PhilStooke

PhilStooke, 6 months ago to mastodon

Hello #Mastodon!

This is my first post on Mastodon. I am usually to be found on www.unmannedspaceflight.com but I will be sharing space-related images here as well.

PhilStooke, 6 months ago to random

This is a map of the Pathfinder landing site with names of rocks and other features. It began as a full panorama from the lander, which was projected into a circular format (a modified polar projection) and then projected onto a greatly enlarged HiRISE image to give accurate positional control.

PhilStooke, 4 months ago to random

Surveyor three landed on the Moon... three times. Its small landing thrusters didn't cut off just before landing as intended so it touched down, lifted off and touched down again, lifted off and touched down a third time, by which time a command from Earth shut the thrusters down. Luckily, being a tripod with a low centre of mass, it was stable enough to remain upright even though the last two landings were on a sloping crater wall. Speaking of which, why do most modern landers have 4 legs?

PhilStooke, 6 months ago to random

And now for something completely different. This is from my new (2024) LPSC abstract. Maps of asteroids Ryugu and Bennu, two top-shaped asteroids. The map projection is roughly tailored to fit - and display - their shapes. These maps first appeared on www.unmannedspaceflight.com and were built up as mission events occurred. Look for the same for Japan's MMX mission in a couple of years. I am currently experimenting with a map of Didymos.

PhilStooke, 2 months ago to random

We got our first good look at non-spherical objects with Mariner 9 at Mars, when it imaged Phobos and Deimos.

Phobos has about a 50% difference between its longest and shortest radii. How can we map that with standard map projections? Or do we need new ones?

PhilStooke, 3 months ago to random

Here are two last views from Apollo 16. Top: Stone Mountain (image AS16-113-18326). Bottom: Smoky Mountains (image AS16-107-17471).

PhilStooke, 6 months ago to random

As with Viking 1 I will show four stages in the development of the Viking 2 workspace. This follows the map with names and adds the various trenches, surface contacts (backhoe touchdowns) etc. Several attempts were made to move a rock and collect soil from underneath it, hoping it might be a protected habitat for any soil organisms.

PhilStooke, 5 months ago to random

And here is an extra map. Asteroid Steins, seen by the Rosetta spacecraft. Here the images have been projected onto a cylindrical map grid and also two polar projections.

PhilStooke, 4 months ago to random

OK, on to the question of where Surveyor 3 actually landed. this set of maps zooms in to the landing site. See the faint white streak running top to bottom in map A. It's a ray from Copernicus. That was why Surveyor 3 rather than Surveyor 1 was chosen to be the Apollo 12 landing site. In Map D you see Surveyor 3, Apollo 12 and a third location, the Surveyor 3 retrorocket impact site. Too bad the crew didn't walk that way!

PhilStooke, 4 months ago to random

OK, so what moon landing did follow Apollo 12? It would have been Apollo 13 but that landing didn't happen, so the next landing mission was Luna 16. Here is a pair of maps showing the site. On the left is a Russian map with the site located on it (Russian cartographers made a strip of maps like these along the equator to support human landing site planning. They are redrawn versions of the US Air Force LAC maps.) On the right is an LRO image.

PhilStooke, 4 months ago to random

Today we complete the zoom-in on Luna 17 and Lunokhod 1. In these LRO images tracks are easily visible so the traverse can be mapped accurately. In 1970 it was not so easy. No high resolution orbital images existed, the exact landing point was not known, and the path had to be estimated from driving commands. The Soviet scientists mapped a large shallow crater in the middle of the path so I tried using that to locate Luna 17, but it was so subtle it barely exists. I got the wrong place.

PhilStooke, 4 months ago to random

This is a 'finder chart' zooming in on the Luna 16 landing site. I make these so I can find the site easily in images. What came after Luna 16? Luna 17, of course. But that's for tomorrow.

PhilStooke, 4 months ago to random

Here is the actual route mapped from tracks visible in LRO images. The crater names (forms of the first names of rover engineers) were not used at the time and only added a decade or so ago, made official by the IAU. The crossroad was where the rover crossed its tracks as it returned to the lander. The northern route was designed to provide a better view, if possible, of distant hills visible on he horizon. Tomorrow: a close-up.

