Monday, May 10, 2021

SpaceX Breaks the 10-Launch "Barrier"

Sunday Morning at 2:42 EDT, SpaceX launched their 27th Starlink mission atop booster B1051, completing the 10th mission of one Falcon 9 booster, a number which has been an aspirational goal for the fleet.  The flight appeared completely nominal in all regards, with B1051 and the upper stage staying on the center line of their planned path, followed by deployment of the 60 Starlink satellites. And this:

SpaceX's live webcast, screen capture, from a looping animation on Twitter posted by SpaceX corporate.  The landed booster looking down from the interstage area at the recovery drone ship's deck on the left, and a view of the booster through the smoke cloud left by the engines. 

The number of ten flights was probably just pulled out of the air (PFA), as a number of launches without major refurbishment.  SpaceX Vice President of Mission Assurance Hans Koenigsman as said essentially the same.

It goes without saying that this is another world record because nobody else is launching recoverable, liquid-fueled, orbital boosters.  In an interesting aside, Eric Ralph at Teslarati lets us in on some industry chatter. 
For the entirety of SpaceX’s operational life, its only two real competitors have – and continue to be – US conglomerate United Launch Alliance (ULA) and European conglomerate Arianespace. Almost like clockwork, both extremely conservative groups – comprised of numerous traditional, entrenched aerospace and military contractors – have gone through a similar cycle of belittlement and dismissal, denial, goalpost-moving, disbelief, and resignation as SpaceX announced plans for reusability, began real-world attempts, and gradually worked out the kinks.

As it became clear that SpaceX would succeed in its efforts to vertically launch and land Falcon 9 boosters and ULA and Arianespace had to move their goalposts from “it’ll never work,” both generally settled on largely arbitrary claims that even if SpaceX could land rockets, reuse would never be economical. ULA went even further than Arianespace with an explicit claim – derived from armchair analysis built on opaque, unspecified assumptions – that SpaceX’s approach to Falcon reuse would “require ten [booster] uses to be profitable.” [PDF]

There's a story that ULA had been analyzing an alternative approach to reuse since 2015.  It seems like an expensive, complex arrangement and it would only save the engine.  It was to be called, “SMART (Sensible Modular, Autonomous Return Technology) Reuse” and was intended for its next-generation Vulcan rocket, still working toward its first launch probably in '22.  Unlike SpaceX returning the entire first stage to a semi-autonomous drone ship, ULA would develop an extremely complex engine section that would detach from Vulcan in mid-air, deploy an experimental inflatable heat shield, and be grabbed out of the sky with a helicopter.  ULA’s original schedule for SMART reuse would would debut no sooner than the mid '20s.

A Spanish-language site featured this montage of B1051's first nine flights.   

Sunday, May 9, 2021

A Ham Radio Series 26 – RF Noise and Coping With It

The concept of overcoming noise is the thread that unifies all of communications theory classes.  Virtually everything is in terms of achieving desired Signal to Noise Ratios (SNRs), and things like showing how much information can be transmitted at a given SNR.  Just as the concept of noise is ever present in theory classes, noise is present everywhere.  It should come as no surprise then that when we tune the radio bands we hear nothing but noise (in the absence of signals on the air).  

Various radio services have developed their own ways of dealing with the noise; the business band radio world, the police radios, VHF Marine radios and a ton of others use FM.  FM is a constant carrier mode; whenever someone is transmitting, the radio puts out the same power.  When the received signal is stronger than anything else coming in the antenna, FM has a capture effect that suppresses the interference, and the circuits aren't as effected by amplitude noise, so that noise is less of a problem.  That allows the receiver to use a squelch system that turns on the audio when the carrier appears and turns it off when the carrier isn’t there.  That has led to the ability to squelch the audio of other people on the channel whom you might not want to listen do, but open the squelch for people you do want to talk to, via Continuous Tone Coded Squelch Systems (CTCSS).

If you listen to the AM broadcast band (yes, it’s still there) or tune the shortwave spectrum, you hear broadband noise.  In general, you’re hearing “white” noise, called that because it contains an unshaped band of noise frequencies all at the same amplitude.  It’s called white noise is by analogy to white light, which is all the colors (which are different frequencies) combined.  White noise sounds like a hiss and if you tune through unused parts of the spectrum with a receiver with no squelch or audio muting, it’s all you hear.  Many people call this static, but the most common term hams use is QRN; one of the many Q-signals that hams have developed for sending in Morse code. 

In Communications Theory, it’s referred to as AWGN, Additive White Gaussian Noise, in case you come across that term.

Identifying Noise

If plain white noise was all you heard, you’d really have few problems.  White noise has been studied to death and it’s a rare (very bare bones) receiver that doesn’t have a noise blanker and often a noise reducer (NB and NR), although their effectiveness can vary.  The real world is full of noise sources of all sorts.  Ignition systems in passing cars produce a ticking or clicking sound, impulse noise, when every spark plug fires.  Switching power supplies, which are built into every LED bulb and many “wall wart” chargers for phones and other things, produce a broad spectrum of single tone-like spikes through the HF spectrum (some work at higher frequencies).  Distant lightning strikes cause impulse noise.  Electric fences make noise.  Many power tools and household appliances make noise; welders make especially bad noise.  Grow lights, fluorescent lights, appliances like air conditioners or refrigerators, solar panel systems (the DC-AC inverters), aquarium heaters, electric light dimmers and more.

I’ve noticed in my (relatively limited) time on the 80 meter band that I hear thunderstorms when cold fronts are a couple of days away as well as when they’re almost here.  From here, when there’s a cold front over the southeast US, from say Louisiana stretching over Alabama and northern Georgia to North and South Carolina, I hear those storms.  Then I don’t hear them as the front gets closer, but then hear them again when the front is close.  80 and 40 meters are worse than higher bands for storm noise.  The ability to hear storms both near and far is a bug, not a feature and makes those bands much less usable during the summer months.

This is just barely scratching the surface, and it might give the mistaken impression that these sources sound like each other.  That’s only in the broadest sense. 

One of the advantages of the modern Software Defined Radios, or radios enhanced by the addition of some DSP and software features, is that you can see the disturbances on a graphical display.  In the late ‘90s through the ‘00s, the amateur radio manufacturers started to add spectrum displays that allowed you to see the band you were operating on.  This led to people noticing odd noise patterns on screen that corresponded to noises they were hearing.  Sites like this one tried to create catalogs of what was seen and what it was coming from.  The ARRL has a very good page of pages on RF interference, noise and one similar to that first link but more encyclopedic.  Small SDRs like the RTL-SDR can be used as spectrum analyzer to help find noise issues. This pair of spectrum plots from the NK7Z site shows an 80 meter noise problem when present (left) and absent.  He's not hearing that low signal on the right while that noise is there, especially if it moves in frequency (as many types of noise do).

Coping with noise

Noise blankers are generally circuits that remove noise spikes like ignition noise rather than more broadband noise like white noise.  Sources like ignition noise, distant lightning strikes, electric fences, and a ton of other things.

