Dr. Harold MasurskyCo-InvestigatorUS Geological Survey
Dr. William M. KaulaCo-InvestigatorUniversity of California, Los Angeles
Dr. George E. McGillCo-InvestigatorUniversity of Massachusettsgmcgill@wawa.geo.umass.edu
Mr. Walter E. Brown, Jr.Co-InvestigatorNASA Jet Propulsion Laboratory
Prof. David H. StaelinCo-InvestigatorMassachusetts Institute of Technologystaelin@ll.mit.edu
Dr. Gordon H. PettengillGeneral ContactMassachusetts Institute of Technologyghp@space.mit.edu
Dr. Gordon H. PettengillPrincipal InvestigatorMassachusetts Institute of Technologyghp@space.mit.edu

Selected References

  • Pettengill, G. H., et al., Pioneer Venus Orbiter radar mapper--design and operation, IEEE Trans. Geosci. Rem. Sens., GE-18, 28-32, Jan. 1980.
  • Pettengill, G. H., et al., Pioneer Venus radar mapper experiment, Science, 203, No. 4382, 806-808, Feb. 1979.
  • Pettengill, G. H., et al., Venus: Preliminary topographic and surface imaging results from the Pioneer Orbiter, Science, 205, No. 4401, 91-93, July 1979.
  • Masursky, H., et al., Pioneer Venus radar results: Geology from images and altimetry, J. Geophys. Res., 85, No. A13, 8232-8260, Dec. 1980.
  • Pettengill, G. H., et al., Venus: Surface electromagnetic properties, J. Geophys. Res., 93, No. B12, 14881-14892, Dec. 1988.
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