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

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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 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.


A view composed of 28 images taken by Curiosity of the Greenheugh Pediment, a “clay-bearing unit” indicating a history of water on Mars.

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