Phil Stooke
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Phil Stooke
@philstooke.mastodon.social.ap.brid.gy
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Professor Emeritus, University of Western Ontario. Space exploration and planetary cartography, historical and present. A longtime poster on […]

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philstooke.mastodon.social.ap.brid.gy
The next mission to launch to Venus was NASA's Pioneer Venus mission, with two components. Here is a NASA look back on its 4oth anniversary:

https://www.nasa.gov/centers-and-facilities/ames/40-years-ago-pioneers-encounter-venus/

The mission consisted of an […]

[Original post on mastodon.social]
The Pioneer Venus Orbiter took this image of the clouds of Venus, and many more, to monitor the clouds and atmospheric dynamics. It was scanned by a photopolarimeter on the spinning spacecraft (not a camera, it only measures brightness one pixel at a time, scanning a line as it spins and using motion along its orbit to move to the next line). This was like the imagers on Pioneer 10 and 11 at Jupiter, and similar to the Soviet Luna 19 and 22 images.
November 26, 2025 at 7:38 AM
philstooke.mastodon.social.ap.brid.gy
Around the time of Veneras 9 and 10, Earth-based radar mapping was improving. This map is a composite of two radar datasets from this period, reprojected to the azimuthal projection I always use for global maps.

One paper was this:

Campbell, D.B. and Burns […]

[Original post on mastodon.social]
This radar map of Venus used data from around 1975, cited in the main text. Global images like this made by delay-doppler imaging are north-south ambiguous and the ambiguity can't be resolved around the sub-Earth latitude so there is usually a bland strip. but here it has been filled by an image which was printed with the ambiguous zone intact. Over several years of observing, images with different sub-Earth latitudes can fill that gap, but they always show the same hemisphere of Venus.
November 25, 2025 at 7:59 AM
philstooke.mastodon.social.ap.brid.gy
Here is a rather crudely reprojected version of the Venera 10 panorama. Once again we don't know the orientation of this map. The lander ended up on a patch of flat rocky slabs, and there seem to be similar rocky areas on each horizon, left and right. Between […]

[Original post on mastodon.social]
This image is a roughly reprojected version of the Venera 10 panorama. It approximates a map geometry and the narrow central part is about 2 m across. It shows the lander sitting on a patch of flat rocky slabs with similar rocky areas on each horizon (probably not very far away, a few tens of meters). Between them is a smooth-looking dark surface, probably gravelly in texture like small patches in the foreground.
November 24, 2025 at 7:46 AM
philstooke.mastodon.social.ap.brid.gy
Here is an old Soviet version of the Venera 10 image, a bit too contrasty so details get lost especially at the horizon. But what we see is different from Venera 9's boulders. This is a nearly flat area with platy slabs of rock interspersed with darker […]

[Original post on mastodon.social]
A Russian image of the Venera 10 panoramic image. It extends from horizon to horizon at left and right, and shows the foreground in the middle. Flat slabs of rock cover about half of the surface with gravelly soil between them. Two objects sit on the surface, a lens cover from the camera and a densitometer instrument on a short arm which was dropped on the surface o measure its hardness.
November 22, 2025 at 7:40 AM
philstooke.mastodon.social.ap.brid.gy
Venera 10 landed in the area shown here at two scales - at left a map spanning 500 km shows major landforms, at right, full Magellan resolution gives us details of part of the landing ellipse. We see mixed geology - the dark areas are smooth (ish) plains […]

[Original post on mastodon.social]
Two maps of the Venera 10 landing site. At left a context map shows bright and dark areas, the bright parts being a hilly area cut by many faults and the dark areas being smoother surfaces probably covered with sediments. A mountain in the south part of the map is a volcano, and flows extend from it to the north and east. Venera 10 could have landed anywhere in a 300 km diameter circle filling much of the map. At right the central part of that landing region is shown in more detail revealing plains cut by ridges and fractures, and part of the hilly area.
November 21, 2025 at 7:24 AM
philstooke.mastodon.social.ap.brid.gy
Venera 10 launched 6 days after V9 (14 June '75) and landed 3 days after its sibling (25 October). This map shows the area. Like Venera 9 it was east of Beta Regio, but 1500 km further south. As with all landers so far the target was essentially unknown, only […]

