The Spin Vector of Venus Determined from Magellan Data
Abstract
A control network of the north polar region of Venus has been established by selecting and measuring control points on fullresolution radar strips. The measurements were incorporated into a leastsquares adjustment program that improved initial estimates of the coordinates of the control points, pole direction, and rotation rate of Venus. The current dataset contains 4206 measurements of 606 points on 619 radar strips. The accuracy of the determination is driven by spacecraft ephemeris errors. An accurate estimate of the rotation period of Venus was obtained by applying an ephemeris improvement technique. The second cycle closure orbits improved ephemeris solutions for 40 orbits (376384, 520528, 588592, 658668, 10021010, 14081412, 17461764, and 21662170) are included and fixed in the geodetic control computations, thus trying the network to the J2000 coordinate system.
 Publication:

International Colloquium on Venus
 Pub Date:
 December 1992
 Bibcode:
 1992LPICo.789Q..27D
 Keywords:

 Ephemerides;
 Error Analysis;
 Estimates;
 Least Squares Method;
 Planetary Rotation;
 Radar Measurement;
 Vectors (Mathematics);
 Venus (Planet);
 Geodesy;
 Magellan Project (Nasa);
 Lunar and Planetary Exploration