Because white noise is random and full spectrum, it can be reduced by simply averaging the audio.  Over the time periods of most modulation, the noise changes many times while the audio doesn’t.  You might see this referred to as correlation filtering in Digital Signal Processing; the algorithm keeps correlated samples like voice and throws out uncorrelated sounds like noise.

Tracking down the source of noise problems can be rough, but there are many example stories you can find online.  If you have a rotatable antenna, you can sometimes tell which direction the noise is coming from, but if it’s not coming from something like a utility box you can report, that’s unlikely to do you much good.  If you point the antenna toward a neighbor and realize you’re hearing them welding or working on a street rod, you’ll probably have to work around that, using the radio when they’re not working.  Sorry, but I know of no way to get rid of all of that noise.

In the best case, you can find it’s coming from something in your house, or that you have control over.  Noise from most electrical things can be dealt with by some combination of putting the wiring through ferrite cores or wrapping the wiring around a larger ferrite toroid and possibly capacitors to ground.  In other words, filtering.  Sometimes it requires a few filters to suppress the noise sufficiently.

If you have the ability to reposition your antenna, that’s always a good thing to try.  Say you stretch out a random wire in your yard and you regularly hear a lot of noise, see if you can move that end so that’s not pointing in the same direction.  Pointing it 90 degrees away should make a big difference if that’s where the noise comes from.  A particularly bad place for an antenna is in your attic or very close to it because attics frequently have a power lines in them and they can carry noise from elsewhere.  Sometimes small position changes can make all the difference.  I realize that applies to lots of people who can’t put up an outside antenna due to a landlord’s approval or a Home Owner’s Association.  A truth that no HOAs or city zoning boards seem to understand is that an antenna causes less hazard to people and their electronics when the antenna is mounted higher and therefore farther from those things.

If your rig is anything other than the lowest entry-level HF radios, it probably has an adjustable Noise Blanker and Noise Reducer function.  Even my $25 RTL-SDR has that, in the SDR# (SDR Sharp) software that runs it.  Many people ask about leaving NR and NB on all the time.  In general, that’s not a problem.  I think Noise Reduction is less likely to be a problem.  It’s possible that leaving a hardware-based NB on all the time can actually create more noise if you set it too high.  This is an excellent video showing the effects of both of the NB and NR in action on a relatively high-end ham transceiver, the Icom IC-7610.  There are similar demonstrations with the IC-7300 which is more of an entry-level transceiver and is said to have the same software.

The more modern radios will also have things like an automatic DSP filter intended to eliminate the sound of someone tuning up, but will also work on noise sources that produce a fixed frequency (heterodyne) tone.  These operate opposite to the way the Noise Reducers work; they’re correlation cancelers not enhancers.  They’re fine on SSB voice and some can eliminate several stations tuning up at the same time.  On CW, they have to be tuned a bit more manually, since if they eliminated all of the single carriers, they’d eliminate the station you’re talking to, as well.

Saturday, May 8, 2021

BATFE Does Friday Drop on Proposed “Ghost Gun” Rules

In keeping with the longstanding tradition of releasing heinous laws late on Friday, when the press has gone home (as if they'd report it anymore), the BATFE announced NPRM 2021R-05, called "Definition of a "Frame and Receiver" and Identification of Firearms."  Except the NSSF Ammoland News did report on the rule drop.  BATFE says the rules
  • Provide new definitions of “firearm frame or receiver” and “frame or receiver”
  • Amend the definition of:
    • “firearm” to clarify when a firearm parts kit is considered a “firearm,” and
    • “gunsmith” to clarify the meaning of that term and to explain that gunsmiths may be licensed solely to mark firearms for unlicensed persons.
  • Provide definitions for:
    • “complete weapon,”
    • “complete muffler or silencer device,”
    • “privately made firearm (PMF),” and
    • “readily” for purposes of clarity given advancements in firearms technology.
  • Provide a definition of “importer’s or manufacturer’s serial number”
  • Provide a deadline for marking firearms manufactured.
  • Clarify marking requirements for firearm mufflers and silencers.
  • Amend the format for records of manufacture/acquisition and disposition by manufacturers and importers.
  • Amend the time period records must be retained at the licensed premises.
I can give you the short answer to any bullet point that refers to definitions: it's whatever we say it is. 

More seriously, I think the rules are arbitrary and don't really define the things they claim to define.  They clarify nothing.  They're saying, more than ever, "whatever we say is a firearm is" and "whatever we say is readily converted is." 
“More than one externally visible part may house or hold a fire control component on a particular firearm, such as with a split or modular frame or receiver. Under these circumstances, ATF may determine whether a specific part or parts of the weapon is the frame or receiver, which may include an internal frame or chassis at least partially exposed to the exterior to allow identification.”
Got that? Any and all parts visible from the outside of the gun which may "house or hold" a fire control component is a gun.  ATF alone may determine whether any part or parts of the weapon may be frame or receiver, and the only thing they seem to say is not a frame or receiver is something only visible by disassembling the gun.  The direct reference to a "split or modular frame or receiver" is apparently trying to fix the problem that their definition of a receiver has been ruled by judges as not applying to an AR-15.  This opens the door to them declaring that AR upper receivers are guns and require a background check.  Which further opens the door to one upper and one lower being associated with each other and You Shall Not swap different uppers onto your lower receiver.  You must buy both. 

Note that in the webpage description on the ATF web page, there is no definition provided for the statement above: “readily” for purposes of clarity given advancements in firearms technology.  The previously discussed version of "readily" included eight hours work in a well-equipped machine shop, which is beyond absurd.  That means blocks of aluminum bar stock are readily converted guns.  I can't see how that could stand a challenge.  In searching the text of the regulations (pdf here), I see no definition of "readily be converted" or "readily be completed."  It's all just jargon that reduces to "when we say it is."  On page 108 of 115 there is a list of eight things that go into consideration of "readily" but offers no clues to what they consider readily or not readily.  

I understand that they want it to be loosely worded enough that they have the ultimate power of life or death over anyone who wants to make their own guns, but being that loose - just creating the term without defining it precisely - is just wrong.  This is the way it has always been, and their line about clarifying the term is bullshit.

The fine folks at 80% arms list this 0% AR-15 lower receiver - I'm guessing that's done as a joke.  That said, at $28.99 (today) they're cheaper than Online Metals, who sells to us low quantity buyers. 

Friday, May 7, 2021

Musk: “Might try to refly SN15 soon”

After becoming the first Starship prototype to survive its flight and landing, CEO Elon Musk delivered that message about SN15 in a tweet today.  

SpaceX has had a couple of days to go over the data from the mission, and the booster was moved some today, although not onto one of the test stands.  It's just standing there.  


Yesterday, SN15 was behind that nose cone test fixture just to its left.  The move was fast, as in a few minutes, and didn't involve a crane lifting it.  It's behind a different stand now, and farther back than it looks.

This morning, the Lab Padre guys got to get a bit closer than their robotic cameras and took this one.  If you look carefully, you can see a missing thermal tile on the lower left corner, near the left edge of the vehicle.  Also, the small patch of tiles a bit lower and in the middle of the body is missing a few. 

Since Starship is all about reusability, the idea of flying it again is compelling.  I balance that against the fact that SN16 is apparently done and could be moved to the pad at any time.  

