Author: Robert Zimmerman

Uranus: one glimpse and that was forty years ago

12:27 pm

Uranus as seen by Voyager-2, natural colors on left, false color on right
Uranus as seen by Voyager-2, natural colors on left, false color on right. Click for original.

I close today our week-long tour of Voyager-2’s fly-by of Uranus in January 1986 with three cool images, the two images of the planet itself above and a close-up of its rings. All three illustrate that though Voyager-2 gave us our first very good first close-up view of this distant world, it also gave us only a tiny glimpse, very superficial and lacking in any larger context.

The two images above were taken on January 17, 1986 when Voyager 2 was till 5.7 million miles away, on approach.

The picture at left has been processed to show Uranus as human eyes would see it from the vantage point of the spacecraft. The picture is a composite of images taken through blue, green and orange filters. The darker shadings at the upper right of the disk correspond to the day-night boundary on the planet. Beyond this boundary lies the hidden northern hemisphere of Uranus, which currently remains in total darkness as the planet rotates. The blue-green color results from the absorption of red light by methane gas in Uranus’ deep, cold and remarkably clear atmosphere.

The picture at right uses false color and extreme contrast enhancement to bring out subtle details in the polar region of Uranus. Images obtained through ultraviolet, violet and orange filters were respectively converted to the same blue, green and red colors used to produce the picture at left. The very slight contrasts visible in true color are greatly exaggerated here. In this false-color picture, Uranus reveals a dark polar hood surrounded by a series of progressively lighter concentric bands. One possible explanation is that a brownish haze or smog, concentrated over the pole, is arranged into bands by zonal motions of the upper atmosphere. The bright orange and yellow strip at the lower edge of the planet’s limb is an artifact of the image enhancement. In fact, the limb is dark and uniform in color around the planet.

The third cool image below of Uranus’s rings was taken just after the closest approach, when Voyager-2 was in Uranus’s shadow and looking back at its rings from a distance of 142,000 miles.
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Ursa Major test flies a new liquid-fueled missile engine for Air Force

10:51 am

Ursa Major's Draper engine being tested in flight

The rocket engine startup Ursa Major last week announced it had successfully completed for the Air Force a test missile launch of its new Draper liquid-fueled rocket engine.

As shown on the right, the Air Force’s Affordable Rapid Missile Demonstrator (ARMD) suborbital rocket was used to fly the engine. More information here.

On January 27, 2026, AFRL and Ursa Major launched the Draper liquid rocket engine on a demonstrator flight. While many details remain classified, the company says the test vehicle reached supersonic speeds during its flight. The test marked a transition from ground-based validation to in-flight evaluation, allowing engineers to study propellant stability, engine throttling performance, and how the system behaves under real flight conditions.

The Draper engine is designed to address key limitations of current hypersonic systems by making them cheaper, more scalable, and easier to operate. It runs on hydrogen peroxide and kerosene, fuels that are safer to store and handle compared to traditional alternatives.

The War Department’s hypersonic testing program has certainly heated up since the military switched to the capitalism model in the past five years. Beforehand, when the military tried to do its own testing, it took it years to get little done, while spending a fortune. Now it is flying suborbital rocket tests with Rocket Lab, Stratolaunch, and Firefly. It is testing new engines on flights such as Ursa’s above. And it testing hypersonic avionics on Varda’s orbiting capsules upon their return to Earth. Based on this commercial activity, it appears the U.S. military might get some real hypersonic capabilities in the very near future.

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Kratos wins $446 million contract to build/operate ground system for Space Force satellite constellation

10:13 am

The military contractor Kratos Defense & Security Solutions was yesterday awarded a $446 million contract by the Space Force to build and operate the ground systems used to control the military’s missile warning satellite constellation.

The contract covers ground management and integration for the service’s Resilient Missile Warning and Tracking program, according to a March 19 statement from Space Systems Command. Kratos will provide the systems used to operate the satellites after launch, including sending commands, receiving sensor data and processing that information for delivery to military operators.

The work supports a constellation being deployed in phases. The first 12 satellites, known as Epoch 1, are being built by Millennium Space Systems, a Boeing subsidiary. A second set of 10 satellites, called Epoch 2, is under contract to BAE Systems. Launches are expected over the next several years.

The method in which this entire constellation is being built and operated once again highlights the profound transformation that has occurred in how the Pentagon works in space since the formation of the Space Force. Beforehand, when the Air Force ran the military’s space operations, it would attempt to design and build everything, and the satellites built would be big and expensive, and take years to complete. Generally, little got built for a lot of money. Moreover, the upper management of the Air Force was in general not interested in space projects, and often gave these projects lower priority.

The Space Force was created during Trump’s first term to change this, giving the military an agency focused on its space needs. It was also designed to put those in charge who had been advocating going from these big gold-plated satellites that were few in number to many small satellites built quickly and cheaply by the private sector.

