¶Starship nails its tenth flight. SpaceX launched a critical test flight yesterday following their June test stand explosion and three consecutive upper stage failures (in January, March, and May). The test’s first launch window on Monday featured a livestream appearance by Musk and Bill Riley, VP of Starship Engineering, but was scrubbed due to an unruly anvil cloud (cumulonimbus incus) in the area, a common launch commit criterion (usually disallowed within about 18 km). Flight 9’s Starship failure investigation had “[identified] the most probable cause for the May failure as a faulty main fuel tank pressurization system diffuser located on the forward dome of Starship's primary methane tank. The diffuser failed a few minutes after launch, when sensors detected a pressure drop in the main methane tank and a pressure increase in the ship's nose cone just above the tank.” The diffuser was redesigned for Flight 10 to substantially decrease the amount of strain and underwent rigorous testing for flight qualification (full Flight 9 report). Tuesday’s attempt roared to life at the top of its window, lifted off into the Texas skies, and ticked off multiple mission objectives one after another (livestream). Super Heavy performed a “deterministic flip” and returned to soft land in the Gulf, simulating an engine-out scenario and only slightly reducing the aggressive angle of attack that caused Flight 9’s booster to fail (and did this all with one unintended Raptor out). Starship achieved orbital altitude (but not speed) during its sub-orbital trajectory that took it to the Indian Ocean, deployed 8 Starlink v3 simulators using its novel “Pez dispenser” for the first time (the simulators reentered on the same ballistic trajectory as Starship), relit a Raptor in space (for the second time), and maintained admirable attitude control and command authority throughout coast and reentry. Starship made a successful and precise soft landing at its target site (filmed by a pre-placed buoy cam) and transmitted live video throughout the entire flight. This was a strong step back on track for the company. Still, the flight left several todos on SpaceX’s list: aft flaps again suffered some burn through, an apparent explosion in the engine bay ripped into the engine skirt, and the ship came down heavily discolored, looking slightly similar to the Shuttle ET (leading hypotheses suggest oxidation of the metal tiles that were included as some of the many heat shield tests on the flight). The company has downplayed heat shield development as a process that will require numerous flights to perfect, suggesting (plausibly) that creating a rapidly reusable heat shield is one of the hardest engineering problems of our day. Starship can now move forward toward other objectives, the most pressing being the deployment of actual Starlink sats, the return of Ship for a catch attempt, and proving in-space fuel transfer needed for both lunar and Mars missions. |
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 | Starship hovering above the Indian Ocean, red-tinged from some as-of-yet unknown torture to the craft’s heat shield during re-entry. Credit: SpaceX |
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¶Weird Papers- Could the Hubble tension—the persistent mismatch between different methodologies of measuring the rate of the Universe’s expansion—be the result of our galaxy being near the center of a massive, lower-density region in the Universe (paper)? Such a void could be the result of a Baryon acoustic oscillation imprinted on the distribution of matter during the early Universe. “For the idea to stand up, Earth and our solar system would need to be near the centre of a void about a billion light-years in radius and with a density about 20 per cent below the average for the universe as a whole.” This is possible, but seems unlikely? Another explanation for the Hubble tension, with slowly growing evidence, is that dark energy might be weakening over time.
- At the center of the Milky Way is a supermassive black hole (Sagittarius A*), as well as a lot of gas, dust, young stars, and probably quite a few stellar-mass black holes. Previous models have assumed around 300 of these “smaller” black holes in orbit around Sagittarius A*, which seems like plenty of black holes to have flying around. However, a new study suggests there could be far more. Because of the available gas and dust in the galactic center, large stars should form easily, live short lives, explode, and form black holes. The more black holes that are created this way, the more disruptive black hole-star interactions would occur, releasing even more gas and dust and accelerating the whole process. This “star grinder” could result in millions of stellar-mass black holes per cubic parsec near our galaxy’s center, a somewhat terrifying image that could explain the low number of large stars near our galaxy’s center and the presence of hypervelocity stars being flung out of the core through gravitational interactions.
