# Issue No. 84

 Sometimes we enjoy giving our issues a theme—this week’s theme is water, in all its forms, from ice to astronaut urine.

# The Orbital Index

Issue No. 84 | Sep 30, 2020

🚀 🌍 🛰
 ¶Mars might have a significant amount of subsurface liquid water. In a “hold my beer” move aimed squarely at Venus’ upper atmosphere, the red planet revealed that it may have multiple subsurface lakes containing liquid water. These lakes, first suggested in 2018, were found in the polar regions underneath 1 km or more of ice. Data gathered by the ESA Mars Express orbiter’s Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument from 2012 to 2019 was analyzed using methodologies similar to those used to find terrestrial subglacial lakes. Any liquid water is likely to be extremely salty, but extremophiles could potentially exist there (paper). Related: NASA's MAVEN spacecraft revealed how Mars lost its atmosphere and much of its water, and the UAE’s Hope mission will continue this research.
 ¶Lunar IceCube. A 6U CubeSat designed to prospect for lunar water will launch on EM-1, the first Artemis mission, and is “the most operationally complex CubeSat to date”. The 14 kg CubeSat will search for water in ice, liquid, and vapor (in the Moon’s very tenuous atmosphere) forms and includes an Iodine-based electric propulsion thruster and the BIRCHES cryocooled volatile-seeking spectrometer (based on an instrument used by New Horizons; pdf). IceCube will spend six months in lunar orbit while testing several small-scale planetary mission technologies. The onboard IRIS radio from JPL will communicate using the open source Interplanetary Overlay Network architecture (parts of it open sourced as pyion & bplib)—more information on the mission software is available from Michael R. Glaser-Garbrick’s Morehead State University thesis. IceCube uses many COTS parts, including a solar array, battery, and power system from Pumpkin, a radiation-hardened Proton 400K flight computer from Space Micro, and Blue Canyon Technologies’s XACT attitude determination and control subsystem (ADACS). More hardware details are available here. Related: another of EM-1’s 13 secondary payloads is the Lunar Flashlight CubeSat mission, designed to search for ice in permanently shadowed lunar crater regions using an onboard laser. Related: Ice Prospecting: Your Guide to Getting Rich on the Moon.
 ¶Space debris is getting worse. The ISS maneuvered again to avoid a fragment from the breakup of Japan's H-2A F40 rocket stage. This is the third debris avoidance maneuver since March, but before that the last maneuver was in 2015—Bridenstine tweeted that “in the last 2 weeks, there have been 3 high concern potential conjunctions. Debris is getting worse!” (Three similar maneuvers did happen in both 2011 and 2012, with two more in 2015.) The New Yorker has a (cutely animated) piece about the perils of space junk. Some good news is that the US Space Command just announced improvements to the space debris tracking data that it shares on a catalog of over 25,000 pieces of junk—debris-debris collisions will now be predicted in addition to ones involving spacecraft. Additionally, researchers announced a preliminary method for daytime laser ranging of debris this spring, which has traditionally been restricted to twilight hours when debris is illuminated by the Sun but the ground station is not. A longer-term solution might be a collaboration between launch countries to charge an orbital use fee and/or monetarily incentivizing debris removal missions, but it’s unclear if this will ever happen at scale. Related: Finally, as if we weren’t building an artificial planetary ring fast enough, Earth may briefly get a new mini-moon, but it’s probably a piece of 1960s space junk coming back home—a Centaur upper stage from Surveyor 2.
 ¶Papers (about water).The bright, salty deposits that NASA’s Dawn spacecraft spotted on Ceres likely come from briny water escaping from a 418 km-across underground reservoir 48 km below the surface (paper). Two reservoirs were spotted by analyzing the dwarf planet’s gravitational field. The salt deposits are young, suggesting that Ceres, the largest asteroid in the solar system, is still an active world. Ceres joins the growing list of solar system bodies that likely host hidden oceans: Enceladus, Europa, Ganymede, Pluto, and the previously mentioned subglacial lakes on Mars.Using Juno’s navigation camera, scientists spotted lightning in Jupiter’s cloud tops (paper), higher than we’d expect if it’s due to liquid water. They believe that ammonia is acting as an antifreeze, keeping around the right combination of liquid water and ice particles for charge to accumulate. The water and ammonia may also precipitate as slushy “mushball” hail (paper). Some of Earth’s water may have come from the breakdown of organic space-born molecules (paper), while the rest could have come from hydrogen locked up in enstatite chondrite meteorites (paper), instead of being delivered by comets and carbonaceous chondrite meteorites that formed beyond the snow line in the outer solar system, as has been previously assumed.Juno took the first image of Ganymede’s north pole. Ganymede, a moon larger than the planet Mercury, is made mostly of water ice. The ice near its north pole appears to have been altered by Jupiter’s intense radiation to become an amorphous material without crystalline structure.
 The recently-released mission poster for NASA’s upcoming Europa Clipper mission to study the Jovian moon’s icy shell and liquid saltwater ocean. It will attempt no landing there (yet).
 ¶News in brief. The search for the slow ISS air leak continues; Firefly performed a successful acceptance test of Alpha’s first stage 📺 with its four thrust-vectored Reaver engines burning for 35s while doing maneuvers; Finnish ICEYE raised an $87 million Series C round for their small SAR satellites; Airbus got a$352 million contract to build the EU’s climate change ice-monitoring CRISTAL satellite (pdf); SpaceX’s SN7.1 mostly-304 stainless steel alloy tank underwent a dramatic, intentional test-to-failure 📺—next we should be seeing the completion of SN 8 with flaps, a nose cone, and three Raptor engines; meanwhile, the first Raptor Vacuum (RVac) has completed testing; a bus-sized asteroid passed (safely) within the Earth’s geostationary ring on the 24th; China launched two ocean monitoring satellites on a Long March-4B without any announcement or air-traffic control warning; and, next week’s Cygnus cargo craft to the ISS will deliver a new astronaut toilet that allows an increased amount of usable water recovery from waste—“Yesterday’s coffee becomes tomorrow’s coffee.”
 ¶Etc.A new paper (co-written by the prolific Avi Loeb) about Venusian panspermia calculates that, while Earth microbes might struggle to survive being launched into space after the heat of a direct meteor impact, an atmosphere-grazing asteroid—like this one from, literally, last week—could pick up airborne microbes and deliver them to another planet unscathed. They estimate that 600,000+ asteroids have grazed our atmosphere, wandered the solar system, and ultimately ended up in Venus's gravity well over the last 3.7 billion years. Some of these would have broken up in the Venusian atmosphere, potentially delivering Earth microbes to their new home. Transfer in the opposite direction would be of a similar scale and also likely.NASA demonstrated a new type of room-temperature fusion in which deuterium fuel is confined in the spaces between the atoms of a metal, yielding a “deuterated” lattice (yes, that is a word) which allows fuel atoms to approach close enough together for a fusion reaction to occur due to the lattice’s negative electrons. Related: another fusion effort is starting up at MIT (detailed talk here 📺). Help NASA bring back frozen ice samples from the moon and win prizes. Floating Point, visually explained. See also 0.30000000000000004.com and float.exposed.An interactive model of Enceladus, as seen by Cassini VIMS and ISS instruments, showing fresh water ice on Saturn’s moon, including in the north polar region which previously was thought to be inactive.
 A view composed of 28 images taken by Curiosity of the Greenheugh Pediment, a “clay-bearing unit” indicating a history of water on Mars.