This new missile warning and tracking constellation demonstrates that this transition is largely complete. It is being built quickly by two different satellite companies, and will be maintained on the ground by a third.

Note: Kratos also builds the hypersonic test vehicles that Rocket Lab launches on its HASTE suborbital rocket. It will soon also fly those vehicles on a Firefly rocket.

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India’s second spaceport to be completed next year

9:26 am

The existing and proposed spaceports in India
The existing and proposed spaceports in India

According to officials in India, the nation’s second spaceport at Kulasekarapattinam is on schedule to be completed by next year, when it will become available for polar launches of the SSLV rocket as well as other commercial rocket launches.

India is moving ahead with plans to operationalise a new launch facility at Kulasekarapattinam in Tamil Nadu. It is expected to be commissioned during the 2026–27 financial year, according to information shared in the Lok Sabha by Jitendra Singh.

The new facility, officially called the Small Satellite Launch Vehicle (SSLV) Launch Complex, is being developed as the country’s second space launch site. The Kulasekarapattinam complex will primarily handle launches of SSLV missions to Sun-synchronous Polar Orbit, a trajectory widely used for Earth observation satellites.

The SSLV rocket is at present controlled by India’s space agency ISRO, though there has been an effort by the Modi government to transfer it to the private sector. It is not clear whether that effort has been successful. ISRO and India’s large space bureaucracy has been resistant. There have also been indications that this new spaceport will be made available to the handful of Indian rocket startups that are developing their own rockets.

The Sriharikota spaceport is ISRO’s main launch site. The Hope Island site is a proposed commercial and private spaceport, whose future remains very uncertain.

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ESA to rent SpaceX Dragon capsule to do a European manned mission to ISS

9:15 am

ESA logo

Capitalism in space: At a European Space Agency (ESA) this week in Switzerland, agency officials announced that it is purchasing use of a Dragon capsule from SpaceX in order to do an extended manned mission to ISS in 2028.

Member states endorsed the concept of EPIC — short for ESA Provided Institutional Crew — a proposed mission intended to provide a medium-duration stay for ESA astronauts aboard the ISS.

The plan foresees acquiring a Crew Dragon mission in the first quarter of 2028 in collaboration with “interested international partners.” Crew Dragon is the crew spacecraft built by US company SpaceX.

According to those officials, this mission will be for at least one month, and include astronauts from ESA and some as yet undetermined international partner astronauts.

This contract illustrates the fundamental shift in power and control in manned space in the past decade. Until 2011, all manned missions were flown on government-built rockets and spacecraft. The agencies controlled everything, and actually acted to stymie competition from the private sector.

Now, those agencies are dependent on that private sector for their manned missions. They are instead merely customers, buying services from competing commercial companies that own the rockets and spacecraft, and rent them out for profit. That SpaceX at present is the only one capable of doing these manned missions for hire makes no different. Soon others will enter the fray.

Moreover, this capitalism model actually gives these agencies more flexibility. Beforehand, ESA had to go through NASA to do such a manned mission, and that would involve a lot of negotiations. Now it simply buys the mission from SpaceX, and flies it when ready.

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SLS/Orion have begun 12-hour trip from VAB to launchpad

8:59 am

Artemis-2 mission flight path
The Artemis-2 flight path. Click for full animation.

NASA engineers today began the long and slow 12-hour trip of the SLS rocket from the Vehicle Assembly Building (VAB) to the launchpad in preparation for a targeted April 1, 2026 launch date of this Artemis-2 mission around the Moon.

NASA’s Artemis II SLS (Space Launch System) rocket and Orion spacecraft slated to send four astronauts around the Moon began rolling to Launch Pad 39B at 12:20 a.m. EDT on Friday, March 20. Rollout operations at the agency’s Kennedy Space Center in Florida were delayed earlier in the day due to high winds in the area.

The trek to the pad is expected to take up to 12 hours, as NASA’s crawler-transporter 2 carefully carries the rocket on top of the mobile launcher approximately 4 miles along the crawlerway.

The launch will send four astronauts on a ten-day mission swinging around the Moon and back to Earth, using a questionable heat shield and a life support system not yet been tested in space. On the first unmanned Artemis-1 mission around the Moon in 2022, the shield experienced far more damage than predicted, with large chunks breaking off. NASA engineers think they understand why this happened, and have decided that they can mitigate the problem by using a less stressful flight path upon return into Earth’s atmosphere.

They don’t really know if this is so, but they hope so. As for the life support system, the plan is to remain in a high Earth orbit for the mission’s first day to test it. If it has problems then, the crew will be able to return to Earth somewhat quickly. If it has problems after heading to the Moon, however, that won’t be possible.

If a private company tried to convince NASA to do this mission with these issues, the agency would say “Hell no!” It is proceeding because, like the Challenger and Columbia failures, it is a NASA-built project and politics and schedule have superseded safety and good engineering procedures

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Engineers regain contact with Proba-3’s Coronagraph probe

8:36 am

The Proba-3 mission
The Proba-3 mission. Click for original.

