exploration – Behind The Black

Psyche completes its Mars fly-by

May 20, 2026 8:01 am Robert Zimmerman

Click for original image.

The asteroid probe Psyche on May 15, 2026 successfully completed its last fly-by of Mars, sending the spacecraft on its way to the asteroid Psyche, with a planned arrival in 2029.

The image to the right, cropped, rotated, and, reduced to post here, was the highest resolution image released by the science team of the Martian south polar icecap.

The image scale is around 0.7 miles per pixel (1.14 kilometers per pixel). The cap itself extends across more than 430 miles (700 kilometers). The image was acquired with Imager A on May 15, 2026, at about 1:53 p.m. PDT.

The white material is the perennial dry ice cap overlaying a water ice cap of larger size.

NASA also released several other images taken during the fly-by, including a close-up of the 290-mile-wide Huygens Crater, located in the Martian southern cratered highlands.

The pictures reveal no significant science, but they prove once again that Psyche’s cameras are working and the spacecraft is pointing accurately.

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Scientists: Europa’s theorized plumes of water vapor might simply be statistical noise

May 19, 2026 8:56 am Robert Zimmerman

Europa in true color, taken by Juno September 2022.
Click for full image.

The uncertainty of science: Based on a re-analysis of data from the Hubble Space Telescope, scientists now say that the plumes of water vapor that Hubble had supposedly detected erupting from the surface of the Jupiter moon Europa might not exist, and could instead simply be statistical noise in the data.

The new paper looks at the last 14 years of data from the Hubble Space Telescope’s Space Telescope Imaging Spectrograph (HST/STIS) focused on Europa’s Lyman-alpha emissions. Lyman-alpha is a specific wavelength of ultraviolet light emitted and scattered by hydrogen atoms. From 2012-2014, the team was pushing the limits of the Hubble telescope’s capabilities.

“One of the difficulties in interpreting the data back then was determining where to place Europa within its context,” Retherford said. “The way Hubble works left some uncertainty in terms of placement relative to the center of the image. If Europa’s placement was off even just by a pixel or two, it could affect how the data gets interpreted.”

As a result, what they thought could be evidence of a water vapor plume could also just be statistical noise. “Our reanalysis took our original 99.9% confidence in the plumes’ existence and reduced it to less than 90% confidence,” said Dr. Lorenz Roth (KTH Royal Institute of Technology, Sweden), the paper’s lead author. “That’s simply not enough evidence to support the certainty of claims we made at the time.”

The plumes might still exist, but the data used here is simply more uncertain that previously thought. It is hoped that when Europa Clipper and Juice both enter Jupiter orbit in a few years they will be able to settle this issue more definitively.

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The weird tilted layers on the floor of Danielson Crater on Mars

May 18, 2026 1:00 pm Robert Zimmerman

Click for original image.

Today’s cool image to the right returns us to a previous cool image from 2022. Then I called this strange terrain visible on the floor of the 41-mile-wide Danielson Crater “freaky badlands,” because of the innumerable layers that are all tilted and appear eroded in the same way by prevailing winds coming from the northeast.

Today’s image shows more of the same. The picture to the right, cropped to post here, was taken on March 26, 2026 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It not only shows these layers, in the full image (which I strongly suggest you look at), it also shows several terraced mesas with the same tilt, each looking almost like wedding cakes that have slumped sideways. The aquamarine colors in the hollows suggest finer-grained dust, while the orange colors on higher terrain suggest coarser materials and bedrock.

As I noted in 2022:
» Read more

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The barren hills west of Jezero Crater

May 15, 2026 10:56 am Robert Zimmerman

Click for full panorama.

Click for interactive map.

Cool image time! The panorama above, cropped and reduced to post here, was created on April 5, 2026 using 46 pictures taken by one of the high resolution camera’s on the Mars rover Perseverance. It also attempts to show this terrain in natural color.

The blue dot on the overview map to the right marks Perseverance’s present location. The green dot indicates where I think the rover was when the panorama was taken. (Note: I think the press release incorrectly lists the Sol number for these dates, but as I am not sure I can only guess.) The yellow lines indicate approximately the terrain seen in the full panorama.

As the press release notes, “the panorama offers one of the richest geological vistas of the rover’s mission, revealing a windswept landscape of diverse rock textures.” It also appears this is the direction the rover is presently headed.

I ask my readers to once again look at this panorama. It shows an utterly barren terrain. There is no life here, and if there ever was it was gone billions of years ago and never did much to shape the landscape. While some at NASA and in the planetary community like to tout the possibility of life on Mars in order to lobby for funding, the reality we see says there is none, and that life will only appear on Mars when humans finally arrive there to build new human societies.

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Brain terrain on Mars?

May 14, 2026 11:00 am Robert Zimmerman

Click for original picture. For full image go here.

Cool image time! The picture to the right, cropped and expanded to post here, was taken on April 2, 2026 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled simply as a “terrain sample”, such images are usually taken not as part of any specific research project, but to fill a gap in the camera’s schedule. The camera team needs to take pictures at a regular cadence to maintain its proper temperature.

When they have such a gap, they try to find interesting things to photograph, and usually succeed. In this case we are looking at what I think the scientists dub “brain terrain,” a feature unique to Mars that is thought related to near surface ice and its sublimation, though at present the origins of brain terrain remain murky. The scale is approximately 100 meters across the width of this picture.

