¶That State of Fuel Transfer. SpaceX’s next Starship launch, assuming it reaches orbit, may attempt a 10-ton internal fuel transfer of cryogenic liquid oxygen as part of their NASA tipping point award from 2020. Cryogenic propellant storage and fuel transfer is a key technology for the HLS variant of Starship to be able to access cislunar space. While Musk has tended to brush off the potential difficulty of fuel transfer, this area of space technology is underdeveloped—in part due to the historic lack of any pressing need for such technology. Cryogenic propellant storage is challenging due to the low boiling points of liquid methane (-162 °C), oxygen (-183 °C), and especially hydrogen (-253 °C). Hydrogen, in particular, requires active cooling to avoid boil-off during storage. Meanwhile, RP-1 and other options (water, peroxide, hydrazine, etc.) tend to freeze in space environments (ex., -60° C for RP-1), requiring active heating for long-duration storage. (The need to heat other fuels is one of many reasons long-duration/multi-restart upper stages use hydrogen, and also why SpaceX modified the paint scheme on some Falcon upper stages to increase temperatures during missions with long coast phases.) Starship, with a nominal 6-bar tank pressure, will employ active cooling, a sun shade, or another method to keep fuel temperatures in the range of -182 °C to -170 °C where both methane and oxygen are liquid. Past work on cryogenic fluid management (CFM) includes NASA’s Robotic Refueling Mission program, hosted on the ISS. RRM1 & RRM2 successfully tested liquid ethanol management and coolant replenishment, while RRM3 had to vent its liquid methane prior to completing fluid transfer tests due to a failed cryocooler that was providing cooling for zero-boil-off (ZBO) fuel storage. In addition to Starship’s potential internal transfer test, NASA’s other upcoming cryogenic-fuel-related 2020 Tipping Point mission is LOXSAT, which is being developed by Eta Space as they also work toward their own orbital propellant depot—ULA and Lockheed have been quiet on their own CFM-related Tipping Point awards. LOXSAT will demonstrate many of the technologies needed for CFM, including active and passive thermal management, ZBO storage, quick disconnects, and testing of autogenous vs. helium tank pressurization. LOXSAT will launch NET July 2024 on Electron and is built on top of a Rocket Lab Photon bus with a 9-month mission duration. We’re keen to see both of these CFM demonstrations launch as they will be pushing technical boundaries that need to advance for the next era of cislunar (and eventually Martian) exploration to become feasible.
The Robotic Refueling Mission payload, while attached to the Dextre robotic platform during its time at the ISS. Credit: NASA Goddard
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| ¶Short Papers
- While NASA’s Kepler mission ended in 2018, data analysis is ongoing. A recent paper looks at the Kepler 385 system, a Sun-like star system 4,670 light-years away, and shows that it likely has at least seven planets—all larger than Earth but smaller than Neptune—orbiting close to their star (and therefore unlikely to be habitable). They are likely rocky and some probably have thick atmospheres.
- A blob of gas orbiting Sagittarius A* at almost ⅓ c may explain bursts of gamma rays observed from the Milky Way’s central black hole every 76 minutes (paper).
- JWST would likely be able to detect evidence of synthetic molecules such as CFCs in Earth’s atmosphere using transmission spectroscopy from up to 50 light-years away. So if there is an Earth-like planet, with a human-like civilization, at a similar developmental stage, that also cools things with CFCS, and it is within 50 light-years of us, we could know soon (paper).
- ALMA detected a possible first protoplanetary disk in another galaxy, in the Large Magellanic Cloud, 160,000 light-years away (paper). Protoplanetary disks are accretion disks around young stars and the first step in the formation of planetary systems like our own.
- Climate simulations suggest that enough dust was kicked up by the Chicxulub asteroid impact 66 million years ago to prevent plants from photosynthesizing for up to two years post-impact (paper). If starvation didn’t get the dinosaurs, the worldwide reductions in temperatures by 15 °C for 15 years might have. …or maybe the space rocks just hit them?
