¶DSOC brings broadband speeds to deep space. NASA has announced successful demonstrations of their Deep Space Optical Comms (DSOC) system which launched aboard Psyche in October. The spacecraft is outfitted with a near-infrared laser transceiver that undocks and temporarily floats free of the spacecraft (but still inside its enclosure) to send and receive at high data rates when paired with a ground-based telescope that uses a superconducting single photon receiver (c.f. Issue 238 for more on laser comms). DSOC achieved ‘first light bits’ on November 14th and, in ongoing demonstrations, reached speeds as high as 63 Mbps—significantly faster than Ben’s parent’s internet connection in Appalachian Ohio. To establish the optical link, JPL’s Table Mountain facility sends a high-intensity laser beacon toward the spacecraft which then uses it to precisely point its transceiver at Caltech’s Hale Telescope at Palomar Observatory, ~130 km south of Table Mountain. The comms link is a technology demonstration with the long-term goal of enabling high-quality video from Mars and as such isn’t being used for actual Psyche mission data. While microwave comms travel the same speed as laser signals, their significantly longer wavelength and wider field of view result in less data transmission and higher power usage. Recent DSOC tests were conducted from ~19 million km away (50x the distance to the Moon) and are the first test of laser comms beyond cislunar space. At 63 light seconds away, the system’s sending and receiving optics must also track the movement of the target while the light is in flight. (With 126 seconds round trip latency, Psyche will also have a hard time getting a headshot in Call of Duty.) Psyche will continue to test DSOC over the distances relevant for Martian communications (0.4 - 2.7 AU) before it arrives at Psyche (1.6 - 4.3 AU) in 2028. |
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¶More details on Starship OFT-2. With OFT-2 a little over a week in the rearview mirror, several additional bits of information have trickled in. As initial reports suggested, Booster 9 performed nominally through ascent and hot staging (slo-mo) and performed its flip for boost back before exploding due to (still) unknown reasons (here’s a gorgeous slo-mo video of takeoff), although propellant slosh is the leading theory (a third party CFD animation of what the propellant might have done during hot staging). Starship successfully continued its second-stage burn until very close to its intended altitude and velocity before commanding an autonomous destruct, perhaps due to tumbling as seems to be visible in this footage shot from an island off the coast of Florida. Musk also mentioned that the remaining four Starships under construction and testing are the last of “version 1” (if you can call a spacecraft that has yet to make it to orbit a meaningful version) and that version 2 will hold more propellant (and perhaps feature an increase to nine engines which could be the higher Isp Raptor 3s), have a reduced dry mass, and improve reliability (whatever that means). |
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 | Starship in the midst of hot staging. |
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¶Papers- A cosmic ray (relativistic subatomic particle) with a kinetic energy of 240 EeV (exa-electronvolts, or 1018 eV) was recently observed by the Telescope Array Project (paper). This is comparable to the (in)famous Oh-My-God particle of 1991 (320 EeV). Even 1 EeV is a million times what we can produce in our particle accelerators. Particles over 100 EeV are very rare, occurring at less than 1 per square kilometer per century. This new detection, nicknamed Amaterasu after a Japanese Sun goddess, confusingly appears to have come from the Local Void, a region near the Milky Way with few galaxies—either our models of how magnetic fields influence cosmic rays are wrong and we’re incorrectly estimating its source, it was produced by an unknown physical process, or something else surprising is going on. Either way, it’s an intriguing detection of a single proton (probably) carrying kinetic energy equivalent to a brick dropped from waist height (or a 90 km/h baseball, as the Oh-My-God particle is frequently compared to). 🤯
- Re-entering spacecraft and debris is changing the elemental profile of the stratosphere, with a distinct compositional drift from the elemental ratios of meteoric smoke to those of spacecraft alloys (paper). “[T]he mass of lithium, aluminum, copper and lead from spacecraft reentry far exceeded those metals found in natural cosmic dust. Nearly 10% of large sulfuric acid particles — the particles that help protect and buffer the ozone layer — contained aluminum and other spacecraft metals.” It’s not yet clear what, if any, impact this may have on the ozone layer and stratosphere as the quantity of re-entering material continues to grow in the future.
- A "heartbeat star" is a binary star system with an elliptical orbit that causes the duo to pass closely at perigee, creating periodic pulses in brightness as tidal forces distort the stars and change their effective size from our perspective. A new study looks at a particularly extreme example, with 200x greater brightness fluctuations than most heartbeat stars, and hypothesizes that gargantuan waves are rolling across the larger star during close approach, cresting, and breaking onto its surface like ocean waves. “Each crash of the star's towering tidal waves releases enough energy to disintegrate our entire planet several hundred times over.”
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¶News in brief. North Korea launched their first spy satellite after two failed attempts ● Japan is investing ¥1 trillion ($6.6B) over a 10-year period into JAXA ● NASA confirmed that ongoing budget uncertainty has pushed back the formal confirmation of Dragonfly (including cost and schedule) until after the release of the FY25 Presidential Budget Request in mid-2024 and is now estimating a launch date of July 2028—Phase C final mission design will progress during FY24 ● China pushed the launch of their Xuntian space station co-orbital space telescope (cf. Issue 236) out six months to June 2025 ● China also launched numerous satellites into orbit, likely tests for their Guowang internet megaconstellation ● Landspace, a Chinese launch startup, announced plans to build a reusable stainless steel rocket ● The Mars Society is launching the Mars Technology Institute to accelerate the development of technologies needed for the settlement of the red planet ● The UK is partnering with Spain and Portugal to contribute a pathfinder satellite to the pair’s telecommunications and Earth-observing Atlantic Constellation ● CryoSat, an ESA polar ice monitoring satellite, finally switched to its back-up propulsion system after a leak was detected in 2016 ● Former NASA acting administrator Steve Jurczyk passed away at 61 ● Ariane 6 had a successful long-duration hot static fire test (video) of its core stage, with hot fire testing of the second stage planned for next month.
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 | The Ariane 6 test model during its long-duration hot static fire test on the launch pad at Kourou, French Guiana. |
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¶Etc.- Scott Manley recently shared a four-part (one, two, three, four) series on the history of the communications satellite.
- NASA has created a next-generation Mars helicopter with longer, stronger blades that is being tested in a simulated Martian environment at JPL.
- In Q2, SpaceX launched 214,095 kg to space, followed by CASC launching 23,069 kg.
- Luxembourg-based Databourg just raised $1M for what we thought was an interesting approach to weather data generation. They are “repurposing existing telecom infrastructure for weather monitoring by leveraging AI [to analyze…] satellite signals from tens of thousands of existing satellite terminals”.
- Using algorithms based on slime mold behaviors to map the filaments between galaxies.
- India is planning for Chandrayaan-4 to be a lunar sample return mission.
- Stoke Space is hiring a software engineer to work on their FTS, e.g., to tell the rocket to blow up only when it’s supposed to blow up.
- NASA received a shipment of 0.5 kg of plutonium oxide from the US Department of Energy, the largest delivery of new radioisotope thermal fuel for heaters and RTGs since production restarted in the US about a decade ago. The goal is to reach production of 1.5kg/year by 2026. (How do we think this was shipped? DHL?)
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New Glenn’s “first stage mid module”, which encapsulates its LOx and LNG tanks, rolled out of Blue Origin’s manufacturing facility near KSC. This is likely flight hardware ahead of a potential launch next year, which will include NASA’s ESCAPADE duo to study Mars’s magnetosphere. Credit: Max Evans/NASA Spaceflight |  |
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