South Korea’s space agency wants to accelerate its launch capabilities

10:53 am

The head of South Korea’s space agency KASA, Oh Tae-seok, yesterday outlined plans to to accelerate the launch cadence of its government-built Nuri rocket, while also beginning research into building a second spaceport along with a specific launchpad for private companies.

Oh Tae-seok, head of KASA, held a press briefing at the agency in Sacheon, South Gyeongsang Province, on Thursday. “This week, the assembly of the first, second, and third stages of the fifth Nuri rocket will be completed,” he said. “From next week, we will begin full assembly of the entire rocket, and after the Launch Management Committee in early August, a September launch is expected.”

Oh also stressed the need to build a repeated launch system after the fifth launch to advance toward an era of “commercial launch services.” “To ensure the economic viability of Nuri, changes are needed in standardization and specification, as well as contracting methods and launch site operations, in addition to the advancement project,” he said. “We are preparing for four launches from 2029 to 2032.”

In addition, the agency plans to accelerate construction of the second spaceport. KASA began accepting candidate site applications for the second spaceport on the 22nd of this month. “We will select the final candidate site in October this year and aim to begin the project in 2028,” the agency said Thursday.

This second news report quoted Oh as also saying this:

“In the 2030s, rather than the current R&D approach, we should consider converting to a system where we commission launch services through purchasing, as NASA does.” This is a model similar to how NASA purchases launch services from private companies such as SpaceX.

In other words, even as he accelerates the use of Nuri, Oh wants to replace it with private rockets. Whether he can do both is questionable, because they act to cancel each other. A cheaper and viable government rocket will make it difficult for private startups to compete.

At the moment South Korea has one truly viable rocket startup, Innospace, which has one launch failure and hopes to try again before the end of the year. That it does not launch in South Korea but in Brazil suggests KASA has not been as cooperative with the commercial sector as Oh wants. His statements about building a launchpad for the private sector suggest he is aware of this.

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Astronomers discover two exoplanets as dense as cotton candy

9:40 am

The observed transits of TOI-791 c.
The observed transits of TOI-791 c by different telescopes
during its 232 day orbit. Figure 9 from the paper.

Using a combination of ground- and space-based telescopes, astronomers have now discovered two exoplanets in the same solar system that have a deas dense as cotton candy.

You can read their paper here. From the NASA press release:

Data from NASA’s TESS (Transiting Exoplanet Survey Satellite) mission has revealed two new “super-puff” planets, giant worlds so light that their density is comparable to cotton candy. Scientists calculate that these Jupiter-sized planets—named TOI-791 b and TOI-791 c—are the “puffiest” worlds ever found.

The planets orbit a Sun-like star named TOI-791 that is approximately 1,113 light years away from Earth. The TESS mission first detected the planets by watching for repeated dips in TOI-791’s brightness, a telltale sign that a planet is transiting, or passing in front of, a star. Further study revealed two large planets with unusual features.

TOI-791 b is nearly the same size as Jupiter but contains just 3.0 percent of Jupiter’s mass. TOI-791 c is even larger than Jupiter but contains just 5.9 percent of Jupiter’s mass.

The data for determining both planet’s density came from follow-up observations using a telescope based in Antarctica. Both planets have long orbits, 139 and 232 days respectively, so these observations took place over a period of eight years, in order to capture multiple orbital transits.

One interesting tidbit: Though the data suggests both planets are spherical, this is not confirmed with certainty. Overall, the nature of such puffy planets is not really understood at this time.

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Genesis cover

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 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

ESA to expand its program designed to encourage its commercial rocket industry

9:10 am

The European Space Agency (ESA) today announced it is expanding its “European Flight Ticket” program, designed to encourage its commercial rocket industry, by offering more rocket startups the opportunity to join.

The European Space Agency and the European Commission are inviting launch service providers across Europe to apply to join the European Flight Ticket Initiative. The objective of the Flight Ticket Initiative is to strengthen Europe’s access to space. European launch service providers compete to deliver missions for In-orbit Demonstration and Validation satellite (IOD/IOV) which test new space technologies in orbit. To support this, ESA launched a new two-part call for proposals.

