Parker Solar Probe Achieves a Major Mission Goal

A video posted today by NASA's Goddard Center says that the probe has achieved one of its major program goals and actually plunged into the corona.  The area that the probe entered is considered part of the sun so this is actually plunging into the sun. 

Saying the probe "touches the sun" is a bit on the poetic side, but the probe passed into the Corona and was touched by particles some of which are going back into denser parts of the sun, so a bit poetic and a bit accurate, too.  From the video description:

The new milestone marks one major step for Parker Solar Probe and one giant leap for solar science. Just as landing on the Moon allowed scientists to understand how it was formed, touching the very stuff the Sun is made of will help scientists uncover critical information about our closest star and its influence on the solar system.

I recalled the Parker Solar Probe both from having written about it back before launch and from seeing a news item once or twice.  It was starting a long term mission that would take it successively closer to the sun on each orbit and eventually reach the highest speed any man made object has ever achieved.  

The probe will be sent on its way atop a second stage mounted on a Delta IV heavy Lifter. It will go into a fairly eccentric elliptical orbit around the sun (see figure below). It will orbit the sun 24 times, and on seven of them will make flybys of Venus to increase its speed and tighten its orbit. The last orbit around the sun will take only 88 days traveling at up to 450,000 mph.

That speed of 450,000 mph is the fastest any man made object has flown by a large margin - the previous record holders were NASA's Helios I and Helios II probes (1974 and 1976, respectively) at 157,000 mph (253,000 km/h).  Still, Parker's 450,000 mph is .00067 of the speed of light.  At that speed, the nearest stars are over 6400 years away.  Add in the fact that we have no known way to generate that speed without multiple gravitational slingshots.

It's pretty cool stuff.  There's nothing I can say that's equal to what Goddard has put up on the project web page, so if you think solar physics and astronomy is interesting, head on over. 

SpaceX Moves Booster 4 Back Onto OLM

After a lot of talk and rumors over the last few weeks about booster 4 being moved to the Orbital Launch Mount, it was moved today.  While it's easy to expect them to start doing the static testing that's a barrier to trying an orbital launch, this is the third time that booster has been on the OLM and there are no guarantees this isn't some sort of test fit that will be followed by dismounting B4 soon.  Still, Elon Musk said he hopes to do the first attempt at orbit "early in January" and that's less than three weeks away.  If they're going to make it, those tests must become high priority. 

Screen capture from Lab Padre.   As it says.

As we've said dozens of times, the first boosters will have 29 Raptor engines.  That helps make this launch pad among the most complex the world has ever seen.  If not the most complex launch mount.  Eric Ralph at Teslarati supplies some details.

... By all appearances, Super Heavy hold-down clamps – mechanical devices designed to hold the booster to its work stand or keep it immobile on the launch mount during a variety of test – work by reaching inside the lip of the booster’s aft ‘skirt,’ which sports a very sturdy ring of steel that 20 Raptor Boost engines mount to and push against. The 20 clamps fit precisely between each of those 20 outer Raptors and grab onto Super Heavy from the inside.

Just before liftoff, all 20 hold-down clamps will rapidly retract back into the orbital launch mount. So will another 20 small quick-disconnect umbilical panels designed to supply every single Raptor Boost engine with the gases they need to ignite. The primary booster quick-disconnect – which connects Super Heavy to power, communications, and propellant supplies – will also retract into a hooded enclosure at some point during the process. Finally, a giant, swinging arm located about halfway up Starbase’s ‘launch tower’ will retract a similar quick-disconnect panel for Starship fueling, retract two claw-like support arms, and swing back for liftoff.

Eric goes on to say that there are probably even more than those just described.  Every Starship launch will require at least 44 separate devices to actuate in rapid and precise succession – 41 for Super Heavy and at least 3 for Starship.  It's my impression that a lot of this hardware was borne out of the idea that was first talked about earlier this year: to move as much infrastructure as possible out of the vehicle and onto what Elon called, "Stage Zero" - the OLM.  All in an effort to minimize the mass of the booster and maximize its payload.  That complicated the design of the OLM and seems that it must have contributed delay to getting the OLM ready for testing.

As of now, the Cameron County road closure page for SpaceX shows the next round of closures starting Wednesday 12:00 p.m. to 8:00 p.m., with "secondary" (backup) days of Thursday (same time) and Friday 8:00 a.m. to 2:00 p.m..   It's probably wishing a bit too much to hope they'll do any testing of B4 this week. 

Weekly Update on the 1 by 1 - part 18

After last week's post, I decided the only way to recover was to start over.  I put that piece of cast iron with the improperly chamfered side into my stock collection and started over.  Cutting off a blank with the 4x6" bandsaw and then squaring it to 1.80 on a side goes fairly quickly, so by Tuesday it looked like this.  Roughly square at 1.80" on a side and 3.25" tall. 

This time, instead of doing everything to make it an octagon, I'll just cut it on the big lathe until it's a cylindrical bar that's 1.750 +/- .005 diameter.  The next step was to mark the center of the top end, then drill with a big center drill to accommodate the live center on my big lathe.  I could have milled the ends of the bar so that they'd be perpendicular to the sides, but I did that on the lathe before centering and chucking the square bar in my four-jaw chuck.  

With the sides of the block 1.80" (they probably differed from each other by a few thousandths) and the desired diameter of the cylinder being 1.750", how much do I remove?   I drew the two shapes up in CAD and it told me that from the tips of the square to the rim of the circle is 0.397".  That's roughly 19 passes cutting .020 (radius) at a time, plus a final cut or two to sneak up on the final size.  Each pass takes about four minutes, which argues that with some clean up time, it should take about two hours.  My lathe has power feed, so I can put everything in position for the next cut and engage the gears.  Do "something else" for the majority of the cut and then go stop it at the critical point.  Four minutes is just enough time to not get much done.

The final cylinder is supposed to have heat dissipating fins that are 3/32" wide, spaced 3/32 from each other, and each 3/32" ring is 1/4" deep in radius.  The actual shape with most dimensions is like this:

I cut all of those features today and started making the 1.000" cylinder bore, getting through the largest single cutting bit I have: 9/16".  The rest of the diameter will be cut with a boring bar with emphasis on getting it the right diameter, smoothed and looking like a cylinder bore should look.

If you haven't noticed the dimensions, from that flat, square, surface that the cylinder is sitting on to the left end of the part is 3/8".  There "should be" enough material there to make that smaller end on the left and part it off once the bore is done.   

Getting the bore right is important stuff and while I've done it on two engines, it still demands close attention.  With luck, I get it completed this week.

Astra to Launch from Cape Canaveral in January

Astra, the California startup in the small sat launch business, announced Monday they will launch from Cape Canaveral this January.  While the company has said that they intend to launch from many places on Earth, their tests to date have been from Kodiak Island, Alaska, at a latitude of 57.4 degrees north while Cape Canaveral is at latitude of 28.4 degrees north; a full 29 degrees lower on the globe.  That translates to more speed toward the east added to the rocket's own as it lifts off for orbit.  After their mission a year ago that made it into space but not quite fast enough to achieve orbit, someone claimed if they had launched from the Cape they would have had the extra 480 meters/second velocity they needed to achieve orbit. 