A month after all contact was lost with the Coronagraph probe of Europe’s two-spacecraft Proba-3 solar observatory, engineers have regained contact with it this week, and have been able to place it in safe mode in preparation for re-establishing science operations.

After more than a month of silence, ESA’s ground station in Villafranca, Spain, received telemetry from the Coronagraph spacecraft. Telemetry is a package of data sent by a spacecraft including information on its temperature, voltages, and health of onboard systems.

The Coronagraph is now in safe mode and stable, and the mission team and operators are running health checks on the spacecraft to understand if any parts of it have been damaged.

The spacecraft’s solar panel is facing the Sun, powering the essential electronics on board, and charging the battery with the remaining power.

Before it can resume observations engineers need to get the spacecraft back up to operating temperature after a month without power.

As shown in the graphic to the right, the Coronograph satellite is the heart of this mission. It records the data, available because the Occulter blocks the Sun from view so that the corona, the Sun’s atmosphere, can be seen. It is almost a miracle that it has survived that month, and can soon resume observations.

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Blue Origin files FCC application for its own 51,600 data center satellite constellation

8:01 am

Blue Origin yesterday filed with the Federal Communications Commission (FCC) an application to launch 51,600 satellites, dubbed Project Sunrise, aimed at creating its own data center constellation in orbit.

The proposed constellation includes up to 51,600 satellites operating in sun-synchronous orbits at altitudes ranging from 500 to 1,800 kilometers. To manage data traffic, the system will primarily use optical links and mesh backhaul networks, supplemented by Ka-band spectrum for telemetry, tracking, and command operations. The spacecraft will utilize multiple antenna variations to maintain efficient coverage across various orbital planes.

You can read the full application here [pdf].

Jeff Bezos
Jeff Bezos, maybe the world’s leader in chutzpah.

Blue Origin also requests several waivers from the FCC’s normal new satellite license requirements, including what I think is a request to waive the FCC’s normal requirement that the applicant launch half its constellation within six years of license approval and complete the constellation three years later. Failure to do so results in financial penalties. The rules were created to prevent companies from getting licenses to grab spectrum from competitors with no intent to launch.

That this Jeff Bezos company is requesting this waiver is what in Yiddish is called chutzpah! Bezos’ other company, Amazon, is clearly going to fail to meet its own license timetable in launching its Leo internet constellation, and was recently lambasted by FCC chairman Brenden Carr for doing so. For Blue Origin to now request this waiver truly is an example of unbelievable gall. I can’t imagine the FCC will do so.

Either way, the competition to put up a lot of satellites continues to grow, with SpaceX and Blue Origin in the best position to make their constellations profitable, because both have their own launch vehicles.

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March 19, 2026 Quick space links

2:44 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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SpaceX completes a Starlink launch

2:14 pm

UPDATE: It appears The Russian launch described below did not occur as indicated by the story I linked to. There is no confirmation anywhere on the web that the launch occurred. If it had, the nature of the payload would have guaranteed some story in Russia’s state-run press. See also this X post, which suggests the lack of information about the scrub is related to Russian concerns about Ukrainian drone attacks.

Original post
———————-
There were two launches today, both of which sent up a cluster of satellites for broadband internet constellations.

First, Russia launched the first 16 satellites in its proposed 700+ satellite Russvet internet constellation, its Soyuz-2 rocket lifting off from its Plesetsk spaceport in northeast Russia. The satellites are built by the Russian company Bureau-1440, which hopes to have the entire constellation in orbit by 2035. Considering that this constellation is designed to compete with Starlink, its pace of launch is ridiculously low. SpaceX can generally launch 700 Starlink satellites in about a month, not ten years. By the time Russia gets this constellation in orbit it will be woefully obsolete.

SpaceX meanwhile proved this point today by continuing its brisk pace in Starlink launches. It successfully placed 29 more Starlink satellites in orbit, its Falcon 9 rocket lifting off from Cape Canaveral Space Force Station in Florida.

The first stage (B1077) completed its 27th flight, landing on a drone ship in the Atlantic, only 26 days after its previous flight. This flight also moved the booster up to just behind the space shuttle Columbia 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
27 Falcon 9 booster B1077

Sources here and here.

The leaders in the 2026 launch race:

35 SpaceX
12 China
3 Rocket Lab
2 Russia (corrected)

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

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Scientists compile catalog of the 69 known rocky exoplanets in the habitable zone

12:49 pm

Graph of the 45 most habitable known exoplanets
Credit: Gillis Lowry / Pablo Carlos Budassi.
Click for original at full resolution.

Scientists reviewing the more than 6,000 exoplanets so far discovered have now compiled a detailed catalog describing the 69 known rocky exoplanets that are also in the habitable zone.