[Original post on mastodon.social]
A map showing the landing area of Venera 10 in 1975. The site is southeast of Beta Regio in an area which was essentially unknown at the time but now seen (in Magellan data) to consist of mixed bright and dark - rough and smooth - patches. What kind of landscape did Venera 10 land in?
November 20, 2025 at 7:17 AM
philstooke.mastodon.social.ap.brid.gy
Here's that map with its crudely separated section. But what's this? Why have I rotated it? As far as I can tell there is absolutely no information about the orientation of the map, so here it is in an arbitrary orientation. I suppose a whole-sky image might […]

[Original post on mastodon.social]
The same map as in the last post, but a distant hillside is separated from the intervening horizon to suggest the valley we can't see into. Also this map has been rotated 90 degrees clockwise, a reminder that as far as I know we have no idea what the orientation of the map should be.
November 18, 2025 at 7:43 AM
philstooke.mastodon.social.ap.brid.gy
I wanted to be able to map the Venera landing sites. We should be able to project the panoramas to a map geometry. I'm not clever enough to figure it out, but veteran space artist Don Davis published drawn maps for Veneras 9 and 10, so I had a start. He […]

[Original post on mastodon.social]
A Venera 9 panorama projected into a rough map geometry. The narrow 'neck' in the middle is about 2 m across. I don't really know how far out the ends should reach.
November 17, 2025 at 8:08 AM
philstooke.mastodon.social.ap.brid.gy
I want to make a map of this Venera 9 site. To start, here is a Soviet-era version of the panorama. I do want to emphasize what an incredible advance this was - the first image of the landscape of another planet, taken in October 1975, before the Viking […]

[Original post on mastodon.social]
A Russian version of the Venera 9 panorama. It is very high contrast, but shows large rocks littering the surface and a horizon on the right. At left an apparent horizon is a local ridge and a distant rocky surface is visible beyond it. Text below the image says that it was processed by the Academy of Sciences of the USSR.
November 17, 2025 at 8:04 AM
philstooke.mastodon.social.ap.brid.gy
If fractured cut the lava channel they are younger than the channel. It's hard to tell where the lava came from, probably one of the set of north-south fractures west of the channel. The 'chasma' is a broad rift valley. The image in this post shows the site […]

[Original post on mastodon.social]
A full resolution (100 m/pixel) image of the Venera 9 landing site. Dark rectangles are places where image data was lost as the spacecraft switched tracks on its tape recorder. The image shows many fractures cutting the surface. A small volcanic cone is visible 75% of the way down the image near the right edge.
November 15, 2025 at 7:40 AM
philstooke.mastodon.social.ap.brid.gy
I missed a day so I will do two maps today. We are zooming in on the Venera 9 landing site. Yesterday it looked rough. This map shows a very fractured surface, cracks large and small all over the image. There were some gaps in radar coverage which I filled in […]

[Original post on mastodon.social]
A Magellan radar mosaic covering an area 500 km across including the landing area of Venera 9 on Venus. The surface is cut by many fractures which show up as white lines. A circle 300 km across shows the region of the landing site.
November 15, 2025 at 7:29 AM
philstooke.mastodon.social.ap.brid.gy
Here is the Venera 9 landing site on Venus. It's on the eastern edge of Beta Regio - remember that first radar map with a big rectangle called Beta? The image here is a combination of Magellan radar images and Magellan topography - not very successful really […]

[Original post on mastodon.social]
A map of an area about 3000 km across showing the location of the Venera 9 landing site on Venus. It's on the east side of Beta Regio, a rugged upland volcanic complex cut by large rift valleys - but that was not known at the time. The surface is rough, shown by bright markings in radar images. At the time we only had low resolution Earth-based radar images. This map shows Magellan radar data obtained much later.
November 13, 2025 at 7:22 AM
philstooke.mastodon.social.ap.brid.gy
Let's look closer at the Venera 8 landing site. Now the mission team knew they could reach the surface it made sense to measure composition with a gamma ray instrument. Earlier probes had mostly studied the atmosphere during descent. The composition was […]

