Continuing our tour of Uranus’ five biggest moons: Ariel

In preparing my cool image last week focused on the best Voyager-2 image of Uranus’ moon Miranda, I came to a realization that was somewhat startling. Voyager-2 is the only time a human spacecraft has gotten close to Uranus, and it was only close for a few days. Thus, the data and images it obtained of the gas giant and its moons is remarkable more sparse than I had ever realized.

You see, when these images were first released in 1986 they were exciting because they gave us that first look. Suddenly, a light was shined on something that had always been shrouded in darkness. It was a flood of data that needed processing.

It is now forty years later. No spacecraft has been there since, and thus we have gotten no more close-up information about Uranus or its moons. Data from Hubble and Webb has helped increase our knowledge of the planet itself, but of the moons nothing really new has been gleaned from this distance.

Uranus' five biggest moons

And so, to highlight how little we know, for the rest of this week I am going give my readers a tour of the few images Voyager-2 gave us of Uranus’ five biggest moons, the five that early astronomers had discovered prior to the space age and shown in the five pictures above, taken by Voyager-2 as it was approaching Uranus from a distance of about three million miles. They are, in order going from closest to farthest from Uranus, Miranda, Ariel, Umbriel, Titania and Oberon, with the images above designed to show their approximate relative sizes.

I already highlighted the strange, patchwork surface of Miranda last week, the smallest of these moons. Below is a mosaic made from the four highest resolution images of 720-mile-wide Ariel, the next out from Uranus, taken from a distance of about 80,000 miles.
» Read more

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A new startup proposes a giant 88,000 satellite data center constellation

Starcloud-4 being deployed
A satellite of the company’s fourth generation Starcloud
constellation being deployed

A new startup dubbed Starcloud has now filed an application with the Federal Communications Commission (FCC) to launch its own giant 88,000 satellite data center constellation.

The FCC accepted for filing March 13 an application by Starcloud, a company based in Redmond, Washington, to operate as many as 88,000 satellites in a range of low Earth orbits to serve as orbital data centers for artificial intelligence and other applications.

โ€œStarcloud is designing its satellite system to accommodate the explosive growth of datacenter demands driven by AI, which is already encountering severe roadblocks to efforts to scale on the ground,โ€ the company wrote in its filing. โ€œBy avoiding the constraints of terrestrial deployment, space datacenters will be the most cost-effective and scalable way to deliver compute this decade.โ€

The company, previously known as Lumen Orbit, has so far only launched one demonstration smallsat, testing the operation of a computer processor in orbit. It plans a second larger demo satellite to launch in ’27 testing a cluster of processors. Based on its own website, it plans to launch the full constellation in four stages, eventually using rockets comparable to Starship, launching many satellites at a time.

The reasoning behind these orbiting data center constellations is that in space there is no real estate to buy or environmental concerns to overcome. You can simply launch the satellites and beam the information to and from Earth. Though it still remains unknown whether this new orbiting data center business model will be profitable, it is definitely becoming a major customer for the new emerging American rocket industry. Even if it fails in the long run, it appears it will fuel the development of a lot of new rockets, all designed to be re-usable, with large capacities, and capable of launching at a fast cadence.

With such a commercial competitive fleet, the entire solar system will be open to the United States and the world.

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Astronomers discover a super-Earth-sized exoplanet covered by a molten ocean of lava

Using the Webb Space Telescope astronomers think they have identified a super-Earth-sized exoplanet, dubbed L98-59d and orbiting a red dwarf star about 35 light years away, that is covered by a very deep molten ocean of lava.

Their results reveal that the mantle of L98-59d is likely molten silicate (similar to lava on Earth), with a global magma ocean extending thousands of kilometres beneath. This vast molten reservoir allows the planet to store extremely large amounts of sulphur deep inside its interior, over geologic timescales. The magma ocean also helps L98-59d to retain a thick hydrogen-rich atmosphere containing sulphur-bearing gases such as hydrogen sulphide (H2S). Normally, this would be lost to space over time, due to X-ray radiation produced by the host star.