However, the location of this brain terrain makes any conclusions about its origin difficult.
» Read more

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Europa Clipper and Juice make simultaneous UV light observations of interstellar comet 3I/Atlas

May 14, 2026 8:52 am Robert Zimmerman

Overview of November 2025 observations.
Click for original image.

By viewing interstellar comet 3I/Atlas when it was between the Jupiter probes Europa Clipper and Juice (on their way to Jupiter) in November 2025, the science teams for both were able to get a 360 degree view of the comet in ultraviolet wavelengths.

“As the comet passed between Juice and Europa Clipper, we were able to informally coordinate observations between the two spacecraft,” said Dr. Kurt Retherford, the principal investigator of Juice-UVS and Europa-UVS. “Crucially, we observed hydrogen, oxygen and carbon emissions. These elements are produced when gases escaping the comet’s nucleus break apart into atoms when exposed to sunlight.”

…“Observing the interstellar comet was some exciting bonus science. The resulting rare and unique dataset includes gas emissions and scattered dust,” said SwRI’s Dr. Philippa Molyneux, co-deputy principal investigator for the Juice-UVS instrument. “This was the first time we’ve had simultaneous direct views of a comet’s coma of escaping gas from two directions. Europa Clipper showed us the night side of the comet, with a great deal of scattered dust, while Juice imaged mostly glowing gas on the day side.”

…The researchers found higher levels of carbon emissions from 3I/ATLAS than expected early on, especially in comparison to typical comets from our solar system, corroborating similar findings through other observations about the interstellar comet’s origin and composition. Observing the trends of emissions over several days revealed how the ratios of these molecules changed and how the comet evolved during its journey through our solar system.

These results confirm once again that while Comet 3I/Atlas is from outside our solar system and has some unique features, it is still remarkably similar to ordinary comets found within our solar system.

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Corroding glacial features inside Martian crater

May 13, 2026 11:25 am Robert Zimmerman

Overview map
Glacier country in the Martian northern mid-latitudes.

Click for original image.

Today’s cool image gives us another nice example of the ample availability of near surface ice on Mars, even if it might take a bit of processing to extract it from the dust and soil. The picture to the right, rotated, cropped, and reduced to post here, was taken on March 31, 2026 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The picture captures in detail most of the floor of a 5.8-mile-wide unnamed crater, located in the northern mid-latitudes of Mars, in a 2000-mile-long strip I like to call glacier country, because practically every image taken there shows extensive glacial features. The white dot on the overview map above shows the location within that strip, with the inset showing the full crater, as well as the surrounding terrain.

The softness of this landscape strongly suggests a topsoil well impregnated with ice. The crater’s rim is itself very soft and subdued, suggesting melting and sublimation over time.

The material in the floor of the crater resembles peeling paint, which in this case suggests the ice there has been sublimating away as well. Nonetheless, there remains a lot under the surface. Future Martian colonists will certainly come to this region to gather ice for their own purposes.

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Curiosity looks closely at the broken slab that had been stuck on its drill bit

May 12, 2026 12:37 pm Robert Zimmerman

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As expected, the science team for the Mars rover hasdecided before moving on it would take a close look at the 28 pound slab of rock that had been stuck on its drill bit and when finally dropped free broken into several pieces when it hit the ground.

The top picture to the right, cropped and reduced to post here, shows that entire rock, labeled Atacama by the science team. The two insets below are close-ups of the delicate layering at the rock’s left edge as well as the drill hole itself. From team’s update today:

The highest-priority activities after liberating the drill included imaging the drill with Mastcam and ChemCam RMI, and imaging into the now-empty drill hole with MAHLI (the image above). The science team made the most of the freshly-broken surfaces created when Atacama fell back to Mars, and the freshly-exposed sand once hidden underneath Atacama.

The exposed sand is off camera, to the right. Expect a paper published about that sand, buried likely for millions of years, sometime in the next year or so.

The delicate flutes at the rock’s left edge are somewhat common rock features seen by Curiosity, made possible by Mars’ thin atmosphere and its one-third Earth gravity. On Earth the gravity and weather generally destroys such things. On Mars the lack of violent weather and light gravity allows them to form, and the thin wind even helps in their formation.

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Springtime on the residual icecap of the Martian south pole

May 11, 2026 11:42 am Robert Zimmerman

Click for original image.

Cool image time! The picture to the right, cropped and rotated so that north is to the top, was taken on March 28, 2026 by the high resolution camera of Mars Reconnaissance Orbiter (MRO).

It shows what the science team labels a “south polar residual cap site.” The location is about 200 miles from the Martian south pole, well within the south polar ice cap. A second picture of this same spot was taken only a few days later, and was labeled “bright and dark fans on patterned ground.” With the second image the science team added their nickname for this location, “Troy,” which makes referencing it easier.

The hatchwork is the mystery here. In fact, the scientists have been monitoring this geology since 2020 to see if there have been any changes, either long term or seasonally. Almost certainly they have spotted seasonal changes, as indicated by the hatchwork itself and explained below, but I don’t access to the higher resolution images that would show any major modifications on a larger scale.
» Read more

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Testing new high speed rotors for the next generation of Mars helicopters

May 8, 2026 8:28 am Robert Zimmerman

Ingenuity with its missing blade, at its final resting place on Mars.
Click for original image.