“This historic launch site has been prepared for a new commercial launch partner in less than year, which is a tremendous milestone for our combined team, and illustrates how SLD 45 sets the pace for access to space.” said Brigadier General Stephen Purdy, Commander of Space Launch Delta 45 and Director of the Eastern Range. “SLD 45, Space Florida, and Astra have moved at a rapid speed to demonstrate critical and responsive launch capabilities. We are excited to welcome Astra to Cape Canaveral Space Force Station.”

Astra and Space Launch Delta 45, a part of the United States Space Force, enabled Astra to launch out of Cape Canaveral in record time – shortening the multi-year approval time to months.

“Launching out of the Cape allows us to serve customers with mid-inclination delivery needs, broadening our market,” said Martin Attiq, Chief Business Officer at Astra. “This is an additional step in our global spaceport strategy and positions us to serve the broad low earth orbit (LEO) market.”

Astra’s launch will be livestreamed in partnership with NASASpaceFlight. Updates will be shared on Astra’s Twitter feed, @astra.

I find that second, short paragraph noteworthy; the one that says US Space Force (through Space Launch Delta 45) shortened the multi-year approval time to months.  I hope that's a sign of a coming "new normal" for US Space Force.  

Neither Mrs. Graybeard or I immediately knew where LC46 is and weren't quite sure we'd heard of it; that's especially ironic because she worked fairly close to it, although that was in the late 1980s.  I found  this map which shows its location as being essentially as far to the east that Cape Canaveral protrudes into the Atlantic.  I circled it in red on the map.  Some poking around shows it was used for the Trident missile development in the '70s and '80s.  Note this map cuts off the northern part of the Cape and a few more launch complexes, including LC39A and LC40 where SpaceX launches from.

There is no mention of the mission specifics beyond being a satellite for NASA and no date more specific than January.  I'll have to keep an eye out for more information. 

The Fertilizer Shortage is Part of Something Bigger

I would say bigger and more malevolent.  It's a direct consequence of the war on fossil fuels.  There are those in the environmental movement who want to kill off the vast majority of humanity, from 95% of humans on the planet to almost completely depopulating the planet.  Even if they don't intend to harm a single person, if they slash natural gas or crude oil production they inevitably will create shortages of the many products that come from those two fields from simple compounds like urea fertilizers to complex drugs.  The world is far more complicated than the simple visions they have, far more interconnected in vast webs of production than the "net zero carbon" people can possibly understand.  

To explain this could take a lot of detours and explanations, but the topic showed up on Watts Up With That today in a short post, “How the War on Fossil Fuels Will Kill People… Urea Edition.”  Urea, yes the same compound in urine, is at the bottom of this story.  While the urea we excrete is produced in our livers, not our kidneys, the urea that's used to create fertilizer is produced through a century old process that turns natural gas into ammonia which is then used to synthesize urea.  A hundred years ago,  German chemists Fritz Haber and Otto Bosch developed a way to produce ammonia from nitrogen (80% of the atmosphere and in billions of chemical compounds so available in virtually any quantity needed) with natural gas (methane, CH₄), stripping the hydrogen from the methane to bond with the nitrogen. 

To say this is an important achievement is massive understatement.  Both Haber and Bosch were awarded Nobel prizes in chemistry for the process.  The first was given in 1918, to Fritz Haber, who developed the process in the laboratory.  The second was given to Carl Bosch over a decade later, 1931, for his brilliant engineering skills that made the process viable on a massive scale.  

It has been said that Haber-Bosch has fed half the world.  Compare the solid black line at the top of this plot to the dashed dark red line, an estimate of the population that could be fed without Haber Bosch nitrogen.  The world with that fertilizer has almost twice the population.

Trends in human population and nitrogen use throughout the twentieth century. Of the total world population (solid line), an estimate is made of the number of people that could be sustained without reactive nitrogen from the Haber–Bosch process (long dashed line), also expressed as a percentage of the global population (short dashed line). The recorded increase in average fertilizer use per hectare of agricultural land (blue symbols) and the increase in per capita meat production (green symbols) is also shown.  From "How a Century of Ammonia Synthesis Changed the World", Nature Geoscience, 2008.

The War on Fossil Fuels has largely been fought by attempting to deprive fossil fuel producers of capital and force the replacement of fossil fuels with unreliable renewable resources (wind & solar). This strategy was best summed up by Saule Omarova, whose nomination as Comptroller of the Currency was scuttled by at least five Senate Democrats.

Her nomination was withdrawn but the important quote from my earlier post was:

In the clip, Omarova, who was born in the Soviet Union and is not a native English speaker, is seen discussing “troubled industries and firms that are in transitioning.” She continues: “And here what I’m thinking about is primarily coal industry and oil and gas industry. A lot of the smaller players in that industry are, uh, going to probably, uh, go bankrupt in, in, in short order, at least we want them to go bankrupt if we want to tackle climate change, right?” 

Combine the pushing of the anti-carbon activists with pressure from the investment sector’s demands “to cut back investment in favor of dividends” have caused the inability to ramp up production fast enough to keep up with surging demand. And this is why we suddenly have a synthetic fertilizer crisis.  They're blaming this on Covid, but reality is that it's only coincidence.   

Final words to Watts Up With That author David Middleton:

The wholesale destruction of our coal-fired power plant infrastructure and an unjustified fear of nuclear power, coupled with the low capacity factors of wind and solar power has made the world increasingly reliant on natural gas for power generations. Efforts to defund the oil & gas industry and the investment community’s demands that we focus on investor returns rather than growth, while also reducing the carbon intensity of our operations have driven natural gas prices through the roof in areas of the world dependent on imported LNG. This has left us in a situation where many nations will have to choose between freezing in the dark this winter or facing food shortages come spring.

 

 

Space News Week Roundup

As usual, a group of small stories each too small to warrant much column space, but that seem interesting to me.  And I really ought to number these - or do something to find them again. 

This morning at 1:00 AM EST, SpaceX launched NASA's IXPE mission and we watched from our side yard.  This is a good time to watch launches from here because the trees have lost some (or most) of their leaves and it's easier to see the first few moments of the flight.  The view isn't as good as this, mind you, but that's about a 45 minute drive from here and would require staying up most of the night.

Photo by Richard Angle for Teslarati, as it says.  

I think I know where this was taken: from a city park on the mainland, looking across the Indian River Lagoon toward the Kennedy Space Center.  Pretty much dead middle of the picture, there's short, reddish, vertical streak that looks like it projects down from the main contrail; that's the first burn of the Falcon 9 first stage as it slows down a bit from its peak speeds as it comes into the densest part of the atmosphere.  Those burns are about 20 to 30 seconds long and more than a minute from the landing.  I had hoped to see that but it was too low in the sky putting it behind several neighbors' houses and trees.  I've only seen that burn once, on a night flight with a Return to Launch Site landing which made it closer and therefore higher in the sky.