[Original post on mastodon.social]
Two maps show the landing site of Venera 8 on Venus. The location has several features of interest. Small dark patches look like smooth lava flows filling depressions in rougher terrain. A small round dome is presumably volcanic i n origin. There are some narrow fractures but not the cross-cutting ridges seen elsewhere.
November 10, 2025 at 7:35 AM
philstooke.mastodon.social.ap.brid.gy
Venera 8 launched on 27 March 1972 and landed on Venus on 22 July. A companion spacecraft launched 4 days later but never left Earth orbit. Venera 8 lander just after dawn at its site and measured light levels but had no camera. It ejected a radio transmitter […]

[Original post on mastodon.social]
A map shows the Venera 8 landing site on Venus. The surface has more going on than our previous sites - volcanoes and tectonic features, and a few small craters.
November 9, 2025 at 7:53 AM
philstooke.mastodon.social.ap.brid.gy
These images give more detail of the Venera 7 site on Venus. In the context map (left) we see an impact crater (Buck), a set of ridges collectively called Unuk Dorsa and a feature described as a 'fluctus' (flow) - in this case a lava flow. The darker plains […]

[Original post on mastodon.social]
Twp maps zooming in on the Venera 7 landing site. At left a context map shows a fairly smooth plains area with a brighter (rougher) lava flow, an impact crater with bright rocky ejecta around it, and some narrow ridges. In the closer view at right we see the ridges more clearly as wavy bight lines - but not very many of them - and a few narrow fractures. Most of the surface is smooth and flat.
November 8, 2025 at 7:31 AM
philstooke.mastodon.social.ap.brid.gy
Here is the Venera 7 landing region. It landed at night and did not take images. The site is close to a large circular corona - a volcanic and tectonic structure 1000 km across called Heng-o Corona. We see several 'dorsa' (ridge) structures and a 'chasma' (a […]

[Original post on mastodon.social]
This map shows the landing area (in a small white square) of Venera 7, the first spacecraft to land on another planet. It is slightly south of the equator and slightly west of the prime meridian, on a low-lying plains area near a large circular volcanic structure.
November 7, 2025 at 7:50 AM
philstooke.mastodon.social.ap.brid.gy
These are closeups, full Magellan resolution, of the Venera 5 and 6 sites: squares 100 km across inside each circle in yesterday's post. The surfaces are all lava flows and lighter patches are rougher surfaces. The thicker, wavy, east-west trending white […]

[Original post on mastodon.social]
Two maps, the Venera 5 landing site at left, Venera 6 at right. Each square image is 100 km across. These are Magellan radar images with radar illumination from left to right. They show generally darkish plains with a few lighter patches which are rougher surfaces. They are crossed by bright wavy lines which are ridges produced by compression and thinner straight lines which are fractures produced by tension. There are no craters. A prominent linear fracture in the Venera 6 site has a meandering channel extending to the southeast (bottom right). It was cut by flowing lava.
November 6, 2025 at 7:30 AM
philstooke.mastodon.social.ap.brid.gy
These maps show the Venera 5 and 6 landing areas, close together. They were still essentially unknown landscapes. The second of two radar maps I showed earlier was the state of the art about this time and all it gives is a vague idea of radar reflectivity at […]

[Original post on mastodon.social]
Three maps show the landing areas of Venera 5 and Venera 6. At left a context map shows two slightly overlapping boxes which are enlarged in the next two maps, one for each lander. The sites consist of lava plains covered with ridges and fractures, but that was not known at the time.
November 5, 2025 at 7:10 AM
philstooke.mastodon.social.ap.brid.gy
Here is the central part of the Venera 4 landing area seen at full Magellan resolution, about 100 m/pixel. The image spans 200 km left to right. White lines are fractures, hundreds of hem - a tectonically disrupted landscape. At right is a band of fractured […]

