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The Magellan Mission
to Venus
The Magellan spacecraft, named after
the sixteenth-century Portuguese explorer whose
expedition first circumnavigated the Earth, was launched
May 4, 1989, and arrived at Venus on August 10, 1990.
During the first 8-month mapping cycle around Venus,
Magellan collected radar images of 84 percent of the
planet's surface, with resolution 10 times better than
that of the earlier Soviet Venera 15 and 16 missions.
Altimetry and radiometry data also measured the surface
topography and electrical characteristics. During the
extended mission, two further mapping cycles from May
15, 1991 to September 14, 1992 brought mapping coverage
to 98% of the planet, with a resolution of approximately
100m. Precision radio tracking of the spacecraft
measured Venus' gravitational field to show the planet's
internal mass distribution and the forces that have
created the surface features. Magellan's data permitted
the first global geological understanding of Venus, the
planet most like Earth in our solar system.
Read more about this mission on the
Magellan Home Page.
All Magellan data sets are now available online.
The
Venus Orbital Data Explorer (ODE)
here at the Geosciences Node provides search
capabilities for Magellan data sets.
| Magellan
Data Sets |
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F-BIDR: Full Resolution Basic Image
Data Record
- F-BIDRs are long, narrow,
almost pole-to-pole image swaths that form the
basic Magellan image data product. They are pieced
together to form mosaics (F-MIDRs) for selected
areas of the planet.
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C-BIDR: Compressed Basic Image Data
Record
- C-BIDRs are compressed image
swaths that are pieced together to form the
compressed mosaics (C1, C2, and C3-MIDRs).
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F-MIDR: Full Resolution Mosaicked
Image Data Record
- F-MIDRs are full-resolution image
mosaics of selected areas of the planet.
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C1-, C2-, C3-MIDR: Compressed Once,
Twice, and Thrice Mosaicked Image Data Records
- C1-MIDRs are compressed-resolution image
mosaics covering a larger area at less resolution
than the F-MIDRs. C2-MIDRs are twice-compressed,
and C3-MIDRs are three-times-compressed.
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ALT-EDR: Altimetry Experiment Data
Record
- The ALTEDR volumes contain
Magellan ALT-EDR (Altimeter Experiment Data
Record) archive products. They also contain
documentation files which describe the ALT-EDRs.
Each ALT-EDR data directory contains the raw
altimeter data returned from one orbit and the
ancillary files necessary to understand the data.
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ARCDR: Processed Altimetry and
Radiometry Composite Data Record
- Along track estimates of
elevation, Fresnel reflectivity, surface
roughness, brightness temperature, emissivity
derived from Magellan altimeter and radiometer
data.
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GXDR: Global Topography and Surface
Property Data
- The GxDR data set consists of
MIT Altimetric and Radiometric Global Data
Records: the Global Topography Data Record (GTDR),
Global Emissivity Data Record (GEDR), Global Slope
Data Record (GSDR), and Global Reflectivity Data
Record (GREDR).
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SCVDR: Surface Characteristics
Vector Data Record
- The Surface Characteristics
Vector Data Record (SCVDR) is an orbit-by-orbit
reduction of Magellan scattering and emission
measurements carried out at Stanford University.
The SCVDR includes near-nadir scattering functions
obtained by numerical inversion from altimetry
(ALT) echoes, results (e.g., rms surface slopes
and Fresnel reflectivity) from fitting analytic
functions to those inversions, scattering function
segments at oblique incidence angles derived from
synthetic aperture radar (SAR) echoes, and
estimates of surface emissivity derived from
thermal microwave radiometry (RAD) measurements.
The SCVDR is one of several inputs to the Global
Vector Data Record (GVDR), a gridded summary of
scattering results, also produced at Stanford.
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GVDR: Global Vector Data Record
- The Global Vector Data Record (GVDR)
is a sorted collection of scattering and emission
measurements. The sorting is into a grid of equal
area 'pixels' distributed regularly about the
planet. For data acquired from the same pixel but
in different observing geometries, there is a
second level of sorting to accommodate the
different geometrical conditions. The 'pixel'
dimension is 18.225 km. The GVDR is presented in
Sinusoidal Equal Area (equatorial), Mercator
(equatorial), and Polar Stereographic (polar)
projections.
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BSR: Bistatic Radar
- The Magellan Bistatic Radar Raw
Data Archive is a time-ordered collection of raw
and partially processed data from bistatic radar
experiments conducted using the Magellan
spacecraft while it orbited Venus. The Bistatic
Radar Calibrated Data Archive contains
time-ordered amplitude- and frequency-calibrated
data, power spectra and voltage cross spectra,
along with ancillary data.
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LOSAPDR: Line Of Sight Acceleration
Profile Data Record
- This archive contains Magellan
Cycle 4, 5 and 6 LOSAPDR (Line of Sight
Acceleration Profile Data Record) products. It
also contains documentation which describes the
LOSAPDRs. Each LOSAPDR product contains the
results from processing of radio tracking data of
the Magellan spacecraft.
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Spherical Harmonic, Topography, and
Gravity Data
- This archive contains Magellan
spherical harmonic models of the Venusian gravity
and topography field, and digital maps of Bouguer
anomalies, free-air gravity accelerations and
errors, geoid anomalies and errors, and topography.
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Radio Tracking
Data
- This archive contains Magellan radio tracking
data in the form of ODF and TDF files.
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Post-Mission Derived Data Sets |
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Full-Resolution Radar Mosaics (FMAPs)
at the PDS Imaging Node
- This archive was produced by the U.S. Geological Survey
after the Magellan mission ended. It contains
full-resolution mosaicked images covering about 92%
of the planet. Images were generated from the F-BIDR
products. This link leads to the PDS Imaging Node
web site.
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