---

The French ArianeGroup has announced plans to accelerate its development of a reusable booster.  

On Monday French Finance Minister Bruno Le Maire announced a plan for Europe to compete more effectively with SpaceX by developing a reusable rocket on a more rapid timeline.

"For the first time Europe ... will have access to a reusable launcher," Le Maire said, according to Reuters. "In other words, we will have our SpaceX, we will have our Falcon 9. We will make up for a bad strategic choice made 10 years ago."

Sounds good, but we should add, "not really."  They're calling this rocket Maïa and the goal is to have it flying by 2026.  This is four years ahead of a timeline previously set by the European Space Agency for the development of a significantly larger, reusable rocket. All of that is good.

The rocket they're talking about, though, is more in the category of a small satellite launcher like Rocket Lab's Electron or Astra's Rocket 3.2 than being their own Falcon 9.  Maïa will have a lift capacity of up to 1 metric ton to low Earth orbit.  It will be powered by a new engine under development called Prometheus, which will be fueled by methane and liquid oxygen, like the SpaceX Raptor and Blue Origin BE-4 (methane/LOX engines are the big new thing in rocket engines, if you haven't noticed).  In comparison, Prometheus has a thrust comparable to a single Merlin 1D rocket engine, which powers SpaceX's Falcon 9 rocket.  Of course, there are nine engines on the SpaceX rocket so it can lift more than 15 times as much as the proposed Maïa in fully reusable mode.

The linked article at Ars Technica goes into some of that European politics behind this (which, I'm betting, is just as opaque and strange to US readers as US politics is to Europeans), but I keep going back mentally to an article I wrote in '18 about how the rest of the world couldn't keep up with the US - which was essentially that they couldn't keep up with SpaceX.  If you think you've seen some arrogance, go read that 2018 article.

---

Finally, I saw a story that had a real "we've come so far" vibe; at least to me.  Space News reports that the Russian space agency Roscosmos has selected a Russian cosmonaut to fly on a SpaceX Crew Dragon for a mission to the International Space Station.  

Dmitry Rogozin, director general of Roscosmos, tweeted Dec. 8 that cosmonaut Anna Kikina will go to the ISS in the fall of 2022 “as part of the crew of an American commercial spacecraft.” In exchange, a NASA astronaut would be part of a crew of a Soyuz mission to the station launching in the same time frame.

Kikina is the only woman currently active in the Russian cosmonaut corps. She was selected in 2012 but has yet to fly in space, although Rogozin and other Russian officials had previously said she would fly in the fall of 2022.

Despite all that, NASA hasn't confirmed the agreement, telling Space News that a seat barter agreement with Roscosmos is still being finalized.  

I just remember so clearly how from 2011 until 2020 that nobody went to the ISS unless they were on a Roscosmos Soyuz.  Now we're trading (bartering?) seats on missions.  

If Kikina does fly on a Crew Dragon, it's likely to be on the Crew-5 Crew Dragon mission, currently estimated to be in the fall of '22, to which NASA astronauts Nicole Mann, Josh Cassada and JAXA astronaut Koichi Wakata are currently assigned. 

 

 

Rashida Tlaib Accidentally Told the Truth

Congress Critter Rashida Tlaib (D - Uranus) accidentally told the truth and provided the best argument against what she was supposed to be arguing for.  Legal Insurrection blog carries the story that Tlaib was trying to advocate that taxpayers should pay off the student loans of everyone in America and demonstrated it's going to be a wealth transfer from middle class working people to the richest workers in America.   

Ms. Tlaib, a member of The Squad, those young, aggressively socialist women who seem to actually be running Washington DC, told her own sob story of still paying off her loans to attend law school and get that job as one our "betters" in Mordor on the Potomac.  The Hill Tweeted this summary.

The response was instant and epic.  First off, Alec Schemmel of KOMO News quoted the rest of her sob story and pointed out how she inadvertently showed the case against the fed.gov taking responsibility for all student loans (don't buy the widespread lie that this is student loan "forgiveness".  The banks aren't going to forgive anything, they're going to get bailed out on your tax bill.) 

“I worked full time, Monday through Friday, and took weekend classes to get my law degree. And still, close to $200,000 in debt. And I still owe over $70,000 and most of it was interest,” Tlaib said during oral arguments on the House floor. “And guess what? I didn’t go to the for-profit entities, I went to legal aid, I worked at the nonprofit organization fighting for the right to breathe clean air, to fight for the worker that was getting their wage taken and stolen from their employer. I went and worked on immigrant rights and so much more,” she continued.

Notice how she didn't point out that as a member of congress she's now making $174,000 a year and she's no longer working for those nonprofits organizations she wants you to think of.  A salary of $174k/year puts her well into the "richest 10%" (someone in the article quotes that as being "in the middle of the top 8%") and yet she wants people making a third of what she does (or less) to pay off her student loans.  

I thought she hates the rich and wants them to pay for everything, but she's one of them.  I'm sure she doesn't think of herself as rich.  She's a working woman, right?  Jazz Shaw of Hot Air added some much needed perspective to her sob story.

Further, Tlaib sought to glorify herself for having gone to work in lower-paying jobs for non-profit organizations after graduating. But when a person who is that far in debt chooses such a career path, that’s their own individual choice. She had a law degree from a well-regarded university and law school. She should have easily been able to find better-paying work in the private sector so she could take care of her obligations and then move on to more altruistic fields once she was financially stable.

There's a lot of stupidity in the idea of having taxpayers pay off everyone's student loans, but the most concentrated stupidity is probably exactly what she very clearly shows here.  The average student with a four year degree has student loans much less than her debt.  The average debt of the entire population with a student loan is $37k.  The majority of student loan payoff money is going to go to people with professional and other graduate degrees: doctors, lawyers, dentists, MS and Ph.D. engineers and others who are in the top 10% of salaries. 

It's upper class welfare.  Perhaps she's trying to appeal to the donor class.  If those professionals who will benefit from this have gratitude to her party, perhaps they'll donate more.  And perhaps she's just another pig at the trough, looking for more slop like all the other pigs.

Remember That Patriot Front March Last Saturday?

Lots of people commented on it and how it looked as much like a Fed Boi false flag as the "Only Feds" one last September.  "Hello, fellow insurrectionists! I'm happy to meet you for the first time so we can all MAGA together. Let's ask the other MAGAs if they have forgotten their AR-15,'s and offer to give them some." 

A very interesting rabbit hole appears on PJ Media this afternoon, courtesy of Stephen Green, who writes and does video podcasts with Bill Whittle regularly.  It seems that there's some evidence being talked about that one of the main voices behind the "rally" on Twitter is an AI Bot, given an AI face blend (made up face) of a pretty young blond woman.  (Because that won't attract attention, right?)

I could quote the entire article here and not take up too much more space, but Stephen's got some Twitter links to go poke around on and there's some funny stuff there.  There’s an entire Twitter thread devoted to this young lady, who joined Twitter last month and whose existence can’t be verified anywhere else.  The guy who posted this picture says he did a search engine dive for the screen name she's using, “Sheryl Lewellen,” and can find only one other thing she supposedly posted: a GoFundMe to help her friend's dog get surgery.  