The graph to the right, cropped and reduced to post here, shows the 45 exoplanets most likely to be habitable, with the amount of energy they get from their star measured relative to that of Earth and the Sun (shown center top). You can read their paper here. From the press release:

The researchers pinpointed 45 rocky worlds that may support life in the habitable zone, and another 24 in a narrower 3D habitable zone that makes a more conservative assumption of how much heat a planet can take before it loses its habitability.

They include some famous exoplanets, including Proxima Centauri b, TRAPPIST-1f and Kepler 186f, as well as others that are not as well known, such as TOI-715 b. The most interesting planets of those listed, according to the authors, are TRAPPIST-1 d, e, f and g, which are 40 light-years from Earth, as well as LHS 1140 b, which is 48 light-years away. Whether these planets could have liquid water depends in part if they can hold an atmosphere.

The worlds that get light from their stars most similar to what modern Earth receives from the Sun are the transiting planets TRAPPIST-1 e, TOI-715 b, Kepler-1652 b, Kepler-442 b, Kepler-1544 b and the planets Proxima Centauri b, GJ 1061 d, GJ 1002 b, and Wolf 1069 b, which make their stars wobble.

The paper includes tables listing the best exoplanets that do transits of their stars, the best with the oldest estimated ages, and the best for testing the limits of the habitable zone itself. As the researchers say in their abstract:

The resulting list of rocky exoplanet targets in the HZ will allow observers to shape and optimize search strategies with space- and ground-based telescopes – such as the James Webb Space Telescope (JWST), Extremely Large Telescope (ELT), Habitable Worlds Observatory (HWO), and Large Interferometer For Exoplanets (LIFE) – and design new observing strategies and instruments to explore these worlds, addressing the question of the limits of exoplanet surface habitability.

In other words, the focus of exoplanet research is now shifting from simply finding these planets to studying them directly, with the potentially habitable worlds listed above the most interesting of all. Astronomers might not find alien life or civilizations on these worlds, but at a minimum they will be doing the first preliminary scouting for humanity’s the first interstellar missions, with the Trappist-1 solar system appearing to head the list.

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Uranus’s moon Oberon, of which we know little

11:38 am

Uranus' five biggest moonsThe historically known moons of Uranus. Click for original NASA press release.

Oberon, as seen by Voyager-2
Click for original image.

Today we finish our week-long tour of the five largest moons of Uranus, all discovered by astronomers before the start of the space age, and imaged successfully if not very completely by Voyager-2 when it did its fly-by of the planet on January 24, 1986. The gallery of these moons above was taken by the spacecraft when it was on approach, still about three million miles from Uranus, and shows them in order from the innermost on the left to the outermost on the right. They are also scaled to show their relative sizes. To see Voyager-2’s close-up images of the four inner moons, posted earlier this week, go here, here, here, and here.

The picture to the right, cropped slightly to post here, is Voyager-2’s only high resolution image of Oberon, the outermost moon of this group. From NASA’s press release:

This Voyager 2 picture of Oberon is the best the spacecraft acquired of Uranus’ outermost moon. The picture was taken shortly after 3:30 a.m. PST on Jan. 24, 1986, from a distance of 410,000 miles. The color was reconstructed from images taken through the narrow-angle camera’s violet, clear and green filters.

The picture shows features as small as 7 miles on the moon’s surface. Clearly visible are several large impact craters in Oberon’s icy surface surrounded by bright rays similar to those seen on Jupiter’s moon Callisto. Quite prominent near the center of Oberon’s disk is a large crater with a bright central peak and a floor partially covered with very dark material. This may be icy, carbon-rich material erupted onto the crater floor sometime after the crater formed. Another striking topographic feature is a large mountain, about 6 km (4 mi) high, peeking out on the lower left limb.

Oberon is about 946 miles in diameter, making it the tenth-largest moon in the solar system. Because of the quickness of Voyager-2’s fly-by, it could get no closer images, and none of the planet’s nightside. Thus, only 40% of the surface has been photographed, and at not very high resolution.

Later spectroscopy from Hubble and other telescopes suggests there is water ice on the surface. Other data suggests Oberon may have a liquid underground ocean, but that conclusion is highly uncertain. Other than these vague facts and the image to the right, we essentially know almost nothing about this moon. Like Titiania, Uranus’s largest moon, Voyager-2’s data merely gave us a tantalizing glimpse, and that glimpse is now forty years old. No other mission has been there since, and none is planned in the near future.

Tomorrow, to summarize this tour, I will outline further what little we know of Uranus and its moons

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German rocket startup signs deal to launch from SaxaVord spaceport in Scotland

9:56 am

Proposed or active spaceports in North Europe
Proposed or active spaceports in North Europe

The German rocket startup HyImpulse yesterday signed a contract with the SaxaVord spaceport on the Shetland Islands in Scotland to do a suborbital test launch at SaxaVord later this year.

