¶For the first time in the US, a rotating detonation rocket engine takes flight. Venus Aerospace, a hypersonic flight startup that has raised $70M to date, flew the first rotating detonation engine (RDE) from US soil in a test flight. RDEs have long been appealing due to their high efficiency, up to ~25% better than traditional engines. This efficiency gain comes from their use of detonation, instead of subsonic deflagration like traditional engines, with a flame front moving at supersonic speeds (video), compressing and almost instantaneously igniting the propellant in front of a shock wave that propagates in a continuous circular pattern. RDEs have been long theorized and developed to early stages, but have rarely flown. JAXA tested an RDE as a second stage of a sounding rocket above the Kármán line, attracted by the technology’s potential for high-Isp upper stage applications, and the Warsaw Institute of Aviation has flown a small test rocket to 450 m (video). Venus, which has developed their own RDE, as well as a Ramjet with detonation features, flew their first rocket from Spaceport America in New Mexico last week. The small test rocket launched from a rail system (video) and flew for ~30 seconds. The craft was powered by Venus’ 9kN thrust RDRE engine (a Raptor, for comparison, is rated at 230x that thrust). Venus is primarily targeting the Defense-driven hypersonic aviation/missile market vs. space applications, but time will tell where RDE as a technology finds its long-term applications. |
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 | Venus Aerospace’s Rotating Detonation Rocket Engine (RDRE) on the test stand. Credit: Venus Aerospace. |
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¶Weird Papers- A surprising, but possibly spurious, observation in JWST data suggests that about two-thirds of galaxies in a deep universe survey rotate clockwise (paper). We’d expect this number to be close to 50/50. This could mean anything from an inherent rotational bias in our region of the Universe (with the weird possibility that we therefore all exist inside of a black hole—see black hole cosmology), to observational bias due to our orbit around the center of the Milky Way, to simply an incorrect analysis—the solo author, a computer scientist, has made similar, and sometimes contradictory, claims in the past based on other datasets, which were later disproven.
- Future Mars landers could perform seismo-electric sensing, detecting Martian aquifers by measuring the electromagnetic signals created as seismic waves from Marsquakes interact with underground water (paper).
- During the COVID-19 global lockdown, aerosol emissions dropped, and the Earth’s radiative emissions decreased slightly (ie, a little less of the Sun’s energy was reflecting off the Earth’s atmosphere, a change of +0.04 W/m2 absorption). A paper detects this phenomenon on the Moon, showing an “anomalous dip in the lunar night-time surface temperatures [...] during April–May 2020, the strict COVID-19 global lockdown period, when compared to the values of the same period during the previous and subsequent years.” (This aerosol masking effect, where aerosol emissions reflect a small amount of the Sun’s energy, compensating for warming that would have already happened due to increased levels of greenhouse gases, has recently been coming into focus as efforts to clean up air pollution make progress. These efforts make the atmosphere cleaner and more transparent, but also increase warming.)
- “Gravitational Effects of a Small Primordial Black Hole Passing Through the Human Body” determines helpfully that: a) it’s best to avoid having a black hole with a mass greater than 1.4 x 1017 g pass through your body, and b) that you don’t actually need to worry about this.
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 | “You may notice the first half of these instructions are similar to the instructions for a working nuclear fusion device. After the first few dozen steps, be sure to press down firmly and fold quickly to overcome fusion pressure.” XKCD #3033 |
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| ¶News in brief. Gilmour Space delayed the first launch of their Eris rocket after the payload fairing accidentally separated during pre-launch preparations (awkward!) ● Space Forge, a Welsh in-space manufacturing startup, raised a £22.6M Series A to support their first orbital mission launching this year ● Norway became the 55th country to sign the Artemis Accords ● Reflect Orbital, a space-based solar illumination and power startup, raised a $20M Series A (mentioned in Issue 291, Reflect wants to use mirrors positioned along the terminator line to make daytime slightly longer for customers on the ground, which doesn’t seem worth it, especially given the potential impact to astronomy) ● Solestial raised a $17M Series A to scale manufacturing capacity of their specialized silicon PV cells for space ● SpaceX has already launched 1,000 Starlink satellites this year ● Tokyo-based satellite maker Axelspace plans to go public in June, marking the fifth IPO of a Japanese space company in the last two years ● Starlab developer Voyager also filed for IPO ● In a rare M&A, SpaceX acquired Akoustis Technologies, a manufacturer of bulk acoustic wave high-band RF filters, for $30.2M via bankruptcy auction ● China launched the first 12 satellites of their planned 2,800-satellite ‘Star-Compute Program,’ featuring advanced AI, 100 Gbps laser inter-satellite links, and onboard processing of remote sensing data to minimize transmission needs ● Russia plans to build a lunar nuclear power plant in collaboration with China’s International Lunar Research Station ● Zeno Power closed a $50M Series B to begin production of their nuclear batteries for extreme environments (such as the Moon’s two-week night) ● Sophia Space raised $3.5M in pre-seed funding to develop orbital data centers for geospatial intelligence applications ● India’s PSLV rocket failed to launch a radar satellite after suffering an issue in its third stage, marking the first PSLV failure since 2017 ● Varda Space landed their third space manufacturing reentry capsule (video) ● China conducted the first daytime laser measurement from the Earth to the Moon with their Tiandu-1 satellite ● Ed Smylie, the NASA engineer who designed the life-saving CO₂ scrubber adapter for Apollo 13’s lunar module, passed away at 95 years old. |
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 | The jerry-rigged carbon dioxide scrubber fabricated from parts found aboard the Apollo 13 spacecraft. This life-saving contraption was developed by NASA engineer Ed Smylie. RIP. |
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