That's right, no Google history at all.  Two Twitter threads.  I just checked and “her” account has been suspended for some reason.

Final words to Stephen Green because he's Vodka Pundit, after all, and he's funny. 

The whole thing is day-old fishy, and it stinks.

Finally, Insanity Wrap would just like to say that “Media Frenzy Over ‘White Supremacy’ Protest Hyped by AI FaceBot” isn’t just the most 2021 headline you’ve ever read, it’s the most 2021 headline possible.

Then again, we do still have three-and-a-half weeks to go until 2022.

 

 

An Unusal Milestone for SpaceX

This Thursday morning, December 9th, no earlier than 1:00 AM, SpaceX will launch their second satellite for NASA in two weeks, the DART mission on November 24th.  Thursday's payload will be the Imaging X-ray Polarimetry Explorer or IXPE.  

The unusual milestone is that IXPE will be the smallest, lightest satellite to ever be launched by itself on a Falcon 9.  

... IXPE was originally meant to launch on the small but expensive and oft-delayed Pegasus XL rocket and weighs about 325 kilograms (720 lb) as a result.

Instead, in mid-2019, SpaceX effectively stole NASA’s IXPE launch contract out from under Orbital ATK in the midst of chronic delays of a different Pegasus XL NASA mission, bidding just over $50 million to launch the smallsat on Falcon 9. Some two years behind schedule when it finally completed the mission, Pegasus XL ultimately launched NASA’s similarly small ICON spacecraft in October 2019 for the equivalent of ~$66 million in 2021.

Note that SpaceX is charging less for a much more capable launch vehicle than Orbital ATK was charging: $50 million vs. the roughly $66 million Orbital ATK charged.  Orbital's Pegasus can put 600 kg (~1300 lb) in low Earth orbit (LEO) while a Falcon 9 can put about 16,000 kg (~35,000 lb) in the same orbit.  $50 million shouldn't present a problem of not being profitable enough.  In various online quotes, I keep reading that a Falcon 9 launch actually costs around $20 million, possibly more if special modifications need to be made or there's something special about the mission (rush, lots of overtime for workers, or something peculiar).  The range that's quoted in the source article is $15 to $28 million.  

This will be the fifth flight for booster B1061, which has launched eight astronauts (Crew-1 and Crew-2), as well as SXM-8 (the Sirius XM satellite) and CRS-23 (cargo supplies to the ISS).  B1061 had a rough landing after its first mission (Crew-1) and looked to have a broken leg.  Or at least a bit of limp. 

Photo by Richard Angle for Teslarati - as labeled.  

IXPE is going look very small and alone in that payload fairing.  I'd like to know why there's no ride-sharing going on, perhaps like NASA putting up several thousand pounds of Cubesats for high schools and colleges everywhere, but maybe that's just me.  

B1061 was successfully static fired on Saturday, December 4th, concluding a thorough inspection and testing of the vehicle.  Judging by our weather, it looks like it should be a pretty morning for a launch and NASA's IXPE website says the weather is 80% chance of favorable conditions.  The trajectory for the launch and booster recovery look to be just south of due east of the Cape, so visibility should be good.  

IXPE during testing.  NASA Marshall Spaceflight Center Photo.

For more on the mission, see NASA's page. 

Weekly Update on the 1 by 1 - part 17

After last week's post, a few commenters said I shouldn't do the approach I outlined.  To borrow a vivid quote from Wandering Neurons (first comment as Anonymous):

Dollars to donuts, as soon as your mill hits that bar edge from the side, or the forces are the least bit uneven, the square bar will rotate out of the V-blocks and bounce around the room violently. More pressure from your vice jaws will only increase the bounce!

In my mind that bounce will likely be into something either expensive, hard to repair, or irreplaceable.  Probably painfully me.  So it was back to the drawing board.  

I had already made my alternate vise jaws by that time, so I had two options: first would be to grab the block by the ends and cut down the pointed ridge with movements along the Y-axis.  The vise is just not quite big enough to handle the rough piece.  The second option would be to put the square blank in the vise along the X axis, clamped more securely, and try to chamfer it.  Unfortunately, I don't have a chamfer cutter, but I do have a large countersink (3/4" diameter) for metal cutting.  It cuts an 82 degree angle, and while I'd rather have a 90 degree countersink so that I cut a 45 degree chamfer this is rough cutting just to get rid of extra material and I think I can live with a 41 degree angle instead of a 45.  

I decided to try the second approach and went off to make a test cut.  While making that cut the cutter slipped in the mill's collet and made a deep divot.  I was noticing that the cut was getting deeper toward the left in this view.  I was milling right to left (climb milling here) and the face that had been cut was definitely wider on the left.  It took embarrassingly long before I realized it must be the cutter slipping in the collet, took a quick look and saw that was going on.  I hit the emergency stop button on the computer which stops the axis from moving but not the spindle motor and then raised the cutter out of contact.  That divot you see got cut in the few seconds it took to stop the CNC, decide what to do, command it to raise the cutter and hit return.

I don't think it's too deep, but frankly don't care.  The finished cylinder is going to look like this (except for some holes I haven't drawn in, yet).  If one or two cooling fins have a divot, it's a "don't care." 

The  square section on the left is 1.75" on a side, the same as the diameter of the finned portion.  The finished length is 2.375" and my rough is now 3.25" long, so I have 7/8 of spare for the lathe chuck to grab.  That 3.25" is also 1/8" longer than my vise will open to.  I could probably spare that 1/8" so that I could clamp the blank on the ends.  I'm just not sure how I'm going to make this thing.

Unfortunately, the cut was done last Monday and I haven't had the time to get back into the shop since then.  What's that stuff about having no limits on time available once you're retired?  No need for a watch, no need for an alarm, all you need is to know when to nap and when to get up?  Sure hasn't been the case for me. 

A Ham Radio Series 28 – Directional Antennas

Over the course of the last few weeks, I’ve been working on and planning a project to improve my ham radio station.  It involves a change to my directional antenna for the six meter ham band.  Somewhere else in the same time interval, I saw a reference to directional antennas for emergency and SHTF communications.  The combination gave me the idea this might be a worthwhile thing to talk about.   

A word about how I’m going to go about this.  In an effort to reduce the amount of nitpicky and often extraneous information that could go into a piece like this, I’m going to make some sweeping generalizations without a lot of time to justify them.  After all, the ARRL Antenna Book is over a thousand pages, and is just one of the books they sell.   

Let me start here.  What I’m going to write about applies everywhere in radio.  It doesn’t matter if you’re trying to operate low power (QRP) or high (QRO), portable or fixed station, low frequency to microwaves, beginner to very experienced.  The antennas will sometimes look very different like a microwave dish versus a VLF vertical, but the concepts are valid everywhere.

