Wednesday, April 14, 2021

Sometimes I Come Up Empty Handed

Maybe that's empty headed?

I've been trying to determine why the Mars Ingenuity Helicopter hasn't flown.  For those who haven't followed, on April 9th, Ingenuity was commanded to spin up its rotors as a test before being allowed to fly.  The test didn't pass.  To quote from the JPL Ingenuity Page:

During a high-speed spin test of the rotors on Friday, the command sequence controlling the test ended early due to a “watchdog” timer expiration. This occurred as it was trying to transition the flight computer from ‘Pre-Flight’ to ‘Flight’ mode. The helicopter is safe and healthy and communicated its full telemetry set to Earth.

The watchdog timer oversees the command sequence and alerts the system to any potential issues. It helps the system stay safe by not proceeding if an issue is observed and worked as planned.

The previously announced date it would fly was April 11th, with data from JPL available by the 12th.  I went looking for updates on the 12th and found reports the flight was put off until NET the 14th.  (As always, NET = No Earlier Than).  That's today as I write this. 

There isn't a test flight date I can find on the JPL, just this interesting statement:

The Ingenuity team has identified a software solution for the command sequence issue identified on Sol 49 (April 9) during a planned high-speed spin-up test of the helicopter’s rotors. Over the weekend, the team considered and tested multiple potential solutions to this issue, concluding that minor modification and reinstallation of Ingenuity’s flight control software is the most robust path forward. This software update will modify the process by which the two flight controllers boot up, allowing the hardware and software to safely transition to the flight state. Modifications to the flight software are being independently reviewed and validated today and tomorrow in testbeds at JPL.

They then list the steps in making sure that software is safe to upload to Mars and say:

Once we have passed these milestones, we will prepare Ingenuity for its first flight, which will take several sols, or Mars days. Our best estimate of a targeted flight date is fluid right now, but we are working toward achieving these milestones and will set a flight date next week. We are confident in the team’s ability to work through this challenge and prepare for Ingenuity’s historic first controlled powered flight on another planet.

It's safe to say there won't a flight on the 14th or 15th, and very likely not before the 21st.  

When you consider the years of development of this system, you'd think the software would have been verified to not have hangups like this.  It brings to mind a software error that didn't show up until well into the Space Shuttle program.  During the countdown, ground based computers were to hand over control to the Shuttle's internal computers at T-31 seconds.  Long after I would have expected handshaking problems between the computers to have been verified impossible, a handshaking problem aborted a countdown.  

This may be the same sort of problem.  Despite Software Quality Assurance and testing, modules were aligning in time to work properly, not by design but by pure chance.  

Tuesday, April 13, 2021

The Age of Reusability in Space is Dawning

Yesterday's post was on how SpaceX began the era of reusable boosters and completely upturned the existing paradigm of "use once and dump the rocket" that had been in place almost exclusively since the earliest days of the space program.  The obvious exception is the Space Shuttle, which recovered the orbiter and solid rocket boosters but still never achieved its goals or met the lofty promises it was sold under.  During the selling of the program, it was argued the Shuttles would bring the cost of launch to $25/pound.  They ended up missing that goal by a factor of 1000; that's right, $25,000/pound.

Last February marked the first example of extending the life of a satellite, when Northrup Grumman's Mission Extension Vehicle 1, MEV-1, successfully docked with an Intelsat satellite (IS-901) and brought back into serviceable life.  The spacecraft was launched in 2001 and was pulled from active service in December 2019 as it ran low on fuel.  Operators commanded the satellite to move into a "graveyard orbit" farther out than the unique geostationary space, as is the established way of handling satellites that have outlived their usefulness.  This wasn't refueling on orbit, IS-901 wasn't designed to allow that.  Instead, MEV-1 docked with the "disposed of" satellite and pulled it back down to the geostationary orbit, bringing it back to life.

Last week, a second Northrup Grumman satellite, (MEV-2) slowly approached and captured another Intelsat satellite, 10-02.  Unlike the first operational capture, this satellite was still in service at the time, not in a graveyard orbit, delivering broadband and other media services across Europe, the Middle East, and Africa.  The satellite, though, was running out of the fuel it needs to adjust its orbit periodically.  It was nearing time to push this one into a graveyard orbit. 

This was all planned well in advance, and MEV launched last year.  Like its predecessor, MEV-2 was launched into a lower orbit and slowly moved outward by electric propulsion until reaching it's goal. 
Jean-Luc Froeliger, vice president of space, space systems engineering and operations for Intelsat, said the cost of servicing is far less than the value of five additional years of satellite service. Waiting five years will also allow Intelsat to replace the 10-02 satellite with a more modern, efficient vehicle. "For us, it's win-win," he said during a teleconference with reporters. "This extension for 10-02 is very valuable to us."
Like the mission last year, this isn't refueling the satellite.  When these satellites were launched, the concept of being serviced remotely on orbit didn't exist.  Instead, the MEV docks with the target satellite and forms a single larger satellite.  That arrangement is for the five years mentioned above.  At that time (if still working; if not, sooner), the satellite will be pushed into the higher graveyard orbit.

Northrup Grumman artwork.

The source article on Ars Technica reports that Northrup Grumman is experiencing increased interests from commercial and government satellite owners. Tom Wilson, a vice president at Northrop Grumman and president of its SpaceLogistics subsidiary says interest from various governments is increasing. "We’re on the cusp of some bigger initiatives with them."
In 2024, Northrop plans to launch a "Mission Robotic Vehicle" that can provide basic inspection and repair services and deploy mission extension pods to satellites. After this, the company plans to develop refueling capabilities and debris removal from the vicinity of high-value satellites. Finally, in the 2030s, the company intends to begin in-orbit assembly and manufacturing capabilities.

Monday, April 12, 2021

I Missed an Important Anniversary

It was on one of the news sources I read, Ars Technica, but I didn't read the Rocket Report newsletter until yesterday.  Last Thursday, April 8th, was the five year anniversary of the first time SpaceX successfully landed a booster on a drone ship.  2016.  It's hard to think of any changes that commercial space efforts of the early 21st century has brought that are more important, and as paradigm changing as recovering and reusing boosters has been.  Before that, around '14, when NASA's commercial crew contracts were being considered, NASA said not to bid using recovered boosters.  It's a "pipe dream," "it'll never happen."

Three years ago, in 2018, the leadership of the European Space Agency (ESA) was saying they had no interest in making reusable boosters.  After all, it's a jobs program and why would they cut jobs?
Truthfully, if Europe ever did develop a reusable rocket, one that could fly all the missions in a year, this would be unhelpful politically. What would the engine and booster factories sprinkled across Europe do if they built one rocket and then had 11 months off? The member states value the jobs too much. This is one difference between rocket-by-government and rocket-by-billionaire programs. [Bold added - SiG]
It took less than a year for the ESA to realize their launch business was going to go away and they announced plans to develop a reusable version of their Ariane family, largely copied from the Falcon 9.  As did Russia.  Even China is investigating reusability, copying the grid fins from the Falcon 9.  

Eric Berger, Ars Technica's space correspondent, puts a personal side to the story.  Eric says he was born four months after the final Apollo mission and for years had a profound sense of regret at having been born too late to see the peak of space exploration.  “I lived with that regret for decades—right up until April 8, 2016.”