To participate in the Flight Ticket Initiative, a launch service operator must first be awarded a framework contract. This allows them to compete for future missions under the Initiative. Avio, Isar Aerospace, PLD Space, and Rocket Factory Augsburg hold such contracts with ESA, following a first selection in 2024.

ESA and the European Commission are now expanding this pool by inviting additional European providers to apply. Companies that expect to be ready to launch before 2028 are encouraged to take part.

The program is also requesting bids for a new round of launch contracts. All bids are due by July 17, 2026.

The five European companies listed above are all either already operational (Avio), or hope to complete their first launch this year. There are several other European startups (Maiaspace, Latitude, HyImpulse) that are not far behind, and will likely bid.

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Four medical research organizations sign deals to do work on Vast’s space stations

8:59 am

Vast's Haven-1 and Haven-2 stations

Capitalism in space: The space station startup up Vast yesterday announced that three medical research companies and one university institute have signed preliminary agreements to continue and expand their ISS biological research on Vast’s Haven-1 and Haven-2 space stations.

Vast, the company building next-generation space stations and space infrastructure, announced today memorandums of understanding (MoUs) with UC San Diego’s Sanford Stem Cell Institute, Auxilium Biotechnologies, LambdaVision, and BioOrbit, advancing its network of microgravity research and manufacturing partners. Vast’s network brings together world-class universities, pioneering researchers, and cutting-edge technology providers to shape the future of microgravity research and manufacturing conducted in low-Earth orbit (LEO).

Though all four have done pure research on ISS, none have been permitted to produce products there for sale on Earth, due to NASA’s anti-commercial regulations. This will change on the new private stations. For example, LambdaVision has already signed an earlier agreement with the Starlab station to use it to manufacture its artificial retinas for sale. Auxilium meanwhile has already demonstrated on ISS the ability to create implantable medical devices using 3D printing. On Vast’s stations it will be able to expand this work by producing saleable products. BioOrbit in turn will use the Haven stations to begin manufacturing the zero gravity pharmaceuticals it has already tested on ISS.

Below is my updated ranking of the five American space stations presently under development:
» Read more

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Conscious Choice cover

Now available in hardback and paperback as well as ebook!

From the press release: In this ground-breaking new history of early America, historian Robert Zimmerman not only exposes the lie behind The New York Times 1619 Project that falsely claims slavery is central to the history of the United States, he also provides profound lessons about the nature of human societies, lessons important for Americans today as well as for all future settlers on Mars and elsewhere in space.

 
Conscious Choice: The origins of slavery in America and why it matters today and for our future in outer space, is a riveting page-turning story that documents how slavery slowly became pervasive in the southern British colonies of North America, colonies founded by a people and culture that not only did not allow slavery but in every way were hostile to the practice.  
Conscious Choice does more however. In telling the tragic history of the Virginia colony and the rise of slavery there, Zimmerman lays out the proper path for creating healthy societies in places like the Moon and Mars.

 

“Zimmerman’s ground-breaking history provides every future generation the basic framework for establishing new societies on other worlds. We would be wise to heed what he says.” —Robert Zubrin, founder of the Mars Society.

 

All editions are available at Amazon, Barnes & Noble, and all book vendors, with the ebook priced at $5.99 before discount. All editions can also be purchased direct from the ebook publisher, ebookit, in which case you don't support the big tech companies and the author gets a bigger cut much sooner.

 

Autographed printed copies are also available at discount directly from the author (hardback $29.95; paperback $14.95; Shipping cost for either: $6.00). Just send an email to zimmerman @ nasw dot org.

SpaceX launches 24 more Starlink satellites

8:28 am

SpaceX last night successfully placed another 24 Starlink satellites into orbit, its Falcon 9 rocket lifting off from Vandenberg Space Force Base in California.

The first stage (B1081) completed its 25th flight (50 days after its previous flight), landing on a drone ship in the Pacific.

The leaders in the 2026 launch race:

76 SpaceX
41 China
9 Rocket Lab (plus two suborbital HASTE launches)
8 Russia

For the third straight year SpaceX leads the entire world combined in total launches, 76 to 70.