Furthermore, let me start with a statement that might surprise a lot of you.  Let’s say you got a Christmas bonus or came across an unexpected chunk of money and want to improve your station.  Needless to say, the same goes if you’re saving up to improve your station.  If you have a reasonably good radio, not even a top-end, extreme-featured radio, just reasonably good, chances are that the best thing you could do to improve your station is improve your antenna system.  If you have that reasonably good radio, an improvement in your antenna system is going to help you more than a power amplifier for the simple reason that the antenna will work on both transmit and receive while the power amplifier just helps on the transmit side.  Probably the oldest cliché in Ham Radio is “you can’t work ‘em if you can’t hear ‘em.” 

Antenna Gain 

What directive antennas do for you that makes them the best thing you can do to improve your station is to provide gain.  In radio speak, gain is to make signals bigger.  It’s what amplifiers do.  Unlike amplifiers, though, antennas are passive devices – you don’t supply power to them so they can’t amplify (remember the first law of physics: you don’t get something for nothing?).  So how do they create bigger (louder) signals?  Think of squeezing a balloon; as you squeeze the balloon you make part of the balloon bigger as you squeeze the air out of the rest of it and the parts of the balloon you are squeezing get smaller.  

As always (first law again!) there are good aspects and bad aspects of this.  The good side is really good.  Let’s say you squeeze the balloon and get four times more power going in the direction the antenna is pointed (6dB gain – which isn’t terribly hard to get).  You haven’t put any more watts out, the power at the antenna is exactly what it was before, but you’ve made your signal at the other guy’s receiver a full S-unit stronger which made your signal much easier to understand.  Furthermore, you’ve done that by reducing the amount of power you put in undesired directions, reducing the amount you might interfere with others.  Even better, that same forward gain reduces your receiver sensitivity in other directions, making it easier for you to hear the desired station if interference isn’t exactly in the same direction as the station you’re working.  In antenna design, they often talk about front to back ratio and even small directional antennas can put 20 dB less power out the back than the front (1/100 the power).  It’s not always specified, but front to side ratio can be more important than front to back in populated places like much of the US.  It’s not uncommon to see front to side ratios of 30 dB (1/1000 the power) and more.   

The bad aspect for many hams is that you need to be able to reposition the antenna to get it to point exactly where you want.  In most cases, that’s done with an antenna rotator that has to be wired into place outdoors and controlled from inside the station.  There are antenna systems where rotation is done entirely electrically, too.   If you need to communicate with other stations in opposite directions, this can be a problem.  In some extreme situations, you might want to switch between two antennas pointed in both directions.  Most of the time, the communications can be arranged to keep from needing that.  The only disadvantage to you is that if you’re trying for stations at very different headings, you tend to need to contact one, then rotate the antenna and try for the other.  

That rarely seems to be a major hardship. 

How Do I Get Me Some?  

How do you get antenna gain?  The simplest way to look at it is that you need to put more metal in the air, but I hope you understand that if you just put up randomly sized hunks of metal in equally randomly chosen places that doesn’t count.  There are many established antenna designs to get gain, and you need to buy or build one of them.  

In broad-brush overview, there are two main types of antennas; those whose performance is determined by being portions of a wavelength, that is, made of quarter, half or full wave elements and those whose performance is largely determined by angular relationships between the elements which tend to be broader bandwidth than the first kind.  Since angles of electrical length can be expressed as physical lengths, it can be easy to lump them together.  

The most common examples of the first kind are commonly called beam antennas, most are actually Yagi arrays (and more properly Yagi-Uda after both original inventors).  Just behind those in popularity are quad antennas; these are based on four sided, full wavelength loops, most often of wire.  There are also arrays of vertical antennas; most commonly four verticals forming a square array.  Quad and Yagi arrays look like this:

The one on the left is a two element quad (full wave loops) while the one on the right is a three element Yagi (half wave elements).  A two element quad is generally considered equivalent to a three element Yagi based on real measurements.  You can justify that by saying “there’s more metal in the air so more gain.”  Again, these are classes of antennas; both kinds are available with different numbers of elements.  There have been antennas that were a hybrid, with a quad driven element and sometimes a quad reflector and then Yagi directors.  There are quads made into hexagons, quads with two wavelength elements and other variations.

While designing for antenna gain is an art form, the general trends are that more elements and longer booms give more gain.  It’s a game with diminishing returns.  Each additional half wave element (always a director) gives improvement but think of it as 10 * log(new number/old number).  That is, going from three to four elements yields 10*log(4/3) or 1.25 dB but going from 10 to 11 elements gives 0.4 dB.  

There comes a point when if you need twice the gain, the way to get there is by adding a second antenna with the same number of elements.  “Stacked Yagis” (two identical antennas), four antennas and even two arrays of four antennas are used where high antenna gain is required, like communicating by bouncing signals off the moon.

The antennas whose performance is largely determined by angular relationships are very common and if you’re old enough to know about outdoor TV antennas, you’ve seen them all your life.  The descriptive name is Log Periodic Dipole Arrays, or LPDA antennas.  

This may look like a tapered Yagi at first glance, but look at the dipoles again. The two halves alternate between two booms that are insulated from each other.  In other words, you see the connector on the bottom front, a signal driving that “dipole” drives the right side, travels down the entire length of the bottom boom to the far end, moves up to the top boom and travels all the way back to just above the connector.  

While a Yagi is typically good for just one amateur band (ignoring antennas that have traps to allow use on multiple bands), LPDAs are common with frequency ranges from 2:1 to 10:1.  My HF antenna for 14 to 30 MHz is an LPDA (and I’ve used it successfully on 50.1 MHz), I’ve seen LPDAs for 50 to 500 MHz.  (My HF antenna is a Tennadyne T6)  The trade is that generally no more than two or three dipoles are active on any frequency, so while they cover a broad band of frequencies, they’re not the choice for a high gain antenna.  We used to say, “they’re an antenna that works poorly over a wide range of frequencies.”  (And, yes I just said I'm currently using one for HF and another for VHF)

Mounting the antenna, towers and such are not really part of this discussion.  All horizontal antennas, whether a simple random length wire, a dipole, or a humongous Yagi for 20 meters work better when mounted over ½ wavelength above ground and in the clear.  For 20 meters, a half wave is obviously 10 meters, about 33 feet.  That’s a very different support problem than a yagi for 40, 80 or 160meters.  For those bands, I think vertical antennas are the best choice for the ham without 40 acres and a big budget.   Note that means that a 2 meter antenna can work fine at just over 3 feet over ground.  From the feedpoint impedance view, that’s completely correct.  It will still work better if it’s higher because of that part about being “in the clear.”

In my case, the work has been lining up a replacement for my 6m antenna, a no-longer manufactured five element, dedicated, six-foot long 6m LPDA with a five element Yagi.  My antenna lists its gain as 7.2 dBi in free space.  The replacement I’ve picked out is twice as long, and has 10.2 dBi gain in free space.  The limiting factor that got me to stop at five elements instead of six (slightly more gain) is the resulting boom length and being able to take down the antenna for a storm.  What the existing 6m LPDA offers that my new antenna won't is it operates acceptably on 2m and even loads on 70cm (432 MHz SSB or CW), but it's not a particularly good antenna on either of those two bands.

