# The Orbital Index

Issue No. 95 | Dec 16, 2020

🚀 🌍 🛰
 ¶SN8 flops. Last Wednesday, Starship SN8 conducted its much anticipated high-altitude flight test 📺—the whole flight is very much worth watching. The test, originally suggested over a year ago, demonstrated the viability of the vehicle's core innovations: multiple configurations of three-Raptor flight, the high-drag belly flop reentry maneuver, and header-tank-fueled propulsive landing. Prior to launch, Musk gave the 6m40s, ~12.5 km test flight a 30% chance of success. It proceeded according to plan until landing, at which point low header tank pressure led to loss of engine power and a faster-than-planned landing, resulting in an enormous fireball that left only SN8’s nose cone on the landing pad. (Here’s a huge 352-megapixel image of SN8… very much from before the launch.) The ‘belly flop’ with its 70° angle of attack and landing flip was particularly impressive—looking much like a happily skydiving 16-story stainless steel grain silo 📺. SN9 is almost complete and is slated to continue SpaceX’s aggressive test flight plans. (However, earlier this week the stand supporting SN9 collapsed and the 50m tall rocket was photographed leaning on the inside wall of SpaceX’s new high bay structure.) SpaceX continues its “hardware rich” design methodology (a list of decommissioned hardware) and has SN10 through SN15 in various stages of production, along with Starship’s first stage, Super Heavy BN1 (its stack shown at right in the image below). Even culminating in a fiery RUD, SN8’s flight was a resounding success for SpaceX and is a major milestone in Starship’s development. Related: SpaceX also launched its second-to-last Falcon 9 of the year, bringing the company’s total 2020 launches to 25.
 ¶Angara tests out. The Russian Angara 5 heavy lift vehicle—we first covered it in Issue No. 77—launched on its second test flight this week (video) after over four years of delays. The original payload scheduled to fly on Angara’s second test flight, Angosat-1, was rescheduled in 2017 on a Zenit-3F flight due to multiple schedule slippages from its original 2016 launch date. This week’s launch carried a mass simulator instead. Angara will now enter regular service with as many as five flights scheduled for 2021, and it will fully replace the Russian Proton-M workhorse in 2024.
 ¶Rocket 3.2 almost reaches orbit. To cap off a week studded with high profile flights, Astra joined the select group of companies that have reached orbital space, narrowly missing full orbit. The Bay Area rocket startup launched their Rocket 3.2 from the Pacific Spaceport Complex in Alaska with a dummy payload onboard for the vehicle’s second launch. They had previously stated that the rocket would likely take three launches to achieve orbit. They have now passed their goal of fully testing the first stage capabilities with both a successful first and second stage firing (video). The rocket came just half a kilometer per second short of reaching orbital velocity and will likely accomplish that milestone with its 3.3 launch.
 Rocket 3.2’s upper stage view from above the Kármán line.