Engineers from JPL and the aerospace company AeroVironment have been testing a new set of high speed rotors that they hope to use on the next generation Mars helicopters, designed to increase their payload capacity by as much as 30%.

The rotors of Ingenuity — the first helicopter to fly on Mars — never spun faster than 2,700 rpm, because at faster speeds it would be approaching the speed of sound (on Mars), when unpredictable things could happen. Engineers are pushing those limits with these new rotors, in a chamber mimicking the thin Martian atmosphere.

The test engineers had taken the precaution of lining part of the chamber with sheet metal in case the blades broke apart during the supersonic experiment. From a control room a few yards away from the chamber, the team watched displays showing data and a view inside the chamber as the rpm climbed as high as 3,750. At that rate, the tips were traveling at Mach 0.98 [just under the Martian speed of sound]. Then the engineers activated a fan inside the chamber that pelted the rotors with headwinds. After each run, they increased in wind velocity for the next run.

The team pushed rotor tip speeds to Mach 1.08, boosting the Mars vehicle’s lift capability by 30%. This breakthrough allows future missions to support heavier scientific payloads, including advanced sensors and larger batteries for extended flight. Next the team tried their luck with the two-bladed SkyFall rotor. Because it is slightly longer than the three-bladed version, only 3,570 rpm was needed to achieve the same near-supersonic speed at the rotor tips prior to introducing the headwinds.

NASA administrator Jared Isaacman has said he wants to send a fleet of helicopters to Mars in 2028, on that first nuclear-powered mission. Whether or not that mission happens as he proposed, there is ample evidence scientists plan on sending more helicopters there in the next few years (see here, here, here). These tests lay the groundwork for those future missions.

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Juno flies past the Jupiter moon Thebe

May 7, 2026 11:07 am Robert Zimmerman

Click for original image.

Though the Jupiter orbiter Juno is in its final orbits as it is running out of fuel, on May 1, 2026 it did a close fly-by of the 50 by 72 mile-wide Jupiter moon Thebe, getting within 3,100 miles.

The picture to the right, cropped and expanded to post here, is the best image released from that fly-by. It is very comparable to a photo taken by the Galileo orbiter on January 4, 2000. Both show the very large crater, dubbed Zethus.

The picture was taken by Juno’s Stellar Reference Unit (SRU) camera, designed not to do science but to “image star fields for navigation.” Thus, the picture is somewhat fuzzy, and was pointed poorly so the moon is on the far right, almost off camera.

It is very unclear how much longer Juno will function. It has apparently survived attempts by the Trump administration to zero out its operating budget, but there have been indications that its fuel supply is low.

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Curiosity unintentionally picks up a rock slab

May 6, 2026 11:15 am Robert Zimmerman

Click for movie. Original images found here, here, here, and here.

In their latest drilling campaign using the drill on the Mars rover Curiosity, the science team picked up a big surprise that could have been a serious problem, but turned out all right in the end. When they tried to extract the drill from the hole, the drill instead stayed stuck to the rock, and picked the whole rock up instead.

The four images to the right show the sequence, sourced from here, here, here, and here.

On April 25, 2026, Curiosity drilled a sample from a rock nicknamed “Atacama,” which is an estimated 1.5 feet in diameter at its base, 6 inches thick and weighs roughly 28.6 pounds (13 kilograms). When the rover retracted its arm, the entire rock lifted out of the ground, suspended by the fixed sleeve that surrounds the rotating drill bit. Drilling has fractured or separated the upper layers of rocks in the past, but a rock has never remained attached to the drill sleeve. The team initially tried vibrating the drill to shake off the rock, but saw no change.

Then, on April 29, they tried reorienting Curiosity’s robotic arm and vibrating the drill again. Imagery in the GIF shows sand falling from Atacama, but the rock stayed attached to the rover.

Finally, on May 1, Curiosity’s team tried again, tilting the drill more, rotating and vibrating the drill, and spinning the drill bit. The team planned to perform these actions multiple times but the rock came off on the first round, fracturing as it hit the ground.

Had they not been able to release the rock it could have seriously impacted the mission, even ended it.

As noted by the science team in their own update today about this situation:

Future activities involve wrapping up the drill campaign on Atacama and, nominally, seeking a more firmly rooted drill target in order to collect drill tailings for analysis, which were lost from Atacama as part of the effort to dislodge the drill bit from the rock.

In other words, they are going to have hunt around for a better drill spot, as they really do want to study some drill samples at this location. They have left the boxwork area and have moved uphill closer to the pure sulfite unit, and want to see how the geology has changed.

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A cool crater in Starship’s prime candidate zone on Mars

April 28, 2026 11:14 am Robert Zimmerman

Overview map

Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and enhanced to post here, was taken on August 16, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). In mid-March it was featured as a captioned image by MRO’s science team. From their caption:

When they form, impact craters dig up material from below the surface and throw it outwards into what geologists call an ejecta blanket. The fastest ejected material travels the furthest so material from different depths can end up at different distances from the crater.

This HiRISE image shows a pedestal crater in Arcadia Planitia that has material of different brightness and color at various distances from the crater. This could tell us more about the material that’s buried below the surface here, but the situation is complex.

The caption however fails to mention the most interesting two aspects of this crater’s ejecta blanket. One, it suggests strongly that there was a lot of near surface ice at impact that melted to produce this splash apron.