 

 

Space News Week Roundup

It has been an interesting week for space news.  We've gone several weeks with nothing noteworthy happening and then this week we got four interesting stories.  Let me present a few other stories that caught my eye.  

From where I sit the big one is that this morning on Twitter, Elon Musk announced that they've started construction of a Starship pad at the Kennedy Space Center, at Pad 39.  

I'm stoked because that means I'll be able to see Starship launches from my backyard.  We've joked that we moved here too late, in '1982 while Saturn V launches ended with Apollo 17 in '72.  We did get to see almost every Shuttle launch but it wasn't the biggest rocket in history.  That may change in '23.

He projects it to be operational by '23, and possibly early '23.

---

There are reports out via Aviation Week magazine that the SLS (Space Launch System) is facing yet another problem.  Linked by Ars Technica's Rocket Report but the magazine we used to call "Aviation Leak" is not allowing nonsubscribers to read anything but one lead-in paragraph.  These two paragraphs are from Ars Technica.

There's an issue with an SLS engine controller. This past weekend, rumors emerged about a problem with the controller for one of the four RS-25 engines that power the Space Launch System. NASA has not officially commented, but Aviation Week's Irene Klotz spoke with Aerojet's RS-25 program manager, Jeff Zotti. Troubleshooting the problem began on November 22, Aviation Week reported.

Schedule impacts yet to be determined ... If necessary, "replacing a line or a component … we're probably talking about multiple days. Replacing an engine, we're probably talking about multiple weeks," Zotti told the publication. "On top of that, we have to assess what that does and how that affects the vehicle and the integration activities that are going on," he added. All of that must be factored into a potential delay of the launch, presently scheduled for February 12. A summer launch for the SLS now seems far more likely than spring.

---

Last March, Rocket Lab announced a heavier lift vehicle called Neutron that's planned to compete with the Falcon 9 and allow them to put heavier payloads into space.  On Thursday, Rocket Lab's CEO Peter Beck unveiled the Neutron.  Well, not in hardware, but in renderings and a slickly produced video.  It's a stubby-looking rocket that they claim is designed that way to ease in recovery.

Neutron, he said, is optimized to serve both for the deployment of megaconstellations as well as geostationary satellites and even interplanetary spacecraft.

"This is what a rocket should look like in 2050," Beck said. "But we're building it today."

Beck says the wider, stubbier rocket is intended to catch more atmospheric drag during reentry, requiring less fuel to slow down.  The structure will be made of a proprietary carbon fiber for strength to weight ratio, much like Starship was originally conceived.  The first stage will have fixed landing legs, and the rocket will only land back at the launch site rather than offshore. 

Rocket Lab famously flew the first 3D printed engine that has successfully (and routinely) made orbit, and they're following up by creating a new engine, Archimedes, for the Neutron.  Like Starship, and (allegedly) the New Glenn, Archimedes will be a methane/oxygen engine.  They intend to aim for at least 10 re-uses of each Neutron, which is (of course) SpaceX's original protocol.  

What got me, though, was the rendering of the fairing opening to release a payload.  Rocket Lab calls it the "Hungry Hippo" fairing and once you've seen that, you can't unsee the kids' hippo game.  

---

Finally, Thursday afternoon,  NASA announced that it had awarded three different teams, each involving multiple companies, more than $100 million apiece to support the design and early development of private space stations in low Earth orbit.  Much like the competition between private sector companies for the Human Landing System, there are three groups of companies that have been awarded contracts.  In fact, with one conspicuous absence (the winners) the companies seem to be the same.  

Blue Origin, $130 million, leading a team including Sierra Space, Boeing, and Redwire Space

Nanoracks, $160 million, leading a team including Lockheed Martin and Voyager Space

Northrop Grumman, $125.6 million, leading a team including Dynetics

Previously, in February of  '20, NASA awarded a $140 million contract to Axiom Space to develop a habitable module that is to be docked with the ISS.  In particular, they're allocated the station's Node 2 forward point.  This award gives NASA four options for a private space station. 

The ISS is only technically expected to remain operational through 2024 - which will be here before you blink a few times.  I'd bet these contractors won't even have completed their design reviews by then, although with Axiom's head start they would seem to have the best chance.  Could the ISS make it to 2030?  Longer?  It's possible but not a certainty.  Then there's the question of whether it could get funded or whether it should even be funded.  What's the public's interest in the space station?  We hear about all sorts of things that seem good for manufacturing or other private sector concerns.  If a company wants to put up their own space station, why not let them and get NASA out of that?   

Is SpaceX Really In Trouble?

A story broke within the last week that Elon Musk sent an email to the company saying that SpaceX could be facing bankruptcy.  The email was sent last Friday, Black Friday, from Elon at work to employees probably relaxing in their turkey-induced comas from the day before or doing their Black Friday shopping.  Musk said, 

I was going to take this weekend off, as my first weekend off in a long time, but instead I will be on the Raptor line all night and through the weekend.

Unless you have critical family matters or cannot physically return to Hawthorne, we need all hands on deck to recover from what is, quite frankly, a disaster.

What's going on?  Is a SpaceX bankruptcy really likely?  It's a bit of a story.  In the immediate aftermath of the email, Musk backed off on the story a bit.  It's not likely, it's not something that is likely to happen without other things breaking down, but it's a possibility.  Here's the tweet, dated Tuesday.

So what's the story?

The story revolves around a relatively sudden realization that Raptor engine production is not going well.  The news broke about a week after CNBC reported that Musk had fired the vice-president of propulsion due to “a lack of progress” in the development of Starship’s Raptor engine. Now, apparently after taking his first good look ‘under the hood’ in a while, Musk says that “the Raptor production crisis is much worse than it seemed a few weeks ago.”

Musk may be a demanding boss, they seriously push to increase their launch cadence and you know there are lots of people working long weeks to do that, but while he may be a hard boss, he's not a full-tilt crazy boss.  Driven, yes; insane, no.

The fact is that apparently Musk had not paid as close attention to the Raptor production facility as he thought and was surprised when he started digging into things.  I think everyone knows that bad surprises are not a good thing to leave for your boss.

This matters because SpaceX has undertaken two immense, unprecedented technological space projects simultaneously. Each will cost billions of dollars—conservatively, $5 billion each, and likely significantly more—to bring to fruition and provide some return on investment. And ultimately, the success of SpaceX hinges on both projects, as they are each to some extent dependent upon the other.

The first big project is well known: Musk wants to get to Mars; not just land on Mars and come back home, but to establish a civilization on Mars.  By his own own estimate, that's going to require "not less than 1 million tons" delivered to the red planet.  In the 60 years of the "space age" the combined efforts of every civilization on the planet have delivered a few tons; probably less than 10 tons combined.  Notice this is not "let's get the government to do this," it's "we're going to do this" where we is SpaceX.  Immediately, the question of "how are you going to pay for that comes up."  Musk is ultimately counting on revenues from Starlink and launch services.  Ultimately, the number of satellites that can be put into orbit by even the Falcon 9 is too low to get the Starlink revenue stream they'll need. 

