The Sun's Other Cycle

The 11 year sunspot cycle has been something I've posted about many times here, and have done six month progress reports on the current cycle (25) regularly - the most recent was at the end of last December, the 28th.  Let me start by refreshing the end of the year solar cycle plot:

My frequent comment is that cycle 25 is doing well, but is still weaker than cycle 23 (red).  Yes, it's stronger than cycle 24 (pink) but that one was the weakest solar cycle in a hundred years.  In this plot cycle 24 is the one on the bottom, and at least as of this plot in December, the grayish plot of cycle 25 hadn't shown itself to be stronger than 23 in even one month's smoothed sunspot number.  

The (roughly) 11 year sunspot cycle, referred to as the Schwabe cycle, has been tracked longer than other measures because it's something that can be done by photographing the sun and applying the rules of counting the spots.  When researchers looked for more subtle signs that required more instrumentation, they found another cycle superimposed on this one that lasted on the order of 100 years or 9 Schwabe cycles, and called the Gleissberg cycle.  Plotted together, they look like this:

Looking at this plot, cycle 24 (last peak on the right) doesn't look particularly weak, especially compared to the cycle at the last null in about 1913, barely above the minima of the Gleissberg cycle.  

Let me change pace for a little more background that I'm sure some readers will appreciate.  This plot of the two types of cycles comes from a story that gets a bit more into it and leads much deeper.  The article is at the top of Spaceweather.com today.  That article is one paragraph which reads:

THE CENTENNIAL GLEISSBERG CYCLE: You've heard of the 11-year sunspot cycle. But what about the Centennial Gleissberg Cycle? The Gleissberg Cycle is a slow modulation of the solar cycle, which suppresses sunspot numbers every 80 to 100 years. It may have been responsible for the remarkable weakness of Solar Cycle 24 in 2012-2013. New research published in the journal Space Weather suggests that the minimum of the Gleissberg Cycle has just passed. If so, solar cycles for the next 50 years could become increasingly intense. Read the paper here.

It would be "bad form" for me to change the way that second to last sentence is displaying in the excerpted paragraph because it might not be clear that I'm the one who modified it.  So I'll say read that second to last sentence again, and put it right here:  If so, solar cycles for the next 50 years could become increasingly intense.

The first link in that paragraph is to climate.gov, where the graphic of the two cycles just above comes from.  The last link is to a full copy of "Turnover in Gleissberg Cycle Dependence of Inner Zone Proton Flux" at a journal called Space Weather of the AGU, the American Geophysical Union.  Much of the research is done with various satellites in and around the South Atlantic Anomaly, where Earth's magnetic field has several oddities.  

I have a lot of questions about the Gleissberg cycle and both the apparent correlations and non-correlations.  If you look at the right end of that combined Schwabe and Gleissberg cycles plot, you'll see one Schwabe cycle that is far higher than those near it and the highest peak in history (back to 1700).  That's cycle 19 in the late 1950s - the one that older hams and radio hobbyists still talk about.  Note that it's before the Gleissberg Cycle peak and the next sunspot cycle, 20, while apparently exactly at the CGC peak, is much smaller than 19.  There are other places in that plot that also seem like the correlation isn't that good. 

And Now for Something Completely Different

It seems the day got away from me, as it appears the weekend might well also, so a totally unrelated, 3D printer story. 

Precious granddaughter (also known as PGD) officially turned into a teenager last month as the clock ticked over to 13.  One of the things we picked off her Christmas list this most recent Christmas was a Taylor Swift CD.  I have no idea how common that is for 13 year olds, but it was easy to do and she was happy to get it.  

Around the middle of January, I broke a plastic measuring teaspoon and thought "why not just print one?" so I found myself looking for models on a few sites.  That's when I stumbled across this, on the public print library at Prusa:

I asked Dear Daughter-in-Law if she thought PGD would like this, got an enthusiastic yes, downloaded the two files and since this was pretty much two full months before her birthday, promptly put it aside. 

When the calendar started getting into March, I setup the printer and did the large piece on the left and then went on to the more intricate piece on the right.  As the printer started getting closer to the end of the print, I could tell it was messed up in a way I'd never seen.  It looked like this:

Compare it to the view on the right in previous picture.  I have no idea why it turned some solid curves into dashed lines, but it clearly did.  The problem turns out to have been the Slicer software I was using, which is from Prusa, like the cookie cutter itself.  

