Tuesday, April 20, 2021

CONTEXT: Harvesting Energy from Wind Created by Motorway Traffic

Posted at 14:47 Permalink

TRACKING WITH CLOSEUPS: Lined Up to Land on a Taxiway: Air Canada Flight 759

“Where's this guy goin'? He's on the taxiway.”

Here is more about the incident. “Air Canada has stopped using flight number 759.”

Is “whoa” the most-misspelled four-letter word in the English language?

Posted at 13:02 Permalink

THE HAPPENING WORLD: Flying Spam: Now Do it on Mars

So, of course you're wondering, “What does it say?” Well, after taking out the skew, perspective projection, thresholding, inverting, scaling up, shifting and multiplying to expand dots to (kind of) squares, you get:

This, in turn, decodes to the URL: https://game.bilibili.com/pcr/1anniversarytocode-h5/

I have no idea what following this link may do to your Social Credit score.

Posted at 10:35 Permalink

Monday, April 19, 2021

CONTINUITY: NASA Ingenuity Mars Helicopter Update

Posted at 20:57 Permalink

TRACKING WITH CLOSEUPS: Bitcoin Miners Increasingly Supported by Transaction Fees

As Bitcoin has matured, the compensation (“reward”) paid to miners for solving a hash and publishing a new block of transactions on the blockchain has steadily fallen following the rule in the original design. The reward Rn for publishing block number n is:

Rn = BTC 50 / 2⌊(n + 1) / 210000)⌋

Thus, the first blocks to be mined received a reward of BTC 50 each, while at the present time (around block number 679750), compensation has fallen to BTC 6.25 per block.

For Bitcoin to be sustainable, the community of miners must continue to find the undertaking profitable. If it becomes a losing proposition, they'll abandon the task and Bitcoin transactions will not be verified and confirmed on a timely basis by a large and diverse enough community of miners to ensure the integrity of transactions.

The idea was that, over time, as the volume of Bitcoin transactions grows, transaction fees paid by users of the currency, while remaining affordable to them, would grow so that miners would continue to find it profitable to clear transactions even as their revenue from coining new Bitcoin continues to fall (eventually to zero, after all Bitcoin has been mined, around the year 2140).

Today I performed an analysis to see what progress is being made toward that goal, and the results are encouraging. I analysed blocks mined in the 24 hour period between 2021-04-18 12:08 UTC (block 679691) and 2021-04-19 12:00 UTC (block 679783), a total of 93 blocks, with a mean time of 15.5 minutes per block (compared to the goal of 10 minutes per block, but note that this period began on a Sunday). The current reward paid to miners for a block was BTC 6.25 for all blocks. When a miner publishes a block, in addition to this standard reward, they collect the transaction fees associated with all transactions they include in the block—the transaction fee is set by users who submit transactions, and miners generally choose the transactions which, based upon their length in bytes and the fee offered, will generate the most revenue for them. Transaction fees for blocks during this period varied from a minimum of zero (two blocks, 679774 and 679779, contained no transactions and thus earned their miners no additional income) to a maximum of BTC 2.864 (block 679703), with a mean value of BTC 1.828.

Thus, for this 24 hour period, transaction fees accounted for 22.6% of the total reward of BTC 751.27 earned by miners, with BTC 581.25 due to the standard reward for mining a block. While transaction fees still account for less than a quarter of miners' revenue, if Bitcoin continues to become a mainstream mechanism for transferring funds and transaction volume grows apace, it seems plausible that transaction fees will eventually provide the majority of income to miners, which will motivate them to continue their essential services as difficulty increases and block rewards decline.

Posted at 19:41 Permalink

CONTINUITY: HP 9825 Repair Part 4: The Processor Reads and Executes ROM Code

Further probing with the logic analyser, correcting its interpretation of bus signals, board swapping with a working machine, and another mysterious release of magic smoke gets closer to the source of the problem(s).

Posted at 13:01 Permalink

THE HAPPENING WORLD: Ingenuity Helicopter Flies on Mars

Update: (2021-04-1912:05 UTC)

Posted at 11:48 Permalink

Sunday, April 18, 2021

THE HAPPENING WORLD: First Flight of the Ingenuity Mars Helicopter: Live from Mission Control

NASA's Webcast is scheduled to start on 2021-04-19 at 10:15 UTC.

Posted at 20:31 Permalink

CONTINUITY: The High Frontier Documentary Now Available to Stream

The High Frontier, a documentary about the life and work of Gerard K. O'Neill and his vision of the human future in space, is now available on popular streaming services such as iTunes and Google Play. Here is my review of Prof. O'Neill's 1976 book, The High Frontier.

Posted at 20:06 Permalink

CONTINUITY: The 1831 City Bank of New York Robbery

At the time, the vault of the bank was protected only by two warded locks: one on the front door of the bank and one on the vault. There was no night watchman. The locks were defeated by copied keys. The amount stolen was around US$52 million in today's funny money. Here is more about the heist.

Posted at 13:29 Permalink


Next comes the realist phase (“After all, from a purely geometrical point of view a cat is only a tube with a door at the top.”).

