December 31, 2025 Quick space links
Courtesy of BtB’s stringer Jay. This post is also an open thread. I welcome my readers to post any comments or additional links relating to any space issues, even if unrelated to the links below.
- Astronomers detect a three-galaxy merger, the third ever discovered
The headline at the link is utter garbage, designed as clickbait. The headline I have given you describes the story’s text accurately. One other detail: All three galaxies also appear to have active nuclei, suggesting the presence of supermassive black holes.
- SpaceX accounts for more than 70% of the world’s total payload mass launched in 2025
This graph is a nice additional data point I will use in my annual global launch report.
- On this day in 1924 astronomer Edwin Hubble announced that the spiral nebula Andromeda is a distant galaxy like the Milky Way
Thus proving that the Milky Way is just one of many galaxies in the universe.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Courtesy of BtB’s stringer Jay. This post is also an open thread. I welcome my readers to post any comments or additional links relating to any space issues, even if unrelated to the links below.
- Astronomers detect a three-galaxy merger, the third ever discovered
The headline at the link is utter garbage, designed as clickbait. The headline I have given you describes the story’s text accurately. One other detail: All three galaxies also appear to have active nuclei, suggesting the presence of supermassive black holes.
- SpaceX accounts for more than 70% of the world’s total payload mass launched in 2025
This graph is a nice additional data point I will use in my annual global launch report.
- On this day in 1924 astronomer Edwin Hubble announced that the spiral nebula Andromeda is a distant galaxy like the Milky Way
Thus proving that the Milky Way is just one of many galaxies in the universe.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
The great debate
https://phys.org/news/2025-12-real-life-niels-bohr-theoretical.html
The graph appears to show “Capacity” to orbit, not actual mass launched to orbit. I believe SpaceX actual mass to orbit is somewhere in the 85% range as compared to the graph showing only 70.8%.
I was a little surprised to see an attempt at quantifying total payload mass to orbit for this year, so quickly . . . until I realized that the tweet merely specified total payload mass *capacity* to orbit. The actual mass tally is, as it says, certain to be even higher for SpaceX, since Starlink payloads usually come close to maxing out payload capacity . . .
Actual mass to orbit is a more difficult and involved process of calculation since national security payloads don’t always provide such detail, leaving us to try to derive it from other data about the launch. BryceTech is probably best known for such efforts, and it is worth noting that their quarterly reports so far (1Q, 2Q, and 3Q) for 2025 show SpaceX in the 83-89% range, I believe. So I suspect that when 4Q is worked out, SpaceX will end up somewhere in the mid-80s for the year
Anton warning of Kessler syndrome which starts with solar storm. ( I think that is what he is saying. )
https://youtu.be/b66ZZ05wKC0?si=iS8DojHjKX07bkcm
What if space debris strikes a refueled Starship while in LEO? Would that cause an explosion?
Steve Richter,
Anton must have decided he needed to do a bit of gratuitous click-baiting to bump up his metrics. The cited paper was published for pretty much analogous reasons – citations are the “click metrics” of science.
What would happen if a refueled Starship was hit by space debris would depend greatly upon how big the debris object was. A strike by something B-B-sized would cause a puncture and almost certainly some leaking of propellant as the vast majority of a Starship’s volume is tankage. If the leak was slow, the Starship could probably re-enter safely. The last test flight featured several deliberately-caused burn-throughs in tankage that produced leaks, but the ship retained structural integrity clear through re-entry and down to the surface. There would not be much risk of an explosion on-orbit. An explosion on re-entry wouldn’t add any space debris so it couldn’t contribute to any notional Kessler Cascade.
If the “debris” object was, say, a derelict Zenit upper stage, though, there would be an energetic event equivalent to an explosion whether or not any actual explosive chemical reactions occurred. That would definitely be a loss-of-vehicle scenario.
Fortunately, the number of really large bits of space debris is fairly low, all are tracked and they are avoidable. The vastly more numerous very small bits wouldn’t necessarily result in significant new debris bits being generated or in fatal damage to a Starship thus struck.
If you’re shopping around for something to worry about, I’d suggest looking elsewhere.
This technology is really impressive:
https://m.youtube.com/shorts/msNxvbvr6ZM
Now, I am wondering if this might be good for flying molds.
You see this matrix press put gentle curves into one piece of metal.
What if you have two such plates as a flying mold?
Fill with UV glue or whatever so you can have something that isn’t layered like 3D prints.
That needs in space for large structures.
“… If you’re shopping around for something to worry about, I’d suggest looking elsewhere. …”
Starship is only going to explode in orbit one time. So yeah, I am very worried about it.