HyImpulse has agreed a launch deal with the Unst spaceport, with the aim of a suborbital launch in quarter three of 2026. It will be the second launch of the company’s SR75 suborbital launch vehicle following a successful lift-off in Australia in 2024, which used a hybrid propulsion system involving paraffin “candle wax” and liquid oxygen. HyImpulse said that initial launch, from Koonibba, showed the vehicle could demonstrate “stable flight validating system performance under operational conditions”.

Under the agreement, SaxaVord will provide launch infrastructure and operational support for the launch of the SR75.

HyImpulse is the second German rocket startup to sign a deal to launch from SaxaVord. Rocket Factory Augsburg plans its second attempt to do an orbital launch from there later this year. In 2024 it was gearing up to do that launch but an explosion during a full static fire test of the rocket’s first stage killed that plan.

Considering the red tape the United Kingdom has imposed on rocket companies, bankrupting two and delaying all launches for years from both SaxaVord and the other proposed spaceport in Sutherland, Scotland, I am surprised these two rocket companies have signed these deals. Maybe the UK’s Civil Aviation Authority (CAA) has been reformed and eased that red tape.

Or maybe HyImpulse will find its plans blocked by the CAA as that agency once again ponders at glacial pace the issuing of a new launch license. Stay tuned.

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OHB wins $285 million contract to build weather satellite constellation for ESA

9:36 am

ESA logo

Capitalism in space The Swedish subsidiary of the European aerospace company OHB yesterday announced it has won a $285 million contract from the European Space Agency (ESA) to build and maintain a six satellite weather satellite constellation.

The company had already successfully launched and tested a single demo satellite, proving a small satellite could do the job.

The foundation for this is the Arctic Weather Satellite (AWS), which OHB Sweden successfully placed in orbit as a demonstrator more than a year ago. The OHB SE subsidiary developed the small satellite on behalf of the European Space Agency ESA in record time, using a deliberately chosen New Space approach. Only three years passed between contract award and launch.

This new constellation is dubbed EUMETSAT Polar System – Sterna (EPS-Sterna), and will supplement and eventually replace the expensive government-built Eumetsat weather constellation presently in orbit.

OHB Sweden is the prime contractor for the delivery of the satellites for the EPS Sterna constellation. The consortium also includes Omnisys in Sweden as the supplier of the microwave instruments, which constitute the primary meteorological payload. A total of 20 satellites will be delivered under the contract. The industrial team includes approximately 30 companies. Germany is also strongly represented by SMEs that will contribute key hardware for the instrument and the satellite platform. The satellites will be procured by EUMETSAT through ESA. EUMETSAT itself will develop the ground segment, procure and provide the launch services, operate the satellites, manage the constellation and distribute the data through its data distribution mechanisms, which has a planned operational lifetime of 13 years.

This contract is another example of Europe’s fast shift in the past three years from the government model to the capitalism model. It took ESA almost a decade to finally decide to make that shift, but once it did it seems to be moving far faster than NASA did to implement it.

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Update on SpaceX’s preparations for the 12th orbital test flight of Starship/Superheavy

9:22 am

Link here. The testing has apparently verified the fueling system of Superheavy at the new launchpad.

Starship Flight 12 took another step toward launch, with Booster 19 completing an initial test campaign on the newly commissioned Pad 2 at Starbase, Texas. Culminating in a short Static Fire test, the series of tests was a first for Pad 2, the Block 3/V3 Super Heavy Booster, and for the upgraded Raptor 3 outside of single engine testing.

As the inaugural vehicle to undergo operations on this pad, B19’s campaign served as both a booster qualification test and a commissioning milestone for the expanded launch infrastructure, paving the way for a long-awaited static fire test of its Raptor 3 engines.

Lots of details worth reading. Ground testing will now shift to Starship. All in all, it does appear that an early April launch is likely.

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Rocket Lab wins $190 million hypersonic test contract from War Department

9:14 am

War Department logo

Rocket Lab yesterday announced it has won a $190 million contract from War Department to do another twenty suborbital test launches using its HASTE first stage version of its Electron rocket.

Rocket Lab Corporation … today announced the signing of its single largest launch agreement yet: a $190 million contract for a block buy of 20 hypersonic test flights with its HASTE launch vehicle for the Test Resource Management Center (TRMC) Multi-Service Advanced Capability Hypersonic Test Bed (MACH-TB) 2.0 program – a U.S. Department of War effort executed in partnership with Naval Surface Warfare Center Crane Division (NSWC Crane) to rapidly accelerate hypersonic flight tests and advanced aerospace technologies shaping the future of defense missions.

Under MACH-TB 2.0 Task Area 1, led by Kratos Defense & Security Solutions, Inc, Rocket Lab will perform 20 hypersonic test flights with its HASTE launch vehicle over a four-year period. The first of these 20 new missions is expected to take place within months of contract signing, demonstrating Rocket Lab’s operational efficiency and ability to move quickly to meet modern warfare demands.