You can read the peer-reviewed paper here [pdf]. This planet is part of a three-planet solar system, all of which transit the face of the star, allowing for excellent observations of their make-up. L98-59d is the outermost of the three.

This is the first molten exoplanet yet detected, though it is likely not the last. As new better telescopes come on-line both on Earth and especially in space, the ability to make more detailed observations of the thousands of exoplanets so far identified is certain to reveal many more strange objects, some of which will be probably far stranger than we can yet imagine.

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New telescope array in Chile is financed entirely by private funds

One of Mothra's 30 mounts
One of Mothra’s 30 mounts. Click for original.

Capitalism in space: A new ground-based telescope array in Chile, dubbed Mothra, is being built using only private financing, and is being designed to map the faint hydrogen hidden between the galaxies and thus produce a more precise map of the universe.

MOTHRA is being built at Obstech / El Sauce Observatory in Chile. The telescope’s construction started in the spring of 2025 and it is expected to become fully operational by the end of 2026. By fusing its many images together digitally, the array of [30 mounts totaling] 1,140 telephoto lenses will be the equivalent of a single 4.7-meter diameter lens. It will be the world’s largest all-lens telescope, with capabilities that are unmatched by any other telescope on Earth or in space.

The funding comes mostly from a donation by British billionaire Alex Gerko, who has apparently donated millions to numerous similar research projects.

This is the right future for science research, and was the way things were done in the U.S. until World War II. Stop depending on the government, which often has political concerns that warp research and always does things inefficiently. Get the private sector, especially rich individuals, to back projects, because they will require the work to be done well, and will care personally about its success.

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Terran Orbital wins contract to build cubesat to go to Apophis with ESA’s Ramses probe

Apophis' path past the Earth in 2029
A cartoon (not to scale) showing Apophis’s
path in 2029.

The satellite company Terran Orbital, owned by Lockheed Martin, has won a contract from the European Space Agency (ESA) to build a cubesat to fly with its Ramses probe that will launch in 2028 and rendezvous with the potentially dangerous asteroid Apophis when it makes its very close fly-by of the Earth on April 13, 2029.

The CubeSat is named after Italian scientist Paolo Farinella and is backed by the Italian Space Agency. After successfully completing the Critical Design Review in January 2026, Tyvak International [a subsidiary of Terran Orbital] will begin the implementation phase, with launch currently planned for 2028.

…Operating aboard the RAMSES spacecraft, developed by OHB Italia, the Farinella CubeSat will be one of two spacecraft deployed to explore the asteroidโ€™s subsurface using low-frequency radar. The satellite will also carry Horus, an optical instrument that acts as both a science imager and navigation camera, and Vista, a dust detector previously flown on the Milani CubeSat from ESAโ€™s Hera mission.

Apophis is estimated to be about 1,200 feet across. When it does its fly-by in ’29 it will get within 20,000 miles of the Earth, dipping within the orbits used by geosynchronous satellites. It will then pass within 60,000 miles of the Moon. At its closest it will for a short time be visible to the naked eye.

Apophis’ orbit means that it has the potential in the next century or so to impact the Earth. This particular fly-by is significant because the Earth/Moon’s gravity will change the asteroid’s path in an unpredictable manner that could either increase or decrease that impact possibility on future fly-bys. And we won’t know until after the fly-by is complete.

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China completes two launches today

China today completed two separate launches from two different interior spaceports. First it successfully placed a military “remote sensing” satellite into orbit, its Long March 6A rocket lifting off from its Taiyuan spaceport in north China.

Next it placed eight satellites into orbit using its Kuaizhou-11 solid-fueled rocket, lifting off from Jiuquan spaceport in northwest China.