The company has already delivered over 1600 satellites to orbit, more than any country or other organization has ever done, and gathered almost 150,000 customers.  The service, though needs more satellites and more customers to meet its goals. 

To reach truly global and reliable service, SpaceX needs to complete its constellation. This is the "Starlink Satellite V2" that Musk refers to in his email. It represents about 12,000 second-generation satellites that are a bit bulkier than the first edition, as they carry more capacity.

To launch these into orbit would require about 300 launches of SpaceX's workhorse Falcon 9 rocket. Although the Falcon 9 is the cheapest and most efficient rocket in the world, that is still a costly proposition. Assuming an internal cost of $25 million per launch, that would be $7.5 billion. And that many launches would likely take seven to 10 years, an eternity for Musk. Finally, these launch costs are on top of the billions of dollars to build the satellites themselves and ground terminals for customers to receive signals.

Don't forget that they're also developing Starbase Boca Chica along with a dedicated Raptor engine factory in Texas.  That's another billion dollars a year SpaceX is spending (well, reported but not confirmed).  

This is why they need Starship so desperately.  While a single Falcon 9 launch puts up 53 Starlink Version 1.5 satellites (they weigh more than the version 1 satellites that F9 could launch 60 at a time), a Starship can probably lift 400 at a time.  That turns the 300 F9 launches into 27 Starship launches - of a vehicle designed to be turned around for reuse within a couple of hours.  There's the reason for Elon's priority on getting Starship running.

Which returns us to the Raptor engines that started this story.  While the first orbital Starship launch is likely to be next month, it's not going to be recovered.  Chances are the next vehicle won't be recovered, either.  Each booster will have 29 engines while each Starship will have another 6 - a total of 35 engines used in each test flight.  It's really not unreasonable to think it will take eight to 10 test flights before the boosters and Starships are being recovered reliably.  While they could do it faster, a conservative estimate is that they might need 300 to 350 engines. 

By comparison, NASA provided Aerojet Rocketdyne with $1 billion a few years ago to restart the production of space shuttle main engines. Four of these will power each Space Launch System rocket. Each individual engine, on top of the "start-up" fee NASA paid, will cost an additional $100 million. For all of this money, NASA will get a maximum production of four engines a year—engines that are not reusable and largely based on technology decades old.

The target price for Raptors is $250,000 each and scuttlebutt picked up online is that the current production engines are running under $1 million but to get to that final price requires the Raptor 2.  The SLS engines, which are essentially the same thrust, price out at nearly $150 million per engine when that "start-up" fee is amortized over the expected production run.  For a use once and throw away engine.  

Unfortunately, we don't know in any detail what the problems they're facing with Raptor production are.  All I can say is that in every kind of product development I know of, "oh, shit!" moments are a regular thing.  SpaceX has had them before and solved them.  My belief is they'll eventually get this situation resolved, too.  

The first test firing of a flight version of SpaceX's Raptor rocket engine.  Elon Musk/Twitter. 

 

 

Planetary Scientists Starting to Grasp How Starship Changes Everything

Back in mid-November, I quoted and linked to an important blog post by Casey Handmer about Starship.  A couple of quotes in there are truly stunning (they stunned me) but he has blogged for years about exploring the solar system and has come to the realization that Starship is so much of a leap over the current ways of doing things that most of the groups who can get the most out of it just don't understand that.   

A longer than usual article on Ars Technica offers some very reassuring information that they're starting to understand.  It starts out with something guaranteed to catch my attention: author Eric Berger re-tells a story I told last night from a different perspective. 

Jennifer Heldmann stared at the computer screens on her desk, watching as a rocket's upper stage slammed into a crater near the South Pole of the Moon. In the name of science, a 2.3-ton chunk of steel struck the Moon with the force of 2 tons of TNT.

It was October 2009, and Heldmann tracked the impact from inside the Science Operations Center at NASA Ames in California. As a 33-year-old planetary scientist, she was working her first major mission for NASA by coordinating observations of the impact with ground-based telescopes.

...

After poring over the data, NASA declared that it had indeed found water in the vapor plume kicked up by the Centaur impact, as well as material ejected by the blast.

The discovery of water on the moon was paradigm-shifting for planetary scientists.  It had long been held that if life was to be found it would be on a body with water - or that had water.  For some years, planetary scientists had been finding ice and water all over the Solar System—on the ice-encrusted moons of Europa and Enceladus, on and beneath the surface of Mars, and potentially in even more far-flung locations, such as the interior of Pluto or Neptune's largest moon, Triton.  As they looked beyond Earth, scientists were beginning to discover water was nearly everywhere.  Maybe, instead of looking for fossils of life in dry lake beds on Mars, they could look for living things in the large oceans of Europa, Enceladus, and those other places.   

We've talked about the Europa Clipper, currently projecting October 2024 launch on a Falcon Heavy, several times here.  As Starship has moved from lofty dream to real hardware readying for orbital flight, it's starting to attract the attention of planetary scientists.  Jennifer Heldman, from that moon mission is out on the forefront.  

Imagine sending a lander to Europa, which harbors a vast, warm, subsurface ocean. During recent NASA planning meetings, scientists contemplated sending a complex spacecraft, costing billions of dollars, to conduct science on Europa. At best, they were hoping to land a payload of science instruments about the size and mass of a mini-refrigerator there.

With Starship, by contrast, NASA might land a cache of scientific payloads the size of a single-story unfurnished house.

"You can really take advantage of the Starship architecture and get to the outer Solar System in ways we haven't thought about before," Heldmann said. "It could provide a revolutionary new way of exploring these worlds."  [Bold added: SiG]

Earlier this year, NASA's group of planetary scientists began to recognize the urgency of getting the space agency on board with using Starship for science missions.  So they wrote a white paper (PDF warning), with Heldmann as the lead author, titled "Accelerating Martian and Lunar Science through SpaceX Starship Missions."

"NASA must develop a funded program aligned with the development approach for Starship, including a rapid development schedule, relatively high risk tolerance compared to traditional planetary science missions, and ultimately a high ratio of potential science value for the dollars spent if successful," the scientists and engineers wrote.

Starship's key differentiator is mass. Today, when a scientist plans a mission to explore another world, there are two big constraints: cost and mass. Starship may have some effect on cost by offering more rocket for less money. But the biggest change is that scientists will no longer need to be hyperfocused on mass. They can carry more instruments, more shielding, more whatever.

One of the reasons spacecraft for these missions are so expensive is the focus on both mass and trying to ensure mission success.  The drive for lower liftoff mass while still minimizing the risk of failure causes the price to skyrocket, which only serves to increase the pressure to ensure that for such a high price tag the mission must succeed.  

Will NASA do anything to take advantage of the opportunities a fully operational Starship can bring?  It's hard to know.  NASA has selected Starship for the Human Landing System for the moon, but there's much more of the Artemis program that can be done directly with Starship, such as not bothering with the Lunar Gateway concept (which SpaceX will launch, also on a Falcon Heavy).  Aside from examples like this, though, NASA likes doing things with multiple bidders and international partners. 