Thursday, May 6, 2021

Getting NASA Out of the 'Getting There' Business

If there's one major positive of the development of private industry spaceflight, it's that NASA is starting to swing their emphasis from the "how" of getting to the places they're interested in over to the mission, the "what to do once we're there" side.  The unmanned side has long been focused on the missions, what the probe was going to do and how it was going to do it, now the idea is spreading to the manned side.  It's one thing to talk about going to the Moon and Mars, which is all they've done for the last 20 years, it's another thing to work on what the missions should be.  Now that manned flight is becoming a commodity, what should those astronauts do?  What should the Artemis program do, besides ensuring they land the first "left-handed midget lesbian" on the moon (thanks to commenter TwoDogs)?

Eric Berger, the space guy at Ars Technica, posted a good, thoughtful look at the subject this week
"It's very exciting that we're starting to lay in the foundations for these key capabilities," said Kathy Lueders, the engineer who leads human exploration for NASA. "This isn't a dream anymore. We've got very, very concrete steps."
Although it's currently only SpaceX providing that launch services, Boeing is still in the midst of trying to qualify their Starliner capsule, and NASA has said they think the more providers the better.  The most recent date for the next Starliner test flight that I can find is "next fall."  Like SpaceX went through, the first mission will be unmanned and once the capsule - and the software that almost lost it on their first flight - are approved, a manned test flight will follow.  That looks to be in early 2022.  Also likely to be in early '22 is the first unmanned flight of the SLS and Orion spacecraft.  NASA has spent a decade and tens of billions of dollars developing those two systems. 

Here's where it gets fascinating.  Extensive quote from Ars Technica (bold added):
NASA selected SpaceX for its Human Landing System contract on April 16, awarding the company $2.89 billion for Starship development costs, one uncrewed demonstration test, and one crewed landing as early as 2024. This seems like a remarkable value.

Three days later, NASA's inspector general released a report that included the cost of the Human Landing System for NASA through this first landing. The report estimated that NASA would spend $17.3 billion for lander development and the first human landing. So with its fixed-price award to SpaceX, NASA saved more than $14 billion in its projected costs for the Artemis landing. Effectively, this means that NASA could squeeze a Moon program into its existing budget rather than needing billions of dollars more in annual budgets from Congress.

This cost savings is but one potential benefit of Starship. The other is an unparalleled capability to deliver cargo to the Moon. After refueling in low Earth orbit, a fully reusable Starship carrying cargo only—meaning it flies to the Moon, unloads its payload, and returns to Earth—could carry more than 50 tons to the lunar surface, according to estimates by physicist Casey Handmer. An expendable Starship, which lands on the Moon and stays, could bring more than 200 tons to the Moon.

Two hundred tons! If it's difficult to conceptualize how much cargo this is, consider the lunar module used by the Apollo Program. In a "truck" configuration for cargo only, it was estimated that this vehicle could bring about 5 tons down to the lunar surface. So Starship would have the capacity to bring more than 40 times as much material down to the Moon, per mission.

The other way of stating that comparison is that in the peak of the Apollo days, it would have taken 40 Saturn V rockets to put the same payload on the moon as one Starship.

It goes without saying that the "fully operational Starship" doesn't exist; neither does the on-orbit refueling that Casey Handmer figured into the numbers that gave 200 tons to the lunar surface (and that NASA is working with SpaceX to implement).  Naturally, that entails risk.  The counterpoint to that observation is that Starship is so far ahead of anything else that even if it misses some of that 200 tons, say it delivers 150 tons, it's still far beyond anything that mission planners have dreamt of having. 

The key to colonizing the moon is much like the keys to colonizing Antarctica.  Most importantly, a supply chain that can bring tons and operate on a routine schedule. 
If SpaceX's Starship program delivers on its promises, NASA would no longer have to consider brief forays on the Moon but could build bona fide cities and allow commercial activity to thrive. Thales Alenia could build large, pressurized domes for habitats. Nokia could build its LTE/4G network on the Moon. We could have mining, manufacturing, space tourism, and so much more. The cost of getting people and materials to the Moon has always been the limiting factor for any of these ventures to take place.
The other advantage to NASA is that they're supposed to be developing technologies for space exploration, and then passing them off to the private sector.  There are desperately needed technologies for life on a hostile planet and NASA has actually created research groups to investigate these.  Marshall Spaceflight Center in Huntsville, AL has an Environmental Control and Life Support System (ECLSS) —that specializes in regenerative life support.  If humans are serious about living on the Moon, surviving six-month journeys to Mars, or settling on the surface of Mars itself, we're going to need to learn to live off the land. Recycling air and water, solving waste issues, and more are essential to that.  Perhaps Marshall could focus less on getting us there and more on keeping us alive once we've made it.

SpaceX graphic.

Wednesday, May 5, 2021

Starship SN15 Flies, Sticks The Landing and Still Standing

This afternoon at 5:24 PM CDT, Starship Prototype SN15 lifted off its test stand into the cloudy skies above Boca Chica, Texas.  Visibility was poor for the entire flight and the normally reliable downlink from the Starship wasn't.  As has always been the case, the flight lasted a few seconds more than six minutes and at 5:30 SN15 landed gracefully and smoothly.

Photo by Jack Beyer, (as you can read).

You will note that SN15 has two Raptor engines firing; SN10, the only prototype to land until today, landed with one engine.  It landed hard, with obvious damage to some of the legs, resulting in an equally obvious tilt.  It exploded 10 minutes after landing.

Screen capture from NASA video

Within the first few seconds after landing, we saw a fire on the concrete at the bottom of the Starship.  Unlike SN10, the fire didn't seem to be under the skirt, and the landing pad area fire control system started drowning the area in water, eventually putting out the fire.  It was probably a minute or two, but seemed like more. 

SpaceX ordinarily covers these launches at their own website, but it didn't show up for me until after the flight.  Their video isn't that good, it's relying on the same downlink after all, but can be seen here on YouTube, queued up to T-30 seconds before the launch.  SpaceX tends to take those down on their website when another mission takes place, while the YouTube video will be there until SpaceX takes it down.

This is a big day for SpaceX, and even for NASA, who now intends to rely on a close sibling of this vehicle to return to the moon by 2024.  There's more to learn, and I suspect the Raptor engines will be closely examined, perhaps sent to their static testing facility to learn more.  Starships are intended to be extremely reusable, more like airplanes than spacecraft; every flight that successfully lands is a step closer to that goal.  SN16 is either 100% done or close to it over in the shipyard so expect it to be on the test stand, probably within a week. 

It's also a big day for the millions of us who think that not only are spaceships supposed to land standing up and be used over, but they're supposed to be shiny metal, too.

Today happens to be the 60th anniversary of Alan Shepard's first suborbital flight in his Mercury capsule, and America's first manned spaceflight.  All things considered, a bigger anniversary to be noted on this day.