I was not prepared for the experience of watching a skinny, black-and-white rocket fall out of the sky against the azure backdrop of the Atlantic Ocean and land on a small drone ship. As whitecaps crashed into the side of the boat, it seemed like a portal opening into the future. This breakthrough in rocket technology washed away any regrets I had about missing Apollo. In my mind, landing a Falcon 9 first stage at sea represented an essential step toward reducing the cost of getting people and payloads into space and unlocked a bright spacefaring future.

After nearly a dozen failed attempts, subsequent landings soon filled a SpaceX hangar full of used rockets. This caught some SpaceX engineers off guard. "It even surprised us that we suddenly had ten first stages or something like that," Hans Koenigsmann, one of SpaceX's earliest hires, said a few years afterward. "And we were like, well, we didn't really account for that."

tenths of a second before touchdown - April 8, 2016, SpaceX Photo

A few months before this flight in December of '15, SpaceX successfully landed on Cape Canaveral.  I remember watching that landing online.  Definitely a huge achievement but still much easier than finding a drone barge hundreds of miles out to sea, hundreds of miles from where the booster gets jettisoned, and then landing on it with the ship moving, rising up and down with the waves.  Putting a moving rocket onto the moving drone ship was an enormous accomplishment.

It was also a very necessary accomplishment.  It clearly costs money to send that drone ship out for a recovery, the ships leave a couple of days before the first "No Earlier Than" date and will stay out there for most reschedules.  The booster returns to Port Canaveral around 3 days after the recovery.  Figure you're paying a crew for the tugboats, the drone and everything else.  The trade is that it costs more to not send out the drone but bring the booster back to the Cape.  Orbital mechanics being the cast iron bitch that it is, every pound of fuel needed for the landing is an amount of payload they can't put in orbit.  Downrange landings are pretty much required.  There's more.

Over the course of it's flight the velocity of the rocket changes from pointing upward to pointing horizontally.  It takes tons of propellant to effectively cancel that horizontal motion, turn the rocket around and bring it back to land.  It takes much less fuel to essentially let it fall in a normal parabolic trajectory and land farther out at sea.  If you read the performance data for the rocket, a Falcon 9 rocket that lands on a drone ship can lift about 5.5 tons to geostationary transfer orbit, compared to 3.5 tons for a rocket that lands back at the launch site. Had SpaceX not figured out how to land the Falcon 9 first stage on a drone ship, it would have eliminated about 40 percent of the rocket's lift capability, a huge penalty.

The cost of fuel for a Falcon 9 flight is around $250,000.  At the time of this booster recovery, they were charging $61 million for an F9 launch.  They were going to offer a ride on this booster for $43 million.  Just about 30% cheaper.  It's amortizing the cost over two missions, why not 50% off?   Let's pretend $61 million is the actual cost of the Falcon 9 to be manufactured, and the company wouldn't lose money throwing the rocket away after one and only one launch.  Like every Delta, Atlas, Titan and you name it that has been launched until April of '16.  Now think if they launched that booster 10 times, their immediate goal.  Doesn't that make each launch cost $6.1 million? 

Last words to the April 8, 2016 article about the flight on Ars.
So when the moment came Friday, and the rocket stuck, Musk was ecstatic. He could hardly say what would come next. “We're a little bit like the dog who caught the bus,” Musk said, smiling. “What do we do now?”

Sunday, April 11, 2021

A Ham Radio Series 24 addendum - The Supply is Finished

The power supply I discussed yesterday is finished and working.  I've hung an oscilloscope probe on the 5V output and watched it.  There are some spikes far beyond the frequency response of the regulator, possibly being picked up from the air by the scope probe.  There are no drops of the 5V supply that I can find.    

First, an overall view as it's used.  If you look between the bottom of the aluminum channel and the benchtop, you can see some red spots.  One right below each of the corners and one below the switch in the middle.  In the old days, I would use rubber peel-and-stick feet.  This time I printed 1/2" on a side cubes and glued them to the bottom of the channel with superglue.

And a closeup of the voltage regulator.  I added a fairly big electrolytic capacitor (330uF) on the output pin after this picture just to try to ensure no drops in voltage are an issue. 

That writing near the brass nut is sideways.  The pin closest to this edge is I for the input, not H,and I'm sure you can figure out what the O is for.  There's a ground solder lug under the middle brass nut amid those parts and wires, where the two black wires and capacitors (blue) are grounded.  It was difficult to decide which way to mount the S/S module; this orientation or rotated 180 degrees because there are drawbacks to both orientations.  This one makes the LED close to the body of the S/S module rather difficult to see the way I'm using it.  On the other hand, the spark plug and ground wires are on the right, close to the end of the tray and where they're going.  Closest to the bottom side of the channel on the right is a twisted bundle of red, black and white wires.  The white wire is an input from the engine's points (or Hall Effect sensor) which comes in on the right, too.

Part of the idea of making this project is that it can be moved to another engine and I build it once.  The power switch (middle, front) is in the ON position in these pictures.  An LED to show "power on" might be a good addition. 

Saturday, April 10, 2021

A Ham Radio Series 24 - Power Supplies part 2 - Linear Regulated Supplies

The initial article in this couple of episodes on power supplies focused on low power supplies and especially the 78XX series of regulators.  There are actually many similar parts and series of parts that provide three pin regulators.  Given how versatile and useful they are, I want to explore a use I have for one.  I've based it on a part I'm familiar with and have in my junk box (ham speak for a box of parts you have from various sources for future projects), the LM323, a 5V 3A regulator. 

The electronic ignition I bought for my Webster engine required a power supply not to exceed 5V.  The company that sells the engine sells a 5V supply to run the system, but in my urge to get going as fast as possible, I put together a system of 3 AA cells in series.  When the cells are new, it puts out in the vicinity of 4.8V but it falls to 4.5V quickly.  The instructions with the ignition module says it works best at 5.0 to 5.5V, but dies quickly over that. Four AA alkalines will kill the module. Three will get it to work, but not as well as it could.  You might recall this picture of the ignition module (right) and battery pack with one battery replaced by a jumper.

After throwing out several sets of these AA batteries I decided to upgrade everything.  I could replace the AA alkaline batteries with the 18650 rechargeable lithium batteries I bought a couple of years ago.  Those are over 8V fully charged and run down to the 6.5V dropout voltage of the regulator.  The circuit is drop dead simple.

The application circuit is assuming that this is on the output of a rectifier and filter combination; I'm not using that so I didn't put that 1uF solid tantalum capacitor there.  I put a 0.1uF ceramic capacitor on the input and a 0.22 uF solid tantalum on the output side.  (Note that the LM123 pictured is their name for the same part tested to full military spec temperature ranges.  There's an LM223 that is for the extended industrial temperature range and the LM323 is for the commercial temperature ranges)

The regulator is in a large, chassis mounted case called a TO-3 (Transistor Outline), and a dimensioned drawing of the package is in the datasheet for the LM323 on that TI page linked above.  I used that to develop a routine for drilling the holes for the TO-3 that I can keep in my CNC library.  Then I set to the task of creating a model in CAD to space the parts from each other.  The LM323 is in blue, with batteries on the right and ignition module on the left.  I didn't model the other parts - and the regulator is mounted on the far side of this channel, with it's input and output pins protruding through the drilled out holes. 

The regulator circuit is built without the electronic ignition module, and checked to verify it puts out 5V properly, which it does.  Tomorrow, I'll add the ignition module and I want to try to run my Webster with it.  The engine has been sitting for a month or six weeks with no attempts to start it. 

The catch is I don't really know what the requirements are for that 5V supply.  It might not work and just need a bigger capacitor on the output to supply current surges the module may require. 