Second, and even more intriguing, the 3,100-foot-wide unnamed crater is located smack dab in the middle of the candidate landing zone on Mars for SpaceX’s Starship spacecraft, as shown by the overview map above. The white dot marks the location of this crater, while the red dots mark the four prime landing sites, as suggested by scientists in a 2021 paper [pdf], based on conclusions drawn from two workshops organized by SpaceX and these scientists. The other dots are other MRO images of this region, and include a number of potential secondary landing sites.

This zone is in the northern lowland plains of Mars, in a mid-latitude region where near-surface ice is plentiful. The splash apron of this crater provides further evidence of that near surface ice.

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Curiosity looks at a small crater as it climbs Mount Sharp

April 22, 2026 11:50 am Robert Zimmerman

Click for full resolution. Click here, here, and here for original images.

Cool image time! The panorama above, created from three pictures taken by the right navigation camera on the Mars rover Curiosity (see here, here, and here), takes a look at a small relatively fresh crater on the slopes of Mount Sharp. From an update from the rover’s science team yesterday:

At the beginning of the week, Curiosity arrived right on target on the rim of the 10-meter (33 feet) “Antofagasta” crater. The crater looked fresh and deep as we had hoped with a nice well-defined rim that didn’t look too eroded, but the bottom of it turned out to be filled with dark rippled sandy material that covered up the most interesting rock layers. There were a few rock exposures just above the sand cover that seemed like they might have been deep enough to have been sheltered from space radiation between the time their sediments were deposited and the crater-forming impact, but reaching them from the rim would have put the rover at such an awkward angle that we wouldn’t have been able to deliver the sample to the instruments.

Click for interactive map.

It’s possible that we might have been able to get into a better position by instead placing the rover on the rippled crater fill, but the chance that the rover could get stuck in all that sand made it much too high a risk. We also looked at the nearby blocks in case they could have been ejecta from the crater, but since all the rocks visible in the crater wall looked very similar to each other, there wasn’t a good way to tell which ejecta blocks might have come from the deeper layers of the crater. Because of this, the team decided against attempting to drill in or around the crater.

The overview map to the right provides the context. The blue dot marks Curiosity’s location when the pictures above were taken. The yellow lines roughly indicate the area covered by the panorama. The red dotted line marks the future planned route, the white dotted line the rover’s actual travels.

Note the flat rocks in the foreground of the panorama, all part of the crater’s rim. Each looks like a large flat paving stone that was very precisely shattered into numerous tiny pieces, all about the same size. Very strange. On Earth you’d assume some craftsman had laid these small pieces down like tiles, but of course, that couldn’t have happened on Mars.

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NASA’s IG: With only Axiom building NASA’s future spacesuits, the agency’s lunar program faces great scheduling risk

April 20, 2026 12:23 pm Robert Zimmerman

Axiom’s two spacesuits being tested underwater in October 2025.
Click for original.

According to NASA’s inspector general’s report today [pdf] on the state of NASA’s effort to create new spacesuits for use by its astronauts on future space stations as well as in its Artemis lunar program, the planned schedules for the lunar landing and those stations are threatened because the agency presently has only one contractor, Axiom, building new suits, and has not established any spacesuit standardization rules should it want to issue contracts to others. From the report’s conclusion:

While NASA is taking steps to mitigate schedule risk, it must also contend with the unique risks inherent to a single-provider environment until future competition is introduced. … If Axiom cannot satisfy its contractual requirements in a timely or cost-effective manner, then NASA could be forced to continue using the problematic EMUs throughout the life of the ISS and significantly adjust its lunar plans. [EMUs are the complex suits presently used on ISS, and would not work well for any lunar landing mission.]

While xEVAS [the new suit concept] is flexible enough to allow for additional providers, doing so may not help the Agency meet its more immediate Artemis goals. Critically, NASA must address existing design and safety risks resulting from the lack of standard requirements for spacesuits to be compatible with various lunar spacecraft and assets.

As shown by the photo above, the development of Axiom’s spacesuit has been proceeding, and seems likely to be available for next year’s Artemis-3 Earth orbit test mission. At the same time, it is still behind schedule, a fact that has been mitigated because NASA’s entire Artemis program is equally behind schedule.

The report lists three commercial companies that might be able to provide alternative suits, and thus some redundancy, as shown by the image below.
» Read more

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Hubble looks at the Trifid Nebula again

April 20, 2026 9:59 am Robert Zimmerman

Click for original image.

Cool image time! The picture to the right, cropped to post here, was taken by the Hubble Space Telescope and released today. It shows a small section of the Trifid Nebula, located about 5,000 light years away.

This location has been imaged numerous times in the past by Hubble. The area shown illustrates some fundamental aspects of stellar and nebula formation. The dark area in the lower right is a thick dust cloud. Several energetic O and B supermassive stars are out of view at the top. The radiation from these stars (indicated by the blue), is hitting that dust cloud and literally destroying it. It appears that the foreground “horn” exists because a larger object is blocking the radiation, allowing dust to survive in the background.

I have no explanation for the background “horn”.

This new image was taken in parallel with an image of the entire Trifid Nebula, taken by the new Rubin Telescope in Chile. Though Rubin cannot see with the same resolution as Hubble, its image is quite worthwhile viewing.

