Issue No. 273

The Orbital Index

Issue No. 273 | Jun 12, 2024

🚀 🌍 🛰

Starship Flight 4. SpaceX’s enormous rocket took off again from South Texas, this time with the sole goal of bringing both the booster and ship softly back to Earth in (roughly) single pieces. An on-time launch of the world’s most powerful rocket delivered excitement from start to finish (livestream, slo-mo liftoff). Despite an engine out on launch and landing (with 33 engines total, Superheavy don’t care), the first stage was able to complete a nominal ascent, hot-staging, temporary hot-staging ring jettison, boost back, and landing burn—all with enough precision that previously deployed buoy cams were able to capture its soft splashdown (BuoyCam, onboard landing clip). This precision should hasten an attempted future launch tower catch, likely at least initially using the under-construction Tower 2 at Boca Chica as a catch-only tower (might not wanna kill Mechazilla just yet) without the addition of a launch mount, deluge system, or fueling hardware. While Superheavy was impressing close to home, Starship conducted a close-to-orbital burn that put it on a trajectory to splash down in the Indian Ocean off the coast of Australia. Just to play in hard mode, SpaceX removed two tiles from Starship’s heatshield and installed a single thinner tile, so that engineers could gather data on the stainless steel hull’s performance in failure scenarios. After an uneventful (because of roll-free, rock-solid attitude control) coast phase, the upper stage began its re-entry. Due to Starhip’s expansive bulk, it again plowed a wake through the plasma sheath that forms as the vehicle compresses the atmosphere in front of it, allowing (mostly) consistent Starlink video through the entire reentry—from a beautiful plasma light show, to (what looked like) bobbing in the ocean after a successful landing. The landing was made even more impressive by the failure of the hot seal around (at least) one of Starship’s forward flaps, burning through the flap which quite spectacularly still actuated during the final flip maneuver before splashdown (the structures and actuator teams must be so proud). Over the entire mission, the flight control software particularly shone, adapting to the dynamics of hypersonic reentry (the 3rd party generated reentry dynamics graphs are super interesting), an engine loss on Superheavy, and bits melting off of Starship. Looking forward, Flight-5 could launch as soon as next month, and, although it feels unlikely to actually feature a booster catch attempt, it should feature an upgraded heatshield that is 2x stronger that may (or may eventually) feature an ablative underlayer for backup heat protection (maybe they should just use pineapples). The FAA’s license of Flight-4 included three outcome scenarios that would increase the speed of future certifications, meaning future flight timing is probably now driven exclusively by SpaceX’s ability to iterate on Starship’s fixes and upgrades, and its capacity to build new hardware.

Plasma during Starship’s well-controlled reentry.

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Starliner and crew reach the ISS. Boeing’s long-delayed first crewed Starliner flight launched and reached the ISS last week. Starliner’s ULA Atlas V, on its 100th mission, functioned nominally and released the capsule below orbit, allowing it to power itself to orbit where it then spent about 27 hours doing checkouts before docking with the ISS. Onboard the up to four-person capsule were experienced NASA astronauts Butch Wilmore and Suni Williams. Two additional helium leaks were detected after launch, in addition to the one that had delayed recent launch attempts, but the affected helium valves were closed successfully. During its approach to the ISS, five of the craft’s 27 available RCS thrusters went offline, forcing a backoff. Four were brought back online and docking was completed successfully. The reason for the thruster issues isn’t yet clear but seems to be a software issue similar to issues seen during the capsule’s OFT-2 uncrewed test in 2022. During the four years since SpaceX started flying crewed Commercial Crew missions, Boeing has fixed multiple issues with Starliner and absorbed at least $1.5 billion in costs. Assuming the rest of the mission goes as planned and NASA certifies the capsule, Boeing will undertake at least six operational Starliner ISS flights at a per-seat cost of $90 million (or more). Starliner still compares favorably to the Orion capsule’s development, clocking in at under $5B (Crew Dragon was ~$3B), compared to the larger cislunar capsule’s $23B+ development cost.

CST-100 approaching the ISS.

NASA won’t approve the Hubble repair mission. NASA rejected Jared Isaacman’s proposal to lead a private Hubble repair and re-boost mission, citing risks of damage to the telescope, such as from thruster volatiles settling onto optics, as well as docking challenges and the fact that most people who know how the thing works have retired. They haven’t ruled out a future mission, though. In other Hubble news, due to ongoing faulty readings from one of the telescope’s three remaining functional gyroscopes (it last got six new ones installed during its last Shuttle servicing mission in 2009), the telescope will transition to an operation mode which uses just one gyro, allowing its other functional one to be kept in reserve. This operation mode, developed 20 years ago as a way to prolong the telescope’s life, and tested successfully in 2008, should have little impact on science observations, although the telescope will now need more time to slew and “will not be able to track moving objects closer than Mars”, an uncommon real world need. (Now’s your chance, near-Earth UFOs!) Engineers concluded that there is at least a 70% chance that Hubble will have at least one working gyro remaining through the mid-2030s, allowing hopefully at least another decade of breathtaking observations.

