On the LEGO Ideas website, user-submitted projects that reach the 10,000-supporter level are evaluated by LEGO to determine whether it can become a shipping product. Which is to say that Marc Sloan’s 2,360-piece “The Moon: Earth’s Companion,” a Moon map poster rendered in LEGO, stands at least some chance of being something one could buy at some point. [Universe Today]
The Global CTX Mosaic of Mars, produced by CalTech’s Bruce Murray Laboratory for Planetary Visualization, is a 5.7-terapixel mosaic of the Martian surface at a resolution of five metres per pixel. The mosaic is available in a number of different formats (via ArcGIS Online, KML, shapefiles), as well as via this online viewer; and the Lab is quite transparent about how they constructed it from Mars Reconnaissance Orbiter Context Camera (CTX) data. [Maps Mania/La Cartoteca]
You must see this. Ken Shirriff got his hands on an example of a navigational device from a Soyuz spacecraft and opened it up to see how it worked. Known as a Globus (its proper name is Индикатор Навигационный Космический—roughly, space navigation indicator), it’s an incredibly complicated marvel of gears and cams, an electromechanical analog computer that showed the capsule’s position on a physical globe. The position was predicted—the Globus received no navigational data. Ken’s got lots of photos of the innards at his website. See also his Mastodon thread. He has hopes of getting the thing operational, so keep an eye out for that.
(Based on the presence of NASA tracking sites on the globe, Ken thinks this particular unit was meant for the Apollo-Soyuz program, but I kind of wonder whether that was a function of the 1967 Rescue Agreement between the U.S. and the USSR instead.)
The Mercury capsule had something similar for a while: the Earth Path Indicator. One example sold for nearly $100,000 in 2019.
The USGS’s Astrogeology Science Center highlights three geologic maps of Mars released in late 2021. The maps are large-scale, focusing on specific Martian features (e.g. Olympus Mons, above).
Though maps have historically covered large areas, with crewed lunar missions on the horizon and other missions across the solar system in the planning stages, large-scale, small-area maps are starting to steal the limelight. These large-scale, small-area maps provide highly detailed views of the surface and allow scientists to investigate complex geologic relationships both on and beneath the surface. These types of maps are useful for both planning for and then conducting landed missions.
The maps are of Olympus Mons Caldera, Athabasca Valles and Aeolis Dorsa. Interactive versions, with toggleable layers over spacecraft imagery, are also available: Olympus Mons Caldera, Athabasca Valles, Aeolis Dorsa.
“A recently released set of topography maps provides new evidence for an ancient northern ocean on Mars. The maps offer the strongest case yet that the planet once experienced sea-level rise consistent with an extended warm and wet climate, not the harsh, frozen landscape that exists today.” Press release, video, article (JGR Planets). [Universe Today]
A new map of Mars reveals the abundance of aqueous minerals—clays and salts that form in the presence of water—that were created during the planet’s distant watery past. “The big surprise is the prevalence of these minerals. Ten years ago, planetary scientists knew of around 1000 outcrops on Mars. This made them interesting as geological oddities. However, the new map has reversed the situation, revealing hundreds of thousands of such areas in the oldest parts of the planet.”
More on the astonishing idea that Earth-orbiting GNSS satellites can be used for navigation at the Moon. The European Space Agency reports that among the instruments carried by the upcoming Lunar Pathfinder commercial mission will be a 1.4 kg satnav receiver that will test its ability to receive GPS and Galileo signals from lunar orbit. “Satnav position fixes from the receiver will be compared with conventional radio ranging carried out using Lunar Pathfinder’s X-band transmitter as well as laser ranging performed using a retroreflector contributed by NASA and developed by the KBR company.” Lunar Pathfinder is currently scheduled to launch in 2024.
Previously: Many Moon Maps; Can GPS Be Used on the Moon?
It turns out that the Geostationary Lightning Mapper (GLM) aboard the GOES-16 and GOES-17 earth observing satellites can do more than just detect lightning—it can also detect bolides, or very bright meteors, thanks to a new automatic detection algorithm. NASA Earth Observatory: “The map above shows the distribution of more than 3,000 bolides detected by the GLMs aboard GOES-16 and GOES-17 between July 2017 and January 2022. Blue points are bolides detected by GOES-16; pink points were detected by GOES-17. The lone pink point over the Atlantic Ocean was detected by GOES-17 during its commissioning phase before it was moved into its operational orbit over the West Coast.” (Bolides in the middle of the map are detected by both, and as you can see there’s a bit of parallax.)
VERITAS is one of two missions to Venus announced by NASA last week. Expected to launch between 2028 and 2030, VERITAS will produce an improved map of the Venusian surface with its two instruments: synthetic aperture radar to generate a high-resolution 3D topographic map, and a spectral emissions mapper to map rock types. News coverage: CNN, Global News, Slate, The Verge. Background from NASA; analysis from the Planetary Society.
