Wednesday, July 28, 2021

CONTINUITY: NASA: RS-25 Rocket Engine “Improved”

Forty years after it first flew as the Space Shuttle Main Engine, the Aerojet Rocketdyne RS-25 rocket engine, which was originally designed for a service life of 27,000 seconds and 55 starts, has been “improved”, delivering a service life of 1700 seconds (6.8% of the original) and 4 starts (7.3% of the original). Thrust has been increased by 6%, along with “some cost savings”—the cost for the 24 RS-25 engines intended for the Space Launch System (SLS) comes to around US$ 146 million per engine.

The engines, routinely refurbished and reused in the Space Shuttle program, will be discarded as twisted wreckage in the briny deep on each flight of the SLS.

Elon Musk estimates the cost of the SpaceX Raptor engine, which has slightly more thrust (albeit less fuel efficiency) than the SL-25, and is intended to be reused numerous times, at less than US$ 1 million for current engines, and a quarter of that for improved versions in volume production.

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TRACKING WITH CLOSEUPS: Tiny Electronic Components

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THE HAPPENING WORLD: Do It Yourself Challenge—CNC Mill to Automated Gun Turret

Bioshock Infinite automated gun turret

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THE HAPPENING WORLD: Who Is an “Astronaut”?

First, it was “What is space?”, now it's who deserves to be called an “astronaut”. (I don't know why Blue Origin's marketing department hasn't seized on my suggestion to call those who fly on Branson's ride below the Kármán line “asterisknauts”.)

As Scott Manley observes, those who fly on vehicles operated by coercive governments, or even those in their employ who do have not yet flown, have been called “astronauts”, including politicians, such as the current NASA administrator, “Ballast Bill”, who went on a taxpayer-funded junket into space. I think the answer is to make the term “astronaut” one of derision, applied to civil service space cadets who have appropriated a noble title rightly belonging to genuine pioneers of space exploration. There's a parallel to this: nobody calls airline pilots or passengers “intrepid aeronauts” these days.

As for those who travel above the Kármán line today, how about “spacers” or, for those who see it as a New Age experience, “space cases”?

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CONTEXT: A Banana a Day

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Tuesday, July 27, 2021

CONTINUITY: Hewlett-Packard 150A Oscilloscope Restoration: Part 1

Here is information about this classic oscilloscope. It used 52 vacuum tubes plus CRT, and was fan cooled, with a furnace filter to clean the air entering the cabinet.

Posted at 14:47 Permalink

CONTINUITY: Dounreay—The Atomic Dream

Britain pioneered the use of a fast breeder fission reactor to generate electricity for the power grid. This is the story of the Dounreay reactor station in northern Scotland, which operated between 1955 and 1994, and is presently being decommissioned, a process whose initial phase is planned to be completed in the year 2036, with removal of all waste from the site by the late 2070s and complete restoration sometime in the 24th century.

Posted at 13:33 Permalink

THE HAPPENING WORLD: California and Other Stupid States Ban High-Performance Computers

There is more information about this on ZeroHedge: “59 Million Americans Prohibited From Buying High-End Dell Gaming PCs”.

It's always fun to pop up any of the Official State Media Web sites, type “California ban” into the search box, and see what it suggests.

Meanwhile, in the heart of Silicon Valley, Palo Alto is contemplating banning gas appliances in existing residences. They will be replaced, of course, with electric appliances which use power that, in the U.S., is primarily generated from—natural gas.

File under “AGE OF STUPID”.

Posted at 12:09 Permalink

CONTINUITY: Intel Process and Packaging Roadmap through 2025

In conjunction with this, and its entry into the foundry market, Intel is renaming its processes to be more consistent with the terminology used by competitors Taiwan Semiconductor Manufacturing Company and Samsung.

Posted at 11:24 Permalink

THE HAPPENING WORLD: Latest Problem for the James Webb Space Telescope—The Name

Another reason to consider adding “AGE OF STUPID” and “CRAZY YEARS” to our classic four rubrics. But then, if I did, they might drown out the originals.

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Monday, July 26, 2021

CONTEXT: Sabine Hossenfelder: Has Physics Become Too Speculative?

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CONTINUITY: Do-It-Yourself Cyanotype Photography

The cyanotype process was invented by astronomer John Herschel in 1842. The chemistry is sensitive only to ultraviolet light, so no darkroom is required. Exposure is usually by sunlight, which contains enough ultraviolet to (very slowly) form an image. This is the process used to make blueprints, and was used for that purpose well into the 20th century.

Posted at 14:47 Permalink

CONTEXT: The Galileo Project: Scientific Search for Extraterrestrial Artefacts

Here is the home page of The Galileo Project at Harvard University and a description of its three initial areas of research. According to project head, Prof. Avi Loeb of the Harvard astronomy department, more than US$ 1.7 million has been raised from private contributions to support the project.