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Final ground testing begins of Katalyst’s Swift rescue spacecraft

April 18, 2026 5:46 am Robert Zimmerman

Katalyst’s proposed Swift rescue mission.
Click for original image.

Only seven months after NASA awarded the satellite repair startup Katalyst the contract to save the Gehrels-Swift space telescope, the company has delivered the completed LINK spacecraft to the Goddard Space Flight Center in Maryland for final ground testing.

Katalyst will move forward with LINK’s vibration and thermal tests using NASA Goddard’s in-house facilities in the coming weeks before installation into Northrop Grumman’s Pegasus rocket at the agency’s Wallops Flight Facility in Virginia.

Gehrels-Swift has been one of NASA’s most productive space telescopes. Unfortunately its orbit is decaying and if nothing is done to raise that orbit it will burn up in the atmosphere in 2029 or so. To extend this timeline engineers have stopped almost all science work in February.

Katalyst hopes to launch LINK as soon as later this year. It was able to get it built so quickly because it was already under construction as the company’s first demo of its repair technology. When NASA put out a bid for boosting Swift, the company shifted gears and reconfigured LINK for this mission.

If successfully, the achievement will be a major coup for this startup.

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Engineers shut down another instrument on Voyager-1

April 18, 2026 5:31 am Robert Zimmerman

The Voyager missions
The routes the Voyager spacecraft have
taken since launch. Not to scale.

Due to the continuing and expected decline in power, engineers have now shut down another instrument on Voyager-1 in the hope of keeping the spacecraft operating for just a few more years.

On April 17, engineers at NASA’s Jet Propulsion Laboratory (JPL) in Southern California sent commands to shut down an instrument aboard Voyager 1 called the Low-energy Charged Particles experiment, or LECP. The nuclear-powered spacecraft is running low on power, and turning off the LECP is considered the best way to keep humanity’s first interstellar explorer going.

The LECP has been operating almost without interruption since Voyager 1 launched in 1977 — almost 49 years. It measures low-energy charged particles, including ions, electrons, and cosmic rays originating from our solar system and galaxy.

…The choice of which instrument to turn off next wasn’t made in the heat of the moment. Years ago, the Voyager science and engineering teams sat down together and agreed on the order in which they would shut off parts of the spacecraft while ensuring the mission can continue to conduct its unique science. Of the 10 identical sets of instruments that each spacecraft carries, seven have been shut off so far. For Voyager 1, the LECP was next on that list. The team shut off the LECP on Voyager 2 in March 2025.

Both spacecraft now have only three operating science instruments. Engineers hope a major reboot on both spacecraft planned later this year might make each operate more efficiently, allowing both to survive maybe until 2030. At a minimum the hope is to make them last until 2027, which would the fiftieth anniversary of their launch.

The bottom line remains: the nuclear power source on board both is running down. The goal now is less gathering science data and more engineering: How long can we keep these spacecraft alive, at the very outskirts of our solar system?

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The movement of surface ash on Mars over a half century

April 16, 2026 12:08 pm Robert Zimmerman

Viking and Mars Express images side-by-side for comparison
Go here and here for original images.

Overview map

Cool image time! In comparing images of one location on Mars taken a half century apart, scientists using Europe’s Mars Express orbiter have discovered that the dark ash covering this region has shifted south by about 200 miles.

The two images above show the change, with a Viking orbiter image taken sometime in 1976 on the left and the Mars Express image taken in 2026 on the right. Both images have been enhanced to match each other, with the white box marking an area seen in close-up by Mars Express.

The overview map to the right provides the context. This region is inside Utopia Basin, one of the largest ancient impact basins on Mars, thought to have been formed by an impact that occurred a little more than four billion years ago. Much of Mars’ dark volcanic dust is thought to come from the Medusae Fossae Formation, a gigantic volcanic ash field the size of India and located on the other side of the planet, in between all of the red planet’s largest volcanoes. Over the eons that ash has gotten distributed across the globe.

In this case, it not only covers large areas of Utopia Basin, but over a half century the prevailing winds in the thin Martian atmosphere has been enough to shift the edge of this particular ash field south by 200 miles.

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DESI telescope completes its nominal mission, mapping more than 47 million galaxies

April 15, 2026 9:56 am Robert Zimmerman

Click for original image.

The Dark Energy Spectroscopic Instrument (DESI) on the Mayall 4-meter telescope at Kitt Peak in Arizona, in Arizona has now completed its initial five-year nominal mission, mapping more than 47 million galaxies to produce a rough 3D map of the universe.

By comparing how galaxies clustered in the past with their distribution today, researchers can trace dark energy’s influence over 11 billion years of cosmic history. Surprising results using DESI’s first three years of data hinted that dark energy, once thought to be a “cosmological constant,” might be evolving over time. With the full set of five years of data, researchers will have significantly more information to test whether that hint disappears or grows. If confirmed, it would mark a major shift in how we think about our Universe and its potential fate, which hinges on the balance between matter and dark energy.

The image to the right shows the map, with the blank areas to the left and right regions blocked by the Milky Way.

DESI will continue mapping for at least another three years, refining its data. I suspect when scientists begin analyzing this information they will find there are more than one way to interpret it.

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Scientists: First data from Europe’s Proba-3 satellites suggest the Sun’s slow solar wind is faster and more chaotic than expected

April 14, 2026 3:20 pm Robert Zimmerman

Click for original image.

