¶Lucy swings by Earth. On October 16th, NASA’s Lucy spacecraft swung by Earth, just 350 km above the surface (lower than the ISS), stealing some kinetic energy from the planet on her way to the asteroid belt (to visit Donaldjohanson) and from there on to Jupiter’s Trojan asteroids. Trapped in Jupiter’s orbital circumference, but 60° out of phase in front of and behind the gas giant, the two groupings of Trojan asteroids have never been visited by humanity. After a year in space, Sunday’s gravity assist will help Lucy reach the first group of Trojans 5 years from now, but not before a second Earth assist three years into its journey. Flying past six L4 Trojan asteroids (Eurybates and its satellite Queta, Polymele and its yet unnamed satellite, Leucus, and Orus) trailing behind Jupiter, Lucy will then return to Earth for a third gravity assist in 2030 before heading off to the second group of L5 Trojans, 60° ahead of the gas giant. There she’ll visit the Patroclus-Menoetius binary asteroid pair. Because Sunday’s flyby was at such a low altitude, procedures were in place to perform debris avoidance maneuvers if conjunctions were detected, and atmospheric drag had to be factored in, forcing a slightly higher altitude than planned due to Lucy’s one partially unlatched solar array. Lucy also snapped photos of the Earth and Moon for funsies (and calibration) as she shot by. |
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¶Stoke’s reusable upper stage. One of the hardest challenges of building a fully reusable upper stage is protecting the large, lightweight engine bell that is required to generate high Isp thrust in vacuum. Starship plans to overcome this challenge with its belly flop maneuver and integrated engine skirt / interstage that covers up what would traditionally be protruding engine bells. Stoke Space, a recent entry into the launch startup arena, was formed by two ex-Blue Origin core propulsion engineers to tackle reusability at a quicker pace than Blue has been able to attain. Stoke’s planned rocket will be fully reusable and lift 1.5 tons to LEO. Its upper stage will be unique, featuring a 30-nozzle hydrolox powerhead whose exhaust plumes merge to mimic the effect of a single, vacuum-optimized engine bell. A prototype was long-duration hot-fired last month with half its nozzles active (video). This powerhead will be protected by an actively cooled heat shield during re-entry, then will perform a propulsive landing back on Earth. Stoke has raised $100M+ in funding so far, but more will likely be needed to get to orbit and full reusability. Next up: hop tests at the company’s new Moses Lake facility in central Washington with a full-scale, 5.8 m fairing-less, second-stage prototype. |
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 | | Stoke’s 30-nozzle hydrolox powerhead firing half of its thrusters during a test in September. |
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| ¶News in (not so) brief. The next attempt for Artemis I is now scheduled for November 14 ● China launched S-SAR01, a 5 m S-band radar satellite on a Long March 2C, their third flight in 6 days ● A launch of Japan’s Epsilon-6 rocket failed to reach orbit and was terminated, JAXA’s first launch failure since November 2003 ● Starship’s second private flight around the Moon (sometime after Yusaku Maezawa’s dearMoon trip) will be with Dennis Tito (and his wife), 82, and famous for being the first private space tourist to the ISS in 2001 ● The Crew-4 astronauts returned after almost 6 months on the ISS ● Startup Orbit Fab won a $13.3M contract to refuel a Space Force satellite equipped with their RAFTI refueling port in 2025 ● Space traffic management startup Neuraspace raised €25M ● Space PV startup Solestial raised a $10M seed ● Starship stacked again… orbital flight in December (maaaaybe?) ● NSF announced that the Arecibo Radio Observatory will not be rebuilt 😢 ● The TESS planet hunter entered safe mode after an unexpected flight computer reset, then safely resumed operation ● SpinLaunch hucked some test payloads for NASA and other potential customers to test G-hardness ● Possibly Proton’s last commercial launch took Angosat-2 to orbit, replacing its failed 2017 predecessor ● A Falcon 9 launched an Eutelsat geostationary communications satellite ● A Russian Proton-M rocket launched the commercial AngoSat-2 to orbit ● Russia also launched a military (probably optical reconnaissance) satellite ● Taikonauts broadcast a science class from Tiangong’s new Wentian lab module (including what looks like a demonstration of the Dzhanibekov effect T-handle flip effect) ● Skyrora’s test flight of their Skylark L suborbital sounding rocket failed just after liftoff from what looks like an engine anomaly—the company is still targeting next year for the UK’s first vertical orbital launch, planned to take off from Scotland (video). |
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¶Etc.- A 1970 letter from Ernst Stuhlinger to Sister Mary Jucunda in Zambia explaining his belief that the exploration of space—specifically his proposal for a Mars mission—leads to a better existence here on Earth.
- YASL (Yet Another Starlink Launch) video, but this time from the point of view of one of the company’s droneships. Worth watching. The vehicle pictured has been to space 14 times.
- In 250 million years, six (or maybe all seven) of Earth’s continents are expected to converge into a new supercontinent, called Aurica, Amasia, Pangaea Proxima, or Novopangaea depending on the precise configuration of present-day continents that merge. New supercomputer simulations suggest that Amasia is the correct model, with the Pacific Ocean (the world’s oldest ocean, left over from when our previous supercontinent broke apart) closing and bringing America into collision with Asia. Related: NASA simulated “multiple supercontinent climate scenarios and their implications for future habitability” and found that models with higher topography ended up icy and with much colder surface temperatures (paper). Beyond being an interesting glimpse of our far future, this is a reminder to include topography when modeling hypothetical exoplanetary climates.
- Relatedly, ‘When will the Earth try to kill us again?’ is a well-written, well-researched look at the Earth’s history of mass extinctions, Large Igneous Provinces (LIPs), and how we could try to predict them in the future. We wrote about LIPs in Issue 177.
- Fundraising space companies are starting to feel pressure from rising interest rates.
- Fittingly timed with DART’s spectacular success, the number of known near-Earth asteroids has now passed 30,000. Of those, at the time of writing, 1,427 have been tagged as having a possible collision event with Earth sometime in the foreseeable future. These are tracked on NEOCC’s Risk List. The most likely collision is currently a 1 in 147 chance of an ~8 m object called 2017 WT28 hitting us in 2104, while the highest on the Palermo risk scale is 1979 XB, a 700 m-wide beast with a 1 in 3,500,000 chance of a collision in 2056. We’ll keep you updated.
- The terrible idea that is LEO billboards— 50 satellites in formation acting as pixels (paper). No. Just no.
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