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NASA IG: Isaacman’s decision to cancel Gateway and SLS upgrades saved billions

8:01 am

Isaacman: Saving billions and actually getting more done

According to a report released yesterday [pdf] by NASA’s inspector general, the decision by NASA administrator Jared Isaacman to not only “pause” the Lunar Gateway station (killing its HALO module) but also cancel SLS’s upgraded upper stage (EUS), its related stage adaptor (USA), and the giant mobile launcher (ML-2) needed for that taller upper stage, saved the taxpayer billions in additional cost overruns, and has likely accelerated the Artemis program significantly.

NASA’s reformulation of the Artemis campaign to meet the President’s National Space Policy and increase its cadence of missions by standardizing the SLS heavy-lift rocket resulted in the termination or repurposing of several Artemis-related systems, including the EUS, USA, ML-2, and HALO.

Over the course of their life cycles, the combined contract values for these efforts ballooned from nearly $2.8 billion to $5.9 billion and NASA extended their contracted delivery dates by up to 7 years. However, our projections indicate that if NASA allowed work to continue to completion, the systems would have cost more and taken longer than what was on contract.

Specifically, the IG estimated that the overruns for the upper stage, the stage adaptor, and the mobile launcher would have ended up costing four to five times their original budgets. Gateway’s HALO module was less out of control, but it was still going to go more than 30% over budget. Overall, all four projects would have cost NASA almost $5 billion in additional expenses, with all four likely to also be considerably behind schedule. The upper stage and mobile launcher were certainly not going to be ready when needed.

The IG made no recommendations. It released this report to provide NASA, the White House, Congress, and the public the information so as to properly judge the agency’s actions, as well as provide guidance to the agency itself.

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Leaving Earth cover

Leaving Earth: Space Stations, Rival Superpowers, and the Quest for Interplanetary Travel, can be purchased as an ebook everywhere for only $3.99 (before discount) at amazon, Barnes & Noble, all ebook vendors, or direct from my ebook publisher, ebookit.

If you buy it from ebookit you don't support the big oppressive tech companies and I get a bigger cut much sooner.

 

Winner of the 2003 Eugene M. Emme Award of the American Astronautical Society.

 
"Leaving Earth is one of the best and certainly the most comprehensive summary of our drive into space that I have ever read. It will be invaluable to future scholars because it will tell them how the next chapter of human history opened." -- Arthur C. Clarke

June 24, 2026 Quick space links

2:58 pm

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.

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Smooth on Mars is apparently not so smooth

11:00 am

Panorama on June 17, 2026
Click for full resolution. For original images, go here and here.

Overview map
Click for interactive map.

Last week I noted how the terrain that stood ahead of Curiosity in its travels on Mount Sharp on Mars appeared to be the smoothest the rover had seen in years.

This week it turns out that upon closer inspection, smooth on Mars is not as smooth as it seems. The panorama above, created from two pictures taken by the rover’s left navigation camera on June 17, 2026 (here and here), provides a much closer view of that smooth ground, and revealed that it isn’t actually smooth at all, but covered with small polygons. The inset on the left shows the area in the white rectangle at full resolution, making the patterned nature of the ground very obvious. From today’s update by the science team:

From up close, the parking spot looks anything but smooth. … There are polygons, veins, lamination, and probably more, once we inspect the higher-resolution images taken today. “Higher-resolution” is the key for why we were in for such a surprise! The features are quite small, a few centimeters across, and therefore we could not see them in the orbital images or from a distance in our navigation and mast camera images. The camera resolution from a distance just isn’t enough to see them. But up close, the terrain revealed all its beauty!

The blue dot on the overview map to the right marks Curiosity’s present position, the white dotted line its actual travels, the red dotted line its planned route. The yellow lines indicate roughly the area covered by the panorama above. The rim of Gale Crater can dimly be seen through the dusty atmosphere 20 to 30 miles away.

Explaining the geological process that caused this patterned surface is beyond my pay grade. My first guess would be it is related to the past presence of water, in the form of liquid or ice, but no one should take that guess very seriously.

As I have said many times, Mars is strange, Mars is wonderful, but above all, Mars is alien.