The aluminum channel you're looking down into above will have printed plastic feet on the far side to keep the regulator case off the bench. 

Friday, April 9, 2021

The 80% Gun Kits From A Different Angle

Of course the big story is the handful of executive actions that Dopey Gropey announced Wednesday.  As an aside Ammoland, the National Shooting Sports Federation newsletter pointed out that these are Executive Actions, not Executive Orders and like everywhere else lawyers run the world, words make a difference. 
In a 2018 article at ThoughtCo., writer Tom Murse noted, “(M)any critics [misunderstand] the definition of executive actions and the difference with legally binding executive orders.”

Executive orders, he explained, are “legally binding directives from the president to federal administrative agencies.”

Executive actions, ... carry none of the weight executive orders carry,” he wrote.
It should be remembered that none of the things Dopey talked about are executive orders.  They're the pResident telling the DOJ to do something.  I want to focus on the action related to "80% of a gun;"  Dopey McUnity wants the DOJ to sketch out a regulatory framework for requiring background checks on purchases of 80% frames, lowers and build kits (he wants them serialized).  Ignoring the obvious jokes and quips about just shifting to 79, 75 or 70% guns (80% is an arbitrary, made-up number) assume these actions to the DOJ become some sort of legally binding orders, in the next six months. 

As virtually everybody knows, 80% guns are a hobby of their own, a hobby that attracts people who like to play with tools, and like all sorts of other Do It Yourself (DIY) hobbies.  To me, though, it gets back to something I've been following with interest for quite some time, the right to repair your own equipment, as talked about in the iFixit manifesto. 

How does a move by a bunch of millennials to be able to fix smartphones or stick an off-the-shelf hard drive in their TiVo intersect with guns?   When you buy a gun, you have the right to repair and modify it.  There are millions of people who work on their own guns, replacing a spring, changing some piece of hardware or something.  Think your 10/22 could be a better competition rifle with a new barrel and trigger?  Go buy yourself the new parts and swap them out!  If you buy a 40 S&W pistol and decide you'd rather have 9 or 10mm, most of the time you can just buy a different barrel.  How many people have you come across who converted a rifle to a different caliber?  All of those are Right to Repair. 

My understanding of the origin of the "not quite a gun" regulations that give rise to the "Ghost Guns" is that it began with simply asking at what point does a gun become a gun.  They started from accepting that we have a right to repair our property and named just the one part that is the gun and can't be replaced without a background check.  It led to ideas like the receiver is always the gun, and you can replace the barrel or put in a new trigger, and every other part, but as long as it's the same receiver, it's the same gun.  Those of you familiar with the rulings on AR pistols know the oddity that a receiver that has never been a rifle can be used as an AR pistol, but if a rifle receiver is used, that makes the pistol a short-barreled rifle, an NFA item.  That's because the receiver is associated in some paper trail with being a rifle, and it will always be a rifle.  While you can repair things attached to that receiver, perhaps replace an 18" rifle barrel with a 20" barrel, you can't make a rifle a pistol. 

The thing the Biden rules are doing is attacking convenience.  They're concerned about it being too convenient to buy a plastic 80% pistol in one package and the parts to assemble it into a pistol at the same time.  Even worse, you can order or buy them at the same time and go home with everything you need to make that pistol.  It's like they'd prefer the 80% plastic gun and the rest of the parts be in different zip codes. 

How about if we give Dopey a kit and time how long it takes him to make a gun out of it?  How about we give everyone on his staff the same test?  If it takes them longer than it would take to buy a gun, they don't need to treat them as fully assembled guns.

In serializing the 80% plastic pistols, which are not guns, they're starting down the slippery slope to no right to repair, and every part in every gun needs to be serialized.   

Thursday, April 8, 2021

Starship SN15 on the Stand - Testing to Begin Soon

As expected, since my last update, SpaceX arranged for a road closure this afternoon, rolled SN15 to the test area about 1 mile from the High Bay, lifted her onto the test stand, and is busily completing the preparations to begin testing.  In this screen capture from Lab Padre camera 6, a worker can be seen standing between the base flaps, while others work on the test stand to the right of him. 

For those keeping track, SN15’s pad arrival comes just nine days after Starship SN11 – the last in a batch of four first-generation prototypes – exploded in midair some 30 seconds before a planned landing. 

One of the questions that pops up in the comments window on Lab Padre is about what happened to numbers 12 - 14.  Think back a whole three months to December of '20 and Starship SN8’s unexpectedly successful test flight, a flight which Elon had said he expected to have a 30% chance of being successful.  Instead, the rocket made it just a dozen or so seconds away from soft landing after more than six minutes in flight, including two minutes free-falling in a belly flop like no rocket ever.  After that milestone, SpaceX made the decision to scrap Starship SN12 and kill SN13 and SN14 before assembly could begin.  Effectively a gamble that SN8-SN11 would produce enough of a foundation for future testing to start off on, it’s hard to say if that gamble paid off.

Tomorrow, SpaceX has reserved a road closure from 7AM to 12PM and included closing the beach, unlike today's road closure to move SN15.  That probably implies they'll begin testing tomorrow, probably with ambient temperature nitrogen to check the Starship's complex plumbing. 

Wednesday, we were treated to another launch of 60 Starlink satellites onboard a Falcon 9, this time from Complex 40 at Cape Canaveral.  These launches are becoming boringly routine, just as everyone would like them to be, and I watched from launch through the first stage cutoff and jettison.  When I came in, the display was anything but its normal, boringly routine.  The view I'm accustomed to is a split screen with the views from the first stage on the left and a view of the second stage engine, glowing red, on the right.  Instead, there was one view, of mostly blue sky and a tiny fuzzy spot that was presumably the second stage still lifting toward orbit.

Suddenly, the video popped on, startling the people announcing the launch.  It was moments until the second and final burn of the first stage, and the view in front of the camera was, again, light blue.  Within seconds, though, I realized that was the ocean and caught a glimpse of the recovery drone ship coming up fast toward the camera.  Within seconds, the successful landing was captured.  There's a continuous loop of the last 20 seconds of the booster's flight on NASA Spaceflight's Twitter account.

This is the seventh flight and landing of booster B1058, arguably the most famous booster in SpaceX history, because the first flight of this one lifted Bob Behnken and Doug Hurley on the Demo 2 mission last May, the first manned launch from the US since 2011.  This was the 79th successful booster recovery. 

The launch also marked the 10th SpaceX mission of the year; and being just past the end of the first quarter of '21, that puts them on a path to close to 40 launches for this year.  The calendar is clear, though, until the next launch, which will be the Crew-2 mission, taking four more Astronauts to the ISS, No Earlier Than April 22nd at 6:11 AM EDT.  Crew-2 will be the first manned spaceflight in history to fly a recovered booster.  Booster B1061 was first used for the Crew-1 launch in November of '20. 

Wednesday, April 7, 2021

Something Here Is Fishy

A link in the daily newsletter I get from FEE (the Foundation for Economic Education) took me to Amazon's Twitter account and a post from Jeff Bezos saying that they want corporate taxes to go up and they support the Biden administration's efforts to raise taxes. 

No, really.

Amazon has also lobbied aggressively for other big-government policies like a $15 federal minimum wage. This should strike you as a giant warning sign; it's something we've commented on this about a godzillion times in the life of this blog.  When Big Business colludes with Big Government it’s virtually always because they know the government roadblocks instituted will reinforce their market dominance and ultimately be to that Big Business's benefit.  After all, Big Business Amazon (in this case) already employs buildings full of accountants and lawyers to navigate the new laws.  Smaller competitors don't.  The expenses are harder on smaller businesses. 