This is the work that Stratolaunch had hoped to grab with its giant Roc airplane and Talon hypersonic test vehicle. Rocket Lab saw an opportunity and quickly reconfigured the first stage of its Electron rocket for the same work, dubbing this version HASTE. In the past three years both it and Stratolaunch have done hypersonic test flights, but Rocket Lab’s work has been more frequent and extensive, doing seven HASTE hypersonic launches to one test by Stratolaunch. That success apparently convinced the military to give Rocket Lab this larger new contract.

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Scientists: Shadowcam images suggest there is little water in permanently shadowed lunar craters

8:58 am

Shadowcam-LRO mosaic
The floor of Shackleton Crater showing no obvious ice deposits,
as seen by Shadowcam, imposed on a Lunar Reconnaissance Orbiter
image. The black cross marks the south pole. Click for original image.

In a new paper published yesterday, the science team for the low-light Shadowcam instrument on South Korea’s lunar orbiter Danuri confirmed their earlier conclusion from 2024, that there appears to be far less water ice than expected in the permanently shadowed lunar craters near the Moon’s south pole. From their abstract:

We used the high-reflectance and forward-scattering optical properties to search for water ice in lunar PSRs [permanently shaded regions]. We found no evidence of widespread water ice in PSRs at abundances above the detection limit of 20 to 30 wt % but could not rule out widespread low-content water ice. A few small locations with both high reflectance and forward-scattering behavior were observed, which could be consistent with >10 wt % ice.

And from their conclusion:

Our manual examination of ShadowCam radiance images that cover all lunar PSRs suggests either that most of the lunar PSRs lack surface ice exposures or that their ice concentration is below the detection limit, approximately 20 to 30 wt % on the basis of the visible reflectance enhancement, which aligns well with previous ShadowCam findings. Only a few candidate high-reflectance anomalies were seen, which, if they are water ice, is consistent with previous sparse detections of lunar surface water ice.

There is still a chance there is water ice in these permanently shadowed craters, but it appears once again that if it exists, it will likely require processing to extract it from the soil, and there won’t be that much available regardless.

These results are not conclusive, but they do suggest that the south pole of the Moon will not be as ideal a location for a lunar base as previously imagined.

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March 18, 2026 Quick space links

2:42 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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Tantalizing Titania, Uranus’s largest moon

11:45 am

Uranus' five biggest moonsThe historically known moons of Uranus. Click for original NASA press release.

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

This week’s tour of the five largest moons of Uranus continues today with a look at the highest resolution picture taken Uranus’s largest moon, Titania, when Voyager-2 did its fly-by of the solar system’s seventh planet on January 24, 1986. The image to the right, cropped and reduced to post here, was taken from about 229,000 miles, and can only resolve objects bigger than eight miles across. From the press release:

Titania is the largest satellite of Uranus, with a diameter of a little more than 1,000 miles. Abundant impact craters of many sizes pockmark the ancient surface. The most prominent features are fault valleys that stretch across Titania. They are up to 1,000 miles long and as much as 45 miles wide. In valleys seen at right-center, the sunward-facing walls are very bright. While this is due partly to the lighting angle, the brightness also indicates the presence of a lighter material, possibly young frost deposits. An impact crater more than 125 miles in diameter distinguishes the very bottom of the disk; the crater is cut by a younger fault valley more than 60 miles wide. An even larger impact crater, perhaps 180 miles across, is visible at top.

Two or three other images were taken by Voyager-2, but they don’t provide any significant additional information. All told the spacecraft was only able to see about 40% of Titania’s surface.

Subsequent research using a variety of orbiting telescopes have suggested there is water ice and carbon dioxide on the surface. This data also hints of the presence of a very very thin atmosphere. These results however are quite uncertain.

As with Uranus’s other moons Miranda, Ariel, and Umbriel that I highlighted earlier this week, the Voyager-2 data merely gives us a taste of what’s there. Forty years later we have learned almost nothing more about these distant worlds.

Tomorrow we look at Oberon. I will then follow-up the next day with a look at what we don’t know about Uranus and its moons.

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Scientists detect the five chemicals that make up DNA/RNA inside Ryugu samples

11:05 am

Ryugu's northern hemisphere
Ryugu as seen by Hayabusa-2 shortly before it grabbed
samples from the surface. Arrow indicates planned touchdown
site.

Scientists studying the samples brought back from the asteroid Ryugu by Japan’s probe Hayabusa-2 have found therein a full set of the five fundamental chemicals that make up either DNA or RNA: adenine, guanine, cytosine, thymine and uracil. From the paper’s [pdf] abstract:

Organic molecules delivered from extraterrestrial materials may have played a key role in supplying building blocks for life on Earth. Here we report all five canonical nucleobases—purines (adenine and guanine) and pyrimidines (cytosine, thymine and uracil)—in samples returned from the C-type asteroid (162173) Ryugu by JAXA’s Hayabusa2 mission and compare the results with data from similar extraterrestrial material.