[E]ven if NASA's leadership decided it wanted to create a Starship-specific program for science payloads, it's doubtful that Congress (or perhaps even the White House) would go along. Members of Congress like jobs in their districts and states, and NASA's traditional contractors provide this. SpaceX, by contrast, focuses heavily on cutting costs and efficiency. It works in comparatively few states and employs fewer subcontractors.

....

Consider the Mars Sample Return mission. NASA plans to partner with an important ally in space, the European Space Agency, to launch a sample retrieval rover (developed in Europe) and an ascent vehicle, built for NASA by Northrop Grumman. This mission, launching no earlier than 2026, could perhaps fly on United Launch Alliance's Vulcan rocket. Then, a European-built return orbiter would launch on an European Ariane 6 rocket to bring the small cache of samples back to Earth.

Such a mission would likely have a broad array of political support because it would fund multiple US contractors and bolster ties with Europe. By contrast, a SpaceX-only mission on Starship would upset NASA's other contractors, the European Space Agency, and the politicians who back their interests.

In shorter form, the problems the planetary scientists face are political problems.  The agency is "old space;" an arthritic bureaucracy.  They're more concerned with spreading money around to different constituencies and the concomitant kickbacks to the right officials than achieving the best missions for the cost.  Changing that is an uphill battle.

Still, there are positive signs.  Today the agency has the Commercial Lunar Payload Services, or CLPS, program, which awards money to private companies to build spacecraft that can carry NASA payloads to the surface of the Moon. CLPS has awarded a half-dozen contracts so far to a diverse array of bidders (examples here) and has a total budget of $2.6 billion through 2028.  Why couldn't they "start small" and create such a program for Mars payloads?  

Such an idea has already been proposed by scientists in the influential Mars Exploration Program Analysis Group, which suggested (pdf warning) that "a Mars-focused CLPS-like program could allow technology development for future exploration as well as delivery of science payloads."  

Remember that comparison of sending a payload the mass of a mini-fridge to Europa with a conventional mission or a single story house with a Starship?  Starship is massive.  If ride-sharing is profitable for smaller satellite builders on a smaller launcher like Falcon 9, imagine a ride-share mission to Jupiter, carrying multiple rovers for which ever moon they land on, or different Jupiter observing satellites.  It could be a regular occurrence, perhaps every couple of years.  A Starship could stay on orbit around Jupiter as well, acting as communications relay back to Earth and lowering the cost of the various satellites.  

Starship's "Photo Opportunity" stacking from August 6, '21.  Screen capture from NASASpaceflight.com.

As long as this piece has been, it's just touching the surface of everything linked herein and the source article at Ars Technica. If this has been interesting, go read.

 

Asteroid Material Returned to Earth Contains Surface Water

In May of 2003, the Japanese Space Agency launched the Hayabusa mission to an asteroid called 25143 Itokawa.  In November of 2005, the satellite touched down on the surface of Itokawa becoming only the second vehicle in history to land on an asteroid.  But there was more.  Hayabusa was intended not just to land on the asteroid, but to return a sample to Earth.  During the November 2005 landing, after a series of troubles, the ground lost contact with Hayabusa, not regaining contact until March of 2006.

The story of the mission reads like a case study in perseverance through difficulty after difficulty.  When the vehicle started back for Earth, it wasn't known for sure if any of the asteroid was successfully sampled.  The capsule potentially containing - perhaps - one gram of asteroid surface - re-entered the Earth's atmosphere on 13 June 2010.  The capsule experienced peak deceleration of about 25 G and heating rates approximately 30 times those experienced by the Apollo spacecraft. It landed via parachute near Woomera, Australia, and was recovered the next day.

Fast forward 11 years and we find that Itokawa contains significant amounts of water.  It has probably flown below most peoples' radars that NASA has confirmed (on almost the same time line) that there's plenty of water on the surface of the moon, as well.  One mission, crashing a used rocket stage into the surface near the south pole, revealed the lunar regolith (sort of lunar topsoil) was 5% water.  Considering the temperatures on the moon and the exposure to hard vacuum, how is this even possible?  Wouldn't water evaporate or, if ice, sublimate?  One of the explanations offered at the time was that the solar wind sends a steady stream of protons out in the Solar System, and these protons could interact with lunar material to produce water.  It was found the temperatures at the lunar poles, in the perpetual shadows where the rocket stage hit, are so far below freezing that sublimation is very slow and rare.

Here's where the story of Itokawa gets a little more interesting. 

Itokawa is what's called a "rubble pile," as it's made up of small fragments produced by collisions among asteroids and then slowly gathered together by gravity. Asteroids like this may have fragmented and re-formed multiple times over their history, and they could be composed of portions of more than one body.

A large, international research team took some of the fragments returned to Earth and subjected them to a variety of imaging techniques. The researchers determined that the outermost 40 to 180 nanometers [1-1/2 to 7 millionths of inch] of rock were transformed by their time in space due to bombardment by high-energy radiation. This region also had elevated levels of water and hydroxyl ions (OH^-). This finding is consistent with the idea that the water was produced by the interaction between protons in the solar wind and silicate-rich materials in the rocks themselves.

Based on the typical depth of the material that was transformed by the solar wind, the researchers could calculate the amount of water in particles of different sizes. And while there's very little here individually, Itokawa has a lot of small, dust-like particles, which have a high surface area relative to their volume. So it all adds up to an estimated 20 liters of water in every cubic meter of the powdery regolith on the asteroid.

Itokawa - ISAS, JAXA photo 

People who study asteroids like this believe that on a rubble pile like Itokawa, all of the dust gets cycled between the surface and interior as the asteroid has collisions over the millennia, and as a body like Itokawa orbits, it sweeps up more dust which has been hit by high energy solar wind.  So even if something is now buried in the interior, it almost certainly was exposed to the solar wind in the past.

It also presents us with somewhat of a way out of a problem.  For years, we've been told that Earth's oceans are probably the result of a massive collision that formed the moon.  Over time, chunks of proto-Earth fell back down, bringing significant amounts of water.  The problem with that is it doesn't agree with observations of the isotopes of the water found on Earth versus other planets.  

But if we go by the elements in our crust, the bodies that arrived on Earth have a different ratio of hydrogen isotopes from the waters in our ocean. Put differently, the oceans have water that (in isotope terms) is somewhat lighter than the water found in the asteroids that have a composition similar to Earth's. The solar wind, in contrast, has hydrogen isotopes that are overall lighter than what we see in our oceans. So the researchers propose that the solar wind has indirectly helped fill our planet's oceans by producing water on dust particles that eventually fell to Earth.

The interesting side here is that the process continues today.  An estimated 30,000 tonnes of dust grains fall from space each year. And these tiny particles will have the highest amount of water per mass of anything exposed to the solar wind. That's not much water in a given year, but it adds up over time, year after year, after thousands, millions or billions of years.