I pretty quickly switched to another slicer software package I have and that one was much closer to the original.  I've since downloaded updated versions of both Slicers.

The two pieces were Priority Mailed to PGD and the first batch of cookies were had a couple of weeks ago.  To borrow/butcher a line, "a splendid time was guaranteed to all" and received by them.

Small Space News Story Roundup 56

A disjointed couple of stories: they don't really go together, but who says they have to? 

The Highly Improbable Approach to launching satellites is gone

Remember the SpinLaunch, the company that planned on spinning satellites in a ground-based centrifuge on the order of 330 feet in diameter until they reached a velocity that could fling them into orbit?  The last post I have about them is from October of 2022.  As we talked about a few times back then, their big and fundamental problem was their flings are harder on the payloads than a typical rocket launch.  The quote I can't forget is the one that went, “It’s a very gentle 10,000 g.”  That's an oxymoron! 

It turns out that SpinLaunch sorta went quiet not long after that test.  You could say they disappeared, for all I heard.  This week they've announced a rather complete change in direction.  They're going to go back to regular rockets. 

"The launch market is relatively small compared to the economic potential of satellite communication," [CEO David] Wrenn said. "Launch has generally been more of a cost center than a profit center. Satcom will be a much larger piece of the overall industry."

The source article at Ars Technica goes into a bit of the details.  I have to say I'm not particularly convinced they've set up a good business plan and have a good chance of success.  I didn't think they had much of a chance with their centrifuge-as-launch-vehicle approach, either.  

The SpinLaunch test vehicle at the end of what appears to have been their last flight test.  It's hard to get a good scale from this video, but it appears to be on the order of 6' long - about the height of the men digging it out of the ground. Screen capture from their video (obviously).

A mission to retrieve Vanguard 1 from the orbit it has been in since 1958

That's 67 years ago.  America had just been shocked by the Soviet Union launching Sputnik 1 in October of 1957.  The newborn American space program had been hard at work trying to get to orbit and the frustration from being beaten to orbit by them was palpable.  It hurt more later in the year when the U.S. Navy's Vanguard rocket failed as the booster toppled over and exploded on its first attempt to put a US satellite into orbit. 

Lately, there has been an effort going to design a mission to retrieve the old satellite and bring it back down; there will be examinations of it for various reasons and then it will probably go into a museum.

The space race was just getting started, and the US Army was the first organization to reach orbit with  Explorer 1 on January 31, 1958.  Vanguard 1 reached orbit on March 17, 1958 as the second U.S. satellite.

The US Naval Research Lab is still the owner of the miniature metal ball of Vanguard 1, and while Explorer 1 reentered in 1970, Vanguard 1 is still in orbit. 

Today, the satellite is in an elliptical orbit with its perigee roughly at 410 miles (660 kilometers), swinging out to an apogee of approximately 2,375 miles (3,822 kilometers) from Earth, with a 34.25 degree inclination.

A team that includes aerospace engineers, historians and writers recently proposed "how-to" options for an up-close look and possible retrieval of Vanguard 1.

A mission like this is probably more complicated than it sounds, due to the satellite not having been designed with any thought given to capturing it a later date.  You can be sure there are no features on the little satellite to grab.  Add to that the fact the it's a small satellite at 3 pounds that's a 5.9 inch diameter aluminum sphere with a 36 inch antenna span.  It would be a delicate, 'handle with care' mission.

Vanguard I satellite, a component of the Vanguard Project, is a small aluminum sphere designed to take part in the International Geophysical Year (IGY) — a series of coordinated observations of various geophysical phenomena during solar maximum, spanning July 1957 through December 1958. (Image credit: NASA)

A hearing has been scheduled for the confirmation of Jared Isaacman as NASA Administrator

The committee announced late April 2 that it will hold a confirmation hearing for Isaacman on April 9 at 10 a.m. Eastern. 

A Little Starship Flight Test 9 News

While SpaceX has not concluded its investigation of the loss of Flight Test 8's Starship, and hasn't nailed down a date for FT-9, they have announced that FT-9 will feature the first reuse of a previously flown SuperHeavy booster.   