Tuesday, May 4, 2021

Bank of America Says "Transitory Hyperinflation" Is Coming

Zero Hedge had the story this morning that ought to send chills up all of our spines.  The setting is that the Bank of America has earnings calls with many businesses they work with (as you'd expect), and they note the number of mentions of "concerns about inflation" they hear mentioned.  In their first calls in the previous two weeks, the number of mentions of concerns was up 400% year-over-year (YoY).  That was more than triple the YoY per company so far, the and the biggest jump since BofA started keeping records in 2004.  This week they needed an even bigger chart.  The YoY increase in mentions of "concerns about inflation" reached 800% YoY shattering the week-old record. 

BoA issued an oddly-worded message in a report, which ZeroHedge presented and I'll repeat:

What exactly does transitory hyperinflation mean?  Haven't all episodes of hyperinflation been transitory?  Weimar Republic, Zimbabwe, currently Venezuela... Countries undergoing hyperinflation either restructure their economies (usually several times) to end it, go to war, or they collapse (or some combination of those) right?  In the broader sense, isn't everything that happens in the world transitory?  

I find this an interesting time to post this due to the posts this past weekend by both Bayou Renaissance Man and Area Ocho about inflation showing up everywhere now.  I did a post about inflation being here on April 2nd (although my intent was to ridicule Modern Monetary Theory) and included a graphic from Reddit with a summary of inflation numbers. 

There's advice for dealing with inflation virtually everywhere.  If there's something you need and you believe your income prospects are not likely to be destroyed, it's cheaper now than it will be next week, next month or next year.  Yes, that means stockpile food and supplies while you can.  Yes, that argues to buy anything now, something which can act to further push up prices (not to mention that I don't want to start another run on toilet paper, or any sort of food).  Back in the raging inflation of the '70s, when the dollar was in free fall due to getting off the gold standard for good, it was pretty commonly said that if you needed something you might finance, like a car, not only would the car be more expensive soon, but you'd be paying it off with dollars that were worth less to you if your job held up.  (Many of us remember getting the maximum raises our employers would pay for years in the '70s).  

Is this the final push to destroy the US or just the idiocy of virtually doubling Federal Spending and going to extremely deep deficits?  Maybe it's just that the economics of the last four thousand years are more right and Modern Monetary Theory is going to cause a total collapse?  Got me.  From the practical standpoint it just doesn't matter very much.

Just keep an eye out, keep your head on a swivel, and be careful.

Monday, May 3, 2021

NASA Sued Over Awarding Human Landing System Contract to SpaceX

Stop me if you've heard this kind of story about government contracts.  Last Monday, it was announced that Blue Origin was filing a suit against NASA for awarding the Human Landing System contract exclusively to SpaceX.  Seemingly within moments, the other competitor in the three-way decision, Dynetics also announced a lawsuit for not being chosen to develop the HLS. Elon Musk's response on Twitter was quintessentially Elon Musk. 

There are times I think some 13 year old boys are running the engineering at Tesla and SpaceX.  This fits that idea.  On the other hand, he's right.  Neither Blue Origin or Dynetics has launched anything to orbit.  Dynetics is relying totally on subcontractors; Blue Origin is supposedly doing it themselves, with the New Glenn, the only rocket currently able to compete with the Space Launch System for the coveted "Most Delayed" award.

In the world of big government contracts, such suits seem to have become the norm in the last 20 years; maybe farther back.  I've been in companies that get the contract and then have to holdup starting work until the legal actions are resolved. 
That means that NASA is now legally unable to use funds or resources related to its Human Lander System (HLS) program or the $2.9 billion contract it awarded SpaceX on April 16th to develop a variant of Starship to return humanity to the Moon. However, just like SpaceX has already spent a great deal of its own time and money on Starship development and – more recently – a rapid-fire series of launches, the company appears to have no intention of letting sore losers hamper its rocket factory or test campaign.
Don't get me wrong; it's good in principle for the competitors to be able to verify that the contract was awarded in keeping with the rules everyone was working to.  Further, I think the tendency for these contract awards to generate these protest lawsuits is a nature of the relentless push of companies to look good in this quarter's bottom line; after all, since we pay executives in stock options and other things to avoid the "millionaire's tax", it's only a natural (perhaps unintended) consequence that they would seek to optimize the stock options.  The government contracts are so big that they mean lots to the survival of all of the companies.  Eric Ralph at Teslarati notes:
The primary argument is generally shared by both protestors. In essence, Dynetics [p. 23; PDF] and Blue Origin [PDF] believe that it was unfair or improper for NASA to select just a single provider from the three companies or groups that competed. They argue that downselecting to one provider in lieu of budget shortfalls changed the procurement process and competition so much that NASA should have effectively called it quits and restarted the entire five-month process. Blue Origin and Dynetics also both imply that they were somehow blindsided by NASA’s concerns about a Congressional funding shortfall.
Blindsided?  They can't be stupid enough to not know that funding shortfalls are likely in a program that isn't climate change or New Green Deal-related.  At the time of the award, I recall posting that NASA said it needed $3.3 billion in funding for this fiscal year to meet the goal of landing humans on the Moon by 2024. Congress provided just $850 million, and as a result, NASA acknowledged that 2024 was no longer a realistic target.  They would have rather had more than one contractor but couldn't do it on just over 25% of what they needed. 

A commenter over on Teslarati's article posted this visual (actually three or four commenters did):

Left to right, SpaceX, Dynetics, Blue Origin.  The lander on the left was bid at $3 Billion less than the cheaper of the other two. 

Things that make you go, "hmmm."

It might be worth quoting Eric Berger (from Ars Technica) who tweeted, "I’ve been told that Jeff Bezos is livid about this, and views overturning the HLS award as a top priority for Blue Origin."  It kind of feeds the story being circulated that Jeff Bezos has a personal grudge against or rivalry going with Elon Musk. 

Sunday, May 2, 2021

A Ham Radio Series 25 – An RF Safety Worksheet

In last week’s post on RF safety,  I mentioned a worksheet that the ARRL provides to help you determine your RF exposure. I thought it would be useful to show the evaluation of my station on one band.  

The worksheet dedicates one page (A) to determining the power at your antenna by looking up the cable you’re using and determining its loss.  As I’ve said before, with a 100 W antenna and some unavoidable losses between the radio and the antenna, the 24.9 MHz (or 12 meter) band is the first place many of us will need to determine exposures.  My antenna is a Log Periodic Dipole Array (often sarcastically referred to as, “an antenna that operates poorly over a wide range of frequencies”) with minimal – but some – antenna gain on 12m.  My cable is RG-213/U, a more recent version of the RG-8/U cables that hams have been using for decades.  Here’s what worksheet A looks like for my station:  

There’s a couple of calculations in there that might be things you don’t think of.  

First, how do I know the loss?  Because RG-213/U is a well established standard cable, I find a datasheet from a reputable manufacturer and find the table of losses vs. frequency they provide.

You can see that they list attenuation at 10 MHz and 50 MHz, not at the 25 MHz I need.  Time for some linear interpolation.

Given those numbers I’ll round up to 0.6 dB loss at 10 MHz and use 1.3 dB at 50, I’ll solve for the slope assuming it’s a straight line between those points, which is going to be close. 

Slope = (1.3 – 0.6) / ( 50-10), which gives and answer of 0.0175 dB/MHz.  That means the loss is that much more 15 MHz higher than the 0.6 dB insertion loss.  That’s found by multiplying 

Loss at 25 MHz = 0.6 + .0175* 15 or 0.863 dB.  