[Original post on mastodon.social]
This is a close-up radar mosaic of Didilia Corona, the landing area of Venera 4 (it failed before landing, we got no data from the surface but good atmospheric data on the way down). It shows hundreds of fractures, signs of tectonic activity, as bright lines. Darker areas are wind-blown sediment. there are also lots of small pits and hollows, probably all volcanic in origin. No obvious impact craters are seen here.
November 4, 2025 at 7:19 AM
philstooke.mastodon.social.ap.brid.gy
This map shows the Venera 4 location, the nature of which was still unknown. Now we see it as a volcanic upland with a high mountain (Tepev Mons) and several coronae or roughly circular volcanic complexes. The day after this, Mariner 5 flew past Mars and […]

[Original post on mastodon.social]
Venera 4 landed in the region shown in these two maps - a wider area at left and more of a close-up at right. The surface is hilly and fractured with many volcanic features - a high mountain and several circular volcanic complexes, one of which Venera 4 landed in or near. There are very few craters in this area.
November 3, 2025 at 7:16 AM
philstooke.mastodon.social.ap.brid.gy
My last post showed where Venera 3 entered the atmosphere of Venus, with the surface mapped as we know it now. At the time this was utterly unknown. This region was not even in the area covered by those radar images. But let's look closer anyway. This map […]

[Original post on mastodon.social]
A closer map of the area where Venera 3 reached the surface of Venus. It could have fallen anywhere in this map. The surface was unknown at the time. These features were seen in Magellan images nearly 30 years later. Most of the area is hilly, with a few volcanic features, some sand dunes and several impact craters.
November 2, 2025 at 6:22 AM
philstooke.mastodon.social.ap.brid.gy
You are trying to hit a planet for the first time. Where do you aim? For the middle of the disk as you approach it? Aim for the edge and you may miss altogether. That doesn't work for Mars where an oblique entry at the edge of the disk is needed to get a long […]

[Original post on mastodon.social]
A map of Venus showing the hemisphere centered on 60 degrees East. The map is the same as in the previous two posted maps except that it has a different central meridian. A large ellipse extending from 60 to 80 east and 20 north to 20 south shows the area where Venera 3 entered the atmosphere, the first spacecraft to reach and contact another planet.
November 1, 2025 at 6:38 AM
philstooke.mastodon.social.ap.brid.gy
Here is the other hemisphere of Venus. Most of the planet consists of plains, some smooth and some with ridges or various small volcanic features. Tessera areas are fractured hilly areas, apparently older than most plains. A few areas called Terra (Ishtar […]

[Original post on mastodon.social]
The second part of the Venus map shown in the previous post - this is the opposite hemisphere, including a continent-sized upland called Aphrodite Terra.
October 31, 2025 at 6:15 AM
philstooke.mastodon.social.ap.brid.gy
I needed a Venus map for my Atlas of Venus Exploration. Magellan was the only source of useful data. I combined two datasets: elevation from the radar altimeter and imaging from the SAR mapper. SAR shows craters and hills up close, but at global scale it […]

[Original post on mastodon.social]
A map of one hemisphere of Venus made from Magellan data. It combines elevations from a radar altimeter with a global mosaic of Synthetic Aperture Radar images (which at this scale mainly show bright and dark (rough and smooth) regions. Place names are added to the map, which is in an azimuthal equidistant projection.
October 30, 2025 at 6:32 AM
philstooke.mastodon.social.ap.brid.gy
The surface of Venus gradually came into view more clearly. Here are two maps from 1965 (the linked paper) and 1969 (this paper:

Rogers, A.E.E. and Ingalls, R.P., 1969. Venus: Mapping the surface reflectivity by radar interferometry. Science, 165(3895), pp […]

[Original post on mastodon.social]
Two maps of Venus - just the hemisphere which faces Earth at closest approach in a curious almost-resonance. The projection is Azimuthal Equidistant. At left, just two features are marked, labelled Alpha and Beta, in a map by Richard Goldstein of JPL. At right a map by Rogers and Ingalls in 1969 is much more detailed. It shows radar bright (rough) areas as white on a dark background.
October 29, 2025 at 7:01 AM