Saturday, May 15, 2021

THE HAPPENING WORLD: Introduction to Logisim Evolution: Open-Source Logic Simulator

Wow! I sure wish I'd had something like this when I was designing the M9900 CPU and M9900 64K!

You can download Logisim Evolution from GitHub. It's free, written in Java, and ready-to-run installable versions are available for Debian (etc.) and Red Hat (etc.) Linux, Mac OS X, and Windows systems.

Posted at 11:00 Permalink

TRACKING WITH CLOSEUPS: Tesla Model S Onboard Systems Battery Runs Down While on Charger

…and the the fun begins.

Posted at 10:34 Permalink

CONTINUITY: Chinese Tianwen-1 (天问) Lands on Mars

In vintage communist style, no streaming video or other contemporary coverage was provided of the landing, only this Stalinesque announcement after the (claimed) success, with the co-ordinates. Independent radio hobbyists have been tracking the telemetry signal from the lander and inferring mission events from its Doppler shift as it performed its final maneuvers and encountered Mars.

Posted at 10:11 Permalink

THE HAPPENING WORLD: Rocket Lab Electron “Running Out Of Toes” Launch

Launch is scheduled for 10:08 UTC on 2021-05-15. Rocket Lab will attempt to recover the first stage from the sea after a parachute splashdown.

Update: Loss of telemetry, end of Webcast without any further information. It doesn't look good. (2021-05-15 11:24 UTC)

Posted at 08:07 Permalink

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

Thursday, May 13, 2021

CONTINUITY: A Mid-Air Collision with No Injuries

Posted at 13:56 Permalink

THE HAPPENING WORLD: Chinese Tianwen-1 (天问) Mars Landing

I don't know if anybody will be streaming the landing attempt. If I come across sources, I will add them to this post. Here is background on the mission.

Posted at 12:18 Permalink

TRACKING WITH CLOSEUPS: The True Cost of Processor Manufacturing: Taiwan Semiconductor Manufacturing Company 7 Nanometre Process

Posted at 12:10 Permalink

CONTEXT: News You Can Use—How to Fill a Klein Bottle

Presented by Clifford Stoll.

Posted at 11:30 Permalink

Wednesday, May 12, 2021

CONTINUITY: Darts in Higher Dimensions

This game/puzzle was originally suggested by Greg Egan, whose science fiction often features intricate mathematical constructs.

The problem is similar and related to, at a deep level, the “Sum of Uniformly Distributed Random Numbers”, about which I wrote in 2006.

Posted at 15:10 Permalink

CONTEXT: Finally—A Mind Controlled Flamethrower

Posted at 11:18 Permalink

THE HAPPENING WORLD: Iron Dome in Action

Here is more on Iron Dome. Remember all the “experts” who said “You can't hit a missile with a missile”?

Posted at 10:37 Permalink

Tuesday, May 11, 2021

CONTINUITY: Vacuum Tube Computer Part 12: Redesigning the Logic Unit and Building Buffers

After experimenting with an actual MC14500, it's decided to extend the design to support full binary arithmetic including carry, which on the original Motorola design requires lengthy bit-twiddling. Driving the resulting arithmetic and logic unit (ALU) will require more fan-out than the instruction decoder provides, so once again it's time to add buffer circuitry. At this point, the largely repetitive circuitry is complete, and it's time to contemplate the messy random logic which the ALU will require.

Posted at 11:43 Permalink

CONTEXT: Sidewinder — The Missile That Changed Air Combat

Posted at 10:15 Permalink

CONTINUITY: Bright Lights: The Story of Neon Signs

Geissler tubes filled with various gases that fluoresce when electrified were popular novelties in the 19th century, often made in whimsical shapes. If you have a Tesla coil, you really ought to have a few Geissler tubes which will light up in its vicinity without a wired connection. You can find them on eBay.

Posted at 08:55 Permalink

TRACKING WITH CLOSEUPS: The Joys of Surface-Mount Components

Posted at 07:59 Permalink

Monday, May 10, 2021


This, just two days after Dogecoin declines 35% in 24 hours after Elon Musk calls it “a hustle” during a skit on Saturday Night Live.

Posted at 14:24 Permalink