Radar mapping of Venus contains missing coverage slices due to orbital geometry and radar geometry
the verdict
INSUFFICIENT LEANING
refutedsupported
the weight of evidence
2 sources for · 0 against
AS REPORTEDno primary record reached; this is what the reporting says
Available evidence acknowledges that radar maps of Venus contain coverage gaps or unmappable bands requiring external data filling, but does not fully detail how orbital and radar geometry cause these missing slices.
Hemispheric View of Venus Centered at the North Pole | NASA Jet Propulsion Laboratory (JPL)
# Hemispheric View of Venus Centered at the North Pole
Jet Propulsion Laboratory https://www.jpl.nasa.gov/ June 3, 1996
The hemispheric view of Venus, as revealed by more than a decade of radar investigations culminating in the 1990-1994 Magellan mission, is centered on the North Pole. The Magellan spacecraft imaged more than 98% of Venus at a resolution of about 100 meters; the effective resolution of this image is about 3 km. A mosaic of the Magellan images (most with illumination from the west) forms the image base. Gaps in the Magellan coverage were filled with images from the Earth-based Arecibo radar in a region centered roughly on 0 degree latitude and longitude, and with a neutral tone elsewhere (primarily near the south pole). The composite image was processed to improve contrast and to emphasize small features, and was color-coded to represent elevation. Gaps in the elevation data from the Magellan radar altimeter were filled with altimetry from the Venera spacecraft and the U.S. Pioneer Venus missions. An orthographic projection was used, simulating a distant view of one hemisp
# Why do radar maps of the surface of Venus have missing slices?
Tags: venus, radar, delay-doppler
- Score: 10
- Views: 1318
- Answers: 1
- Answered: yes
- Asked by: user12102
- Asked: 2017-07-31
- Edited: 2017-08-04
- Site: space
## Question
The visually opaque clouds of Venus still pass radio and some microwaves, and so powerful radar signals can be used to map the surface. This is probably done using some kind of delay-Doppler technique, the Arecibo is big but it's not going to resolve features this small, and even if it could (which it can't), building a map pixel-by-pixel would not be a reasonable use of time.
So I would assume the gap is somehow related to the delay-Doppler geometry, but I can't figure out how.
The caption for the color map shown below from the National Air and Space Museum says:
A radar map of Venus collected by CEPS scientists. This shows most of one hemisphere of the planet, with a thin band near the center for which the mapping technique cannot produce an image. Dark areas are smooth or covered by fine material from impact craters, while bright areas are very rough. These maps are being used to study geologic processes beneath the dense atmosphere
Everything we examined (2)
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