I’ll round that to 0.86 dB.  Notice that the numbers we used to start (1.3 and 0.6 dB) are per hundred feet.  Since my coax is 50 feet, the loss is 0.43 dB. 

Now how to I turn that loss into percentage?  I’m guessing that’s probably a new thing to people.  Remember a dB is a power ratio, where
dB = 10*log (ratio)
is the value in dB and log denotes the base 10 logarithm.  We want to find the ratio that gives a loss: loss means negative dB.  It’s -0.43 dB not +0.43.
(-.43) = 10 log (ratio), so 
(-.43/10) = log (ratio)
10^(-.43/10) = ratio = 0.906 or 90.6% of the power remains.  

Out of 100 Watts, 90.6% or 90.6 W makes it to the antenna.  Note that in step J, they want to solve for the number of watts lost.  That’s (1-.906) or 0.094 times 100 or 9.4 W lost.  

Worksheet B takes this process almost to its conclusion.  It multiplies the powers found at the end of A and then leaves you to find a few more details. 

The Duty Factor is based on recommendations from the ARRL RF Safety page.  It considers digital modes as the worst case, and my mental model for this page is operating the FT8 mode, which has taken the ham radio world by storm.  

This sheet shows my 100% duty factor and 50% transmit time (built into FT8) means I deliver 45.3 W average to the antenna.  By the first table (in the last article) we can see that evaluation is required on 12m if I deliver 75W to the antenna, and I’m delivering 45.3W.  The harder question is in the second table in that post, which has required distances for people to be from the antenna, depending on antenna gain.   

The manufacturer’s website for my antenna has one number for gain, 7.24 dBi.  That’s between the 6 and 9 dB gain entries and the numbers shown are for the number of meters from the antenna people should be excluded.  The right column is for uncontrolled (general population) exposure, the one we should be using for this.  The worst case would be going to the next higher gain and saying people should be 7.5 meters from the antenna or 24.6 feet.  The antenna is at 20 feet above ground, so a 6’ tall person would have to be 20.2 feet from the front of the antenna.  Since that’s inside the fence on my property, I believe that keeps uncontrolled exposure below the limits. 

Antenna gain is a concern of mine because it doesn't mean what people tend to think it means when dealing with powers.  I've seen this misconception with professionals, so I'm sensitive to it.  Antenna gain doesn't mean that if I put 100 Watts into an antenna with a gain of 6 dB (4 times) that I'm getting 400 watts out.  That's impossible.  If I put 100 Watts in, I get 100 watts out.  What antenna gain means is that one antenna puts more power in some direction than another reference antenna, and it does that by taking power from all the other directions and putting it where the antenna is pointed.  That last table looks suspiciously like they're saying there's more power out of the antenna, but there isn't.  It's stronger in one direction, compared to another antenna but that's all.  I'll cut them some slack because this is work in the extreme near field of the antennas and that's absurdly complex to model. 

Saturday, May 1, 2021

The War on Meat

While it turns out that the widely reported story that the latest Biden "infrastructure" bill had provisions to limit beef consumption to a few ounces a month was a fake news story tracked to the UK Daily Mail, that's a minor distraction.  There really is an all out war on eating meat, especially beef, which is grounded in nothing but pseudoscience and propagated rumor.  It has been going on for years and if you're like most people, you've probably have heard some of the arguments so long you tend to think they're true. 

We've covered some of this sort of stuff here.  Junk science is a pet peeve of mine and you'll hardly find an area of science more filled with junk than diet recommendations.  I'll link to this piece because it carries a great table of spurious correlations of the kind that show up in what I've called "he-who" studies:  "he who eats (or does) X is more likely to get Y;" that sort of thing.  There's a great deal of desire on the part of many people to know what they should eat.  Simply saying, "eat what your grandparents ate, not industrial foods" which is honestly as a good a recommendation as anything, doesn't get accepted well.  The alternative, real, randomized controlled experiments that would last for decades, is prohibitively expensive, hard to do, and nobody wants to wait.  As we noted while going through my wife's cancer 24 years ago, it takes five years to get five year survival data; extrapolate that to it takes a lifetime to get life extension data. 

The rest of the world does appear to want to institute a carbon tax on meat because of grossly exaggerated figures on the amount of impact animal farming has on methane production.  First off, the methane from cows is 1.8% of the greenhouse gas emissions in the US.  Second off, methane doesn't come from cattle farts, it comes from cattle burps.  I realize that might be a minor distinction, but the EPA, those high priests of junk science, jumped on the "regulate cattle farts" bandwagon under Obama.  The UN claims cattle create 18% of global greenhouse gas emissions - more than comes from transportation - but they're lumping in all livestock, not just cattle, to include poultry, lamb and all sources of meat.  They're also including the effects of animal feed production, feed harvesting, feeding the animals, the farm vehicles that tend to these animals and everything up to the emissions from the slaughterhouse.  A third of that 18% is blamed on deforestation specifically in Brazil.

Both of those summaries are dishonest.  First, it's not fair to blame methane production in chicken farming on cattle farming, and it's unfair to include everything that the goes into food production to just the tailpipe emissions of vehicles rather than the equivalent entire life cycle associated with transportation.  Second, the part about deforestation is dishonest for two reasons; the easiest being that there's no equivalent deforestation in the US, or in other parts of the world.  In the US the story is reforestation.  We have more trees today than a hundred years ago.  The other reason is that not all grassland could be forest and not all forest can convert to grasslands.  There is some relation between the two, but it's not simple subtraction.  Simply, much of the planet can't be dense forest and can only be grassland. 

Chances are, you've heard until you're subconsciously convinced that low fat foods are healthier.  That data was always suspect, but that cynical observation applies that says old science theories don't go away because the weight of evidence pushes them aside; they go away because old scientists who support them die off.  Since about 2000 there have been many good quality meta-analyses of all the studies that have been done before and concluded the evidence is just too weak to matter.  The diet-heart hypothesis that lifetimes of eating fatty foods and having elevated cholesterol levels led to heart attacks has had conflicting data, like that in older adults higher LDL is associated with longer life, long enough for studies to have essentially concluded the diet-heart hypothesis is dead. 

What about vegetarianism?  It's another belief that has far more faith behind it than evidence.  Seven years ago, I ran a review on a book I'd read by health writer Denise Minger, called "Death by Food Pyramid."  Denise was a 17 year old who had thought she should become a raw food vegan but was unaware of the constant effort required to not destroy her health.  Vitamin B12, for example, just doesn't come in plant matter, at least not to any level that eliminates the need for supplementation.  In Denise's case, she simply needed 17 teeth fixed.  At 17, she went to the dentist and after way too many disconcerting "hmm" sounds, heavy sighs, and pokes with pointy metal objects, found she needed to have 17 teeth worked on - coming from never having had dental problems before she became a vegetarian.  In the space of one year. 