The uncertainty of science: According to the first published paper [pdf] from Europe’s two Proba-3 satellites, scientists have found the slow solar wind that comes from the Sun is sometimes far faster than expected, and is also far more chaotic. From the second link above:

Just like wind on Earth, solar wind can be fast or slow, smooth or gusty. Fast solar wind usually flows in a smooth current from magnetic structures called coronal holes. In contrast, slow solar wind is variable and gusty, making understanding how it works more difficult.

Scientists think that slow solar wind is generated by the Sun’s magnetic field lines changing how they are connected, merging and separating again. This process pushes out blobs of plasma (electrically charged gas) in so-called ‘streamers’: large, bright rays in the corona.

…Previously, scientists found that close to the Sun’s surface, slow solar wind should have speeds around 100 km/s. Instead, Andrei’s team tracked some blobs of plasma moving at 250–500 km/s.

The graph to the right, Figure 4 in the paper, shows Proba-3’s tracking of a variety of these blobs. Not only did some move faster than expected (the arrows above the gray line marking earlier data), their speeds changed with time, with some actually speeding up.

The reason the Sun’s fast wind is relatively stable is that it emanates from magnetic structures dubbed coronal holes because the magnetic field lines there are is somewhat calm and stable. The slow wind meanwhile comes out through much more active and unstable regions of the magnetic field, with its field lines jumping about as well as connecting and unconnecting from the field’s structure in a chaotic manner.

This research suggests that the slow wind is chaotic and thus unpredictable, almost like the weather on Earth.

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Orion’s risky return-to-Earth happens tonight at 8:07 pm (Eastern)

April 10, 2026 9:47 am Robert Zimmerman

The Earth and Moon during the lunar fly-by on April 6, 2026.
Click for original image.

After spending ten days in space, including a swing around the back of the Moon, the four-person Artemis-2 crew is now preparing for its return-to-Earth this evening, splashing down off the Pacific coast near San Diego.

At 10:53 p.m. EDT [last night], the Orion spacecraft ignited its thrusters for 9 seconds, producing an acceleration in velocity of 5.3 feet-per-second and pushing the Artemis II crew toward Earth. The crew is now more than halfway home.

About two hours before the burn, there was an unexpected return link loss of signal during a data rate change affecting the transmission of communications and telemetry from the spacecraft to the ground. Two-way communications were reestablished, and flight controllers resumed preparing for the upcoming burn with the crew shortly after.

…The third return trajectory correction burn is scheduled for April 10 at about 1:53 p.m. ahead of re-entry procedures.

This is I think the second time Orion has had a short loss of communications with ground control. In addition, the crew had to cancel a planned manual piloting demonstration of Orion while it flew past the Moon because of a leak in an internal helium tank, used to maintain pressure in the oxygen tank as the propellant is used. The leak was inside the European-built service module, which will be jettisoned before re-entry and burn up in the atmosphere.

Mission managers say this leak has not impacted any engine burns, but it will require attention before the next flight.

The return to Earth however carries the biggest risk of the entire mission. Orion’s heat shield is questionable. During its first use in the 2022 unmanned Artemis-1 flight around the Moon, it did not behave as expected, with large chunks breaking off instead of thin layers ablating away. Though mission engineers have adjusted the flight path through the atmosphere to mitigate stress, there is great uncertainty about that solution.

I have embedded NASA’s live stream of the return-to-Earth below. It begins at 6:30 pm (Eastern), though the first return event, jettison the service module, doesn’t occur until 7:33 pm (Eastern).
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Martian mountains on Mount Sharp

April 9, 2026 11:45 am Robert Zimmerman

Click for larger full resolution image. For original images go here and here.

Click for interactive map.

Cool image time! The panorama above was created using two pictures taken by the high resolution camera on the rover Curiosity on Mars (here and here).

The overview map to the right gives the context. The blue dot marks Curiosity’s position on the day before these pictures were taken, climbing through the foothills on the flanks of Mount Sharp. I do not know if it traveled again before taking these two pictures above. The white dotted line its past travels, while the red dotted line its planned future route. At present Curiosity has climbed about 3,500 feet up the mountain. It is still about 15,000 feet below the peak, which is about 25 miles away and not visible from here.

The yellow lines indicate where I think the panorama is looking, though I admit that I am not sure. The view is distant, since this is high resolution camera. This panorama might actually be looking in a completely different direction, downhill at one of the hills that Curiosity previously drove past. The air is very dusty, which means if the rim of Gale Crater is in the background, 20-30 miles away, we can’t see it.

Regardless, the science team has finally finished its many nine-month-long survey of the boxwork geology, and has sent Curiosity climbing again. I think these pictures are part of their review of the future terrain, as they plan the rover’s route through the lighter-colored sulfate terrain higher on the mountain. If instead they are looking downhill, they were taken both to review previously viewed geology as well as to measure the dustiness of the atmosphere.

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Feathery eroding layers on Mars

April 7, 2026 11:01 am Robert Zimmerman

Click for original image.

Cool image time! The picture to the right, cropped, reduced, and enhanced to post here, was taken on February 23, 2026 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team calls “layers exposed around [a] streamlined feature”.

The elevation difference between the mesa top on the left and the canyon floor on the right is about 1,000 feet. The layers are the terraces stepping downward along that drop.