All big tech companies, Facebook, Amazon, Google, Twitter, Netflix; all of them got where they are by disrupting the existing business environment - puncturing the equilibrium.  Because of that they all live in abject fear of being knocked out of dominance by another small, disruptive company.  Cronyism with Big Government is a way they fight back.  Why innovate when you can buy a congress critter? 

It remains as valid now as it has been forever: ask someone if the people who pay the sales tax a company collects on what they sell are the same people who pay who the company's income tax.  If they don't think they're the same group of people, the company's customers, they're economically illiterate.  As this meme (also from FEE) points out, in conditions where the prices a company can charge can't go as high as the tax increase demands, studies have shown that the company's employees are subjected to conditions that get the rest of that revenue.

Let me let you in on not quite a secret:  Amazon and Jeff Bezos know this. They just hope that you don't, and that you mistake their attempts at cronyism for altruism.

Tuesday, April 6, 2021

Relativity Space's 3D Printed Rockets Are Starting to Look Like the Real Deal

As Relativity Space continues to work toward their first orbital launch before the end of this year, the company is looking less like an aspirational idea and more like a real space hardware manufacturer.  The company got on my radar back in '19 when they successfully got to the next level of venture capital funding to develop the 3D printing processes for building the vehicles and the engines.  

Make no mistake: there's a difference between having successfully printed part of a launch vehicle and putting that vehicle into orbit.  Orbit is hardArs Technica reports that the company's 3D printing technology seems to be working. Two recent milestones in the development of the company's Terran 1 rocket, in fact, suggest the tech is working really well.
In an interview, Relativity CEO Tim Ellis said the company recently printed the second stage that will be used on the inaugural flight of the Terran 1 rocket, which is presently scheduled to take place before the end of 2021. The stage was printed at a rate of about 1 linear foot per day, so in printer time it took about three weeks in total to produce the 20-foot tall second stage.

"We're now confident in this build process," Ellis said. "Not only is the second stage now completed, but we're 75 percent of the way through printing the rocket's first stage."
There's a 14 second time lapse record in this video.  It appears to be a laser sintering process that operates by melting powdered metals in a continuous flow while moving the laser print head.  The process is similar to one 3D printers have been using for almost a decade.

And there's a video of the engine full duty cycle test here - 3 min 25 seconds long.
Relativity has also been able to prove the merits of 3D printing by rapidly changing the metal used in the thrust chamber of its Aeon engine—nine of which will power the rocket's first stage. Engineers started out using a nickel-based alloy inside the thrust chamber because it was an easier material to work with during the manufacturing process. But a copper-based alloy has better conductivity and allows for higher combustion temperatures—and therefore a higher-efficiency engine.
Around the same time as these tests were taking place, Relativity secured a frankly incredible $500 million in funding. That funding will very likely not only get them through development of their Terran-1 rocket, a small sat class launch vehicle closer to Rocket Lab's Electron and not the heavier lift Falcon 9.  That funding might well get them through their next development.  Like Rocket Lab, Relativity Space has announced a program to develop a Terran R, in which R is for Reusable, that will be in the Falcon 9's payload class.  

It's hard to exaggerate just how extraordinarily flexible Relativity's apparent 3D-printing process seems to be.  It's turning out to be the key technology as the company works to prepare Terran 1 for an orbital launch debut as early as later this year.

With the second stage printing complete, the company has begun installing an Aeon vacuum engine, avionics, and a separation system for the first stage. The Long Beach, California-based company intends to ship the second stage to its facilities at Stennis Space Center, in Mississippi, for testing this summer. Assuming a successful test campaign, the stage will then be moved to Florida, where it will be integrated with the first stage for launch.

The first flight will not carry a payload, and the record of companies (and nations) achieving orbit on their first attempt doesn't inspire us to spend a lot of time planning a celebration.  When asked about the chances of reaching orbit with this first flight, CEO Tim Ellis said he was confident the company would gain a lot of knowledge about the launch vehicle. "The expectation is that we're going to learn a lot," he said.  The second flight of a Terran 1 will carry a payload for NASA.

Monday, April 5, 2021

SpaceX Getting Back to Normal at Boca Chica

Work pace and operations appear to be getting back to normal at Boca Chica.  At 6:45 CDT, someone tweeted to Elon Musk "How's the investigation into SN11's RUD going." Elon replied with this:

Teslarati space correspondent Eric Ralph covers the story, and while he really doesn't say much more than that, he does add some context.  It's not uncommon to see small fires around the engines during these test flights, as it doesn't seem uncommon to see small fires during the launch of many vehicles.  Eric Ralph adds 
... it’s possible that the “small [methane] leak” Musk has blamed for SN11’s failure was visible on Raptor engine SN52 less than 30 seconds after Starship lifted off, leaving plenty of time for a high-pressure fire to severely damage the faulty engine and its adjacent partners. The SpaceX CEO says that the resultant fire “fried part of [the] avionics” controlling one or all three Raptors, “causing [a] hard start” that damaged or destroyed one or all of the engines when they attempted to begin their landing burns.

This is the picture that Eric Ralph says is at 52 seconds into the flight.  It doesn't look like a methane/oxygen torch in this photo but if that fire was burning while the engines were supposed to be off, until 5:49 when telemetry cut off, that's almost five full minutes of flame impinging on something.  Is this grasping at straws for an explanation?  I don't know. 

This morning, they rolled Bluto The Crane to the test stand area giving rise to thoughts SN15 would follow this morning or tomorrow.  The surprise was that a piece of Ground Support Equipment, obviously a tank although I can't tell what kind of tank it is (other than "big"), was rolled to the test stand area and is being put in place.  The tank looks as big as a Starship prototype. 

I want to call your attention to the far left of the picture: that's Test Stand 1, and it has been modified since you last saw it.  A thrust puck tester (what the scrolling caption calls the "New puckshucker") was installed over the weekend during the night shift. 

The thrust puck is the name given to the base of the bottom tank in the Starship, the liquid methane tank.  The reaction force of the three raptor engines, potentially as much as 1.5 million pounds of thrust, pushes upward on the thrust puck and the bottom of the tank.  In the early days of the Starship prototypes, SN01 and SN02, a failure was traced back to the thrust puck.  It seems in their testing plans for SN15 they're treating it as completely new and going back to the very first tests they ever did.  This tester will press on SN15 before it has any Raptor engines installed.   

Today's fun fact is found by looking at that link on testing the first two Starship prototypes.  That was 13 months ago: March 3, 2020.  It seems like ancient history because of the pace they build and test at. 

With no road closures announced on the Lab Padre scrolls at the moment, it doesn't look like SN15, fully stacked and apparently ready to roll, will go to the test area tomorrow.  The week is young; it might well be on Test Stand #1 by Friday.  

Sunday, April 4, 2021

I'm Not Saying to Buy a 3D Printer For Things Like This

I'm saying if you happen to have a printer around, it can solve problems like this.  

A couple of years ago, my old shop vac failed.  That article describes how I found the fusible link that was protecting the motor was nothing more than a piece of solder.  It had heated enough to get soft and open the power connection, keeping the motor from running.  I was appalled.  Nevertheless, I put a piece of solder in it and the vacuum worked - for few weeks until that piece of solder softened.  I eventually tossed out the thing and bought a battery powered Ryobi for cleanups around the shop, the house and when washing the cars. 