The most visible sign of SpaceX making headway with Starship's first stage—called Super Heavy—came at 9:40 am local time (10:40 am EDT; 14:40 UTC) Thursday at the company's Starbase launch site in South Texas. With an unmistakable blast of orange exhaust, SpaceX fired up a Super Heavy booster that has already flown to the edge of space. The burn lasted approximately eight seconds.

This was the first time SpaceX has test-fired a "flight-proven" Super Heavy booster, and it paves the way for this particular rocket—designated Booster 14—to fly again soon. SpaceX confirmed a reflight of Booster 14, which previously launched and returned to Earth in January, will happen on next Starship launch With Thursday's static fire test, Booster 14 appears to be closer to flight readiness than any of the boosters in SpaceX's factory, which is a short distance from the launch site.

SpaceX says 29 of the 33 Raptor engines on Booster 14 will be flight proven, so while not exactly their goal of "no-touch reuse" it's a giant leap in that direction.  At liftoff, SuperHeavy is the most powerful rocket ever built with nearly twice the thrust of the Saturn V that got people to the moon -  16.7 million pounds of thrust.  Without the Starship, Booster 14 itself is 232 feet tall.  

Reuse has come to be accepted as the way things should be, and that shouldn't be a surprise.  Nobody would seriously talk about flying a commercial airliner once and throwing it away.  Spacecraft may fly with smaller safety margins than a car or commercial airliner; that is, the difference between forces the rocket is calculated to be able to survive, and those that it will be exposed to during a real flight, but that's because of the brutality of the mission.  In the car or the Airbus, the extra weight of stronger designs is much less of a burden to live with than with a rocket.  

The first time SpaceX reused a Falcon 9 for a paying customer, it was practically a year after the initial flight and many inspections and tests to ensure everything still behaved as it should.  That mission was in 2017.  They now have over 425 flights of reused boosters.  Reusing B14 is the best way to verify that they knew what they're looking for as they inspected and retested it.  

SpaceX hasn't released a date for the next flight of B14 with its new Starship, but it's still early in the buildup to FT-9 and more likely to be in May than April.  The ship assigned to FT-9 is still in its factory at Starbase.  There have been no test firings of the ship, so it will need to roll out to a test stand for its own static firing tests.  Once that's accomplished, they typically move the ship back to the factory for more work, inspections and finishing touches, before returning it to the pad.  

Booster 14 during Flight Test 7, January 16, 2025. Image credit: SpaceX

I hadn't thought of Fram2 this way

Stephen Greene, "Vodkapundit" at PJ Media, surprised me with an observation about the Fram2 polar orbiting mission that never occurred to me.  It's so obvious when you read that it really resonates.  

"...To boldly go where no man has gone before" launched every episode of Star Trek that I watched in reruns as a kid, but Monday night I watched as two men and two women did it for real aboard a Crew Dragon spaceship that put human beings into a polar orbit for the first time ever.

Son of a biscuit, he's right and we've just been calling it an orbital mission, just like all the other privately-run manned missions to orbit that we've seen.  Except it really isn't.  Nobody has ever done a mission that orbited over one of the poles every half orbit. 

He then goes on to say a few words about the crew members and each of their backgrounds before adding another poignant note:

None are former fighter pilots, NASA astronauts, or government employees of any kind. All show the kind of daring that would make Captain James T. Kirk proud.

Even dedicated space buffs were a bit taken aback when news of Fram2 reminded us that human beings had never flown a polar orbit before. You might wonder why, but Fram2's five-day mission has a stellar rationale. 

What's the rationale?  Nobody has made big deal about it, but while they're bringing a lot equipment for various scientific experiments, perhaps the most important experiment is that they're going to be exposed to the Van Allen belts - through holes over the magnetic north and south poles.  Nobody has been exposed to these belts since the Apollo program, and even the Apollo astronauts avoided the worst doses by transiting quickly through the Belts.  

Fram2 won't fly through the most dangerous parts of the Van Allen Belts but they'll fly through them every orbit, enough to gather data. 

For those of us who grew up in the start of the "space age," watched Mercury, Gemini and Apollo as they happened, this is turning into the space age we always expected to see, just delayed until later.  Still, while we don't know how much they're spending on this mission and the things they're doing, we know that it's all being funded by one man, Chun Wang.  I know he has been called a billionaire, and haven't seen an estimate of his net worth, but between Wang and Jared Isaacman with his Polaris program missions, it's clear that someone who can spread around a few hundred million dollars doesn't have much trouble getting into space if they want to.  Those with less to spread around now can take suborbital spaceflights, like Blue Origin's New Shepard flights. 