“One-gyro mode substitutes magnetometers, sun sensors, and star trackers for the failed gyros. It is a multi-step process that positions Hubble closer and closer to a target based on the accuracy of its sensors. The first step uses the magnetometers, sun sensors, and the remaining gyro to help point Hubble within 10 degrees of the target, allowing the more accurate fixed head star trackers to take over. The fixed head star trackers work with the remaining gyro to point the observatory within tens of arcseconds (1 arcsecond = 1/3600 of a degree) from the target, allowing the use of Hubble’s highly accurate fine guidance sensors. The fine guidance sensors then take over, finding their assigned guide stars in the sky, putting the observatory within 150 milliarcseconds (1 milliarcsecond = 1/3600000 of a degree) of the target. Those sensors may make further adjustments, which are determined by the science instrument(s) used in the observation, and move Hubble to within 20 milliarcseconds of the target center.” Credit: NASA

News in brief. The Chang’e 6 ascent vehicle and service module successfully docked in lunar orbit ahead of sample delivery to EarthRocket Lab successfully launched the second of two satellites for NASA’s PREFIRE mission Russian cosmonaut and ISS commander Oleg Konenko became the first person to reach 1,000 cumulative days in space Japanese propulsion startup Pale Blue raised a $7.5M Series B to continue developing water vapor thrusters Ariane 6 will make its debut launch on July 9 (about four years late) Rocket Lab founder Peter Beck was officially knighted by New Zealand and is now Sir Peter Beck ⚔️ Firefly landed a large multi-launch contract for their Alpha vehicle with Lockheed Martin for 25 launches (15 guaranteed, 10 optional) China’s Space Pioneer raised >$200 million for their Tianlong-3 reusable, mega-constellation-launching rocket ESA signed an agreement with commercial space station provider Vast to study how the Haven-1 space station could fit into ESA’s plans for cargo and crew in LEO Canada plans to invest $197M into the Square Kilometer Array Observatory (SKAO) that is set to become the world’s largest radio observatory upon completion in 2029 China launched three satellites aboard the commercial CERES-1 rocket NASA is exploring faster and more affordable alternatives for Mars Sample Return by funding studies with industry partnersLockheed Martin, SpaceX, Blue Origin, Aerojet Rocketdyne, Northrop Grumman, Quantum Space, and Whittinghill Aerospace  Astroscale went public in the Japanese market Virgin Galactic conducted their final mission with the VSS Unity spaceplane, taking three private astronauts and a Turkish researcher to suborbital space Apollo 8 astronaut William Anders passed away at 91 in a crash while doing loops solo in his privately-owned Beechcraft T-34 Mentor. RIP, and deepest respect.

Anders took “Earthrise” on December 24th, 1968, while on the first crewed trip to lunar orbit. It has been described as “the most influential environmental photograph ever taken.”

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  • Last week we incorrectly attributed the Swedish surface ion research payload on Chang’e 6 to Switzerland. Sweden is not Switzerland.
  • Japan will be flying the world's first wooden satellite, made from magnolia wood, which is a potentially more sustainable and less polluting option than metal for demisable satellite structures when they burn up in the atmosphere.
  • Here are videos from the Chandra X-ray Observatory of Cassiopeia A and the Crab Nebula, each composed of over two decades of observations, showing changes in debris and radiation after both of these massive supernovae. The Crab Nebula, 6,500 light-years away, exploded in 1054 AD and left a pulsar. Cassiopeia A, meanwhile, exploded about 340 years ago, with the visible blast wave expanding outward into the interstellar medium, accelerating particles to high energies, and reflecting a second shock wave back inward. It also left behind a neutron star.
  • ESA’s first fully owned and operated cubesat, OPS-SAT, launched in 2019, ended its mission after deorbiting quicker than expected due to increased solar activity. This was the first satellite open for public use and resulted in numerous publications. It hosted experiments on AI, aided search and rescue activities, and *checks notes* conducted the first stock market trade from orbit. Fortunately, this groundbreaking satellite paved the way for the OPS-SAT Space Lab service with plans to launch more spacecraft labs soon. 
  • All about Tin Whiskers.

Chang'e-6 on the lunar farside, captured by its surprise small rover. Its samples were successfully transferred to its return and reentry craft in lunar orbit for the trip to Earth.

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