— Terry Pratchett, The Unalduterated Cat

Posted at 11:27 Permalink

CONTEXT: NASA to Spend US$2,941,394,557 on SpaceX’s Lunar Starship

If I were inclined toward a cynical, Stygian, and conspiratorial outlook instead of my customary sunny and optimistic disposition, I might interpret this news as follows.

Look, NASA doesn't really want to land on the Moon. If they did, they'd have been working on, you know, landing on the Moon, instead of spending billions on a Lunar Tollbooth which will complicate any missions to the surface but spread that delectable taxpayer (and borrowed, and freshly-printed) money around to the congressional districts and states of the politicians who fund the agency. As Robert Zubrin has observed, “NASA used to spend money to fly missions. Now they fly missions to spend money.” If those pesky politicians should demand they actually land on the Moon, which might get the juices up among the hoi polloi and motivate demands for NASA to actually expand the human presence beyond Earth as opposed to flushing money down the toilet on the Space Launch System (SLS) and other grotesque extravagances, then why not choose the cheapest alternative, one with (under the NASA view of things) the highest technological risk and then, when it inevitably fails, say “We told you so. Now, can we return to our incremental plan for flags and footprints sometime around 2030, or 2040, or, well…when we're ready? And how about a budget bump in the next fiscal year?”

Further, in choosing the SpaceX Starship, they not only get the NASA camel's nose under the SpaceX frenetic incremental refinement development tent, they, by spending less than what they're wasting every year on SLS, its ground support equipment, and Orion (the “deep space exploration vehicle” without a toilet), get the whole NASA camel into the heart of Starship development, sending “hither swarms of Officers to harrass our people, and eat out their substance”, bury it in paperwork, cripple it by hordes of inspectors, sub-sub administrators for diversity, and all of the other reasons no human has ventured beyond low Earth orbit since 1972.

But this may all backfire on NASA, and that would be just wonderful. If there's one thing we've learned over the years, it's not to bet against SpaceX. (Eric Berger's wonderful book, Liftoff, which chronicles the start-up and hard-scrabble years developing and debugging the Falcon 1, is an excellent look into the driven SpaceX culture.) What if SpaceX takes the three billion, nods to the NASA minions, continues their frenetic development pace, and succeeds? A functioning Super Heavy, reusable tankers, and lunar Starship, all of which are required to deliver on the NASA contract, will render SLS, Orion, Gateway/GLOP/whatever they're calling it, impotent and obsolete, and be able to deliver tens of tonnes of cargo and dozens of paying passengers to the Moon on a monthly schedule, while NASA is still pursuing its plans to send four civil service space cadets on brief excursions “every year or two” at a billion or so a pop.

Well, at least when they get there, they'll be able to stay at Bigelow’s lunar hotel, which will have toilets, even in the economy rooms affordable on NASA per diem.

Posted at 10:40 Permalink

Saturday, April 17, 2021

TRACKING WITH CLOSEUPS: Flip Clocks: the Non-Digital “Digital” Clock

The way they get the hour to flip exactly when the seconds go from 59 to 00 while allowing sloppy manufacturing and assembly tolerances is very clever.

Posted at 15:42 Permalink

CONTEXT: Emulating Nixie Tubes (or Anything Else) with Programmable LCD Displays

Bet you've never see a nixie tube reboot before!

Posted at 12:38 Permalink

CONTINUITY: Chain Making Machine

Posted at 10:56 Permalink

Friday, April 16, 2021

THE HAPPENING WORLD: SpaceX: NASA Selects Starship for Human Lunar Landing System

Update: here is the NASA Source Selection Statement [PDF]. (2021-04-16 22:15 UTC)

Update: this is the NASA video announcement of the SpaceX selection for the Artemis Human Landing System. (2021-04-16 23:55 UTC)

Posted at 21:31 Permalink

TRACKING WITH CLOSEUPS: What Shall We Call the Hill?

Posted at 16:41 Permalink

CONTINUITY: HP 9825 Repair Part 3: Logic Analyser and a 43 Year Old Patent to the Rescue

After going about as far as possible with an oscilloscope (although back in the day we went way deeper into the woods with just a ’scope), it's time to hook up a logic analyser and see what the CPU and memory are doing. Aiding in the process is U.S. Patent 4,075,679 [PDF], granted in February, 1978 and assigned to Hewlett-Packard, whose 606 pages contain, inter alia, a complete commented source code listing of the ROM and extensive logic, circuit, and timing diagrams. How deep was the damage to this vintage machine when its power supply went all berserker?

Posted at 13:42 Permalink

CONTEXT: New Insights in the Search for Planet Nine

Here is the musical composition mentioned in the interview, Planet 9, op. 3, by Eduardo Marturet, in its premiere performance by the Miami Symphony Orchestra on 2021-03-14.

Posted at 12:01 Permalink

THE HAPPENING WORLD: Lots of Launches Coming Up

There hasn't been an Ariane 5 launch since August, 2020—eight months ago.

Posted at 11:00 Permalink