To let Stephen Greene have the last words:

It won't be long before millionaires will enjoy short stays aboard luxury space stations in low Earth orbit, just like the ISS but much more comfy. After that, maybe a brief "spacation" won't cost much more than a trip to Disney World. 

The complete whiteness of Antarctica is seen from SpaceX's Dragon during the first-ever human polar orbit during the Fram2 mission. (image credit Fram2/Chun Wang via News13 in Central Florida)

How Bad Was Starliner's Flight? I Had No Idea

Eric Berger at Ars Technica has put up a summary of an interview he had with Butch Wilmore and Suni Williams yesterday at Johnson Space Center in Houston.  It's the deepest, most informative thing I've come across about the Starliner Crewed Flight Test mission; the story is both riveting and a high pucker factor.  While the two spent most of the day giving five to ten minute interviews. Berger has a closer relationship with Butch Wilmore and they ended up talking for a half hour.  Berger writes:

I have known Wilmore a bit for more than a decade. I was privileged to see his launch on a Soyuz rocket from Kazakhstan in 2014, alongside his family. We both are about to become empty nesters, with daughters who are seniors in high school, soon to go off to college. Perhaps because of this, Wilmore felt comfortable sharing his experiences and anxieties from the flight.  

The story is definitely worth your time to read, and as I usually do, I'll pass on some excerpts to try to whet your appetite for the story.  

The story starts after launch and their first night in orbit in an unexpectedly cold Starliner capsule.  As they're approaching the Space Station, you'll probably recall they lost some thrusters and the ability to control Starliner.  They knew they should dock with the ISS and felt that they'd be safer there, but they didn't know that their Starliner would hold together or if more failures would come.  As Starliner's thrusters failed, Wilmore lost the ability to move the spacecraft in the direction he wanted to go. 

He and his fellow astronaut, Suni Williams, knew where they wanted to go. Starliner had flown to within a stone's throw of the space station, a safe harbor, if only they could reach it. But already, the failure of so many thrusters violated the mission's flight rules. In such an instance, they were supposed to turn around and come back to Earth. Approaching the station was deemed too risky for Wilmore and Williams, aboard Starliner, as well as for the astronauts on the $100 billion space station.

But what if it wasn't safe to come home, either?

"I don't know that we can come back to Earth at that point," Wilmore said in an interview. "I don't know if we can. And matter of fact, I'm thinking we probably can't."

In the lead-up to this moment, Butch remembered talks he had with Boeing leaders before the mission. 

"Before the flight we had a meeting with a lot of the senior Boeing executives, including the chief engineer. [This was Naveed Hussain, chief engineer for Boeing's Defense, Space, and Security division.] Naveed asked me what is my biggest concern? And I said the thrusters and the valves because we'd had failures on the OFT [uncrewed flight test] missions. You don't get the hardware back. (Starliner's service module is jettisoned before the crew capsule returns from orbit). So you're just looking at data and engineering judgment to say, 'OK, it must've been FOD,' (foreign object debris) or whatever the various issues they had. And I said that's what concerns me the most. Because in my mind, I'm thinking, 'If we lost thrusters, we could be in a situation where we're in space and can't control it.' That's what I was thinking. And oh my, what happened? We lost the first thruster."

The story gets worse from there.  Wilmore adds: "And this is the part I'm sure you haven't heard. We lost the fourth thruster. Now we've lost 6DOF (6 Degrees of Freedom) control. We can't maneuver forward. I still have control, supposedly, on all the other axes."  

Now they simply could not control the Starliner to the degree they needed to.  The two of them realized they were in a very precarious situation, and it literally was just barely good enough to only probably not get them both killed. There was no need to talk about that with each other; they're both experienced enough as astronauts to know what the situation meant.  That's when the mission control in Houston came up with the scariest solution.  

Turn the entire system of thrusters off and back on again.  Really.  And some of them started working again.

Butch Wilmore and Suni Williams at the docking port entry to the ISS, soon after their June 6th arrival at the ISS. Image credit: NASA

I'll leave it there as it's fairly close to the actual docking with the ISS and the rest of the story.