In all of these struggles over diet, we have the same conflicts of interest of special interests that we've had with the Covid fiasco.  Everyone pushes to get their favorite industries pushed by the USDA Dietary Guidelines.  The vegetarian movement is largely pushed by the Seventh Day Adventist church, and some influential doctors they've won over to their side, like Dean Ornish, a diet book author and M.D., and Walter Willet, the very influential head of Harvard's School of Public Health.  The lowfat crowd is pushed by the grain and cereal industry.  The push to get people to eat less meat and saturated fat is pushed by the vegetable seed oil industry, which may well be the absolutely worst things in our processed foods. 

Someone who has spent the last several years fighting to get the USDA Dietary Guidelines fixed is Nina Teicholz, who went from being a low-fat, vegetarian food writer to an omnivore heading the Nutrition Coalition, an organization trying to get the dietary guidelines to more honestly assess science that has been pouring in within the last 20 years.  This an hour long, but very worthwhile talk on many of these topics. 

At the risk of overstating the obvious, If a Government Committee Recommends Something, Do The Opposite, as I said here.  If they tell you to limit red meat, maybe you should eat more of it.

Friday, April 30, 2021

Sometime in the Next Year

Everybody knows the story behind the attempt at humor.  It prompted a long research project by Mrs. Graybeard into whether "those" is the proper word or whether it should be "are they menthols?"  And a nearly half hour long attempt on my part to remove the apostrophe in "menthol's."  It's not referring to something in the possessive.  It's not the menthol's cigarettes.  

Thursday, April 29, 2021

SLS Core Stage Now In the VAB on the Kennedy Space Center

The SLS core stage was shipped (literally, by barge) from the Stennis Space Center to the Kennedy Space Center here in Florida this week.  The barge arrived in Florida on the 27th, traveling to the turning basin in front of the Vehicle Assembly Building.  Transfer to inside the VAB was accomplished this afternoon.  At this point, it's now being referred to as the core of Artemis 1: the first, unmanned mission the SLS will fly.   

Teams from the center’s Exploration Ground Systems and contractor Jacobs will perform checkouts ahead of integrating the massive rocket stage with the twin solid rocket boosters, Orion spacecraft, and additional flight hardware ahead of the Artemis I launch.

Artemis I will be the first integrated test of SLS and Orion and will pave the way for landing the first woman and first person of color on the lunar surface. It will be a proving ground for deep space exploration, leading the agency’s efforts under the Artemis program for a sustainable presence on the Moon and preparing for human missions to Mars.
As you would imagine, it's not exactly a trivial exercise to handle something massively heavy yet fragile to loads it wasn't designed for, but that's coming very soon as they need to transfer the core stage to a vertical position for the beginning of the integration process.

The twin solid rocket boosters are completely stacked; that was completed in early March.  Despite their similar appearance to the Space Shuttle Solid Rocket Boosters, they're reported to be the largest and most powerful solid rockets ever made.  Each booster produces 3.6 million pounds of thrust.  An important detail to point out is that, like the Shuttle, those SRBs will support the entire weight of the core stage and everything that's mounted to it.

John Honeycutt, the SLS program manager, said, “with the delivery of the SLS core stage for Artemis I, we have all the parts of the rocket at Kennedy for the first Artemis mission.”  NASA is still aiming for a launch before the end of the year, although they'll openly say that's “challenging.”  The original date published was this coming November, but that was before the test window at Stennis ballooned up to nine months.  To have the schedule hammered that badly and not move the launch date out by more than a month would be truly remarkable.  FWIW, I think this goes beyond challenging all the way to improbable.  I wish them luck but I'd be really surprised if this isn't delayed until well into '22.  I think a three month delay into late February/early March would still be remarkably good.

I can't let this column go without noting that part of the quote above made my skin crawl and filled me with dread.  “Artemis I will .... pave the way for landing the first woman and first person of color on the lunar surface.”  So the goal of the Artemis program is to send identity politics into the universe?  If there's anything about humanity that deserves to die off on earth and not spread it's identity politics.  It was bad enough when they said Artemis was to land the first woman and the next man on the moon, but that's apparently too mild today. 

I think I've been clear that I think SLS has been a horrendously bad waste of money.  The decision to kill a program after so much has been spent on it is a tough one for a politician to make.  They're subject to the sunk cost fallacy over things like this.  They have to admit they threw away billions on something like SLS and never got anything for it.  

Wednesday, April 28, 2021

Farewell and RIP Michael Collins

Since I ran across this meme a couple of years ago, it has come up whenever references to Michael Collins, pilot of the Apollo 11 Command Module, as being the "loneliest man in history" come up.  I think it's sobering to add three words to the meme.  "Michael Collins is the only human, living or dead, in human history not contained in the frame of this picture."

We learned that Michael Collins died earlier today after battling cancer.  He was 90 years old.  

"He spent his final days peacefully, with his family by his side," the family said in a statement. "Mike always faced the challenges of life with grace and humility, and faced this, his final challenge, in the same way. We will miss him terribly."

With Collins' death, only 10 of the 24 humans who have flown into deep space remain alive: Collins' colleague on the Apollo 11 mission, Buzz Aldrin, as well as Bill Anders, Frank Borman, Charlie Duke, Fred Haise, Jim Lovell, Ken Mattingly, Harrison Schmitt, David Scott, and Tom Stafford.

Eric Berger, space columnist at Ars Technica, has a good biography posted.  After some details of his time in NASA, he concludes this way.

After this historic flight, Armstrong became famous as the first human to walk on the Moon. He bore it with dignity and quietly retreated from public life to work as a professor at the University of Cincinnati. He died in 2012 at the age of 82. Aldrin has lived a more public life, battling alcoholism but emerging as a cultural hero and living icon of the Moon program.

By contrast, Collins went on to a career of service, working as director of the National Air and Space Museum as well as other positions. He was a sober and intellectual figure after the Moon landing and was the poet of the mission, writing perhaps the finest astronaut autobiography of the Apollo age, Carrying the Fire: An Astronaut's Journeys. For anyone interested in a true accounting of what life was like as an astronaut (and watching two friends go down to the Moon), this book is essential reading.

Collins retired as an astronaut after the Apollo 11 mission and, in doing so, turned down a chance to go down to the lunar surface himself. According to Slayton, Collins was his first choice to serve as commander of Apollo 17, which would become the final mission to the Moon. This was even before the launch of Apollo 11. Collins replied by thanking Slayton for the offer but said he had grown tired of the grind, and if Apollo 11 went well he was planning to step aside. Collins has now finally found a deserved and eternal rest.

In 1994, Mrs. Graybeard was working as a technician on the Space Shuttle Solid Rocket Boosters up on the Cape, and I was working for Southeast Area Defense Contractor doing radio design.  When July approached, the KSC announced there would be a celebration of the 25th anniversary of Apollo 11, and all three astronauts would be there.  Families were invited.  Somewhere around here I have some photographs I took of Armstrong, Aldrin and Collins.  Of course, we just watched from the crowd, which included some of the people who were working various jobs in support of Apollo 11.   

When I was younger, I used to wonder how Collins had felt about training all his adulthood for the possibility of going to the moon, and then not landing and walking around.  Later, I came to think he was doing his job, just like Neil Armstrong and Buzz Aldin.  His job was an integral part of theirs.  True, he was closer to the moon than billions of people have ever been, he just wasn't touching it.  As Robert E. Lee famously said, “Do your duty in all things. You cannot do more, you should never wish to do less.”  First and foremost, Michael Collins was doing his duty.