When I tossed out the old Shop Vac brand, I kept the 2" hoses and all the accessories but the Ryobi uses a different sized hose so everything sat in a few corners.

The Ryobi actually worked OK, but about a year ago, I got tired of it not being working every time I needed it and bought a different brand, higher power shop vacuum; a Ridgid.  Now I could leave the vacuum in a corner and if I can hook up the old and new 2" hoses I can reach the entire metal shop.  Except the hoses don't mate.  Both ends of both hoses are the same smaller diameter (about 2-1/4") that plug into a bigger hose fixture in either an extension wand or the vacuum body or the fixtures designed to go on the hoses.

As an RF engineer (working at Radio Frequencies), this is second nature.  We always would need  multiple cables (colloquially called hoses) to get across a few benches and need to connect things that wouldn't connect.  There is literally an entire industry of making and selling adapters between things we might try to connect and a set of laws that reflect on what we see.  ("Given a need for N adapters, the engineer will never find more than N-1", and so on).  I knew what I needed, I needed a plastic adapter big enough to plug both ends into.  Nothing more than a plastic pipe that had to be a specific size. 

This sounds like it should be doable on my 3D printer.  It doesn't take long to design a pipe.  Make a cylinder of the right length, right inner and outer diameters and you're there.  A couple of days ago, I made a test piece just to make sure a couple of inches of what will eventually be four inches long would fit the hoses.  It fit just fine. 

I was about to print a full-sized version, when something hit me.  The Ridgid hoses have a feature I've never seen before: the mating sections to the hoses have triangular, saw tooth-like pin on a flexible lever.  It mates with a section on the fixtures or the vacuum cleaner itself and acts as mechanical insurance.  I decided to create a model of that and add it to the full sized adapter. It took a couple of hours to draw that (essentially point by point), turn it into a solid model and set it up to print.  The whole adapter took six hours to print, but here it is coming off the printer. 

And here it is doing its intended job - joining the old Shop Vac hose (right) and the Ridgid hose (left).

Here's a closer view of the Ridgid locking tab.  This doesn't look quite right, so I'll have to look at it a bit more closely.  Perhaps the mating teeth on the adapter are a bit too close to each other.  Or maybe it's just slightly out of position.

As you might expect, I didn't declare it done without vacuuming up around the shop and pulling the cleaner by the hose. No problems.

I'm not sure the adapter I needed doesn't exist anywhere, but I had looked around a bit without finding them. In terms of just the plastic for the print, this cost about 45 or 50 cents. There is no compensation for CAD time or anything else.  I'm not saying it makes sense to buy $300 or $325 worth of printer, filaments, dry boxes, and everything else to print an adapter.  I'm just saying if the printer is in your shop, the problem is solved. 

Saturday, April 3, 2021

Happy Easter!!

It's Easter, Resurrection Sunday, and as I do regularly, I look at what I've done for the major holidays in the past, and often modify them quite a bit.  Not wholesale tear it up and start over, but some extensive additions and deletions.  

Looking for the Living One in a Cemetery

24 1-3 At the crack of dawn on Sunday, the women came to the tomb carrying the burial spices they had prepared. They found the entrance stone rolled back from the tomb, so they walked in. But once inside, they couldn’t find the body of the Master Jesus.

4-8 They were puzzled, wondering what to make of this. Then, out of nowhere it seemed, two men, light cascading over them, stood there. The women were awestruck and bowed down in worship. The men said, “Why are you looking for the Living One in a cemetery? He is not here, but raised up. Remember how he told you when you were still back in Galilee that he had to be handed over to sinners, be killed on a cross, and in three days rise up?” Then they remembered Jesus’ words.
9-11 They left the tomb and broke the news of all this to the Eleven and the rest. Mary Magdalene, Joanna, Mary the mother of James, and the other women with them kept telling these things to the apostles, but the apostles didn’t believe a word of it, thought they were making it all up.
12 But Peter jumped to his feet and ran to the tomb. He stooped to look in and saw a few grave clothes, that’s all. He walked away puzzled, shaking his head.
Luke 24:1-12  Message Translation

A couple of days ago, Larry Lambert over at Virtual Mirage left an open forum with the suggestion of posting of whether or not you're "a person of science or as a person of faith."  I don't think those are opposites, such that one can only be one or the other and I'm sure that Larry knows that many scientists are Christians so it had to be left to prompt conversation.  

Coming from my background, becoming an evangelical Christian was a large change.  I had studied biochemistry and microbiology in college through my third year before life imposed some detours, eventually getting my degree and starting my career as an engineer late in life (over 30).  I had been an amateur astronomer, so between them I was deeply marinated in the standard model of Cosmology as well as conventional biological evolutionary theory.  Frankly, I wasn't giving it much thought any longer, but my wife had re-affirmed her faith (she had first accepted Christ as child) and I was having all of my mental models disrupted.  She had started a subscription to Bibical Archaeology Review and the constant refrain from archaeologists, not religiously motivated, along the lines of "we thought this was old Jewish folklore, but here it is" got me thinking "if that's true, maybe there's more that's true."  Strobel's The Case for Christ, played a role in filling in the gaps in my historical knowledge.

Easter is the most important day in Christianity and far more important than Christmas because of the resurrection.  Everyone has a birthday, but history only records one resurrection.  The resurrection is essential to Christianity; without it there simply is no reason for Christianity to exist.  Since virtually everyone, including honest atheists, agrees Jesus was a real man in history (I've always found it amazing that Jesus' existence is better attested in ancient sources than that of Julius Caesar - but no one claims Julius Caesar was not a real person) and died on the cross, the question becomes whether or not it can be verified that Christ was seen after the resurrection by someone other than the closest circle of disciples. Strobel says:

Did anyone see Jesus alive again? I have identified at least eight ancient sources, both inside and outside the New Testament, that in my view confirm the apostles’ conviction that they encountered the resurrected Christ. Repeatedly, these sources stood strong when I tried to discredit them. 

Could these encounters have been hallucinations? No way, experts told me. Hallucinations occur in individual brains, like dreams, yet, according to the Bible, Jesus appeared to groups of people on three different occasions – including 500 at once!

In the end, after I had thoroughly investigated the matter, I reached an unexpected conclusion: it would actually take more faith to maintain my atheism than to become a follower of Jesus.

I still think a great summary is "Five Confounding Facts About Jesus' Resurrection" a 2016 post at Donald Sensing's Sense of Events (who doesn't seem to have posted since last summer but has left his archives up).  He has done several excellent posts on the subject, including Jesus and History and links to articles put together by working scientists, "On what basis would a scientist accept the Resurrection?" and "Is Belief in the Resurrection Unscientific?

Enjoy your day.  Enjoy your families. As usual there's a pork butt going in to the smoker but only after 24 hours in the ultra-controlled sous vide cooker.  Pulled pork tonight. 



Friday, April 2, 2021

Trying to Bring Modern Monetary Theory to Conservative America

To begin with, credit where credit's due - to Zendo Deb at 357 Magnum for the link that got me started, but I forgot which post the link was in.  I had to save the article to read later, so I copied the URL down and promptly lost the context.  I just know it was in one of her lists of links.  You do read her, don't you? 

The story is a link to an article on The American Conservative called "Modern Monetary Theory for Conservatives" by an author named Jonathon Culbreath.  Since his author page has three articles there in the last year, it's safe to say he doesn't provide a lot of content for TAC.  The little biography I can find for him simply says, "Jonathan Culbreath is a writer living in Southern California. He is an assistant editor at The Josias, a site dedicated to the recovery of Catholic Social Teaching."