PhilStooke, 4 months ago to random

As promised, an additional Apollo 12 map today. This is half of an EVA 1 map from a future project. The white lines show pre-LRO estimates of the EVA path and the dark lines shows the EVA based on footprint tracks. The inset shows the ALSEP layout. I hope to have the full EVA map and much more released in about 18 months.

PhilStooke, 2 months ago to random

The first person who ever mapped a non-spherical world was Tom Duxbury, then at JPL. Here he is looking very jovial. He made an ellipsoidal grid and overlaid it on Mariner 9 images to establish its size, orientation, rotation etc. This also gave him approximate locations for surface features. He plotted them on a map grid in the form of a Mercator Projection of lower and mid-latitudes and two circular polar maps. The projection was based on a sphere, not modified.

PhilStooke, 5 months ago to random

Something different today. I'm not adding images, just showing coverage of some post-Lunar Orbiter images. At left, areas covered by Apollo images (except for high altitude images taken during departure from the Moon, including Apollo 13). These are the panoramic camera, Metric camera and Hasselblad images. At right, areas covered by the three later Zond spacecraft. Zonds 6 and 7 are low resolution, but Zond 8 images are high resolution and very high quality. Next... Clementine.

PhilStooke, 5 months ago to random

Today's mission is Perseverance. As with Curiosity there is no lander, just tracks and marks left by the descent stage thrusters. I won't extend coverage to the traverse but you can follow it on www.unmannedsapeflight.com. This map is made from a rover panorama projected onto a HiRISE image. Tomorrow: Tianwen-1 and Zhurong.

PhilStooke, 4 months ago to random

Let's look at the scenery at the Surveyor 7 site. I made this image of the hills north of the lander from single frames scanned at LPI. What a place it would be to walk around. I scanned lots of Surveyor stuff at LPI, Flagstaff and LPL in Tucson about 20 years ago, enough for a panorama of each site (but not all as good as these panorama fragments).

PhilStooke, 4 months ago to random

We now move on to Surveyor 5 (Surveyor 4 crashed). The spacecraft landed with two footpads on the wall of a small crater and the third outside the crater, just about the worst possible situation for stability. It skidded down into the crater but remained upright and operated perfectly after that. I always attributed its survival to its having 3 legs but now I will credit its survival to a low centre of mass and wide-splayed legs.

PhilStooke, 5 months ago to random

This is the Tianwen-1 landing site with the first few drives of the Zhurong rover. The background is a HiRISE image. Two names are informal and added by me, not by China. TAR is a Transverse Aeolian Ridge, what might be called a dune (but technically not). This was going to be the last of my Mars landing site images, but I have decided to add the final resting places of Spirit and Opportunity, taking us nicely up to Christmas.

PhilStooke, 4 months ago to random

The top part of this map is one section of a 2-part map of EVA 1 for Apollo 14. Mitchell's 'quadruplet' crater is identified as well as some of the activities including collecting 'football-sized' rocks. The bottom part of the map is a summary of activities at the end of EVA 2 when Mitchell visited Turtle Rock and Shepard walked out to the ALSEP to check the central station antenna (not labelled on this half of the map). Tomorrow: getting some context.

PhilStooke, 5 months ago to random

This is the final resting place of Spirit, at the SW edge of Home Plate in the Columbia Hills. Spirit became stuck in soft soil on the edge of Scamander crater. The name Achiles would normally have two 'L's but I think this spelling is from the source. Tomorrow: Opportunity.

PhilStooke, 4 months ago to random

This is the Apollo 14 landing site. The 'quadruplet' craters (the 4th crater will show up tomorrow) are not named on mission maps but were referred to by Ed Mitchell. MET was the small cart they pulled around. The 'dark spot' is probably a small rock or crater showing up in high sun LRO images but its identity is not very obvious in surface images. Maybe it was a bit of debris (packaging etc.) blown there during the LM ascent.

PhilStooke, 4 months ago to random

So here is the workspace, showing trenches and other contact points plus the 3 positions of ASI. The first attempt to move it to a rock was off target so it was picked up again and moved to the rock. Tomorrow, some context for this map.

PhilStooke, 4 months ago to random

And an extra today - some hills showed up to the north of the rover, just visible over the horizon. This is an attempt to locate the hills. You can see the Lunokhod panoramas here:

https://planetology.ru/panoramas/lunokhod1.php?language=english