Issue No. 251

The Orbital Index

Issue No. 251 | Jan 10, 2024

🚀 🌍 🛰

Vulcan flies but Peregrine falters. ULA’s inaugural Vulcan Centaur launch took off successfully on Monday, delivering Peregrine, the first NASA CLPS lander—also Astrobotic’s first lunar lander, and also also the US’s first lunar lander in 50 years (excluding the 2009 LCROSS impactor)—, into a trans-lunar injection. Unfortunately, Astrobotic has reported a “critical” propellant loss (imagery consistent with this) and initially experienced spacecraft orientation control issues when trying to face the Sun for charging. The lander was targeting the Sinus Viscositatis lava plain outside the Gruithuisen volcanic domes after 17-19 days in transit and up to 39 days in lunar orbit, which is unfortunately now out of the question. Peregrine is the first of what is now 8 CLPS missions (from 4 providers), intended to kick off a new era of routine, commercial lunar exploration. The 2-meter tall Peregrine lander carries 21 payloads from 6 countries, five of which are funded through CLPS, including near-IR and neutron spectrometers, radiation and volatile monitoring sensors, a lunar landing LIDAR, and the requisite retroreflectors for laser ranging (Astrobotic press kit). Included also are multiple small rovers. The next CLPS mission up to bat, Intuitive Machines’ Nova-C, is scheduled to launch in mid-February, and Astrobotic has its next mission nominally scheduled for November. The Vulcan rocket, however, performed well as ULA’s long-awaited new launch vehicle, originally planned for launch in June 2021. It is 61.6m tall, 5.4m in diameter, and is powered by Blue Origin’s BE-4 methalox engines—while not the first methalox to reach orbit, LandSpace’s Zhuque-2 snagged that title, BE-4 engines are much more powerful. Here are lots of Vulcan technical details. Many more Vulcan launches are coming, with something like 38 launches planned for Amazon Kuiper alone—ULA is planning to eventually launch two per month, a huge ramp from just three launches in 2023.

ULA’s inaugural Vulcan Centaur flew from Cape Canaveral on Monday. Credit: Gregg Newton/AFP/Getty Images

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A Long Duration Rotating Detonation Test. NASA Marshall in Huntsville conducted a successful hot fire test of a 3D-printed Rotating Detonation Rocket Engine (RDRE) last fall. The RDRE test emulated typical deep-space and lunar lander burns with a 251 second burn. The in-development engine showed an increased thrust of 26 kN after a previous shorter duration test in 2022 clocked in at 18 kN. Rotating detonation engines create a detonation chain reaction that moves in an annular (ring) pattern, allowing the hypersonic flame front to travel continuously around the combustion channel while newly injected fuel and oxidizer enter the chamber before the next detonation pass (explainer video). The detonation’s flame front moves more quickly than uncombusted propellant, enveloping and combusting it while maintaining constant volume (isochoric)—this is compared to the subsonic deflagration combustion occurring at constant pressure (isobaric) in traditional liquid rocket combustion chambers. RDREs represent an improvement on pulsed detonation engine (PDE) designs where the chamber must be cleared in between each detonation, leading to lower total efficiency. A small RDRE was tested in space by JAXA in 2022, successfully producing 500 N of thrust after the sounding rocket it was launched on shut down nominally. Both PDEs and RDREs exchange engine simplicity (propellant doesn’t need to be compressed, for instance) for advanced material science—the most recent RDRE was 3D-printed out of NASA’s GRCop-42 alloy. RDRE designs promise more efficient chemical propulsion options, producing as much as a 25% efficiency gain compared to existing upper-stage engines for the same fuel mass. Detonation stability has historically been the challenge, but with this long-duration test, RDREs may be edging into the realm of production reality. (Related: NASA’s Houston we have a Podcast covered the RDRE in depth back in July.)

Computational Fluid Dynamics (CFD) has been critical to the development of modern RDREs. Here a visualization shows the detonation front and the trailing oblique shock wave that helps expel combustion product gasses while sustaining the detonation (in this case for an air-breathing engine).

News in brief. The Aditya-L1 Solar Observatory entered its destination orbit at Sun-Earth L1 Ingenuity traveled 260 m in 132 s on its 70th flight China completed construction of a new commercial launch pad on Hainan island (hopefully an alternative to their inland ports which tend to drop booster debris on people’s houses) and plans to launch a Long March 8 from it this year China also launched 4 meteorological satellites The National Labor Relations Board (NLRB) has accused SpaceX of wrongfully firing eight employees who circulated a letter criticizing Elon Musk —SpaceX is in turn suing the NLRB for what it says are the Board’s  “unconstitutional” actions The ISRO successfully tested a novel fuel cell power system aboard POEM3 (a re-purposed fourth stage of the PSLV which becomes a short-lived satellite hosting low-cost hardware tests after deploying its payload) Russia and the US agreed to continue joint ISS flights until 2025 (offering each other redundancy to ensure that the station has NASA and Russian crew in the event of a SpaceX or Soyuz failure) The UAE’s Mohammed bin Rashid Space Centre will develop an airlock for NASA’s Lunar Gateway (for lunar orbit space walks!) and fly an astronaut to it on a future Artemis mission Sweden’s first privately funded GEO satellite, Ovzon-3, launched on a Falcon-9 JPL has had some workforce reductions due to Mars Sample Return budget uncertainty India is working with SpaceX for the first time to launch a communications satellite aboard a Falcon-9 later this year With Northrop Grumman pulling out of CLD, NASA awarded more funding to the remaining Commercial LEO Destination programs to replace the ISS, with Blue Origin-led Orbital Reef receiving $42M and Voyager-led Starlab getting $57.5M JAXA released its first test images from its XRISM telescope, showing galaxies and star clusters in unprecedented resolution in the X-ray spectrum.

An X-ray image of supernova remnant N132D in the Large Magellanic Cloud captured by XRISM’s Xtend instrument. These stellar remnants are barely visible in optical light but very bright in X-rays.

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Juno conducted its closest flyby in 20 years of Jupiter’s volcanic moon Io, coming within 1,500 kilometers of the exceptionally volcanic world’s surface and delivering some stunning images. Another close flyby is scheduled for February 3rd

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