Was wondering if the exhaust from Starship as it launches from LEO would leave a damaging residue. Grok says no:
“…. The vast scale of space ensures that any temporary gas plumes become too diffuse to pose collision risks or other interference to satellites—molecules have negligible mass and momentum for causing damage, and they merge into the background interplanetary medium without accumulating as “space smog” …”
also asked Grok if the exhaust from a Starship LEO launch would blow on other satellites in the vicinity. Grok says only within 100s of meters:
“… even optimistic calculations for a large rocket like Starship suggest that a satellite would need to be within 150–500 meters and intercept a fraction of the exhaust for seconds to experience a delta-v of 10–70 m/s, which might shorten its orbital lifetime from years to months but not cause immediate deorbit or disruption. …”
To Steve,
Here is a run-down of 2025….big 144 page PDF
https://planet4589.org/space/papers/space25.pdf
Pages 29–66 address your concerns
Page 21 should be your focus.
To quote:
“At the end of 2025 there were 32214 cataloged objects in orbit or beyond and the total known mass in orbit
increased to 16193 tonnes…”
I love this name–“Orbituaries”
“Table 15: Uncontrolled Reentries 2025”
Number Mass (t)
Active Payloads 734 170.4 tons
Dead Payloads 368 103.3 tons
Rocket Bodies 109 182.2 tons
Operational debris 54 6.7 tons
ASAT debris 108 -?
Collision debris 133 -?
Other fragment debris 360 0.7 tons
More on Constellations
https://planet4589.org/space/con/conlist.html
“Space Force officers’ DC home torched in anti-Trump attack—GoFundMe approaches $100,000”
“Two active-duty US Space Force officers were victims of an apparent targeted attack after their Washington, DC home was broken into, vandalized, and intentionally set on fire while they were out of town, according to a GoFundMe page created for the family.”
“Jason Taylor and Kaylee Taylor returned to find their residence heavily damaged by fire, with most of their belongings destroyed. The couple’s vehicle was reportedly vandalized with spray-painted messages reading “* Trump” and “* the Space Force.” These photos were not shared on the fundraiser, however.”
“The incident occurred on Sunday, Dec. 28. Both Taylors are active-duty members of the United States Space Force. They were not home at the time of the attack and were traveling with their infant daughter, Rae.”
“‘While they were out of town, their home was broken into, robbed, vandalized, and intentionally set on fire,’ the GoFundMe page states. ‘Kaylee and Jason… and their beautiful baby girl, Rae, lost pretty much everything they owned.'”
“The fundraiser says the family lost clothing, furniture, baby items, keepsakes, and other essentials. A family cat, Marlee, died in the fire. ‘Tragically, in the fire they also lost their beloved cat, Marlee, who was a cherished part of their family,’ the page reads.”
https://thepostmillennial.com/breaking-space-force-officers-dc-home-torched-in-anti-trump-attack-gofundme-reaches-66k-in-support
Jeff Wright:
Re: link at top. I wrote a paper on the Copenhagen and Niels Bohr physical model, so have some interest. I would have paid real money to be in the room when Einstein and Bohr went at it.
Steve Richter,
Compared to the other things you were apparently worried about – based on your self-reported Grok inquiries – I’d have to say that a Starship exploding on-orbit seems almost a rational fear by comparison. You seem to be one of those people who – for whatever strange quirk of personality – isn’t happy unless also scared to death about some bugbear or other derived from your obvious lack of any significant science education. At least Stone Age tribespeople on Pacific islands or in the Amazon Basin have a decent excuse for being hagridden by irrational fear of evil sprits and such. What, I wonder, is your excuse?
James Street,
Cue the next breathless legacy media report that ignores leftist and Islamist political violence and warns us all about the dire threat from White Christian Nationalists. 3, 2, 1…
Blair–
Tim Maudlin & Sheldon Goldstein:
The Copenhagen Interpretation and Bohmian Mechanics
(January 2024)
https://youtu.be/rjnaJ7oTHoE
1:46:31
“… What, I wonder, is your excuse? …”
What can I say. It helps my thought process. Quick aside, Grok is awesome in regard to answering question without ever impugning the asker!
It will be interesting to see if SpaceX can safely launch from LEO to the Moon and Mars. Safely as in not disturbing other satellites. And yeah, the first explosion in orbit caused by a $1 trillion valuation private company will be its last. What a lawsuit goldrush that will be.
First this crime.
https://spaceexplored.com/2023/10/03/alabama-tears-down-saturn-ib-from-i-65-welcome-center/
Now this:
https://x.com/TheOldManPar/status/2006759071928693083
Steve Richter wrote: “Was wondering if the exhaust from Starship as it launches from LEO would leave a damaging residue. Grok says no:”
“It will be interesting to see if SpaceX can safely launch from LEO to the Moon and Mars. Safely as in not disturbing other satellites.”
