(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.)
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.
“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.
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.)
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.
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.
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.
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.)
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]
A new unified geologic map of the Moon, based on digital renovations that updated 1970s-era geologic maps to match more recent topographic and image data gathered by lunar orbiters, was released by the USGS last month. The map is “a seamless, globally consistent, 1:5,000,000-scale geologic map”; the paper version (25 MB JPEG) provides azimuthal projections beyond the 55th parallels and an equirectangular projection between the 57th parallels. [Geography Realm]
The map legend colors represent the broad types of geologic units found on Titan: plains (broad, relatively flat regions), labyrinth (tectonically disrupted regions often containing fluvial channels), hummocky (hilly, with some mountains), dunes (mostly linear dunes, produced by winds in Titan’s atmosphere), craters (formed by impacts) and lakes (regions now or previously filled with liquid methane or ethane). Titan is the only planetary body in our solar system other than Earth known to have stable liquid on its surface—methane and ethane.