Ryugu samples contain nearly equal amounts of purines and pyrimidines, whereas Murchison is enriched in purines and Bennu and Orgueil in pyrimidines. Samples from Ryugu, Bennu and Orgueil, which have a similar mineralogy and elemental composition, show purine-to-pyrimidine ratios negatively correlating with ammonia.

These observations indicate that the nucleobases in these samples may have formed via a shared pathway depending on the physicochemical environment of the respective parent bodies. The detection of diverse nucleobases in asteroid and meteorite materials demonstrates their widespread presence throughout the Solar System and reinforces the hypothesis that carbonaceous asteroids contributed to the prebiotic chemical inventory of early Earth.

In other words, the data from these samples suggests that the formation of life on Earth was greatly aided by the deposition of these carbon molecules from asteroids onto the Earth.

At the same time, some caution must be exercised. At present we only have samples from three asteroids, one of which (Orgueil) was obtained shortly after it crashed on Earth. It will take a much larger census of many in-space asteroids to confirm this hypothesis.

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Solar scientists: We finally think we know the location of the Sun’s dynamo

10:42 am

The Sun's interior
NASA graphic used in the press release and
annotated to post here.

The uncertainty of science: Using three decades of data gathered during the last three solar cycles, scientists now think they have finally determined the location of the Sun’s dynamo in its interior, at a transition point about 125,000 miles below the surface called the tachocline. From the abstract of their paper [pdf]:

The exact location of the solar dynamo remains uncertain–whether it operates primarily in the near-surface shear layer, throughout the entire convection zone, or near the tachocline – a region of sharp transition in the solar rotation, located at the base of the convection zone, approximately 200,000 km [125,000 miles] beneath the surface. Various studies have supported each of these possibilities.

…Our analysis reveals that the gradient of rotation displays ‘butterfly’–like behavior near the tachocline, which is similar to the magnetic butterfly diagram at the surface. This result supports the idea that the solar dynamo has a deep-seated origin, likely operating either near the tachocline or throughout the convection zone, thereby disfavoring the recent scenario of a shallow, near-surface dynamo. This finding may also have important implications for understanding how stellar dynamos operate in general. [emphasis mine]

Even though scientists have known for more than a century that the Sun’s eleven-year cycle of flipping the polarity of its magnetic field is the fundamental cause of the sunspot cycle, they actually know very little about the dynamo that causes that magnetic field, as this study implies. They not only don’t have any understanding of the fundamental processes that creates that dynamo or causes it to flip polarity every eleven years, they still aren’t entirely sure where it is located within the Sun.

Thus, the highlighted sentence above is one large understatement. Of course knowing the dynamos location will have “important implications for understanding stellar dynamics.” This study is a first good stab at the problem, but it also shows us how little we actually know.

Remember this when anyone tells you “the science is settled” about climate change. The Sun is the number one influence on the Earth’s climate, and its solar cycle appears to be an important factor in that influence. Until we have a better understanding of the Sun, its magnetic field, and the dynamo that creates it, no climate prediction will be worth anything. Such predictions will be all guesswork, and likely put forth for political reasons.

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Why are commercial space startups shifting their focus to the military? $185 billion is the answer

9:21 am

War Department logo

In the past two years a number of space startups as well as established companies have shifted their work focus from getting NASA or commercial contracts to pursuing projects from the War Department.

The best example of this has been Sierra Space, which until three years ago was entirely focused on building a Dream Chaser reusable mini-shuttle to bring cargo to and from ISS, as well as partnering with Blue Origin to build their proposed Orbital Reef space station.

Then, in late 2023 the company underwent a major management and staffing shake-up aimed at winning military and national security contracts. At the same time work on its LIFE inflatable module — intended for Orbital Reef — practically ceased, while the effort to get Dream Chaser finished seemed to slow to a crawl, eventually causing NASA to drop it as an ISS cargo vehicle.

Sierra Space however is only one example. During this time Rocket Lab shifted its focus somewhat to the military in developing HASTE, its suborbital test version of its Electron rocket, in order to win substantial hypersonic test contracts from the Pentagon. And then there’s Tory Bruno, who quit his job as CEO of the rocket company ULA to take a job at Blue Origin heading a national security team aimed at winning that company military contracts.

So what has caused this shift? Has investment in the civil space industry dried up?

Hardly. The number of rocket startups continues to grow, fueled by the many new and established satellite companies planning constellations of tens of thousands to millions of satellites as well as the orbiting manufacturing possibilities presented by the five space stations under development. There is a lot of investment capital pouring into these efforts

The reason for this shift — which really isn’t so much a shift but a new focus that many companies are adding to their portfolio — is provided by an article today in Air & Space Forces Magazine, describing the War Department’s recent decision to add $10 billion to the budget of its Golden Dome project, raising it to $185 billion, while noting this:
» Read more

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March 17, 2026 Quick space links

2:48 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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Voyager-2’s only close-up image of Uranus’s moon Umbriel

12:38 pm

Uranus' five biggest moonsThe historically known moons of Uranus. Click for original NASA press release.