What makes these layers interesting is how they have been exposed. The material that makes up the layers appears very sandy and delicate, so it breaks away it very small pieces, just like sand on a beach. The result is this feathery look. If you look close you can see that some small craters have been partly obliterated by that erosion, with their existence only marked by their remaining rim, on the high side.
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Cracked bedrock on Mars?

April 6, 2026 2:01 pm Robert Zimmerman

Click for full image.

For today’s cool image we return to Mars. The picture to the right, cropped and brightened to post here, was taken on December 3, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The focus of the picture was a strange crater in the floor of Mawrth Vallis, a channel that drains northward from Mars’ cratered southern highlands to its northern lowland plains. You can see the crater in the full image if you click on the picture. It is intriguing because its rim is strangely abrupt and flat on all sides, something that is not seen with impact craters, which have a raised rim of material plowed out by the impact.

In the picture to the right I have however focused on the two small 50-70-foot-high mesas and cracked ground that surrounds them. What struck me was the dry appearance of this landscape. Located at 23 degrees north latitude, it is in the dry tropics of Mars, where little near surface ice is found. The cracks emphasize this conclusion, as they so well resemble the cracks you see in dried mud on Earth.
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Voyager-2’s most detailed look at Neptune’s moon Triton

April 3, 2026 3:10 pm Robert Zimmerman

Click for original image.

Today we conclude our tour of the Voyager-2 fly-bys of Uranus in 1986 and Neptune in 1989 with what is the most detailed look at the alien surface of Neptune’s moon Triton, taken on August 25, 1989 and shown to the right, cropped, rotated, reduced, and sharpened to post here.

Taken from a distance of only 25,000 miles, the frame is about 140 miles across and shows details as small as [a half mile in width]. Most of the area is covered by a peculiar landscape of roughly circular depressions separated by rugged ridges. This type of terrain, which covers large tracts of Triton’s northern hemisphere, is unlike anything seen elsewhere in the solar system. The depressions are probably not impact craters: They are too similar in size and too regularly spaced. Their origin is still unknown, but may involve local melting and collapse of the icy surface.

A conspicuous set of grooves and ridges cuts across the landscape, indicating fracturing and deformation of Triton’s surface. The rarity of impact craters suggests a young surface by solar system standards, probably less than a few billion years old.

What this photograph as well as the handful of other Voyager-2 images of Triton tell us is that we only have gotten a tiny taste of what’s there, only enough to tell us we don’t understand what we are seeing in the slightest. This is a truly alien world, cold, dark, and composed of materials far different then that found in the inner solar system. Its formation is a mystery, and its subsequent geological history a cypher. Scientists have made some guesses, but to get a real understanding we need to go back, and be there for a long time.

In fact, this is the final conclusion of all of the Voyager-2 images from both Uranus and Neptune. That probe gave humanity its first good close look at these distant worlds, but the look was still a quick and very superficial one. The images and data left us with far more questions than answers.

Unfortunately, there is at present no mission approved and under development to go to either Uranus or Neptune, though several have been proposed. Thus, it will likely be at least two decades before any mission gets there, if that soon.

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Neptune’s rings, as seen by Voyager-2 in 1989

April 2, 2026 2:05 pm Robert Zimmerman

Click for original image.

Cool image time! The picture to the right, cropped, reduced slightly, and sharpened to post here, was taken by Voyager-2 on August 26, 1989 shortly after it had completed its close fly-by of Neptune, looking back at the planet from a distance of about 175,000 miles.

The two main rings are clearly visible and appear complete over the region imaged. … Also visible in this image is the inner faint ring at about 25,000 miles from the center of Neptune, and the faint band which extends smoothly from the 33,000 miles ring to roughly halfway between the two bright rings. Both of these newly discovered rings are broad and much fainter than the two narrow rings.

These long exposure images were taken while the rings were back-lighted by the sun at a phase angle of 135 degrees. This viewing geometry enhances the visibility of dust and allows fainter, dusty parts of the ring to be seen. The bright glare in the center is due to over-exposure of the crescent of Neptune. The two gaps in the upper part of the outer ring in the image on the left are due to blemish removal in the computer processing. Numerous bright stars are evident in the background. Both bright rings have material throughout their entire orbit, and are therefore continuous.

While Voyager-2 took other pictures of these rings (here, here, here, here, and here), I think this picture shows the rings best, if not terrible well. Images using the Hubble and Webb space telescopes as well as others have not been better.

The rings were first confirmed to exist in the mid-1980s, shortly before Voyager-2’s fly-by. We now think there are five rings total, all made of dark material, likely a mix of carbon-based molecules, much of it the equivalent of dust and soot.

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The new Rubin telescope discovers over 11,000 new asteroids in first observations

April 2, 2026 11:07 am Robert Zimmerman

Click for full animation.

The new Rubin Observatory, a ground-based telescope in Chile, has discovered over 11,000 new asteroids in its first preliminary observations, with most in the main asteroid belt but a large number in the Kuiper Belt beyond Neptune and 33 previously unknown near-Earth asteroids.

The graphic to the right, annotated by me to post here, shows all of Rubin’s asteroid detections in light blue.

