Issue No. 96

Happy Holidays from The Orbital Index! We hope that you are enjoying distanced celebrations with your friends and families, watching the once-in-800-year planetary conjunction, and are looking forward to it being a year that isn’t 2020. —Andrew & Ben

The Orbital Index

Issue No. 96 | Dec 23, 2020


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Machine learning isn’t just for space. It’s also for space newsletters. For your enjoyment, we fine-tuned the GPT-2 machine learning language model on our archives and you won’t believe what happened next! Our favorite output: Geese are probably not extraterrestrial in origin (paper). But, check out the rest of the space news from an alternate reality as well! 

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As always, it's probably not aliens. Back in 2019, Breakthrough Listen detected a very narrow, unmodulated, drifting, transient radio emission at 982.002 MHz from the direction of Proxima Centauri, a member of the Alpha Centauri star system and our closest stellar neighbor at only 4.2 light-years away. Proxima Centauri is a red dwarf star (when you hear this, you should think: powerful planet-sterilizing solar flares) with at least two planets, one of which is in its “habitable” zone. Dubbed BLC-1, this is the first candidate signal in the Breakthrough Listen project that has gotten through both their layers of automated filters designed to throw out noise / human-made emissions and then manual inspection. They are currently writing analysis papers and repeatedly stressing that, since we don’t know of a mechanism in nature that creates such a narrow band emission, this signal is almost certainly terrestrial interference of an unexpected type. While almost certainly not aliens, this signal presents an opportunity to tune our SETI filters, learn about novel sources of terrestrial interference, and practice for the day when we finally receive a signal for which there is no abiotic explanation. Nadia Drake has a good writeup.

The Square Kilometer Array. The world’s most ambitious radio telescope project took a step forward last week with the UK signing a final agreement to host the headquarters of the Square Kilometer Array (SKA) at the Jodrell Bank Observatory outside Manchester, a UNESCO world heritage site for its work in early radio astronomy. The SKA itself, a massive long-baseline interferometer array, will be built in an expansive spiral of antennas (with core installations in Australia and S. Africa—video) designed to maximize the buildable number of baseline lengths/angles for the greatest scientific flexibility (a truly random scattering of antennas would yield more length/angle combinations, but would be highly impractical to build and connect together). When complete, the SKA will be made up of thousands of mid-frequency dishes and up to 1 million low-frequency antennas and will be the most sensitive radio telescope (by ~50x). It will operate over a wide frequency range (eventually 50 MHz to 30 GHz—Arecibo for comparison operated at 300 MHz to 10 GHz) and, using phased array antennas, SKA will be able to host multiple users at once and survey the sky 10,000x faster than current radio telescopes. SKA will re-re-re-verify general relativity, look at how early stars and black holes formed, and drastically increase our SETI abilities. Phase I of construction ends in 2023 and provides 10% of the telescope’s final power.

A rendering that captures the massive scale of the SKA’s mid-frequency core dish cluster in Western Australia. 📺

Chang’e 5 arrives. Chang’e 5 successfully delivered 1.7 kg of lunar samples to Inner Mongolia, the first lunar samples since 1976 and the first ever from the youngish Oceanus Procellarum region. The Chang’e 5 orbiter adjusted its trajectory after releasing the sample capsule in order to avoid slamming into the atmosphere and is now heading to the L1 Sun-Earth Lagrange point for an extended mission of Sun observation and operational tests. With Chang’e 5’s success, its backup craft, Chang’e 6, is now available for a new mission in 2023, either to the Moon’s south pole, or, if the Queqiao relay satellite is still functioning well, perhaps to the Moon’s far side. Meanwhile, China continues its building cadence of ambitious missions, with an upcoming asteroid sampling mission, more lunar exploration, a Mars sample return mission (pdf), and maybe a mission to Jupiter... on top of their crewed orbital station that starts assembly next year.

News in brief. China launched its new Long March 8 vehicle on its maiden flight carrying 5 satellites—the LM-8 has a throttleable RP-1/LOX first stage that is intended to eventually be reusable; Lockheed is buying Aerojet Rocketdyne in a cash deal valued at 4.4B, meaning Lockheed will now build both Orion and the SLS’s engines; Rocket Lab launched a Japanese radar imaging satellite; OneWeb is back in business and launched 36 more Internet satellites—they will require $1 billion more in investment to complete their 650 satellite constellation in 2022; NASA postponed review of its proposed planetary defense Near Earth Object (NEO) Surveyor asteroid mapping mission due to budget uncertainty; India launched its CMS-01 communication satellite; SpaceX launched their 26th and last mission of 2020— a classified NRO satellite— and stuck their 70th recovery; Capella Space released 50 cm resolution SAR images (which cannot see through buildings); Amazon unveiled their flat-panel Kuiper constellation terminals—the relatively small phased array antenna has the transmit and receive elements layered to decrease size and cost; Russia, unfortunately, tested another kinetic direct ascent ASAT weapon (this is the only spacewar we want to see anytime soon); and, in the same vein, the US Navy has sailors, the US Army has soldiers, and apparently the US Space Force has ‘guardians’. ☄️🤺😬

Long March 8 Y-1 takes off.

Etc.

Matt Smith caught the Great Conjunction of 2020 between Saturn and Jupiter, which can both be seen along with their major moons.


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