Let me start by saying the article doesn't cover anything new about Modern Monetary Theory (MMT hereafter); he quotes liberally from Dr. Stephanie Kelton's book The Deficit Myth (subtitled Modern Monetary Theory and the Birth of the People's Economy) about the topic.  (Is anyone besides me creeped out by the term "People's Economy?")  The only thing that seems new is the attempt to convince people who see endless deficit spending as leading to serious trouble in the long term that deficits are fine.  MMT says governments aren't like people or companies or anyone else in the real world who need to have a balance sheet that balances.  Culbreath thinks conservatives should be OK with deficit spending, but just care about what the spending pays for. 
As predicted, conservatives have responded to the latest $1.9 trillion stimulus package with outrage about our growing national debt, and the taxes that will be required from our children and grandchildren to pay for it. While there may be many things to criticize in the package, it is significant that despite the fact the defense of the family is supposed to be a hallmark of conservative politics, not even a generous family policy embodied in an expanded Child Tax Credit could assuage many conservatives of their mortal fear of government spending.

This reluctance to accept government expenditure can be explained by many factors, some of them ideological and political. But one important and somewhat understudied factor is a faulty and outdated economic theory. Without defending all the details of the latest stimulus package, conservatives should re-examine the economics that underlie the tendency on the right to condemn any instance of large-scale government spending. On the basis of such a re-examination, the policy conversation could then shift away from whether government spending is economically justifiable and towards what kinds of spending are productive and worthwhile.
The article goes on about the theory and generally talking it up.  In general, the article (like everything I've read before) says "you're wrong in the way you think about things" but doesn't offer proof.  There are no reports that some other countries have done this and the world has gotten better for them.  As one of my economic mentors, the (long-retired) Mogambo Guru put it long ago (2009),
Whether or not this theory is true, I don’t know, but I don’t think so, as I have never read anything like, “From the moment that the government started creating and spending large amounts of money, everything got better and better, and the more money that was created for the government to spend, the better things got, until they reached Utopia and everybody lived happily ever after.”
And that's the problem I have with MMT.  As I said when I first read about it, "Well, actually, it's not new.  And it kind of dignifies it to call it a "theory."  It's a particularly stupid idea, which is to say the idea is to do what they always do: just keep spending what you don't have.  They just gave it a name they can hide behind." Remember, in science, a theory is an explanation for observed facts that have been demonstrated in controlled experiments.  If the theory - explanation - is proven to successfully predict what's going to happen in the experiments, it's standing is improved.  If proven often enough and well enough, and most especially never fails to predict, it becomes considered to be a natural law.   The only idea in economics that approaches the level of natural law is the Law of Supply and Demand.

What would it take to convince you that their way of looking at money is more accurate than the view that has held for all of human history?  Would it take more than some glib pronouncements from some professors?  Perhaps watch it work in various economies around the world over some length of time?  I would like to see it tested in various economies for a few nation*centuries, which just ain't happening.  I wouldn't live long enough to see it, anyway.

Any good theory should produce predictions that can be tested.  An easy example to think of is the theories in Newtonian Physics.  The predictions of the laws of motion are easy to create and easy to test.  One of the predictions of MMT is that there's really no such thing as inflation caused by too much monetary creation.  MMT says inflation is caused by too much demand for supply. 
Inflation only occurs, at least in any damaging degree, under certain conditions. Foremost among those conditions is full employment. When the economy is at full employment, which it rarely is, then the overall purchasing power within the economy may be considered to be at full capacity. At this point, an injection of more money into the economy might result in inflation, since it would likely push demand to outstrip supply, thereby causing prices to soar higher and purchasing power to decline at a dangerous rate.
Conventional economists say inflation occurs when sellers value what they're selling more than what buyers are offering.  In the case of rampant government spending, the seller says they can't buy what they need with the dollars being offered and demand more.  Are we having inflation?  To borrow a graphic from Gun Free Zone:

I'd say that real inflation isn't coming, it's here.  Their MMT fails to predict this, because with about 60% of the work force employed we're a long way from full employment and they say full employment is a precondition for inflation.  Furthermore, consider the Jimmy Carter years in the 1970s when inflation was the highest in the century.  Employment wasn't full then either (graph of employment levels in this post).  I say MMT fails the test of being able to predict the outcome of an experiment. 

Thursday, April 1, 2021

Norwegian EV Startup Could Challenge Tesla’s Market Dominance

Is the age of the self-recharging Electric Vehicle dawning?  To some extent, it dawned years ago with the concept of regenerative braking - the ability to use the kinetic energy of the car to turn a motor into a generator charging the batteries as the car was dumping energy out of its forward motion.  Realistically, this wasn't enough. The cars still need to be recharged, but what if the car could generate enough power to charge itself when not running?  The laws of thermodynamics say, "there's no such thing as a free lunch," so that energy has to come from somewhere.  Evaluation Engineering magazine today talks about such a concept from an unexpected source: an Electric Vehicle startup in Norway.
The Fjord Motor Company, a Norwegian electric-vehicle startup, has announced it’s accepting deposits for orders of its unique and revolutionary Mocky SUV Crossunder. The five-place Mocky is packed with all of the features offered by its competitors, including a 350HP fully electric drivetrain (available in 2- or 4-wheel drive), a 300-mile range, a center screen display, and reconfigurable seating.
The feature that stands out from other “green” automotive market leaders, like Tesla with its ultra-fast-charging vehicle offerings, and Toyota with its “self-charging” hybrids, is a true, off-grid, point-of-energy-source, self-charging capability. Fjord’s Mocky incorporates a patent-pending tire design, developed in collaboration with Korean global tire giant Yancancook, that features a water-wheel-like tread that’s said to also have exceptional hydroplaning and snow/mud performance.

When the car isn't needed for driving, it can be parked in a convenient stream and the configuration of the car changed from the driver's position to allow the energy from the stream to turn the tires and charge the car.   Fjord makes it more convenient with electrohydraulic jacks behind the rear wheel wells, so that the car just has to have its back half in the running stream.  All the driver has to do is ensure the car is pointed as close to upstream as reasonable and command ChargeStream™ on the Mocky’s center-screen controls.

Fjord estimates 10% to 80% charging times of around 10 hours, so it's better if you can leave the car while you're at work, or can accept less charge, but it's also feasible for electric car camping if you can park alongside a stream.  The longer the car is in the stream, the better.  Now Fjord makes a claim I don't think is reasonable: 110% charge efficiency due to excess battery heat being used for cabin warming.  They also claim the heat can make dinner using a cleverly integrated fish-poaching pot located in the frunk.  I think we'll have to wait for some objective reviews of the car from some reviewers that can measure these things.  I should point out that for the risk averse buyers, the Mocky comes with standard dual SAE J1772 DC charging ports.

Fjord Motor Company publicity photo of the Mocky from Evaluation Engineering.  Bearing more than a slight resemblance to Ford's recently introduced Mustang Mach-E, Fjord Motor's Mocky offers comparable range and performance, as well as its industry-leading HydroCharge self-charging system and an autopilot that gets smarter as you drive it.

An autopilot that learns?  Artificial Intelligence Autopilot?
"Apart from killing Toyota’s ‘self-charging’ hubris, and Tesla’s now-Lilliputian charging rates and abilities, the only unaddressed advantage Tesla has over Fjord is autonomous self-driving, though Elon Musk has delivered more hot air than full capability to date," said Lief Niessan, CEO of The Fjord Motor Company.