Grok is correct, and Starship will not disturb or damage other satellites. The exhaust is at a pressure, preferably a low one, but it dissipates rather quickly. If you ever get a chance to watch a launch shortly after sunset, then you will see the exhaust plume as it expands in the sunlight in the vacuum of the upper atmosphere. It is quite a sight.
The concern is more for operations near space stations. Arriving and departing vehicles necessarily exhaust some amount of their thrusters onto the space station structure, and that worries the space station owners, operators, and designers. Depending upon the propellants, the residues can be relatively harmless. For Starship, the main engine exhaust is water and carbon dioxide. Water can be mildly corrosive for some materials, so thruster use is limited to very small amounts until the vehicle gains a wide distance and the thrusters are aimed in a different direction, reducing the amount of impingement on the space station. Starship’s thrusters are methane boil-off, so we will have to see how they maneuver around space stations, if they do.
Some spacecraft use hydrazine or other corrosive propellants. These kinds of propellants are not desirable for use near space stations, or other spacecraft, for that matter. Hydrazine would be a less desirable choice for spacecraft that service or tug or extend the life of other spacecraft. Hydrogen peroxide is more desirable as its exhaust from the catalyst are steam and oxygen.
In mechanical engineering, choice of materials is important.
Damaging residues are not the only concern. There can be simple contamination without damage. When building satellites, one of the reasons for the cleanroom environment is to make sure that molecules do not condense onto the optical surfaces. Optics are not just the lenses or the windows but are also the solar arrays, which may have their efficiencies reduced, and the heat radiators, which may also reduce their efficiencies. The thermal blankets can also have their thermal characteristics change when molecules condense onto them, too.
“And yeah, the first explosion in orbit caused by a $1 trillion valuation private company will be its last. What a lawsuit goldrush that will be.”
Probably not. It would not be the first burst upper stage, and it would not be the last. Although these days the rocket companies work much harder to prevent such ruptures, accidents happen. The best way to mitigate the resulting debris field is to have these upper stages in a low Earth orbit that is below the usual populated orbits. I believe that SpaceX already does this with its Starlink satellites, putting them into a lower initial orbit, and if they do not work properly once released, they tend to de-orbit naturally and without the need for a retrograde burn. Once they prove themselves to be working properly, they can be maneuvered to their operating orbital slot.
Steve Richter,
It seems to be what you use instead of a thought process.
Suffering fools gladly is part of the design requirements for a commercial Large Language Model like Grok. But it ain’t part of mine.
For the rest, I’ll leave you in the capable hands of Edward – not that I expect you to profit from his explanatory forbearance.
Jeff Wright,
If you have something you regard as valuable, leaving it outside in the Deep South for 40 years isn’t really the way to show that. And when it rusts away, you’ve got no cause to get all judge-y about tearing it down before pieces start falling off and hurting somebody. Abuse of historical artifacts is the real crime there, not cleaning up the mess after the fact.
Anent the imminent test stand demolition, there aren’t going to be any more Saturns or Shuttles. So what, exactly, would be the point in keeping this rusting monstrosity around? A lot of Apollo-era stuff has been successfully repurposed at Stennis and even in Huntsville. So why cry over stuff that, literally, no longer is of any earthly use? Jared needs to do a lot more of this sort of thing – clear out the literal rot so as to spare NASA any further maintenance expense or liability risk. Not every piece of Apollo-era ironmongery is sacred.
It saddens me to hear you say that.
It is bad enough for Greens to tear down dams, factories, and powerplants without Libertarians tearing everything else down too.
What angered me the most about the Saturn demolition is that it was a violation of the law:
https://en.wikipedia.org/wiki/Alabama_Memorial_Preservation_Act
That didn’t stop zealots in Birmingham or Huntsville. The law was put into effect to stop all the statue removals, like those of Columbus.
So what the citizens want doesn’t matter.
In technology news
https://phys.org/news/2026-01-electron-atomic-scale-crystals.html
Jeff Wright,
You wrote: “It is bad enough for Greens to tear down dams, factories, and powerplants without Libertarians tearing everything else down too.”
You have compared useful, productive constructs with a useless test stand that no one cares about. The Saturn 1 is historical. Test stands, generally, are not. Some things should be preserved for future reference, but other things must be demolished for progress. If we kept everything around, we would be cluttered in junk with nowhere to build the next factory or power plant. I volunteer at a museum, where we have to choose what is worth preserving and what is not. Not everything is worth preserving. I said “we,” but it is the curator who makes that decision.
I agree with Dick about the Saturn. If Marshall Space Flight Center, NASA, Alabama, Congress, or the Smithsonian had thought it worth preserving, then they should have preserved it. They didn’t, so obviously they didn’t.