Issue No. 163

The Orbital Index

Issue No. 163 | Apr 6, 2022

🚀 🌍 🛰

Artemis I’s Wet Dress Rehearsal. During the upcoming WDR test the massive SLS rocket will be filled with liquid hydrogen and oxygen propellant and taken through a full launch countdown to T-10 seconds, stopping just before igniting the core stage’s four RS-25 engines. The initial WDR was scrubbed on Sunday due to malfunctioning fans on the mobile launcher which could have led to a hazardous gas build-up. (The launch zone was also harmlessly struck by lightning a few times.) Then on Monday the WDR proceeded through partial oxygen loading, with a small hiccup due to temperature limits being reached, but was eventually called off when a tank vent control panel on the hydrogen tank malfunctioned near the end of the day. The next attempt is likely in a couple of days. Multiple attempts and iterations are expected during this critical practice run. NASA has provided minimal coverage of the tests, omitting mission control sound, due to export control concerns. The claim is that the government is “really super sensitive to cryogenic launch vehicles of this size and capability” because they’re analogous to ballistic missiles. However, mission control sound was shared for Shuttle launches and the majority of ballistic missiles are not cryogenic due to their need for storage and rapid launch. It’s all a bit odd.

SLS waiting for its next attempt for a full Wet Dress Rehearsal.

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Do most countries tweet their breakups? Roscosmos Director Dmitry Rogozin penned a tweetstorm again threatening Russian abandonment of ISS operational cooperation. It remains unclear how this could happen, even if Russia’s current cosmonauts pack up their Soyuz and abandon the Russian segment or completely detach it (?!) as they dramatically threatened. Rogozin suggests that cooperation will resume only once the partner space agencies’ countries lift sanctions (NASA, ESA, CSA & JAXA). While it seems unlikely that the International and Russian segments will ultimately be separated, NASA is studying their options. Some former NASA astronauts think that it would be possible to replace the functions of the Russian segment, particularly those needed for orbit maintenance and collision avoidance—here’s a visualization of the station without that segment. However, despite the posturing and tweetstorms, day-to-day activities are apparently normal for ISS operational teams.

Transporter-4. On April Fools Day, SpaceX launched their fourth dedicated SSO rideshare mission with 40 spacecraft onboard. The largest payload was the German hyperspectral Environmental Mapping and Analysis Program satellite at 980 kg. Other payloads included 5 ÑuSat visible + IR Earth observation sats, 12 Swarm 1/4U (400g) Spacebees, GNOMES-3 (radio occultation weather forecasting), Albania's first satellite (Albania-1), amateur radio BDSat, and D-Orbit’s ION SCV orbital transfer vehicle that will host or later release “four Kleos Space CubeSats, three CubeSats from the University of Chile, and a passive payload for Spacelust called Upmosphere.” Due to their recent (and mostly unexplained) falling out, this will be the last Transporter mission with Spaceflight, Inc, which brokered payloads on this mission for Lynk Global (direct cell phone to satellite comms test) and HawkEye (transportation monitoring). SpaceX’s Transporter-5 is scheduled for June with Transporter-6 to follow in October.

News in brief. SpaceX is ending production of its pretty darn new Crew Dragon capsule—according to Gwynne Shotwell, they will continue to refurbish and reuse the fleet of four, focusing on “fleet management” (and Starship) China’s maiden Long March 6A launch was successful, deploying two satellites from the very upgraded Long March 6 with solid boosters—it can send 4 tons to a 700 km SSO orbit The UN banned the use of mercury as a satellite propellant—despite some excitement about a four-year-old proposal by Apollo Fusion (now an Astra subsidiary that doesn’t use mercury as a propellant), no thrusters have used mercury during flight since sub-orbital test flights in ‘64 & ‘70 Blue Origin’s New Shepard took space tourists on a suborbital hop for the fourth time including Gary Lai the Chief Architect for the launch system Kubos (Andrew’s old employer) and their Major Tom mission control software were acquired by Xplore South Korea successfully test-fired its first solid-fuelled rocket booster Astronaut Mark Vande Hei safely returned to a geopolitically unstable Earth with cosmonauts Anton Shkaplerov and Pyotr Dubrov Japanese SAR company Synspective raised a $100M Series B; the aerospace parts manufacturing startup Hadrian raised $90M; and, Impulse Space raised $20M for their orbital transfer vehicle—the company was founded by Tom Mueller, 1st employee at SpaceX and lead on the Merlin engine Again, satellite imagery disproves Russian lies about civilian deaths Rocket Lab launched two BlackSky EO sats Amazon’s Project Kuiper contracted for “the largest commercial procurement of space launch services in history,” signing up for 83 launches from ULA (47), Arianespace (18), and Blue Origin (12, with an option for 15 more) to launch the majority of their planned 3,236 satellite internet service constellation The Sun is starting to act up as it heads towards its next solar maximum (happening in ~2025), releasing an X-class flare on March 30th, resulting in stunning auroras.

March 30th Aurora over Sweden. Credit: Mia Stålnacke



  • A recent ISS spacewalk was imaged from the ground.
  • Scott Manley explores the history of rotating artificial gravity and some of the nutty experiments done in early space programs to quantify how humans would respond to it. (We wonder what the review committee thought when they received “let’s stick a human inside a centrifuge for a week and see what happens when they throw darts!”).
  • A few weeks ago we talked about Pioneer 10. Its sibling and backup, Pioneer 11, launched 49 years ago today after Pioneer 10 had traversed the asteroid belt. Since Pioneer 10 was safely through the belt, P11 was retargeted to slingshot around Jupiter and visit Saturn for the first time, where it would verify the gravity assist to be used by the already-on-route Voyager 2. On Sep. 1, 1979, Pioneer 11 passed within 20,900 km of Saturn’s cloud tops at a velocity of 114,200 km/h, detecting the planet’s liquid hydrogen atmosphere and magnetic field and discovering two new moons. The craft later passed the orbits of all of the planets, continuing to operate for 22 years. It was last heard from in 1995 when it was more than 6 billion kilometers from Earth.
  • Rocky exoplanet Kepler-16b definitely orbits two stars at once. This circumbinary planet is 245 light-years from Earth and orbits its binary suns every 228.8 days (paper). We should probably just rename it Tatooine… although since it’s outside the habitable zone, it’s probably more Mars-like. ☀️☀️
  • A massive ice shelf collapsed in East Antarctica (where coastal glacial ice used to be stable) and is clearly visible from space.

Solar Orbiter recently snapped this stunning photo of a massive solar prominence against the full disk of the Sun. It has the minor superlative of being the largest prominence caught in a full disk image, as opposed to a more zoomed-in image or with a chronograph blocking the disk.

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