National Geographic looks at the rivalry between two early cartographers of Mars who based their maps on observations made during Mars’s “Great Opposition” in 1877: Nathaniel Green, whose Mars “was a delicately shaded world with landforms that gradually rose from vast plains and features that blended into one another” (pictured here) and Giovanni Schiaparelli, whose Mars had more detail—including those famous canals—but was less accurate.
A new study maps the possible locations of subsurface water-ice reservoirs, vital for any crewed missions. [Sky & Telescope]
Kenneth Field’s virtual globe of Mars follows in the footsteps of his 2016 map.
Interactive maps showing the locations and paths of the Curiosity and Perseverance rovers. [Maps Mania]
The Closest Stars is the latest astronomical map produced as part of Kevin Jardine’s long-running Galaxy Map project: it shows stars within 10 parsecs (32.6 light years) of our solar system. (Earlier maps covered much more territory: this map goes out to 6,000 pc.)
It’s fascinating, and has a lot of interesting information, but there’s a problem. Like all maps, it reduces three dimensions to a flat plane; as such it distorts the distance of stars that are substantially above or below the galactic plane but not very far away on the x or y axis. Take Beta Comae Berenices: it’s 9.18 pc away and as such should be at the edge of the map, but because it’s 9.18 pc away on the z axis, at nearly a right angle to the plane, it appears on the map as one of the closest stars. The distance above or below the plane is marked in parentheses, but that’s not enough: a label can’t compensate for a misleading position on the map. On the smaller-scale maps this isn’t as much of an issue, because the galaxy is more or less a disk or a lens, but within a 10-pc radius? This isn’t the right projection for the job.
How do you depict elevation on a map of Mars? Earlier this year, Daniel Huffman posted a roundup of hypsometric tints for Mars.
I have a peculiar hobby of collecting Martian hypsometric tinting schemes: those sets of colors that cartographers use to depict elevations on the Red Planet. It’s a fascinating cartographic frontier. While the classic (and somewhat flawed) way of showing Earth’s elevations is to use a color scheme that starts with green lowlands, and then proceeds through some combination of brown/yellow/orange/red until it reaches white in the highest areas, there’s no standard yet for Mars. Maybe centuries from now, one of the schemes below will become that standard.
Huffman looks at fifteen schemes in total in the post, and in this video on YouTube:
Two geological maps of Venus have been published in Earth and Space Science. Produced by Vicki L. Hansen and Iván López, they each cover a 60-million-square-kilometre section of Earth’s twin: the Niobe Planitia Map Area geologic map (above, top) ranges from the equator to 57° north, and from 60° to 180° east longitude; the geologic map of the Aphrodite Map Area (above, bottom) is the Niobe Map Area’s southern hemisphere equivalent, covering the area from 60° to 180° east longitude, but from the equator to 57° south.
The March 2020 issue (PDF) of Calafia, the journal of the California Map Society, has as its theme the mapping of space. It also has something from me in it: my review of the third edition of Nick Kanas’s Star Maps: History, Artistry, and Cartography. An excerpt:
It’s important to remember a book’s target audience—its imagined ideal reader. In the case of Star Maps this is Kanas’s younger self, who came to map collecting via his lifelong interest in amateur astronomy. “I was frustrated that there was not a single book on celestial cartography that could inform me about the various aspects of my collecting,” he writes in the preface to the first edition. “What I needed was a book that not only was a primer for the collector but also had sufficient reference detail to allow me to identify and understand my maps. Nothing like this appeared, so I decided to write such a book some day” (p. xxi). In other words, for a compendium this is a surprisingly personal book, one that reflects his own journey into the subject and, presumably, his interests as a collector.
I’ll post the full review on The Map Room once I’ve checked my draft against the published copy. In the meantime, check out the issue of Calafia (PDF) in which it appears. (Update, 24 Jun 2020: Here it is.)
Star Maps: History, Artistry, and Cartography
3rd edition
by Nick Kanas
Springer Praxis, Sept 2019
Amazon (Canada, UK) | Apple Books | Bookshop
More on the question of whether GPS can be used for navigation on the lunar surface—that is to say the existing constellations of Earth-orbiting GNSS satellites, not a new constellation of satellites around the moon. A new study suggests that the answer is yes: GPS and other navigation systems could be used.
Cheung and Lee plotted the orbits of navigation satellites from the United States’s Global Positioning System and two of its counterparts, Europe’s Galileo and Russia’s GLONASS system—81 satellites in all. Most of them have directional antennas transmitting toward Earth’s surface, but their signals also radiate into space. Those signals, say the researchers, are strong enough to be read by spacecraft with fairly compact receivers near the moon. Cheung, Lee and their team calculated that a spacecraft in lunar orbit would be able to “see” between five and 13 satellites’ signals at any given time—enough to accurately determine its position in space to within 200 to 300 meters. In computer simulations, they were able to implement various methods for improving the accuracy substantially from there.
A mini-network of relays—a couple of satellites in lunar orbit, say—could improve accuracy further. [Geography Realm]
Previously: Many Moon Maps.
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