# The Orbital Index

Issue No. 168 | May 11, 2022

🚀 🌍 🛰

 ¶Tianzhou-4. China successfully launched Tianzhou-4 on a Long March 7 to resupply the Tiangong space station (which is increasingly being referred to as the CSS) ahead of the crewed Shenzhou-14 next month (NET June 5). Tianzhou automated resupply spacecraft are built on a core module design derived from the Tiangong station itself. At 4.2 m in diameter and 18 m long, they can deliver up to 6.8 tons of cargo to the station and are also used to refuel the station’s electric propulsion system. Shenzhou-14’s crew will prepare the station for its second and third modules: Wentian and Mengtian. These modules are on-orbit labs hosting Chinese and international experiments—over 1,000(!) have already been approved. Wentian and Mengtian will launch in July and October, respectively. Following their attachment to the Tianhe core module, Shenzhou-15 will launch near the end of the year, after yet another resupply mission, bringing the station’s number of Taikonaut occupants to a record six (for a short time until the return of Shenzhou-14). And next year the real fun begins with the launch of the station’s co-orbiting Xuntian Chinese Survey Space Telescope (CSST), which will be able to survey 40% of the sky with its massive 2.5 gigapixel camera. The co-orbiting design will also enable repairs, upgrades, and refueling, which makes a whole lot of sense.
 Tianzhou-4’s Long March 7 (CZ-7) just before liftoff from pad 201 at Wenchang Space Launch Center.
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 ¶Back from the dead. Several weeks ago, Starship Booster 7 appeared destined for the scrapyard after photos emerged of its badly damaged downcomer, the plumbing that delivers methane from its upper tank to the booster’s engines. The booster was taken off the test stand and transported back to the construction facility, 3.5 km away. Many “tank watchers” suspected that this was the end of Booster 7 and that SpaceX would switch focus to Booster 8. But just 3 weeks later, Booster 7 has made its way back to the launch complex and has been reinstalled on the test stand for additional testing and a potential static fire—this means an orbital launch is unlikely to be delayed by the need to replace the booster. However, FAA approval for a Starship orbital launch is still forthcoming, with the agency recently delaying their determination of the environmental impact assessment process for a fourth time—the process is now targeting May 31. We’re not holding our breath.
 A leaked photo of Booster 7’s damaged downcomer. The rings around it are likely either slosh baffles for the liquid oxygen in the lower tank or stiffening rings to keep the downcomer from rupturing when the methane tank is filled and pressurized.
 ¶(Short) PapersBased on the planet-rich composition of some white dwarf stars, we have long known that they often consume or fling away their planets as they expand through their red giant phase before collapsing. In support of this theory, Chandra recently spotted x-ray flashes from the white dwarf G29-38 consistent with planetary debris actively falling into the dead star (paper).However, perhaps not all debris falls into the star. We also just spotted what looks like an exoplanet in the habitable zone of a white dwarf (paper), meaning that it may have formed from the charred debris of previous planets after the star went through its red giant phase.We already know that amino acids can form in space, likely on dust grains in the Interstellar Medium (ISM). Now we have a realistic model and experimental results that suggest that peptides (short chains of amino acids) can form in space as well (paper).If exoplanet TRAPPIST-1e had technological life dumping CFCs into its atmosphere as Earth does, JWST might just be sensitive enough to detect it. “We find that with the launch of JWST, humanity may be approaching the cusp of being able to detect passive atmospheric technosignatures equal in strength to its own around the nearest stars” (paper).Absurdly, our best clocks are now so sensitive that we can detect the relativistic differences in their tick rates due to one clock being 1mm deeper into the Earth’s gravity well than another one (paper). 🕰🤯
 XKCD #1248
