Issue No. 34

The Orbital Index Issue No. 34 | Oct 15, 2019 🚀 🌍 🛰

¶Space debris tracking. LeoLabs announced that they plan to build four additional radar installations for tracking space debris. Their current installations can track objects down to about a 10 cm diameter, but with their new installations they’ll theoretically be able to track objects as small as 2 cm. In general, current radar systems tend to be limited on the lower end to objects in the 5-10 cm range. Systems like LeoLabs’ and the US Air Force’s upcoming Marshall Islands-based Space Fence will improve coverage, but still won’t see the 128 million objects from 1 mm to 1 cm. For perspective, a collision with a 10 cm object will likely completely destroy a satellite, a 1 cm object will likely disable it, and a 1 mm object may disable a subsystem. At closing velocities around 10 km/s, the kinetic energy of even an untrackable chip of paint is greater than the destructive power of an equivalent mass of stationary TNT. Whipple shields around the ISS’s crewed areas are built to absorb impacts with objects of up to around 1 cm. For anything bigger, an avoidance maneuver is used (if we see it coming). This very detailed article about Space Fence also examines the variety of space situational awareness systems currently deployed worldwide. ¶Lunar ISRU is starting to feel a bit more real. Researchers recently extracted 96% of the oxygen from simulated lunar regolith (paper), with the other useful byproduct of the process being powdered metal, potentially useful for metallic 3D printing and other applications. Lunar regolith is composed of oxygen, silicon, aluminum, iron, calcium, and magnesium (these last two having higher concentrations than on Earth), with small amounts of other elements. Oxygen makes up around 40% of the regolith but is trapped in the form of oxides. In the experiment, oxygen was extracted from powdered regolith using a molten salt electrolysis method at 950° C leaving powdered metal (previous extraction techniques yield less oxygen or require melting the regolith at 1600° C). The extraction process takes 50 hours and is based on the “FCC Cambridge process” which was developed over a decade ago and has recently been commercialized for terrestrial use by Metalysis in the UK. Another group is researching a laser-sintering-like process that could be used to create roads, building foundations, and landing pads out of regolith. A demo mission for this approach, named Moonrise, is scheduled for 2021. Meanwhile, the ISS hosted BioRock this summer, an experiment to use several different microbial biofilms to extract minerals and metals from rocks, a process aptly named biomining. ¶News in brief. Alexei Leonov, the first human to walk in space (colorized video), has passed away at 85 (he was also a painter, and later commanded the Soyuz that docked with an Apollo module in the joint US-Soviet spaceflight that symbolically ended the space race); an air-launched Pegasus XL successfully launched NASA’s $252 million ICON spacecraft to study the Earth’s ionosphere; speaking of air-launched rockets, Virgin Orbit has partnered with SatRevolution and a group of Polish universities to attempt to become the first private company to launch a spacecraft to Mars (weighing up to 50 kg); meat was 3D printed in space; and, 20 new ~5 km moons were discovered orbiting Saturn, bringing its total to 82, and out-mooning Jupiter which has just 79. ¶Etc. ISRO released a photo taken of the moon by Chandrayaan-2 with a record-breaking 30 cm per pixel resolution. An animation of what it would look like from Earth (if it were still habitable and not a Venusian hellscape) when the Andromeda galaxy collides with the Milky Way. Bumble, one of NASA’s Astrobee flying robots, took its first fully autonomous flight around the ISS. An open-source robot capable of dynamic movement (kind of like Boston Dynamics' Spot). While we’re at it, how about open-source seeds, blueprints for civilization, insulin, other medicines, and of course lots of open-source space resources. The world’s largest optical lens (video). An Australian team recently set a new Water Rocket Altitude Record. 3 million light year long filaments of gas fuel the growth of galaxies and supermassive black holes (Science paper), supporting the cold dark matter model of galaxy formation. “It is generally believed that filaments in the universe fueled the formation of clusters of galaxies … at places where the filaments crossed.” Tim Dodd has been at full thrust lately, getting candid interviews with some high-profile figures. This week he talked with NASA administrator Jim Bridenstine about the Commercial Crew program while visiting SpaceX HQ. An animated explanation of why “habitable zone” is a very poor naming choice. Basically, it depends on the characteristics of the planet as well as the star—planets with thin atmospheres would need to be closer to their star to have the same temperatures as planets with thicker atmospheres do further out. (This is a good one to watch with kids.) The fairly adorable SpaceBit rover will be onboard Astrobotic’s 2021 commercial lunar lander. A Twitter thread about gender equality, space, and puppets. SpaceX to replace Falcon 9’s titanium grid fins with steel on Starship’s Super Heavy booster. “They could afford to cut it close because they all had Global Entry.”

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