[comp.archives] [sci.astro] Re: Range Data from Venus

pgf@athena.mit.edu (Peter G. Ford) (08/25/90)

Archive-name: magellan/23-Aug-90
Original-posting-by: pgf@athena.mit.edu (Peter G. Ford)
Original-subject: Re: Range Data from Venus
Reposted-by: emv@math.lsa.umich.edu (Edward Vielmetti)

In article <26762@usc.edu> stein@iris.usc.edu (Fridtjof Stein) writes:
>This morning I saw the first Venus pictures from Magellan on TV. 
>I guess they were artificially shaded range images. I'm very interested in
>the original range/radar data for my work. Does anyone know:

The shading in the images is derived directly from the radar backscatter
intensity (a function of surface tilt, roughness, and composition). It
isn't "artificial", and it isn't directly related to range data, which
are also obtained by Magellan, but at a lower resolution.

>o Is there anything planned to make that kind of data accessible?

Yes. Lots. Provided the spacecraft cooperates, it will generate about
800 megabytes per day!

>o Which format will be used (like the DEM = Digital Elevation Model of the
>  Dept. of the Interior U.S. Geological Survey)?

The image data are recorded in two formats: VICAR and PDS. The former 
is primarily used by the Jet Propulsion Laboratory. The latter is a
new NASA standard. Each image will contain labels in both formats.

>o When and where can I get/buy/ftp the data?

All Magellan data will be distributed via NASA's planetary data system.
CD-ROM disks will be available through the National Space Science Data
Center (NSSDC), Goddard Space Flight Center, Greenbelt, MD.

>o Is there already some range data around from other planets or moons?

There are good images of radar backscatter for the moon and for Venus.
Poorer quality images have also been made of Mars and of some asteriods.
Range and/or frequency data have also been obtained from Mercury,
Saturn's rings, and the Galilean satellites. Many will shortly be
published on CD-ROM from NSSDC. Ask them for the "Pre-Magellan Radar
CD-ROM".

Peter Ford
MIT & Magellan Project