“As a startup, we had limited engineering resources and cash available to us, so we looked for an AI (artificial intelligence) toolset that was available in the Open Source community to form the basis of the Mocky’s self-driving capability,” continued Niessan. “Our engineers worked closely with OpenAI and we managed to score a beta copy of their GPT-3 Artificial Intelligence toolset.”

For those unfamiliar with GPT-3, the toolset features an AI engine that was trained by crawling the entire expanse of the internet. GPT-3 has been demonstrated to compose music, write essays, perform medical diagnosis, and has even been used to complete partial photographs.
Niessan relates some of the interesting issues they've encountered with OpenAI "trained by crawling the entire expanse of the internet" in the Evaluation Engineering article.  He relates, for instance, that the system would add 2π MPH (or 3π kmh on metric highways) to the legal speed limit, having determined a speed that created the shortest travel times and carried an almost zero probability of a speeding citation being issued.

Fjord Motor Company is nothing if not innovative.  Pricing for the base model Mocky 2WD starts at $39,995 (USD), which includes StreamCharge™, dual J1772 DC charge ports, and the in-frunk fish-poaching pot.  While the cost of the self-driving option was not revealed by Fjord at press time, Lief assured us that active members of the Open Source community who deliver more than 500 lines of useful code to GitHub would receive the autonomous EV option at no cost.

Wednesday, March 31, 2021

Surprise Bill in Florida House; Second Amendment Preservation Act

I learned today that this week a new bill has been submitted to the Criminal Justice & Public Safety Subcommittee in the Florida House of Representatives.  HB1205 is a "2nd Amendment Preservation Act" much like the laws passed in other states.  The full text of the bill (pdf) is online.  The bill was introduced by Kaylee Tuck, a young representative from south central Florida; district 55 which covers parts of Okeechobee County just north of the Lake. 

I don't know what the chances are for bills this time in the session, but I'll go ahead and email everyone on the committee anyway asking they pass the bill and send it to the full House.  My representative isn't on this committee but he's a Rino and a shining example of the problem with Term Limits - people who have been in office get name recognition, so when they limit out of one office, they run for the one down the hall or on the other side of the capital and move over there.  Still a lifetime career politician just with varying titles.  

The forum where I found out about HB1205 had this video by a channel called Guns&Gadgets describing the bill and going through some of it page by page.  It's a 10 page bill; the first four are "Whereas" statements and the last five are the actual rules.  It seems like a good bill to me. 

Tuesday, March 30, 2021

Starship SN11 Discovers a New Failure Mode

Unfortunately, we don't know what it is just yet.  All we know for sure is what little we've been able to see with our own eyes.  SN11 lifted off from Boca Chica at 8:00 AM CDT, into a dense fog.  SpaceX's video stream, which included the usual photography from cameras around the ship, showed a seemingly normal ascent to 10km (6.2 miles), cutting off engines one at a time while climbing, until it hovered at altitude for a few seconds.  The descent looked normal (although they were losing video regularly) until the engines started up.  This was the last frame update from the vehicle.  As you can see, the mission time was 5:49.  This is 10 to 15 seconds before landing.  

This SpaceX mission video is part of a (much) longer video Everyday Astronaut posted that was live streamed this morning.  I've queued up the video to start around 38 seconds before ignition and liftoff.   Really of note is that there seems to be an explosion coinciding with the ignition moment in the picture above.  He has video of chunks of SN11 falling to the ground and is visibly worried about his cameras, set up where the chunks are falling.   Late this afternoon, Elon tweeted a reply to him saying, "Barely a scratch. :) Back on the stand soon! Will report conclusions as soon as we know them."

Did it explode due to something going on at this instant, or did the FTS (Flight Termination System) detect something so far from normal that it blew the craft?  Wish I could answer that.

I don't think it was the FTS deciding it had to destroy the vehicle.  The FTS system terminates a flight if it goes well off course or shows strong evidence of not being in control.  That takes time and everything was looking pretty normal until it didn't.  This looks to me like an engine explosion, from the things I can see.

As that second to last tweet says, SN15 is a few days away from the test stands to test "hundreds of design improvements" in all aspects of design.  Somewhere in the next couple of weeks, Booster BN1 will be brought to a different test stand for its testing.  In observing how quickly they were pushing to get SN11 ready to fly, I'd been thinking it was almost a formality to get SN11 out of the way and get onto testing 15, but learn as much as possible from 11 while you can.

Monday, March 29, 2021

The Flight of the Smellicopter

An interesting article popped up today in Electronic Design's email news, about navigating micro drones by using a sense of smell. Navigating a drone or some equipment using smell has a lot of practical uses; the obvious one would be looking for a gas leak in a place with natural gas utilities, but there are others, such as the way bloodhounds have long been used for tracking people by scent. What about a missing child? What about environmental hazards, chemical leaks, and other industrial accidents?

The problem with using smell to navigate is that while we do have things that function as synthetic noses, they aren't very good.  (Where's my drummer?  They just don't smell good. (rim shot))  That's why a team led by Ph.D. candidate Melanie Anderson at the University of Washington thought they'd use the smell-sensing antennas of a Manduca sexta moth to produce a drone that they call the Smellicopter.
Why a moth antenna? In addition to sensing wind and vibrations, these fast-responding, highly sensitive transducers capture olfactory information that the insect uses to find food and mates. A sensed odor induces a complex series of chemical reactions, culminating in an “action potential” that propagates down the antenna to the brain of the insect. An electroantennogram (EAG) measures the aggregate electrical activity of the olfactory neurons in an antenna by measuring the voltage drop across the antenna.

“Nature really blows our human-made odor sensors out of the water,” said lead author Melanie Anderson, a UW doctoral student in mechanical engineering. “By using an actual moth antenna with Smellicopter, we’re able to get the best of both worlds: the sensitivity of a biological organism on a robotic platform where we can control its motion.”

That point was amplified by co-author Thomas Daniel, a UW professor of biology who co-supervises Anderson’s doctoral research. He added, “Cells in a moth antenna amplify chemical signals. The moths do it really efficiently—one scent molecule can trigger lots of cellular responses, and that’s the trick. This process is super-efficient, specific, and fast.”

If you hear of the University of Washington being attacked, I wouldn't be surprised if Ms. Anderson's lab at UW were to be set upon by the animal rights people because she's plucking the antennas off live moths for this experiment.  In this photo, the antenna is the little round loop on forward (left) end of the drone.  The moths are put into a refrigerator to anesthetize them before the antenna is plucked off, but there's only two antennae per moth so the moths are either regenerating the antenna or they're sacrificing the moths. 

All that aside the way they handle the signals from the moth is plain old analog electronics.  They measure the output of the antennas. Output was between 10 µV and 1 mV in response to stimuli, so they set the gain to 1,000 after some experimentation. The moth's antenna output impedance was high, though, between 500k and 750k ohms (500 and 750,000 ohms), and the system picked up electrical noise too easily.  That was easily solved with an active filter and more amplification - the output stage has a gain of 11. 

The drone pictured with the modification for using the moth antennae is a commercial/open source model called the Crazyflie 2 Nanodrone.  Without the antenna sensor (another EAG, or ElectroAntennoGram) it weighs 23 grams.  Once outfitted for their experiments and characterizations, it can fly up to seven minutes on its 250 mAH battery. 