 ¶Papers.Building on NASA’s seminal Twins Study, 19 additional papers were recently published about the effects of spaceflight on the human body. They highlight six spaceflight-induced systemic changes (paper): oxidative stress, DNA damage, mitochondrial dysfunction, changes in gene regulation, gut biome changes, and alterations in the length of telomeres (paper). The most significant finding, based on samples from 59 astronauts, was around spaceflight-induced mitochondrial dysfunction (paper), which helps to unify observations of immune, circadian rhythm, and organ dysfunctions and provides a potential target for protective therapies for use during space travel. A special issue of Cell covers these and other spaceflight biology topics.Based on OSIRIS-REx’s gravimetric mapping of Bennu, it appears that Bennu’s center is less dense than its outside (paper), possibly because of a period of rapid spin in the past due to the YORP effect. Bennu is currently spinning faster over time due to this same effect, and if the trend continues long enough, it may spin itself apart.An interesting paper review and discussion about how tiny dust particles in the interstellar medium act as chemical factories, manufacturing molecules essential for the eventual formation of life.Radiocarbon locked up in preserved tree rings may tell a history of nearby supernovae. Radiocarbon (14C) is a cosmogenic nuclide that is created in the atmosphere when cosmic rays interact with nitrogen, and a recent study found a preliminary correlation between spikes in 14C and the approximate dates of nearby supernovae. Tree rings can provide both samples of these isotopes and precise dating.The giant 7,800 km-wide ring structure on Ganymede may be the largest impact structure in the solar system, potentially resulting from the impact of an object ~150 km across (paper). The ring, in the upper right of the picture below, is the likely impact site. Looks like it may have hurt. 🤕
 ¶News in brief (also mostly about rockets). Virgin Orbit targets December 19th for a second orbital launch attempt for their air-launched rocket, this time with 10 NASA CubeSats onboard; NASA is considering commercial Mars data relay satellites; China launched their GECAM satellite to watch for gravitational wave electromagnetic counterparts (visible events that correlate with gravitational wave detections); Isar Aerospace raised $91 million for their Spectrum vehicle (targeting a 2022 launch) and Orbex raised$24 million for their Electron-esque booster (also targeting 2022); Space Rider, Europe’s first orbital spaceplane, is really happening and received a €167 million contract; a secret NRO satellite finally launched on a Delta 4 Heavy rocket after two previously scrubbed attempts; Beresheet 2 has been announced for a 2024 launch and will include an orbiter and two small landers targeting different parts of the Moon; a Virgin Galactic test flight was aborted safely when the rocket motor failed to ignite; and, NASA announced their 18-astronaut “Artemis Team” who will all train for, and some may return to, the Moon, and also outlined their science priorities for the first crewed mission, including recovery of cryogenic volatiles from permanently shadowed lunar regions (which, at 23 kelvin, are colder than Pluto).
 ¶Etc.On the 21st, Jupiter and Saturn will appear just 0.01º apart, their closest conjunction since July 1623, almost 400 years ago. A 55-minute teardown of Dishy McFlatface. 📺“The Data to Discovery program offers a unique opportunity for a small select group of interns to work as a team directly addressing hard problems in science, while under the mentorship of data visualization and design experts from JPL, Caltech, and ArtCenter.”The plentiful material that Hayabusa2 returned from Ryugu may start to answer the many mysteries around the formation of chondritic meteorites and the abundant, tiny, bead-like chondrules they contain, some of the oldest material in the solar system.NASA released their 2020 NASA State of the Art Report of Small Spacecraft Technology, including radiation mitigation strategies for small spacecraft missions. Here’s the direct link to the 327-page PDF. NASA also released a 168-page PDF about conjunction assessment and collision avoidance best practices.“You have a few grams of deuterium in your body, which comes all the way from the Big Bang.” You might say we’re made of Big Bang stuff.Solar Thermal Propulsion is fairly simple: get a spacecraft very close to the Sun and use the abundant heat to expel hydrogen fuel out of a rocket nozzle, gaining an efficiency 3x better than traditional chemical rockets. The challenge, however, is in surviving for a few hours at only a million miles away from our star, roughly half the distance of the Parker Solar Probe’s closest approach.A good writeup about the stack-shifting technique, which can be used to search sky imagery for new outer solar system bodies like the still-hypothetical Planet 9.There are rumors that the Chang'e-5 orbiter could have an extended mission to visit 2016 HO3, a “quasi-satellite” asteroid that stays near Earth and may be visited by the ZhengHe Near Earth Asteroid sample-return mission in the mid-2020s. (Also, learn how to pronounce Chang’e the right way.)
 2016 HO3 (aka 469219 Kamoʻoalewa) hasn’t been further away than 100x the distance to the Moon, nor closer than 38x the lunar distance, for the last ~100 years. ZhengHe is a proposed Chinese mission to collect samples from 2016 HO3 before dropping them off at Earth and continuing on to a comet (pdf).