- Also in this turbulent region of our galaxy are, apparently, space tornados. Slim filaments of material are seen in ALMA data (paper), with researchers saying that we “can envision these as space tornados: they are violent streams of gas, they dissipate shortly, and they distribute materials into the environment efficiently.” Seems like a great part of the neighborhood. 🌌🌪️
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 | “We haven't actually seen a star fall in since we invented telescopes, but I have a list of ones I'm really hoping are next.” XKCD #3072 |
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¶News in brief. NASA began building up Artemis III’s SLS (currently set to launch in 2027), starting with the boat tail and engine section of the core stage, in the Vehicle Assembly Building at Kennedy ● Ground station provider KSAT plans to build its own satellite constellation that will serve as in-space relays, providing more contact opportunities than ground stations alone ● SpaceX launched their 100th Falcon 9 of the year (pacing two months ahead of 2024) ● Indian EO startup Xovian Aerospace raised $2.5M in pre-seed funding to build an RF monitoring constellation ● The eighth elusive X-37B spaceplane mission launched aboard a Falcon 9 ● Alaska Airlines switched to using Starlink instead of IntelSat for in-flight connectivity (here’s a growing list of airlines with Starlink support) ● After reading our item last week about animals in space, Russia launched the Bion-M No. 2 spacecraft carrying 75 mice and 1,500 flies into polar orbit to study how they respond to the polar radiation environment ● The UK Space Agency will be absorbed into the UK’s Department of Science, Innovation and Technology ● SpinLaunch raised $18M, closing a $30M Series C, to accelerate the development of their LEO broadband constellation—purportedly compatible with their eventual kinetic launch system but launchable, for the time being, via traditional rocket ● NISAR deployed its ample antenna (c.f. Issue 300) ● Three Chinese astronauts conducted a six-hour spacewalk outside Tiangong, prepping for the walk with a newly installed space station AI overlord chatbot and using one of the station’s EVA suits for a milestone twentieth time ● Rocket Lab launched its 70th Electron mission, ‘Live, Laugh, Launch’, placing five satellites in LEO for a mystery customer
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 | The 70th Rocket Lab mission takes off from the company’s New Zealand launch facility, carrying five small satellites to space for an undisclosed customer. Credit: Rocket Lab, @theinnerarchive |
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¶Etc.- The Open-source CubeSat Workshop is back on Oct 25th and 26th in Athens, Greece.
- BPS.space shared a great recap of the process of building a 111,507 N⋅s solid rocket motor, which will take an amateur rocket to suborbital space.
- Terrawatch Space on NASA’s new commercial Landsat RFI and its potential impact on the future of EO. “Landsat isn’t famous because it is the oldest EO mission. It is famous because a pixel from 1984 still matches a pixel today. That’s calibration chains, ground infrastructure, validation campaigns, i.e., decades of investment. Commercial operators generally don’t bother with that, because their customers usually want ‘better, faster, cheaper,’ not necessarily ‘comparable over 40 years.’”
- Apparently, a turbopumped rocket was built in Almería, Spain, by students in the late 1960s (unclear if it flew). Students have not yet achieved a turbopump-fed flight in the US or elsewhere.
- In Canada, meanwhile, students recently attempted a spaceshot with the largest student-built rocket ever flown. The 13-meter-tall, liquid-fueled rocket separated prematurely and may not have reached 100 km, unfortunately (video). It has been worked on by 700 students since 2018 and, if it did reach space, would be Canada’s first rocket to do so in 25 years.
- A team of SWRI engineers discovered Uranus’s 29th moon (currently called S/2025 U1 before IAU official naming) using ten 40-minute-long JWST exposures to resolve the 10 km wide moon near Uranus’ main ring system.
- NASA and IBM have released a long-short vision transformer-based heliophysics model (GitHub) using nine years of Solar Dynamics Observatory data for predicting solar eruptions and space weather.
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Potentially the largest black hole observed to date, with a mass of 36 billion M☉ (Solar masses), may reside within the large Cosmic Horseshoe galaxy (paper). This black hole’s mass was estimated by measuring its gravitational lensing effect, as well as its effect on the velocities of nearby stars. Below is an image of the massive Cosmic Horseshoe galaxy, seen lensing a distant blue galaxy, which forms the striking Einstein ring encircling it. The highlighted images are another object being lensed into a radial arc by the detected black hole at the galaxy’s center, which was used to estimate its mass. Such a large black hole lends support to the idea that supermassive black hole creation can occur, possibly via direct collapse, before stars during galaxy formation—Ethan Siegel has more. Credit: NASA/ESA/Tian Li (University of Portsmouth) |  |
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