Rest in peace Michael Collins.  The world is a better place for you having passed this way.

Tuesday, April 27, 2021

After Successful Static Test, Elon Says SN15 to Launch “Later This Week”

The headline on Teslarati was "Musk says upgraded SpaceX Starship to launch “later this week” after static fire test" which would imply that they got the results they wanted from last night's static fire.
Starship SN15 static fire completed, preparing for flight later this week
Today, Lab Padre said SpaceX had issued another over-pressure notice.  The road closure was on and off from 12 Noon to 8PM CDT and it was hard to see if they were going to do a static firing until well after 7PM Eastern.  It was 6:48:47 PM CDT and 7:48 here.  

The commentators on the channel said they had looked at different cameras carefully and are convinced this is a single Raptor firing.  The speculate the reason is that yesterday they tested all three engines with the main tanks while this evening's test was to test one engine with the header tanks.  Those are the two small tanks that hold the fuel and oxidizer for landing.  The LOX tank is at the very nose of the Starship while the methane tank is actually inside the main methane tank, much closer to the engines. 

To put it in perspective, serial numbers 8 through 11 flew between December 2020 and April 2021.  All four failed to complete the tricky maneuver of falling belly first, flipping vertically, lighting two engines and coming to a soft landing.  SN10 landed successfully, but it was a hard landing, collapsing legs.  10 minutes later one tank exploded destroying the vehicle. Lifting a good summary from Eric Ralph at Teslarati:
All four failures ultimately had different causes. Starship SN8 lost fuel tank pressure, starving its Raptors and causing a near-total loss of thrust seconds before touchdown. One of SN9’s Raptors failed to ignite for a landing burn, triggering an even more aggressive impact with the ground. Starship SN10 landed in one piece but its lone landing engine underperformed when it began to ingest helium ullage gas – a quick-fix implemented after SN8’s pressurization issue. SN11 exploded almost immediately after attempting to ignite its three engines for landing, failing even earlier than its predecessors.

All four flight tests saw each respective Starship prototypes narrowly miss a fully successful and survivable landing, providing SpaceX a great deal of data and direct experience to improve the rocket’s design and operations with. Two of the four failures – SN9 and SN11 – appear to have been the fault of one or more of Starship’s three Raptor engines. Beginning with Starship SN15, SpaceX has moved to an upgraded iteration of the next-generation engine, raising hopes that whatever changes the company has implemented will substantially improve reliability and thus the odds of a successful high-altitude launch and landing test.
What does "later this week" mean?  Weather-wise, it looks like Thursday might be the best day, by the Weather Underground forecast.  Friday looks to be cloudy all day with some thunderstorms around all day.  Thursday looks to have lower chance of rain, and clouds clearing out by the late afternoon to evening. 

Monday, April 26, 2021

Monday Got Away From Me

I started down the road on a post but it's just not writing itself.  

Six years ago, I had called Obama's EPA the High Priests of Junk Science.  Biden's EPA - or whoever is driving this driving this New Green Deal agenda is even worse.  Stuff like saying they're going to force us to eat no more than four pounds of beef a year.  I've met people who will eat four pounds in no more than two days.  Their health deteriorates if they don't.  If the administration's intent is to kill off Americans, like we just talked about, that's the only thing that makes sense.

Well, at least we got to see a static firing of SN15 this afternoon, a minute or three before 6PM EDT.

Sunday, April 25, 2021

Licensed Hams - A New Rule on May 3rd

The American Radio Relay League reminds all amateurs that in case you've missed it, the new RF exposure rules take effect on Monday, May 3rd

The FCC has announced that rule changes detailed in a lengthy 2019 Report and Order governing RF exposure standards go into effect on May 3, 2021. The new rules do not change existing RF exposure (RFE) limits but do require that stations in all services, including amateur radio, be evaluated against existing limits, unless they are exempted. For stations already in place, that evaluation must be completed by May 3, 2023. After May 3 of this year, any new station, or any existing station modified in a way that's likely to change its RFE profile - such as different antenna or placement or greater power - will need to conduct an evaluation by the date of activation or change.

I did a fairly deep dive into the requirements last May, before I had my Ham Radio Series, so they're not on that separate page, but the first part is "A Little Radio Safety Techno-Geekery", and some examples of how to go about the calculations are in the second part, "A Little More on RF Power Safety and Ham Radio."  Besides my writings, the league itself offers things to help you.

"RF Exposure and You" is available in PDF format for free download from ARRL at,
ARRL also has an RF Safety page on its website at,
The ARRL also has a worksheet that helps in the process.

Here's the odd part.  There are no instructions that this is to be filed with the FCC or anyone else.  I suppose that means you're expected to do the calculations, and keep them on file in case you're questioned at some point.  I would presume that would be if a neighbor complains you're interfering with their TV or Stereo or other form of entertainment and an investigation is started.  Thankfully, with the switch to HDTV and cable, those complaints seem to be fewer than back with analog TV.  

As the ARRL points out, the major change in the rules is that before now, hams were generally exempt from this requirement.  That exemption goes away.  

There is no preferred format stated for the analysis, but sticking with that ARRL worksheet might be a good thing. 

As a quick review, let's look at table 1 in the first of my two posts.  This shows the power at the antenna that requires analysis:

If you operate a typical, off the shelf ham transmitter/transceiver with 100 Watts output power, you don't have to address any exposure until you get to the 12m band, because there are unavoidable losses between the output of the transmitter and the antenna, and even tenths of a dB loss will get you below the 100 Watts that requires evaluation on 15m.  

The next table in that article tells you the distances (in meters) from an antenna with one of four gains where the power is expected to exceed the FCC power density limits.  Always use the "Unc." column, for uncontrolled exposure - note those are always farther away, which means lower power.  The "Con" column, controlled exposure, is for people working in the industry, expected to be more aware of the need for caution.

Note that you may reduce power by the transmit duty cycle because these are time averaged powers; the chart says 50% and without lots of effort to measure that, it isn't unrealistic.  Even "full power, full time" modes like RTTY (Radio Teletype) don't turn on the transmitter and leave it on for minutes on end.  The league says to use 40% of power for CW, 20% for SSB with no speech processing, 40% for SSB with heavy speech processing,  You should also reduce the power getting to the antenna by the loss in the transmission line to the antenna. 

If I reduce the 100W power to 85% to account for the transmission line (following the example in the second article) that leaves 85 watts at the antenna.  If I reduce that to 30% for the transmitter duty cycle, it's now at 25.5 Watts, far short of the 75 W that requires analysis by the first table.  Notice that each frequency band calculates the powers for four different antenna gains.  In the very simple cases, say your 12m antenna has 3 dB gain.  That means the distance from the antenna where the power exceeds the safety limit is 3.8 meters, or 12-1/2 feet, in the direction the antenna is pointed.  If nobody is closer than 3.8 meters from the antenna, you're good. 

That's even below the power to the antenna that requires analysis for the 10m band.  

