# The Orbital Index

Issue No. 52 | Feb 20, 2020

🚀 🌍 🛰
 It’s a bit hard to believe, but this issue marks one full year of The Orbital Index. We’ve immensely enjoyed diving down Internet rabbit holes and writing about space each week. And, we’ve even gotten to meet some of you! As we look forward to more weeks of writing and meeting more of you, we thought this would be a good moment to pause and reflect on the ongoing development of the newsletter and its community. It’d be swell if you could take 3 minutes to complete a quick survey about how you read The Orbital Index and what you think should come next. (We’ll also put it at the bottom so you can read the important space stuff first.) To another 942,000,000 km trip around our star with weekly doses of rockets and space exploration (and not too much radiation),— Andrew and Ben🎈🎂 🎉
 ¶NASA announced funded concept development of four interplanetary missions. One or two of these Discovery-class missions will be selected next year for continued funding. The missions under consideration include the Io Volcano Observer (pdf), a mission to study volcanic Io through a series of close flybys and learn how tidal forces shape planets; Trident, a flyby mission to study the frost geysers and (possible) icy subsurface oceans of Neptune’s moon Triton; and, two missions to Venus, including a spherical lander probe called DAVINCI+ (pdf) which will look for lost oceans, and VERITAS, an orbital synthetic aperture radar and infrared imager to determine whether Venus has active plate tectonics and volcanism, seeking to answer how a planet so similar to Earth could end up so different. NASA’s Discovery Program typically funds missions that cost less than $300 million, including such past successes as the Kepler space telescope, the Lunar Reconnaissance Orbiter, the Mars Pathfinder and Mars InSight landers, and Dawn, with the upcoming Lucy and Psyche missions to asteroids launching in 2021 and 2022.  ¶PapersAccording to a recent study, asteroids orbiting main-sequence stars (like our Sun) will be destroyed as the stars age by their increased luminosity alone. This is due to the YORP effect (which we’ve mentioned a few times in the past), in which heating from sunlight slowly spins up asteroids until they fly apart. “When our sun dies and runs out of fuel in about 6 billion years [...] its luminosity [...] will bombard our asteroid belt with increasingly intense radiation, subjecting the asteroids to the YORP effect and breaking them into smaller and smaller pieces.” Hubble has detected the smallest clumps of Dark Matter yet seen by looking at the way it gravitationally lensed quasars moving behind it.Here are two paper summaries from Brian Koberlein for Universe Today about the continuing Crisis in Cosmology over the nature of Dark Energy, if it even exists. First is evidence that we’ve been wrong about the reliability of the brightness of Type Ia supernovae, which gives a result for the expansion rate of the Universe without requiring Dark Energy. However, a second method of calculating the Universe’s expansion rate using gravitational lensing still requires Dark Energy to match our observations. Both paper summaries are compelling, and it remains clear that there’s something odd going on in the Universe that we definitely don’t yet understand.Recordings of geoneutrinos—neutrinos coming from within the Earth—by the Borexino detector at the world's largest underground laboratory indicate that radioactive decay is a significant source of the Earth’s internal heat, driving processes like volcanoes and the Earth’s magnetic field.Results from New Horizons’s flyby of Arrokoth (née Ultima Thule) in the Kuiper Belt suggest that the snowman’s lobes orbited each other and drifted together slowly, supporting a model of planetesimal formation where bodies form slowly by the gravity-driven collapse of clouds of solid particles (paper), rather than rapidly by high-speed collisions, as the competing theory of hierarchical accretion suggests.Using data from the last 150 years, it appears that destructive solar superstorms occur every 25 years or so (paper). Carrington Event-level storms may happen with little warning and be more common than thought. No further research is needed.  ¶News in brief. William Gerstenmaier, NASA’s ex-chief of the human spaceflight division, has joined SpaceX; the Mars 2020 rover has arrived in Florida; Spaceway-1 reached its high graveyard orbit without blowing up (and will now drift in its slow orbit for millions of years); a Cygnus spacecraft launched 3,400 kg of supplies and experiments to the ISS; an Ariane 5 launched a Japanese communications sat and a Korean environmental monitoring sat; SpaceX and Space Adventures announced plans to fly tourists aboard Crew Dragon in 2021-2022; Rocket Lab won a contract to use their launch vehicle and new Photon bus to send NASA’s CAPSTONE CubeSat to test out a near rectilinear halo orbit around the Moon—the orbit that the partially crewed Lunar Gateway will use if it ever gets built; and, India proudly showcased its anti-satellite weapon at an arms bazaar. 😠  ¶Etc.Christina Koch is reunited with her pup after 328 days apart (in space).NASA is crowdsourcing solutions for mechanical Venus rovers (with a$15,000 prize to the best entry), and Scott Manley has a video about past proposals for mechanical computers and sailing rovers to explore the hot planet, such as AREE. Quindar Tones are those characteristic beeps you hear in every old space audio recording.The ESA is developing a pair of rovers to explore the Moon’s surface.An in-depth NYT piece about how the United Arab Emirates’ Hope orbiter was developed in collaboration with U.A.E. researchers (many of whom are women under 35) and US universities—it launches for Mars this summer.Breakthrough Listen has released a 2 petabyte optical and radiofrequency dataset from large telescopes around the world—dig in and see what you can find! Meanwhile, the SETI Institute and the Very Large Array in New Mexico (see the movie Contact) are teaming up to search the VLA’s existing data stream for technosignatures.Casey Handmer takes a detailed look at why Starship shouldn’t be staged, and it all comes down to payload efficiency. “While the Saturn V delivered about 4.5% of its launch mass to orbit, the Electron delivers [...] only 1%”. Only part of betelgeuses is dimming.A look at a few of the lasting ‘mysteries’ of the Spitzer Space Telescope mission.Lest you think Spinlaunch is the only crazy in town, Amazon has patented a mechanism for throwing satellites into space with a multi-drone-guided whip… on a boat. Note, though, that Amazon (and other tech companies) have a history of patenting things that they’ll never actually build, such as Amazon’s underwater fulfillment centers.