It's an interesting article, digging into how the biology department told the mechanical engineers how the moths work their way upwind to the source of a smell, as well as digging into the details of how the engineers have made the drone work.  Biomimetic designs, literally life-copying designs, are becoming a big thing (as was always expected) and this a good look at how it's going on. 

Sunday, March 28, 2021

Oh the Precious Goal in Life to Be A Victim

There was a story this week, toward the bottom of the news where it belongs, about a dude who considers himself a woman, but hasn't actually had the surgery that matters the most, yet.  You know, the surgery Rush used to call the Chopadickoffofme.  When poor dude goes through the TSA checks to get on an airplane, they always find this anomaly between his legs and need to resolve it.  Dude has gone screaming to any camera and microphone that he can find to scream to about (I suppose) how unfair it is that the scanners can't read his mind and learn how he identifies.  The story on the Blaze says that model and content creator Rosalynne Montoya recently shared an experience with social media users and insisted that TSA is transphobic.  
"Can we talk about how horrible it is to travel while being transgender sometimes?" Montoya asked in the now-viral video, which has been seen by at least 18 million people at the time of this reporting. "I always have immense anxiety leading up to going through security. And this means that I totally recognize the privilege of having all of my documents correct. So, the gender marker on my license, for example, says 'female.'"

"But, going through the scanner, there's a male scanner and a female scanner in the TSA checkpoint," Montoya continued. "And, looking at me, you know, I look like a woman and I am a woman. So, that's great. I love having systemic privilege when I feel unsafe, which is in an airport. But, going through the scanner, I always have an 'anomaly' between my legs that sets off the alarm.
Pardon me if I get your pronouns wrong, but the TSA isn't transphobic; they're bomb-phobic. 

He/she/xe/xshe (whatever) tells the sad story about always having the anomaly between his legs if he goes through the scanners as a woman and has an anomaly in his chest if he goes through as a man.  Apparently he was committed enough to get breast implants, so augmented, but not committed enough to get subtracted from. 

The story is also covered at PJ Media, who got in contact with TSA and reprints much of the way they address the situation. 

I have a simpler example.  Back two days before New Years Day of Y2K, Mrs. Graybeard and I were hit by a pickup truck while riding our bikes.  She had several stainless rods inserted in her back; we call it a pound but don't really know what it weighed.  As a result, she was given a card by her doctor to hand to the TSA.  It states she has implants that will show up on their scanners.  We've taken at least a dozen trips in the intervening years and Every Single Time she goes through the scanners, they stop her for more thorough investigation.  Every Single Time we've asked the TSA about the cards they say (in effect) "nice cards, but we have to be sure."  Essentially, anyone could print up cards like that. 

And that's what's going on with Rosalynne Montoya.  Anybody could say they're a trans woman and have a pound of explosives between their legs.  Once the anomaly shows up, they have to prove it's safe.  They're responding to the risk, not the person. 

Saturday, March 27, 2021

A Ham Radio Series 23 - Introduction to Power Supplies

One thing that every radio and virtually every accessory needs is power.  In some cases, especially handheld portables, the power is supplied by batteries; in many other cases the power is obtained from the AC power lines.  Typically 120V 60 Hz in the US and 220V 50 Hz in much of the rest of the world.  If you're operating a 100W output power transceiver that may run on 12V and take 20 Amps on peaks a few percent of the operating time, for example, that can be run off a deep cycle 12V battery, like the marine or RV batteries or it can be run on a line-operated power supply.

I want to take a short dive into line-operated power supplies.  The details of building one vary with the requirements, but they're well within the range of things amateur builders can design, build and get running.  For low power supplies, say the 1 to 2 amp supplies that you might be familiar with for little things around your house, there are literally less than 10 parts in the entire thing.  More parts are required for something like that 12V 20 to 30 amp supply, but aren't really much more complicated, conceptually. 

Broadly speaking, power supplies can be divided into two kinds: linear and switching.  Linear supplies use components called voltage regulators which are analog components; that is, the voltages and currents in them and through them are smoothly varying, continuous in time.  These regulators operate like the feedback circuits I've talked about before.  Somewhere inside the regulator is a reference voltage.  The output voltage is compared to this reference continuously, producing an error signal that causes the circuit to turn the voltage up if it's too low and turn it down if it's too high.

Switching regulators, as the name implies, use switching techniques to change the input voltage to the output voltage, so they're on-off circuits more like digital than analog.  They use components called regulators as well, but they work on different principles; a very common technique is Pulse Width Modulation.  Briefly, the switched on/off voltage they're producing gets filtered into clean DC, and if it the voltage runs too low, they keep the pulses on longer (so that they're wider) and if the voltage is too high, they turn the pulses off sooner (making them narrower) reducing the output voltage.   

The advantage of switching regulators is they tend to be more efficient, sometimes reaching efficiencies of 85 to 90% or higher.  The linear regulators are lower efficiency.  That might matter to you for running things when the grid is down and you're trying to stretch every watt you can produce.  The advantage moves over to the linear regulator when you want an electrically "quiet" regulator.  The fast switching voltages in the switching reply produce broad spectrum electromagnetic interference (EMI).  Nevertheless, I can assure you that every system I worked on in military, space and commercial aviation for the 40-ish years I worked in those fields were switching power supplies.  Their drawbacks can be designed around.  After almost 30 years using the same linear supply in my ham station, I switched to a switching supply 15 months ago and haven't heard it on the receiver at all.

The biggest advantage of the linear regulators for the hobbyist and experimenter is that they are incredibly easy to use.  How easy?  How about "just add two parts?"

This example is based on the series of parts called the "seventy eight hundred" series.  The last two digits are the voltage.  Over the years they've been produced (since the late 1970s) they've been produced in 5V (7805) 8V (7808) 12V (7812) 7815 and more.  Furthermore, they're available in different packages and can deliver different currents depending on the package they're in.  They're the 78L series (low power) 78M series (medium power) 78P (high power) series, for example.  There's also a 79XX series for negative voltages. 

The bigger the case, the more power dissipation the part can handle.  The TO-3 (TO is from Transistor Outline) is the highest power (78P05, for example) while the TO-92 would be the lowest power 78L05.

What makes these so easy to use is they're extremely rugged; they've been designed to handle anything that could happen to the regulator.  Too much current?  It'll shut down, and then turn on again periodically to see if the condition cleared.  You could short the output to ground and it will just stay shut down until the short is removed.  If you over heat the part by drawing too much current, it just shuts down.  If you see the power turning on and off, that's the first thing to suspect. 

Practically, the input voltage will be coming from a transformer that drops the wall voltage down to "a few" volts above the desired regulator output voltage, rectified with a diode bridge and filtered with a large capacitor (although not as large as if there were no 78XX regulator there). It never hurts to read the datasheet, and the sheets for these, along with other design notes and help, are extremely widespread on the 'net. The power dissipation in the regulator is the voltage drop across the regulator times the current it's delivering, so say you're putting 8V into a 7805 putting out 5V at 1 Amp; that dissipation is 3W (8V-5V)*1A. 

That's not all in the world of linear voltage regulators; there are adjustable regulators - and ways to make the 78XX series adjustable, too.  There are higher power regulators, and ways to make higher power with lower power regulators.  There are regulators optimized for lower voltage drops across the part, Low Drop Out or LDO regulators, so that instead of putting 8V into a 5V regulator you'd use 6V or 5.5V (depending on the part).  

It's literally an entire world of circuit design open to anyone interested in making something useful.