Issue No. 208

It’s our fourth-anniversary issue! We find it a bit hard to believe that we’ve been doing this for 208 weeks, but here we are. All we ask for our birthday is that you take a moment to share this free space newsletter with a friend or coworker. ❤️ Andrew & Ben 🚀

The Orbital Index Issue No. 208 | Mar 1, 2023 🚀 🎂 🛰

¶Hall thrusters go argon with Starlink V2 mini. Sunday, SpaceX shared photos of a stack of ~790 kg Starlink V2 “minis”. Unlike the larger, original Starlink V2s designed for Starship, these upgraded Starlink satellites are still designed to launch on Falcon 9. The company then proceeded to launch its first batch of 21 to LEO on Monday evening (check out a cool new camera angle captured from their upgraded stack deployment tension rods). Standout features on the new satellites include “more powerful phased array antennas and the use of E-band for backhaul—which will allow Starlink to provide ~4x more capacity per satellite than earlier iterations” and in-house argon Hall thrusters with 2.4x the thrust and 1.5x the Isp of their first generation thrusters (they’ve now hit 1 kW/kg, likely excluding its PPU). These Hall thrusters will be the first to fly in space using argon as the propellant—long deemed too low-efficiency to be appealing as a propellant, argon’s exceptionally low cost makes it attractive for large constellation use (the previous-gen thruster’s krypton costs ~100x, while industry standard xenon is ~1,000x, and both are produced in war-torn Ukraine). SpaceX (and the recently-acquired Swarm team who worked on the thruster) have managed to hit 2,500s Isp and 50% efficiency with these new thrusters using a center cathode design along with other unrevealed optimizations. Here is an exceptionally detailed thread about them. (Semi-related: If you’ve ever wondered what would happen if you stuck your hand in the plume of a Hall thruster, well, you’re reading the right newsletter. Just go here.) SpaceX also released details of astronomy-impact (ultra-black space-rated paint, dielectric mirror film, panels capable of being angled) and space debris mitigations that are included with V2 mini. A stack of Starlink V2 minis pre-launch. The Orbital Index is made possible through generous sponsorship by:   ¶‹Sponsored› Xometry is where leaders in aerospace are turning to bring their big ideas to life in 2023. Like you, they need instant quoting, quality parts, and competitive pricing on injection molding, CNC machining, 3D printing, laser cutting, and more. Get your instant quote today so that we can help get your ideas off the ground. ¶(Short) Papers Yet another new form of water ice has been discovered (paper). There may be as many as 300. Oh, and also a new type of salt water (paper), which could show up on Europa. Six large, mature galaxies were spotted by JWST which may have formed only 500-700 million years after the Big Bang (paper)—the result is preliminary because we don’t have spectroscopic data yet. These galaxies appear way more mature than we’d expect to see so early in the Universe and, if confirmed, would challenge our assumptions on galaxy and star formation in the early Universe (this seems to be happening a lot since JWST came online). The spectroscopic CARMENES instrument on the Calar Alto Observatory in Spain released 20,000 observations on 300+ small, nearby stars which include data on 59 new or previously unconfirmed exoplanets, with a dozen of those being potentially in liquid-water habitable zones (paper). The Event Horizon Telescope (EHT) strikes again, combining radio telescopes from across the planet, this time to image magnetic fields around quasar NRAO 530, a Super Massive Black Hole that is emitting powerful jets of radiation pointed more or less directly at us. The EHT’s absurd resolution lets scientists image at the scale of one light-year on an object 7.5 billion light-years away (paper). That’s equivalent to roughly half-kilometer resolution from Earth to Pluto. Low-frequency gravitational waves (microhertz) with the right frequency should cause detectable resonance in the orbits of binary objects, like the Earth / Moon system. There is a proposal to use accurate lunar distance measurements (via existing lunar retroreflectors left by Apollo and Soviet missions) to detect such orbital variations and to model the low-frequency gravitational wave background (paper), a region of the gravitational wave spectrum that has so far been unexplored. “Space-time is like some simple and familiar system which is both intuitively understandable and precisely analogous, and if I were Richard Feynman I'd be able to come up with it.” XKCD #895 ¶News in brief. NASA is partnering with Israel to launch the country’s first space telescope—the Ultraviolet Transient Astronomy Satellite focusing on short-duration events like supernovae and neutron star mergers—in 2026 ● Tyvak (a subsidiary of Terran Orbital) won a $2.4 billion contract to build 300 LEO communication sats for Rivada Networks with deployment planned to start in 2025 ● China launched a comms sat on a Long March 3B and Horus-1, an Egyptian EO sat, on a Long March 2C ● Malawi-based Galamad Aerospace raised $1M to work on a new CubeSat platform ● MRO photos of China’s Zhurong rover show it unmoved since September 2022 (it went dormant during the Martian winter and is rumored to have failed to re-establish communications early this year) ● Crew-6 was called off with two minutes on the clock due to a ground system issue involving the Falcon 9’s TEA-TEB engine ignition fluid ● SpaceX sent Inmarsat-6 F2 toward GEO ● Satellite servicing and hopeful debris-removal company Astroscale closed a $76M Series G round ● The uncrewed Soyuz MS-23 headed to the ISS as an emergency replacement for the leaking Soyuz MS-22, it also brought up 429 kg of equipment and supplies ● Texas Governor Greg Abbott requested $350M from the state legislature to form a Texas Space Commission (pdf) ● Momentus announced that its Vigoride space tug which launched on T6 is doing well and that two more launches are planned for this year, along with a $10M raise, a $10M share repurchase, and a $8.5M class action suit settlement, which should remove some baggage the company has been struggling to overcome ● ULA announced a NET May the 4th launch date for Vulcan—carrying Astrobotic’s CLPS Peregrine lander (originally planned for launch in June 2021)—along with plans to ramp launch cadence up to twice per month.   ULA’s first Vulcan Centaur in the midst of being stacked at the company’s vertical integration facility in Florida. ¶Etc. A design has emerged for a Chinese lunar lander, which would carry two astronauts NET 2029. A NASA safety panel is concerned that, due to Artemis’s slow cadence, “NASA’s concerted attention to a healthy safety culture may have diminished, leaving NASA vulnerable to the same flaws that contributed to previous failures.”. A 500-meter-long asteroid with roughly the same size and shape as the Empire State Building passed by the Earth in February and was imaged by planetary radar.  An interactive, satellite EO-driven article about the extent of damage in Ukraine. And a similarly well-done visualization of rising seas and coastal erosion in Senegal. Data submitted as part of the Paris Agreement’s UNFCCC Global Stocktake process still rarely relies on Earth observation data throughout the majority of tropical reporting countries—only two of the 56 tropical countries track fires using satellites (paper). On the other hand, Global Forest Change (GFC) was developed with IPCC reporting requirements in mind and is the one outlier EO product that was used by half of the countries to measure land extent and change. It could serve as a pattern for developing successful EO products that help countries report higher-quality climate data.  “How do you make a battery that works for months in conditions that melt lead solder, boil electrolytes in battery cells, and are the equivalent of being a kilometer underwater?” NASA and Advanced Thermal Batteries, Inc. are working on a battery that could power a Venusian lander for a full Venus solar day (which is ~120 Earth days long). The molten salt thermal battery would utilize Venus’s ambient temperature to keep the alkali halide electrolyte at its required temperature. Curiosity found rippled rocks on Mars—clear evidence of sediment solidified billions of years ago on the bottom of a shallow lake.

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