Recently in CONTEXT

Tuesday, January 26, 2021

Was ʻOumuamua an Artefact of an Intelligent Extraterrestrial Civilisation?

Posted at 13:43 Permalink

Monday, January 25, 2021

Blue Origin's Rockets and Rocket Engines

Posted at 13:02 Permalink

Sunday, January 24, 2021

Solid Iodine Thruster for Microsatellite In-Orbit Propulsion

This thruster uses electricity to sublimate a solid block of elemental iodine and ionises the liberated iodine gas for propulsion. Thrust is low, but it is simple, light, has no moving parts, and should have a long life. One application is de-orbiting microsatellites at end of life, reducing space junk.

Posted at 15:18 Permalink

Saturday, January 23, 2021

Animated View of Fuel Flow During a SpaceX Starship Hop

Note how the pressurised “header tanks” are essential to feeding propellant to the engines during the flip maneuver just before landing.

Posted at 19:15 Permalink

Monday, January 18, 2021

Burning Oxygen in an Atmosphere of Propane

Isaac Asimov wrote a science fiction story, “The Dust of Death” based on a similar premise. We now know that the atmosphere of Saturn's moon Titan is composed mostly of nitrogen, with methane less than 5% by volume.

Posted at 21:37 Permalink

Sunday, January 17, 2021

Building an Apollo Ground Service Equipment Panel Prop

Putting a collection of those cool Apollo-era control panel switches to “work”.

Posted at 14:52 Permalink

Friday, January 15, 2021

Humidifiers: Simpler Is Better?

Not mentioned: if you have a lot of lime scale (calcaire) in your water, the the wick of an evaporative humidifier will become less and less effective as its pores are clogged with scale deposits. So, even if you don't have a problem with smelly gunk growing in the humidifier, it's best to replace the wick(s) at least once per season or when you notice the relative humidity falling below where it's normally maintained.

Posted at 20:40 Permalink

Wednesday, January 13, 2021

Heeees back!

Posted at 19:35 Permalink

Monday, January 11, 2021

The Nuclear Salt Water Rocket

Posted at 13:00 Permalink

Sunday, January 10, 2021

1962 Italian Magazine: “The World of 2022”

Posted at 14:51 Permalink

Friday, January 8, 2021

The Closest Star to the Solar System: Proxima Centauri with Parallax Nick

Posted at 14:41 Permalink

Thursday, January 7, 2021

SAT Score Inflation over 45 Years

Posted at 19:50 Permalink

1975 Mainframe CPU Module — Amdahl 470

In the 1970s, I worked right down the street from Amdahl headquarters and across the orchard from Intel's starship. I never imagined such hackery was being perpetrated chez Amdahl. Had I known, I might have applied for a job there.

Posted at 00:40 Permalink

Monday, January 4, 2021

Empire of Stupid: “Amen and Awomen”

Posted at 15:09 Permalink

Sunday, January 3, 2021

Average Colour of Solar System Bodies

The Earth is purple? Who knew?

Posted at 12:39 Permalink

Saturday, January 2, 2021

Welcome Aboard the R.100

For a detailed account of the British airships R.100 and its government boondoggle competitor R.101, see Nevil Shute's magnificent book Slide Rule.

Here is a video about the R.101 by Bill Hammack, author of the book Fatal Flight.

Posted at 13:13 Permalink

Friday, January 1, 2021

Jill Tarter: Signals from Proxima Centauri, Advice from Carl Sagan, and SETI @ 60!

Posted at 20:06 Permalink

Thursday, December 31, 2020

The New Spirit—1942 Donald Duck Propaganda for the U.S. Income Tax

In 1942, the U.S. Income Tax, which was previously paid by only 13 million people, was increased and extended to hit more than 50 million, or 75% of all working Americans. It was called the “Victory Tax” and promoted as supporting the war the U.S. had just entered. In October, 1942, Time magazine called it “The biggest piece of machinery ever designed to separate dollars from citizens.” The Treasury Department enlisted Disney Studios and Donald Duck to promote the tax as a patriotic “privilege, not just your duty.”

“Taxes to beat the Axis!”

The film was nominated for a 1943 Academy Award as Best Documentary.

Posted at 11:59 Permalink

Wednesday, December 30, 2020

Ice Age Woolly Rhinoceros Carcass Found in Siberian Permafrost

Posted at 14:34 Permalink

Tuesday, December 29, 2020

Earth During a Solar Eclipse

Posted at 12:24 Permalink