China’s state-run press provided no further details on those eight satellites. It also did not provide any information about where the lower stages of both rockets crashed inside China. As the Long March 6A uses very toxic hypergolic fuels, that can dissolve your skin if you come in contact with it, this lack of information tells us a lot about China and its government.

The leaders in the 2026 launch race:

32 SpaceX
12 China
3 Rocket Lab
2 Russia

SpaceX continues to lead the entire world combined in total launches, as it did in both โ€™24 and โ€™25.

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SpaceX launches 29 more Starlink satellites

SpaceX this morning successfully placed another 29 Starlink satellites into orbit, its Falcon 9 lifting off from Cape Canaveral in Florida.

The first stage completed its 6th flight, landing on a drone ship in the Atlantic.

The leaders in the 2026 launch race:

32 SpaceX
10 China
3 Rocket Lab
2 Russia

SpaceX continues to lead the entire world combined in total launches, as it did in both โ€™24 and โ€™25.

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SpaceX launches 25 Starlink satellites; reuses 1st stage for 32nd time

SpaceX earlier today successfully launched another 25 Starlink satellites, its Falcon 9 rocket lifting off from Vandenberg Space Force Base in California.

The first stage (B1071) completed its 32nd flight, landing on a drone ship in the Pacific, moving into fourth place in the rankings of the most reused launch vehicles:

39 Discovery space shuttle
33 Atlantis space shuttle
33 Falcon 9 booster B1067
32 Falcon 9 booster B1071
31 Falcon 9 booster B1063
30 Falcon 9 booster B1069
28 Columbia space shuttle

Sources here and here.

The leaders in the 2026 launch race:

31 SpaceX
10 China
3 Rocket Lab
2 Russia

SpaceX continues to lead the entire world combined in total launches, as it did in both โ€™24 and โ€™25.

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March 13, 2026 Quick space links

As BtBโ€™s stringer Jay is on vacation, here are a few links I spotted that donโ€™t deserve full posts. 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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Miranda, the smallest of Uranus’ spherical moons

Miranda as seen by Voyager-2
Click for original image.

Cool image time! The image to the right, reduced and sharpened to post here, was created from photographs taken on January 24, 1986 by Voyager-2 as it made its fly-by of the gas giant Uranus. From a later 1996 release:

Miranda, roughly 300 miles in diameter, exhibits varied geologic provinces, seen in this mosaic of clear-filter, narrow-angle images from Jan. 24, 1986. The images were obtained from distances of 18,730 to 25,030 miles; resolution ranges from 1,840 to 2,430 feet. These are among the highest-resolution pictures that Voyager has obtained of any of the new “worlds” it has encountered during its mission.

On Miranda, ridges and valleys of one province are cut off against the boundary of the next province. Probable compressional (pushed-together) folded ridges are seen in curvilinear patterns, as are many extensional (pulled-apart) faults. Some of these show very large scarps, or cliffs, ranging from 1,600 feet to 3 miles in height — that is, higher that the walls of the Grand Canyon on Earth.

This is really the only close look we have of this distant world. The other hemisphere remains a mystery, as it was in darkness when Voyager-2 zipped past. And though some of the individual shots that make up this mosiac are more detailed, they don’t provide that much more information.

Nonetheless, to my uneducated eye Miranda looks like a ball of thick molasses that some giant stirred a bit as gravity forced it to settle into its spherical shape. In this case the molasses is likely a mix of ice and other materials, not yet fully identified. The result is a tiny misshapen planet with some of the roughest topography known in the solar system, including one 12-mile high cliff face (the white streak at the image bottom) thought to be the highest in the solar system.

We don’t yet have a true understanding of the geological processes that formed this strange landscape, nor will we have until we have a lot more data, including a global map of the entire surface. And that won’t come until a spacecraft is sent there to look more closely. Right now no such mission is in the works. No NASA missions have been funded, though several have been proposed. And a Chinese mission was apparently canceled last year.

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