Issue No. 94

The Orbital Index

Issue No. 94 | Dec 9, 2020

🚀 🌍 🛰

Machine Learning in Space. The cost to train deep neural networks is decreasing at 50x Moore’s Law, leading us to believe that machine learning, as applied to space science and industry, is very much in its infancy. Cutting edge applications of ML to space, outside of Earth observation, are roughly grouped into three categories: a) combing through large datasets to perform pattern matching that previously required human judgment (e.g., spotting craters, exoplanets, and galaxy cluster & quasar spectra), b) quickly approximating expensive optimizations or physical simulations (e.g., optimizing telescope time or approximating galactic-scale hydrodynamics, atmospheric distortion for adaptive optics, the fundamental equations of quantum mechanics, or, in a critical unlocking of yet another tech tree node for humanity, protein folding), or c) making autonomous decisions because throughput or speed-of-light delay prevent humans from doing so (e.g., OSIRIS-REx’s autonomous sampling of Bennu, Mars 2020’s landing systems, and ESA’s new PhiSat-1 which will use a cheap processor from cell phones and drones to prioritize images for downlink). We expect that the next few years will see many more space applications of AI/ML, both in these broad categories and in new ones. (Related: ML is pretty impressive when applied to Earth observation data too, for example here’s every individual tree canopy in West Africa.)

Mars Reconnaissance Orbiter’s HiRISE camera took this picture of Mars, in which a new crater cluster was subsequently spotted for the first time using AI.

Robots in Space. Two groundbreaking robotic sample return missions dominated much of the space news this week.

  • On the 5th, a capsule holding grains of rock and dust sampled from Ryugu hit the Earth’s atmosphere at 11.6 km/s and safely parachuted into the Australian outback. Hayabusa2 launched on December 3, 2014, took four years to reach Ryugu, then did a bunch of science (including shooting it with a tantalum bullet and dropping numerous deployables on the body—here’s a detailed PDF about the mission), before returning with ~100 mg of samples, having covered a total of 5.24 billion kilometers. The mission isn’t over for Hayabusa2 though—it’s now headed toward asteroid 1998KY26 for humanity’s first rendezvous with a fast rotating asteroid in 2031 and a flyby of 2001CC21 along the way.
  • After 19 hours of drilling and scooping samples, Chang’e 5’s ascent vehicle spring-launched and then blasted off, returning to lunar orbit carrying ~2 kg of regolith. It successfully rendezvoused with the return vehicle, transferred the sample, and the return vehicle has embarked on its multi-day return trip. These will be the first lunar samples returned since the 70s and the first sample return mission for China. The rendezvous of the ascent vehicle and the return segment used microwave radar that was accurate down to 0.1° and able to lock on to a circle with a 3.33 cm radius.

100 for Falcon 9. SpaceX launched its upgraded Cargo Dragon spacecraft, based on Crew Dragon (basically sans seats, life support equipment, SuperDraco abort motors, and navigation interfaces), for their 21st commercial ISS resupply mission. This version of Cargo Dragon is certified for five flights compared to its predecessor’s three, and it conducts automated docking instead of Canadarm-captured berthing. This continues the trend of NASA’s increasing comfort with SpaceX’s equipment reuse. The booster supporting this 100th successful flight of the Falcon 9 rocket was flying its fourth mission (all since debuting with Demo-2 last spring). CRS-21 features a new commercial module for the ISS, the Bishop airlock from Nanoracks, which is certified for an initial 100 depressurization / repressurization cycles. It will relieve constrained airlock availability and, with both NASA and ESA as initial customers, begins to realize NASA’s goal of transitioning to being a customer on a more commercial station.

News in brief. Starship scrubbed its first non-hop test flight attempt at the last second yesterday, another attempt should happen today; Space Capital recently launched its third fund which will focus on applications of space technology (aka doing stuff, likely involving AI, with the burgeoning quantities of Earth observation data); ESA selected the ClearSpace-1 mission (for €86 million) to experiment with capturing the Vespa upper stage from a 2013 Vega launch and deorbiting it; Russia launched 3 Gonets communication satellites, China launched Gaofen-14 on an upgraded LM-3B, Japan launched their JDRS-1 communications satellite, and a Soyuz launched FalconEye 2, an Emirati military satellite after its predecessor was lost in a Vega launch failure in July 2019; China is continuing to develop their proposed super heavy Long March 9 launch vehicle for a 2030 debut—comparable to the Saturn V, it is 93 m tall and has a 10 m core stage; Russian spaceport officials keep being sacked; SpaceX will get $886 million from the FCC over 10 years to subsidize Starlink broadband for 642,925 rural homes and businesses in 35 states—this amounts to $1,378 per customer, which will put a dent in their per-user terminal cost that’s been estimated at up to $2,000 per ‘Dishy’; Chuck Yeager, first human to move faster than the speed of sound, died at 97; and, Aevum revealed their Ravn X launch system, a two-stage liquid-fueled rocket launched from a large uncrewed drone aircraft (pictured below) and capable of delivering 100kg to SSO—they hope to have a first test launch in 2021.


Gaia’s latest release contains data on 1.8 billion sources, with 1.4 billion of them also having stellar motion information. Here is an image of the entire sky created from an earlier version of this release, and below is an image showing the stellar motion of 40,000 stars within 100 parsecs of the Solar System over the next 80,000 years. (ed. yes, we are happy that we’re able to end the newsletter with full-sky survey images two weeks in a row!)

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