The submission to MPC [Minor Planet Center] comprises approximately one million observations, taken over the span of a month and a half, of over 11,000 new asteroids and more than 80,000 already known asteroids, including some that had previously been observed but were later “lost” because their orbits were too uncertain to predict their future locations. You can interact with all of Rubin’s asteroid discoveries in the Rubin Orbitviewer, which uses real data to provide an intuitive way to explore the structure of our cosmic backyard in three dimensions and in real time. Also, visit the Rubin Asteroid Discoveries Dashboard to learn about the new objects Rubin has uncovered.

…Among the newly identified objects are 33 previously unknown near-Earth objects (NEOs), which are small asteroids and comets whose closest approach to the Sun is less than 1.3 times the distance between Earth and the Sun. None of the newly discovered NEOs pose a threat to Earth, and the largest is about 500 meters wide.

Astronomers predict that Rubin will eventually find 90,000 new near-Earth objects, with some expected to pose a risk of hitting the Earth. It does this by repeatedly surveying the southern sky with its large mirror, then identifying new objects with its sophisticated software.

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Voyager-2 discovered Neptune to be a planet of quickly changing weather

March 31, 2026 10:53 am Robert Zimmerman

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Cool image time! When Voyager-2 flew past Uranus in 1986, the data showed the gas giant’s weather to be relatively sedate and quiet, with little changing during the fly-by. Scientists expected this: Uranus’s distance from the Sun meant it got little energy to fuel an active climate, with any activity produced by internal heating due to the gravitational pressure of its mass. And Uranus did not produce that much heat internally.

When Voyager-2 passed Neptune three year later, the scientists expected something similar, or even less, due to Neptune’s greater distance from the Sun. Instead, Voyager-2’s data showed Neptune’s weather patterns to be changing constantly and quickly, as illustrated by the three images of the Great Dark Spot to the right, the biggest storm on Neptune at that time and located in the planet’s southern mid-latitudes.

The bright cirrus-like clouds of Neptune change rapidly, often forming and dissipating over periods of several to tens of hours. In this sequence spanning two rotations of Neptune (about 36 hours) Voyager 2 observed cloud evolution in the region around the Great Dark Spot at an effective resolution of about 60 miles per pixel. The surprisingly rapid changes which occur over the 18 hours separating each panel shows that in this region Neptune’s weather is perhaps as dynamic and variable as that of the Earth. However, the scale is immense by our standards — the Earth and the [Great Dark Spot] are of similar size.

In Neptune’s frigid atmosphere, where temperatures are as low as 55 degrees Kelvin (-360 F), the cirrus clouds are composed of frozen methane rather than Earth’s crystals of water ice.

Subsequent observations by the Hubble Space Telescope in 1994 found this Great Dark Spot was gone, replaced by a comparable storm in the northern hemisphere. Further Hubble observations found Neptune’s storms tend to last about two years, fading as they drifted towards the equator. Those observations however also detected storms drifting away from the equator. Other research suggested the storms might be influenced by the Sun’s sunspot cycle.

All of the data post-Voyager-2 remains very coarse and uncertain, as we are looking at Neptune at a great distance. Thus, no theory about what is happening carries much weight, especially because we do not know why Neptune produces so much more internal heat than Uranus, fueling this fast-changing weather. For example, Neptune gets 1/20th of the energy received by Jupiter, yet its atmosphere appears even more active and variable.

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Voyager-2’s view of clouds on top of clouds on Neptune

March 30, 2026 11:45 am Robert Zimmerman

Click for original image.

Time to continue our cool image tour this week of the Voyager-2 archive of Neptune, taken during the spacecraft’s August 25, 1989 close fly-by of the gas giant, zipping only 2,700 miles above the cloud-tops. This remains the only mission to visit Neptune so far.

The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken two hours before Voyager-2’s closest approach. From the caption:

These clouds were observed at a latitude of 29 degrees north near Neptune’s east terminator. The linear cloud forms are stretched approximately along lines of constant latitude and the sun is toward the lower [right]. The bright sides of the clouds which face the sun are brighter than the surrounding cloud deck because they are more directly exposed to the sun. Shadows can be seen on the side opposite the sun.

These shadows are less distinct at short wavelengths (violet filter) and more distinct at long wavelengths (orange filter). This can be understood if the underlying cloud deck on which the shadow is cast is at a relatively great depth, in which case scattering by molecules in the overlying atmosphere will diffuse light into the shadow. Because molecules scatter blue light much more efficiently than red light, the shadows will be darkest at the longest (reddest) wavelengths, and will appear blue under white light illumination.

The resolution of this image is 6.8 miles per pixel and the range is only 98,000 miles. The width of the cloud streaks range from 30 to 125 miles, and their shadow widths range from 18 to 30 miles. Cloud heights appear to be of the order of 31 miles.

Of all the high resolution images taken of Neptune by Voyager-2, this is the only one that clearly shows some dimensionality. Later photographs taken by Hubble and other ground- and space-based telescopes can only show global views that are far less sharp than the global views produced by Voyager-2.

This picture hints at Neptune’s very complex weather patterns, which has no well-defined surface and is made up mostly of gas and liquid. Though scientists have used Hubble to roughly track those weather patterns, they can only glean the most basic facts. For example, its fast-changing weather appears to be driven by high winds, thought to move as fast as 1,300 miles per hour. This fact however is woefully incomplete and very uncertain, as we have no way to track detailed weather patterns at multiple depths.

Our tour will continue tomorrow.

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