 ¶Meet OSIRIS-APEX. NASA greenlit a mission extension for OSIRIS-REx, currently en route back to Earth with samples from Bennu. After releasing the sample return capsule in Sept 2023, our plucky hero will be renamed OSIRIS-APEX and will head off to intercept and orbit the Apophis asteroid for at least 18 months as the massive object lumbers toward its infamous 2029 close encounter with Earth. Using its maneuvering engine proven at Bennu, OSIRIS-APEX will descend and impinge the asteroid’s surface with its thrusters to expose subsurface material. While Apophis no longer has an impact risk in 2029 (as feared when it was first discovered), it will be “the closest an asteroid of this size has gotten in the 50 or so years asteroids have been closely tracked, or for the next 100 years of asteroids we have discovered so far. It gets within one-tenth the distance between the Earth and Moon during the 2029 encounter. People in Europe and Africa will be able to see it with the naked eye, that's how close it will get." An international workshop on Apophis also happens to be this week. NASA is also extending seven other worthy missions, with no real surprises among them: MAVEN, InSight, LRO, MSL (Curiosity), New Horizons, Mars Odyssey, and MRO.
 ¶News in brief. Astroscale’s ELSA-d successfully rendezvoused with its debris-simulating test target (cf. Issue 108) ● SpinLaunch spun up their yeet machine again and this time hucked an optical test payload to 7 km—so you can now see exactly what it looks like to be thrown upward at 1,600 km/h (definitely worth watching) ● Jim Cantrell’s Phantom Space ordered 200+ rocket engines from Ursa Major for their upcoming Daytona launch vehicle ● High-altitude tourist balloon startup World View announced that it has 1,000 reservations (note that the reservation is $500 while the flight will be$50,000) ● Crew-3 returned safely to Earth hours before SpaceX launched another 53 Starlink sats (resulting in some lovely early morning lighting effects) ● Space Force’s SpaceWERX technology arm selected 125 industry teams to each receive \$250k to develop concepts for orbital debris cleanup and orbital assembly services ● Chinese NewSpace startup Deep Blue Aerospace completed a kilometer-level VTOL rocket test.
 Deep Blue’s Nebula-M VTOL test rocket (center) is a small dot amid the Chinese countryside. Vertical velocity appeared high on landing (video), likely leading to an explosion or other damage (not shown 😞).
 ¶Etc.NASA recently released a visualization of 22 known black hole binary systems in the Milky Way and Large Magellanic Cloud.The trailer for NASA’s Psyche mission was also released. David Oh, the Project Systems Engineering Manager and Engineering Technical Authority for the Psyche mission, wrote about the exciting upcoming mission to a metal asteroid in Issue 138.Meanwhile, China is planning a 2025 mission, similar to NASA’s en route DART, to subtly redirect an asteroid with a kinetic impactor. The country is also working on a separate mission to visit an asteroid, grab samples, return them to Earth, and then head out again to rendezvous with main-belt comet 311P/PANSTARRS.West Japan Rail Company’s Gundam-style, telerobotic heavy equipment robot is mounted on the end of a crane. 🦾 A Russian SOZ ullage motor disintegrated in high orbit, producing 16 trackable debris—this is the 54th such failure of this design in a highly elliptical orbit. Jonathan McDowell’s discussion thread is interesting.Not to be outdone by Oxford University’s analysis of a planet made out of blueberries (cf. Issue 158), University of Sussex researchers have published a detailed paper answering the critical related question: could a planetoid consisting entirely of cows support a methane atmosphere? Yes, but at 1019 incompressible cows, “the cost, necessary rearing area, and required nutrition are impossible to meet at the current time.”  Astrobites followed up with a critical analysis of this paper and other recent cow-culations. 🐄💨
 Odd radio circles (ORCs) are rings in the radio spectrum much larger than galaxies. We only know about five of them, with the first detected in 2019. We also don’t know what causes them yet—shockwaves from merging black holes, active galactic nuclei, starbursts, or something equally energetic. MeerKAT has now imaged an ORC in unprecedented detail and it may be more than a million light-years across (10X the diameter of our galaxy).