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Boeing wins $2 billion satellite contract from Space Force

9:05 am

In what appears to be the first major space contract Boeing has won in awhile, the Space Force yesterday awarded it a $2 billion contract to build two new military communications satellites, part of the War Department’s MUOS constellation.

The Boeing Co., El Segundo, California, has been awarded a maximum $2,002,862,607 fixed-price-incentive-firm-target contract for the Mobile User Objective System (MUOS) service life extension Phase II effort. This contract provides for the design, development, build, launch support, and on-orbit test support of two MUOS satellites. Work will be performed in El Segundo, California, and is expected to be completed by Sept. 30, 2035. [emphasis mine]

Boeing won the contract competition over Lockheed Martin, which had built the previous MUOS satellites.

I highlight the fixed-price nature of the contract. Boeing’s space-related division in the past two decades has had trouble dealing with such contracts, its corporate culture having become spoiled with cost-plus contracts, which are essentially blank checks. Its fixed-price Starliner contract is the best example, but the company’s repeated inability to stay under budget or get things done got so bad that by 2020 NASA announced it would no longer entertain any contract bids from the company, a policy that it still follows.

For Boeing, making this fixed-price contract work is literally a make-or-break situation. It needs to beginning producing such contracts on-budget and on-time, or else it will die.

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Some details about SpaceX’s secretive Starfall demo mission

8:40 am

Artist's rendering of Starfall provided during today's live steam
Artist’s rendering of Starfall provided during the launch live steam

In reading every report in the past day about SpaceX’s Starfall demo mission, in which it tested a returnable capsule capable of doing manufacturing in space or point-to-point transportation of cargo, the only one that appeared to provide any details about the mission itself was this article at NASAspaceflight.com.

And even those details are unconfirmed and somewhat sparse:

The Starfall demonstration vehicle stayed attached to the Falcon 9 second stage in LEO [low Earth orbit] for around 1.5 orbits. The second stage then deorbited itself and the Starfall capsule, after which Starfall was jettisoned and prepared for reentry. SpaceX released limited information about the mission, and it is unknown whether the Starfall demonstration vehicle carried any payloads, though instrumentation was likely used to measure reentry forces.

Following reentry, Starfall separated its two halves, deployed its parachutes, and splashed down in the Pacific, approximately 1,300 km off the west coast of the United States.

That’s all we presently know. Based on SpaceX’s tight-lipped approach, this mission was probably paid for by the War Department. In 2021 the Air Force had issued the company a $47.9 million contract to test point-to-point cargo transport by rocket “anywhere on the Earth in less than one hour, with a 100-ton capacity.” That cargo requirement suggested the rocket had to be Starship. It is very possible the contract was later amended to fit the 20 ton capability of Falcon 9, and this flight was the first demonstration of this cargo transport capability.

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June 23, 2026 Quick space links

2:55 pm

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.

  • Starliner remains in limbo according to Space News
    Ars Technica claims NASA has a tentative launch date of August 1, 2026, but no one believes it. As I first reported in May, NASA has given all crewed missions to SpaceX through 2030, leaving Boeing and Starliner nothing. It thus appears Boeing no longer wants to spend any money on it.
  • Vast gets a $32.75M tax credit from California
    The company seems proud to stay and even expand in California, which could be a big mistake as long as that state’s government remains decided leftist and hostile to private enterprise.
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Leonardo da Vinci: An art director, a painter, and a man whose life epitomized the uncertainty of existence

2:16 pm

Leonardo da Vinci: Flights of the Mind

I recently have finished reading two books on the life and work of Leonardo da Vinci. One is not worth mentioning, as it was poorly written but had the benefit of including a lot of da Vinci’s drawings from his many manuscripts. There are many such books, and the internet makes this work even more accessible, so why plug a bad book?

The other book, however, is very much worth recommending. Charles Nicholl’s 2005 biography, Leonardo da Vinci: Flights of the Mind, is a finely detailed work that carefully documents what is know, and what is not know, about da Vinci’s life.

And there are endless uncertainties. Nicholl’s makes these clear, and then provides a lot of good background information to give the reader a good sense of where reality lies, while recognizing much of what we know about Leonardo and his life remains guesswork that can never be resolved.