Posted at 12:12 Permalink

THE HAPPENING WORLD: After Almost Twenty Years, Pirs Docking Module Departs International Space Station

The Pirs module was launched to the International Space Station (ISS) on 2001-09-14. It has supported numerous dockings of Soyuz and Progress craft, and as the airlock for many spacewalks from the Russian segment of the station. It is being towed away from the station by a departing Progress cargo ship, which will deorbit and burn up in the atmosphere later today. The operation frees up the docking port for the Nauka laboratory module, expected to arrive at the station in a few days.

There had been speculation that vacuum welding between the module and its ISS attach point might interfere with undocking, but this has been shown to be unfounded. The attach point will be inspected by cameras on the station's robotic arm to verify it is ready to receive the new module.


2021-07-26 19:13 UTC

Posted at 10:59 Permalink

TRACKING WITH CLOSEUPS: Explaining the Chain Fountain Phenomenon

Why, in particular, does metal ball chain rise over the lip of the container, while other kinds of chains don't?

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Sunday, July 25, 2021

TRACKING WITH CLOSEUPS: Contemporary Human Evolution Driven by Female Sexual Selection for Male Cognitive and Behavioural Traits

Here is the full paper, “Sex-biased reduction in reproductive success drives selective constraint on human genes” [PDF].


Genome-wide sequencing of human populations has revealed substantial variation among genes in the intensity of purifying selection acting on damaging genetic variants. While genes under the strongest selective constraint are highly enriched for Mendelian disorders, most of these genes are not associated with disease and therefore the nature of the selection acting on them is not known. Here we show that genetic variants that damage these genes reduce reproductive success substantially in males but much less so in females. We present evidence that this reduction is mediated primarily by cognitive and behavioural traits, which renders male carriers of such variants less likely to find mating partners. These findings represent strong genetic evidence that sexual selection mediated through female mate choice is shaping the gene pool of contemporary human populations. Furthermore, these results suggest that sexual selection accounts for 21% of purifying selection against heterozygous variants that ablate protein-coding genes.

Posted at 13:46 Permalink

THE HAPPENING WORLD: The Case for Autonomous Vehicles

Note: this video was sponsored by Waymo, a subsidiary of Alphabet, Inc., the parent company of Google. Waymo is the spin-in company created to commercialise the technology developed by the Google self-driving car project. Waymo currently operates a driverless taxi service in Phoenix, Arizona, in the U.S., and is, at present, the only such service which operates without human back-up drivers.

This Veritasium video tries out the service, interviews some people from Waymo, and argues that even at the present “SAE Level 4” degree of autonomy, driverless vehicles are safer than the average human driver, so their introduction should be expected to reduce the number and consequences of motor vehicle accidents. This is the case made in the February 2021 Waymo Safety Report [PDF], which is referred to in the video.

This is far from a unanimous opinion, and presented by advocates engaged in developing and selling the technology. But here's their pitch.

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CONTEXT: Double Jupiter Gravitational Assist

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CONTINUITY: Restoring and Demonstrating an Early 1900s Nernst Lamp

The Nernst lamp was invented in 1897 by German physicist and chemist Walther Nernst (who would win the 1920 Nobel prize in chemistry for his work in thermochemistry). The Nernst lamp was an incandescent electric light which used a ceramic rod composed of oxides of yttrium and zirconium instead of the carbon filament employed by the contemporary Edison light bulb. The Nernst lamp produced about twice the light for a given amount of electricity as carbon filament bulbs, and emitted a whiter, more sunlight-like spectrum. Because the light-emitting element was already completely oxidised, it did not require a vacuum or inert gas environment, and operated with no problem in air (although lamps were usually enclosed in a glass bulb to protect objects from touching the hot element).

The main disadvantage was that the ceramic used did not conduct electricity at room temperature, and needed to be initially warmed to its conduction temperature by a separate heater, after which it would self-heat through electrical resistance. Consequently, Nernst lamps required a “starter” circuit not unlike that of fluorescent lights to initially engage the heater and then disconnect it after the light came on.

Due to its efficiency and more natural light, the Nernst lamp became popular, initially in Europe where it was manufactured by AEG in Germany. In the U.S. George Westinghouse licensed the design in 1901 and manufactured it domestically as it evaded Thomas Edison's patents on his light bulb, selling more than 130,000 by the year 1904.

Subsequently, development of tungsten filament bulbs, which emerged in their modern form during the 1910s and were more efficient and less complicated and expensive than the Nernst lamp, rendered it obsolete. Today Nernst lamps are scarce and expensive collectors' items and even more rare to see in working condition.

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Saturday, July 24, 2021

CONTINUITY: Total Internal Reflection and Evanescent Electromagnetic Waves

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