Umbriel as seen by Voyager-2
Click for source.

Today’s cool image continues our tour of the five largest moons of Uranus, as seen by Voyager-2 in 1986 during its close-up visit. The family portrait above, taken from more than three million miles away during Voyager-2’s approach, shows the relative sizes of those five moons as well as their location relative to Uranus, with Miranda in the closest orbit and Oberon the farthest. I have already posted close-ups from Miranda and Ariel. Today’s image moves us outward to Umbriel.

The image to the right is Voyager-2’s best picture. In fact, it is really Voyager-2’s only close-up image, and as you can see, it is not that close or sharp. I have not reduced it at all. This is how NASA released it. From the NASA press release:

The southern hemisphere of Umbriel displays heavy cratering in this Voyager 2 image, taken Jan. 24, 1986, from a distance of 346,000 miles. This frame, taken through the clear-filter of Voyager’s narrow-angle camera, is the most detailed image of Umbriel, with a resolution of about 6 miles.

Umbriel is the darkest of Uranus’ larger moons and the one that appears to have experienced the lowest level of geological activity. It has a diameter of about 750 miles and reflects only 16 percent of the light striking its surface; in the latter respect, Umbriel is similar to lunar highland areas. Umbriel is heavily cratered but lacks the numerous bright-ray craters seen on the other large Uranian satellites; this results in a relatively uniform surface albedo (reflectivity). The prominent crater on the terminator (upper right) is about 70 miles across and has a bright central peak.

The strangest feature in this image (at top) is a curious bright ring, the most reflective area seen on Umbriel. The ring is about 90 miles in diameter and lies near the satellite’s equator. The nature of the ring is not known, although it might be a frost deposit, perhaps associated with an impact crater. Spots against the black background are due to ‘noise’ in the data.

This lone picture of Umbriel by Voyager-2 illustrates even more starkly the very sparse data we have of Uranus and its moons. Voyager-2 is the only spacecraft to ever visit this planet, and it only did a quick fly-by, just long enough to give us this one dim snapshot view. It is forty years later, and no other missions have flown there, nor is any planned in the near future. There are proposals, but none are yet approved.

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Modeling says the Small Magellanic Cloud passed through the Large Magellanic Cloud 200 million years ago

11:18 am

Illustration of collision of Magellanic clouds
Click for original graphic.

According to new computer modeling, some astronomers now believe that a collision between the Small Magellanic Cloud (SMC) and the Large Magellanic Cloud (LMC) 200 million years ago best explains the chaotic movement of the stars in the former.

The SMC contains more mass in gas than in stars. Gas cools, contracts under gravity and settles into a rotating disk, the same process that shaped the spinning plane of our solar system. But when researchers, including those at University of Arizona, previously measured the motion of the SMC’s stars using the Hubble Space Telescope and the Gaia satellite of the European Space Agency, the SMC’s stars were not orbiting around the galaxy’s center the way stars in most galaxies do.

The possible reason, Rathore said, is a collision. A few hundred million years ago, the SMC crashed directly through the LMC’s disk. The LMC’s gravity disrupted the SMC’s internal structure and sent its stars into random, disordered motion. Also, the LMC’s gas applied a tremendous amount of pressure to the SMC’s gas and destroyed its gas rotation.

The graphic to the right illustrates that collision, based on the computer modeling. It appears the Small Magellanic Cloud’s passage through the Large Magellanic Cloud acted to shake the smaller cloud apart, spreading its stars and gas across a wider space.

You can read the paper here [pdf]. There is of course a great deal of uncertainty in these results, but they add weight to the general theory that galaxy formation is strongly impacted by such collisions. As the scientists note in the conclusion of their paper, “The SMC gives a front row view of group processes driving dramatic morphological and kinematic transformations.”

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The first Artemis lunar landings might not go to the Moon’s south pole

10:09 am

It appears from remarks recently by one NASA official, that while the south pole remains the agency’s main lunar base target, it is now looking into other landing options in order to make those first manned landing less risky and easier and quicker to achieve.

Amit Kshatriya, NASA Associate Administrator was very vague in his statement, but nonetheless this was what it appears he was saying:

We have opened up the, I would say, the performance specification for the early landing missions in as many ways as we can, in terms of different lunar orbits we want to take, or different other constraints … to make it as agile as possible, to recognize performance limitations in some of the machines we have and let our providers tell us, hey, if you took these constraints out of the way, how could we go faster? So we’re going to do that.

The agency’s administrator, Jared Isaacman, is also pushing to quickly begin sending a lot of unmanned landers to the south pole by next year. Thus, under this plan, we might actually find out first whether there really is water in those permanently shadowed craters, before committing our manned lunar base to this location.

This new approach makes a great deal of sense, especially since the data that has looked into those craters has been very inconclusive, some positive and some negative.

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