What Nicholl does best however is give a much more accurate portrayal of da Vinci as an artist and scientist. The myth that exists today is that da Vinci was mostly a failed painter and sculptor who repeatedly failed to finish his projects. This is wrong. In life he was actually quite successful as a painter, his work well admired and in demand. He only failed to complete a handful of projects, and in each case the failure was not his but his client. In one case, the Sforza Horse, he was unable to cast the giant sculpture because his client sold the bronze to make war weapons. In another, The Adoration of the Magi, he failed to finish the painting because his client simply paid him too little. And in a third, the Battle of Anghiari, the client decided to make it a competition between dueling frescos by da Vinci and Michelangelo. and after learning this da Vinci chose not to participate.

In between he completed many great works, such as the Mona Lisa and the Last Supper. And in fact, even the three incomplete works above made him famous, because all three were completed enough to show their unique originality and beauty. Da Vinci had style, and his work was always stunning to the eye.

Even so, like those unfinished works, almost everything da Vinci did hold mysteries and questions that today cannot be answered. » Read more

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Scientists: Interstellar Comet 3I/Atlas is very old, as much as 12 billion years old

12:51 pm

Webb data
Click for original image.

Based on spectroscopic data obtained by the Webb Space Telescope in the past year as interstellar Comet 3I/Atlas zipped through our solar system, a team of scientists have now concluded that its make-up suggests it is extremely old, as much as 12 billion years old, which means it was formed in the very early universe not that long after the Big Bang.

You can read their paper here [pdf]. The graph to the right was published by NASA of the infrared spectroscopic data produced by the Webb Space Telescope that supports this conclusion. That data shows the comet was lacking in isotopes commonly found today, while enriched in isotopes expected only in the early universe. From the paper’s abstract:

[W]e report isotopic measurements of the interstellar comet 3I/ATLAS, which reveal an elemental composition unlike any Solar System body. The water in 3I/ATLAS is enriched in deuterium, at a level of D/H = (0.98 ± 0.06)%, which is more than an order of magnitude higher than in known comets, while its range of 12[Carbon]/13[Carbon] ratios (141–191 for CO2 and 123–172 for CO) exceeds typical values found in the Solar System, as well as nearby interstellar clouds and protoplanetary disks.

Such extreme isotopic signatures indicate formation at temperatures ≲ 30 K in a relatively metal-poor environment. When interpreted with respect to models for Galactic chemical evolution, the carbon isotopic composition implies that 3I/ATLAS may have accreted as long ago as 12 billion years, following a period of intense, early star formation. 3I/ATLAS thus represents a preserved fragment of an ancient planetary system.

As the scientists add in what I think is an understatement, “Its distant origin in space and time makes 3I/ATLAS a uniquely-valuable object studies tool for Galactic archaeology.”

That the comet is still remarkable similar in many other ways to comets in our solar system also tells us that the formation processes that form all solar systems are somewhat common. The solar system in which Comet 3I/Atlas formed was different from ours only that it formed when the universe was young, and thus somewhat different in make-up. Otherwise the processes were the same.

At the same time, Comet 3I/Atlas has given us a window into the early universe, and suggests future interstellar comets will do the same. And there will be future interstellar comets, because we are now developing the observational tools to see them as they routinely fly past on a regular basis.

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Namibian government rejects Starlink

10:52 am

The Namibian government today announced it has rejected SpaceX’s application to provide Starlink to that country, apparently because the company will not comply with its laws that require ownership by Namibia citizens.

As a result, the regulator upheld its earlier ruling, stating that Starlink’s application remained non-compliant with the ownership and control requirements contained in Section 46 of the Communications Act, No. 8 of 2009. CRAN acknowledged that Low Earth Orbit satellite technology has the potential to improve connectivity across Namibia but stressed that all telecommunications operators must comply with the country’s legal and regulatory framework.

The authority also clarified that exemptions from the ownership requirements under Section 46(2) of the Communications Act can only be granted by the Minister of Information and Communication Technology and cannot be determined by CRAN through a reconsideration process.

In Africa such ownership laws almost always include a racial quota, requiring a certain percentage of ownership go specifically to blacks. SpaceX across the board refuses to do this.

The government apparently got 624 comments from the public asking it approve SpaceX’s application, but the regulators threw out all but 2 of those comments for what appears to be minor language or procedural issues.

