Issue No. 246

The Orbital Index

Issue No. 246 | Nov 29, 2023

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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).

Starship in the midst of hot staging.

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.

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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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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