I think that between the various resources I've linked to here, both the ARRL's handouts and my articles, you should have what you need to determine how to do the analysis for your station.  As a general approach, there's nothing wrong with making worst case assumptions.  Saying you're delivering the full 100 Watts to the antenna - or a full 100% duty cycle.  That way you know you're always delivering less power to anyone near the antenna and that they're always safer than the limits. 

Saturday, April 24, 2021

NASA's Getting What It Wanted - Independent, Reliable Access to Space

As we sit here today, the International Space Station has two American spacecraft docked to it.  The last time two manned, American, spacecraft with two separate crews were in space together was the Gemini 6 and 7 mission in 1965.  Today, the crews of the Crew 1 and Crew 2 missions are sharing the (relatively) spacious inside of the ISS. 

Today, we're three months short of the 10th anniversary of the last flight of a Space Shuttle.   NASA had to rely on the Russians for rides to the ISS; who promptly raised prices once they knew they had a captive audience.  Yesterday, SpaceX launched the Crew 2 mission at 5:49 AM local time.  It was the third manned mission that they've launched in under 11 months.  In itself, that's a healthy launch cadence, but since these missions are for months at a time on the ISS, it's likely they won't need to launch much more frequently.  I bet they could if there was a need.
"It took 10 years to get there, to achieve this bold vision for commercial crew," said NASA's acting administrator, Steve Jurczyk, during a news conference after Friday morning's launch. "It’s been amazing what the team has been able to accomplish."

The "team" is a collaboration between engineers at NASA and SpaceX that have worked to develop and certify the Crew Dragon system for human spaceflight for a fixed price of about $55 million per seat. Since 2017, NASA had been paying Russia more than $80 million for an astronaut to ride into orbit.
As I've mentioned before, I've read that back in 2014 when SpaceX was proposing reusable rockets, it was four years before they actually succeeded at recovering a rocket at sea.  NASA told them, in essence, "don't bid that; it's a pipe dream that'll never happen."  Fast forward to Friday morning and the reused Crew Dragon capsule Endeavor was launched on a reused, recovered booster.  In a moment of candor, Elon Musk showed that the progress in their reusable Falcon 9 system is surprising even him.
After the launch, SpaceX founder and Chief Engineer Elon Musk said he felt increasingly confident in the prospects of developing a reusable launch system. "It’s only recently that I feel like full and rapid reusability can be accomplished," he said. "I wasn’t sure for a long time, but I am now."

With the Falcon 9 and Crew Dragon, SpaceX has gotten mostly there. However, the Falcon 9 rocket's upper stage is expended after a launch, and the Dragon capsules undergo significant refurbishment between flights. Musk sees this launch system as an interim stage to full reuse, and SpaceX is still learning lessons. The company has already flown one of its Falcon 9 first stages nine times and will soon fly it a tenth time. The plan is to push the limits of the Falcon 9 with the company's own Starlink missions, Musk said.

"There doesn’t seem to be any obvious limits to the reusability of the vehicle," he said. "We intend to fly the Falcon 9 rocket until we see some kind of failure."
I've worked on designing radio systems for satellites before and it always amazed me to think that the level of screening, testing and documenting the parts is the most stringent of all components.  Then we'd build most rockets, use once and throw away.  I suspect that they're going to find their Falcon 9 boosters will easily exceed the 10 flight milestone.   

Changing perspective wildly, I was able to watch the launch from my back yard as usual, and we were treated to a gorgeous flight, much like the one I wrote about last June.  It looked like a typical night launch until the two stages poked above the day/night terminator at altitude, and suddenly the whole contrail started glowing a bright, light blue.  When the booster cutoff and was jettisoned, the spreading  contrail from the upper stage glowed and I immediately saw the light pulsing stronger and weaker.  Within a few seconds I realized I was seeing the booster guiding itself toward it's eventual landing using its nitrogen thrusters.  Every time the first stage fired them, a spreading arc of white radiated out of it, in whichever direction, also turning light blue.  I got to see the first entry burn, but the landing burn is below the horizon from here.  Photographer Trevor Mahlmann at Ars Technica caught several great photos. 

Here's what you're looking at.  The lowest bright spot is the second stage on the way to orbit.  The bright spot higher in the frame is the booster.  Below it are two spreading lobes of the bright reflection of its thrusters.  Farther out from booster in the upper right is the spreading arc of a slightly earlier firing of the thrusters. 

Friday, April 23, 2021

Earth Day Addendum for the Climate Change Peeps You Know

We all have those acquaintances or maybe family members that have drunk the Kool-Aid about a Climate Catastrophe. The ones who seriously believe the nonsense that it's a critical, problem and the world is going to end in 10 years or whatever we're down to.  Admittedly, most True Believers aren't going to believe what I'm going to show you.  There might, however, be people you talk with who are more data-driven and this will be like putting a pebble in their mental shoe.  They'll have to pay attention to it.

This graphic is from Dr. Roy Spencer, posted at Watts Up With That and at his own blog.  For those who don't know Dr. Spencer, here's his bio page.  What this shows is the predicted sea surface temperature trends predicted by 13 different CMIP6 climate models that were run 68 different times.  Those are plots in the various colors, behind the bolder, black line.  The black line is 42 years of measured data from the National Oceanographic and Atmospheric Administration (NOAA).  Clearly, for most of the plots, starting around 1992, the CMIP6 models dramatically over predict the temperature rise.

If you're not familiar with this sort of plot, the Y-axis is the temperature anomaly, stated as the difference between the 1979-1983 average and the measured or predicted data, plotted per year.  Dr. Spencer concludes that the real warming is half of the model predictions, but the model predictions are spread out over a wide band. The latest observation (right end of the black curve) is approximately 0.3C warmer than the 1979 start of these series, while the predictions range from one lower than the measured temperature at 0.1C to 1.5C higher. 

Dr. Spencer is a reasonable scientist, he admits there are things he doesn't know and more.
A related issue is how much the deep oceans are warming. As I have mentioned before, the (inarguable) energy imbalance associated with deep-ocean warming in recent decades is only about 1 part (less than 1 Watt per sq. m) in 300 of the natural energy flows in the climate system.

This is a very tiny energy imbalance in the climate system. We know NONE of the natural energy flows to that level of accuracy.

What that means is that global warming could be mostly natural, and we would not even know it.

I’m not claiming that is the case. I am merely pointing out the level of faith that is involved in the adjustments made to climate models, which necessarily produce warming due to increasing CO2 because those models simply assume that there is no other source of warming.
That's the big issue we're facing: the reliance on models that don't match measured data and a reluctance to actually do the work to test a model.  The data is often hard to measure and truly global.  Just what does global average temperature even mean and how can it possibly be measured with the accuracy? 

Last words to Dr. Spencer:
Why does it matter?

It matters because there is no Climate Crisis. There is no Climate Emergency.

Yes, irregular warming is occurring. Yes, it is at least partly due to human greenhouse gas emissions. But seldom are the benefits of a somewhat warmer climate system mentioned, or the benefits of more CO2 in the atmosphere (which is required for life on Earth to exist).
There's no reason to spend trillions of dollars on the climate.  That will create real suffering and buy nothing good.