My guess is that SpaceX refused to bribe these petty dictators, and so they denied the application.

Namibia, like South Africa, is making a foolish decision here, and as a result it is making itself a backwater, likely to trail the world in economic growth and prosperity for decades to come.

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SpaceX to raise $20 billion more by selling bonds

9:49 am

As part of its need for cash both to support its planned major capital projects and partly it appears to pay off some debt, SpaceX now plans to sell bonds in order to raise an additional $20 billion more.

The proceeds from the bond offering will mostly be used to refinance a $20 billion bridge loan SpaceX took in March as it prepared to go public. Such loans basically ensure that companies planning to go public have the money they would need to wait out an unfavorable turn in market conditions.

As the article at the link notes, however, SpaceX is hardly cash poor, having on hand over $100 billion after its initial public offering (IPO) of stock two weeks ago. On the surface this bond sale seems unnecessary, but I suspect its purpose is merely refinancing some already existing debt in order to save the company some money.

The propaganda press has been making much in the past week about the drop in SpaceX’s stock price following its original burst during the IPO, often spinning the drop as proof that SpaceX is not that valuable a company (see this NBC report for example). After raising to above $200 per share from its initial price of $135, it has since dropped to about $160. All of this is entirely normal. New stocks that capture the public’s interest all do this. The stock is simply now finding its natural market price, which by the way is still higher than that initial price.

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China’s Shenlong X-37B copy deploys a satellite

9:33 am

Shenlong in orbit shortly after launch
Shenlong in orbit shortly after launch.
Click for source.

According to data from the space surveillance company LeoLabs, China’s Shenlong mini-reusable shuttle — similar to the X-37B — deployed a object sometime before June 22, 2026.

At 02:30 UTC on 22 June 2026, LeoLabs detected an unknown object in the vicinity of the Chinese Shenlong reusable spaceplane.

This object did not correlate to any other object in our catalog. It was first observed by our Tracker radar in New Zealand.

This is not the first time a Shenlong in orbit released an object. On two previous flights in 2023 and 2024 it did the same. The Shenlong in orbit now was launched on February 7, 2026, the fourth mission of this X-37B copycat.

Overall, China has released very little information about Shenlong. We have no idea if the same or multiple Shenlongs have launched on the four known missions. No official pictures have ever been released, though the image of it to the right was apparently captured in orbit by amateur astronomers shortly after that February launch.

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Scientists skeptical of dark energy fight back!

9:06 am

Will cosmologists every enter?
Will cosmologists ever enter?

The uncertainty of science: In apparent direct response to the June 11, 2026 press release by cosmologists claiming that their data is correct and that the universe’s expansion is accelerating in the early universe and thus dark energy must exist, a different team of scientists today issued their own press release and research paper stating that the evidence of that acceleration is faulty and based upon a false assumption about supernovae.

The original discovery of dark matter and the acceleration was based on the brightness of a certain type of supernova in the early universe, which also assumed that brightness was always the same for every explosion. The new research says otherwise.

The team analysed the supernovae from the Pantheon+ dataset, one of the most comprehensive catalogues of its kind, and incorporated a recently proposed correction that takes into account the age of the stars that eventually produce these supernova explosions. They also checked whether the inferred acceleration of the expansion rate is indeed the same in every direction, as is assumed in the standard cosmological model. “There is increasing evidence that the brightness of Type Ia supernovae depends on the age of the stars they come from,” said Professor Sarkar, a co-author of the study. “If this effect is not accounted for, it can lead to the erroneous conclusion that the expansion rate is accelerating.”

After applying the correction, the researchers found that the data no longer support a picture of a uniformly accelerating universe. Instead, their analysis suggests that cosmic expansion is overall slowing down rather than speeding up.

Their conclusion is blunt: “There is thus no evidence for isotropic accelerated expansion of the Universe, which can be ascribed to either a Cosmological Constant or more general dark energy.”

In other words, there is solid disagreement within the cosmological community about the existence of dark energy. Some believe it exists, based on the supernova data. Some do not, because the data depends on too many assumptions about those supernovae that further observations suggest are wrong.

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