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May 14, 2021 Archives

Friday, May 14, 2021

CONTINUITY: Andy Weir: Project Hail Mary, Writing, and Life

There are essentially no spoilers for the novel in this interview.

Posted at 16:12 Permalink

CONTEXT: What Happens If You Distill Red Wine?

This experiment used a water distiller which did not, unlike a spirits still, separate the ethanol from the water. Consequently, both the water, alcohol, and any volatiles with a boiling point less than water were in the distillate. Interestingly, most of the flavour and colour compounds are less volatile and remained in the distiller. How would “reconstituted concentrated wine” fare in a blind wine tasting?

Posted at 13:18 Permalink

TRACKING WITH CLOSEUPS: Inside a 10 Gigabit per Second USB-C Cable

The tip of a ball-point pen is shown for scale. Not all such cables use these micro-coaxial conductors: some use shielded twisted pairs. The conductors in the centre are for compatibility with USB 2.0.

Posted at 12:04 Permalink

CONTEXT: SpaceX: Starship Orbital Flight Test Plan

SpaceX have filed a document, “Starship Orbital - First Flight FCC Exhibit” [PDF], as part of their application to the U.S. Federal Communications Commission for a license to downlink S band telemetry from the flight test. This document provides details of the flight, with the “Flight Profile” as follows:

The Starship Orbital test flight will originate from Starbase, TX. The Booster stage will separate approximately 170 seconds into flight. The Booster will then perform a partial return and land in the Gulf of Mexico approximately 20 miles from the shore. The Orbital Starship will continue on flying between the Florida Straits. It will achieve orbit until performing a powered, targeted landing approximately 100km (~62 miles) off the northwest coast of Kauai in a soft ocean landing.

Both stages will land at sea. The orbital stage (Starship) is planned to make a “soft ocean landing”, which presumably means a propulsive landing ending in a splashdown in the ocean off Hawaii. The booster (Super Heavy) will do a partial boost-back and land offshore in the Gulf of Mexico. It is not stated whether this will also be a splashdown or a platform landing, but as no suitable platform is known to exist or to be under construction, the former is the way to bet. If there's no plan to re-fly these vehicles, soft water landings demonstrate the landing capability, allow intact recovery to permit post-flight examination and analysis, and does not put the Starbase infrastructure at risk from a landing attempt on-site.

Some have quibbled with SpaceX's designating this a “Orbital” flight despite its plan to complete less than one complete orbit around the Earth. But from a dynamical and engineering standpoint, once you've achieved a perigee and apogee outside the atmosphere, you're in orbit, and it doesn't matter how many times you go around, even if it's less than one, before you perform a retrograde burn and re-enter the atmosphere. From a flight test perspective, the thermal, flight control, and mechanical stresses on the vehicle are identical, and allow testing return from an arbitrary orbital mission with the same orbital parameters. Targeting the splashdown off Hawaii avoids performing the re-entry over the western U.S., as would be the case for a return to the Starbase in Texas, with the attendant possibility of scattering Starship debris along the trajectory if it ends badly.

Here are the technical details of the application to the FCC. According to this document, the period covered by the application is 2021-06-20 through 2021-12-20, so the flight could occur any time in this June through December window.

Posted at 11:10 Permalink