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September 14, 2021 Archives
Tuesday, September 14, 2021
CONTINUITY: Nike-Hercules—When U.S. Cities were Ringed with Nuclear-Tipped Missiles
When I was a kid, my parents took me on a week-end tour of a local Nike-Ajax site, probably in 1958 or 1959. They showed you everything, except inside the circular berm where they did hazardous propellant maintenance operations. (Nike-Ajax used toxic hypergolic liquid propellants in its second stage.) Afterward, the site was converted to the nuclear-tipped Nike-Hercules, and no tours were offered.
At the peak, there were 265 Nike-Ajax sites in the U.S. The longer range Nike-Hercules covered a larger area, and was deployed in only 130 locations, with the excess Nike-Ajax sites decommissioned.
Posted at
12:49
CONTINUITY: Tour of the International Space Station Kibō Module
This tour, presented in 360° immersive video (hold down your mouse button within the image and move the pointer to pan and tilt your viewpoint), is conducted by European Space Agency astronaut Thomas Pesquet. The audio is in French, with English subtitles. The Kibō (きぼう) or Japanese Experiment Module (JEM) was launched to the International Space Station by three space shuttle missions in 2008 and 2009, and is the largest single module of the space station. It includes a pressurised laboratory section and an external pallet with an airlock for moving payloads back and forth to the laboratory, with a robot arm to manipulate them. There is also an “attic”, which provides much-needed storage space on the crowded station.
Posted at
12:04
CONTINUITY: Vacuum Tube Computer Part 17: Arithmetic/Logic Unit
Finally, all of the previously design, built, and tested pieces of the computer begin to come together at its heart: the unit which performs the arithmetic or logic operation designated by an instruction. This is simpler than you might imagine, as it consists mostly of selecting a result among multiple logic inputs that compute the results of the various functions, all of which have been previously constructed.
Posted at
11:32
CONTINUITY: On the Road with Tesla “Full Self Driving” Beta 10
Here is another report, driving in San Francisco and deliberately putting the car into difficult situations.
Two things amaze me about this deployment of “full self driving” on the litigious streets of Safetyland. First, that paying customers are so forgiving of a product which, after ten releases, still does not remotely do what it is claimed to—drive autonomously without a vigilant human driver ready to take over an in instant when it “disengages” or is about to turn into oncoming traffic. Second, that Tesla, a public company with PricewaterhouseCoopers as its auditors, is not required to qualify its financial statements with risk factors due to liability from mass deployment of a flawed product with such potential risk to life, limb, and third-party property damage, and that its directors seem fine with the situation. (Here are the declared risk factors from Tesla's most recent Form 10-K filing with the U.S. Securities and Exchange Commission.)
Posted at
11:00
TRACKING WITH CLOSEUPS: SpaceX Starlink Group 2-1 Mission
I have cued the video to start one minute before launch: scroll back if you wish to watch from earlier in the countdown. This was the tenth successful launch and landing for Falcon 9 first stage booster B1049, the oldest booster currently in service, having made its first flight on 2018-09-10. This booster joins B1051, which achieved the milestone of ten flights on 2021-05-09, meeting the original design goal of ten flights per booster. Elon Musk has said that SpaceX will continue to inspect and re-fly boosters, building experience in long-term re-use. I suspect that “fleet leaders” with the greatest number of flights will be reserved for in-house Starlink missions, where a loss due to unanticipated aging issues would not impact an external customer.
Posted at
10:32