“The Late Heavy Bombardment was followed a few billion years later by the Comparatively Light but Oddly Specific Bombardment.” XKCD #2845
| ¶News in brief. Chandrayaan-3’s propulsion module quietly returned to an ultra-high Earth orbit as ISRO experiments with the future technologies for a lunar sample return mission ● The first Vulcan launch, with Astrobotics’s CLPS lander onboard, has slipped into early 2024 due to ground systems issues—with SLIM’s landing in mid-Jan and Intuitive Machines targeting a launch on January 12th, the race for a first commercial lunar landing is very much on ● Satellite imagery startup iQPS went public on the Japanese market at 3.4B yen ($23.7M) ● Ingenuity took off on its 67th flight and flew 393 m for 2+ minutes ● NorthStar Earth & Space raised a $14.7M Series D to support the deployment of the first four satellites in their space situational awareness constellation ● Iran launched a 500 kg biocapsule (possibly containing unknown animals) to 130 km aboard its domestically-produced Salman rocket ● Egypt joined China and Russia’s International Lunar Research Station (ILRS) ● Momentus is unable to confirm the deployment of three satellites from the Transporter-9 mission—an as-of-yet-unidentified third-party deployer was used on this mission as the satellites didn’t need propulsion ● SpaceX launched for the 90th time this year ● Landspace’s methane-fueled Zhuque-2 rocket took satellites to SSO on its third launch, a milestone for the company—the company is also working on a 200-ton-thrust full-flow staged-combustion methalox engine and the stainless-steel Zhuque-3 which will be able to carry 18 tons to LEO with a reusable first stage ● Hubble’s gyro issues have been resolved ● Helicity Space raised a $5M Seed for very early-stage fusion engine development ● China launched two satellites with the commercial CERES-1 Y9 rocket and sea-launched an internet technology satellite ● Psyche took its first picture of a distant star field and was able to detect a coronal mass ejection due to being a very “magnetically quiet” spacecraft.
A mosaic made from “first light” images acquired by the twin cameras aboard Psyche. The stars shown are from the Pisces region of the sky, where the cameras happened to be pointed for this first functional imaging test.
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- Correction: Last week’s issue included a link to a paper that failed to discuss the probabilities of solar system disruption in the scenario of a close pass from another star. Here’s a link to the correct one.
- DARPA, the agency famous for funding weird stuff (like the Internet, GPS, etc.), is funding 14 companies to explore what a future cislunar economy might look like, with proposals for “self-sustaining, monetizable, commercially owned-and-operated lunar infrastructure.” The award recipients are the (mostly) usual suspects: Blue Origin, CisLunar Industries, Crescent Space Services, Fibertek, Firefly (spacecraft docking, refueling, and repositioning), GITAI (robotics for infrastructure), Helios, ICON (structures from regolith), Nokia of America, Northrop Grumman, Redwire Corporation, Sierra Space (carbothermal oxygen extraction), SpaceX, and Honeybee Robotics (building LUNARSABER, a 100-meter-tall deployable structure that “integrates solar power, power storage and transfer, communications, mesh network, PNT, and surveillance”).
- The OSIRIS-REx return capsule indeed had a drogue parachute deployment failure. “In the design plans for the system, the word “main” was used inconsistently between the device that sends the electric signals, and the device that receives the signals. On the signal side, “main” meant the main parachute. In contrast, on the receiver side “main” was used as a reference to a pyrotechnic that fires to release the parachute canister cover and deploy the drogue. Engineers connected the two mains, causing the parachute deployment actions to occur out of order.” Human factors are important. Very fortunately, the main parachute was able to function without the drogue and the capsule’s precious samples arrived intact.
- “My $500M Mars Rover Mistake”
- Australia’s first lunar rover will be aptly named ‘Roo-ver’ per public vote and is set to launch on a NASA CLPS mission to the Moon’s South Pole no earlier than 2026.
- Send your name to Jupiter orbit on Europa Clipper.
- XKCD tackles ‘What if we aimed the Hubble Telescope at Earth?’ (This is narrated by our favorite Randall Munroe and appears to be the start of a new video series based on his What If? books!)