Tag: engineering

More strange terrain in the Martian “Death Valley”

2:39 pm

More strange terrain in Hellas Basin
Click for full image.

Today’s cool image, rotated cropped, and reduced to post here, might show what the science team for the high resolution camera of Mars Reconnaissance Orbiter (MRO) have labeled “strange banded terrain”, but anyone who has spent any time perusing images of Hellas Basin, what I have labeled the basement of Mars because it has the lowest elevation on the planet, will recognize the features.

They might be inexplicable, but for Hellas Basin they are entirely familiar. Just take a look at some of my earlier posts:
» Read more

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Perseverance: update on launch rehearsal and helicopter

11:25 am

Two news stories today about the launch of the United States’ next Mars rover, Perservance.

First, ULA yesterday successfully completed a dress rehearsal countdown with the Atlas 5 rocket that will launch Perseverance on July 20 at 9:15 am (Eastern)..

The rover will be mounted onto the rocket at the end of this week.

Second, JPL provided this press release describing how Perseverance’s test helicopter Ingenuity will be deployed on the Martian surface, where it will then test to see if such helicopters will work in the Martian atmosphere.

Sixty Martian days (dubbed sols) after landing in Jezero Crater on February 18, Perseverance will find a nice large flat area and deploy the helicopter six sols later. The helicopter will then begin its 30-sol test program. If it is found to work, future rovers will almost certainly be equipped with such helicopters, acting as scouts able to go places the rover cannot.

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Local authorities in Scotland have approved spaceport concept

8:56 am

Capitalism in space: Local authorities in northern Scotland have recommended that planning of a private spaceport in Sutherland should move forward.

Will this happen? I wonder, based on this detail from the article:

Councillors on Highland Council’s north planning applications committee will consider the proposals for Space Hub Sutherland on Friday.

The local authority has received 457 objections to the plans and 118 representations in support of them. Impact on the environment and risk to human health are among the reasons for the objections.

Local community councils have supported the project because it is expected to create new jobs.

The article implies that the local communities support the project, but I’m not sure. Either way, in our fear-driven society today getting that many objections would be is a major hurdle for any project to leap.

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Trump official skeptical of point-to-point suborbital transportation

8:45 am

During the FAA’s annual commercial space conference, the executive secretary for Trump’s National Space Council, Scott Pace, expressed strong skepticism about plans by some companies to develop point-to-point transportation using suborbital spacecraft.

“I still see that as somewhat speculative and somewhat over the horizon,” he said. “I see us working right now on trying to get the suborbital market up, running and sort of stabilized. I think people look forward to the possibility of point-to-point passenger and cargo travel, but right now just getting routine suborbital access to space and pushing hard on the unmanned hypersonic and military applications is where the action is.”

“Maybe it’s not too soon to think about,” he added, “but I still think that’s a bit farther out until I see how the initial market settles out.”

In this context Pace noted his primary focus was in helping Virgin Galactic and Blue Origin get their space tourism businesses off the ground. Virgin Galactic has been making noises that it wants to do point-to-point transportation as well. His skepticism of this is actually quite realistic, since Virgin Galactic has not even completed its first commercial tourism flight and its rocket and spacecraft are underpowered as well.

If Pace’s skepticism is however aimed at SpaceX’s Starship plans to do point-to-point transportation, he is exhibiting a typical Washington bureaucrat’s timidity about new technology.

Meanwhile, Virgin Galactic has gotten a contract from NASA to train private astronauts. To my mind this is NASA’s attempt to keep this company above water, as it certainly isn’t the most qualified to do this kind of training. If I wanted training for going on a private space mission, SpaceX and Boeing would be better places to get that preparation.

The deal however has done wonders for Virgin Galactic’s stock, causing it to rise almost 16% yesterday following the announcement of this contract. Great timing for Richard Branson, who by coincidence just happens to be trying to sell some of his stock at this moment.

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A gravel pile floating in space that might hit the Earth

2:10 pm

flat rock near Osprey
Click for full image.

Come October the probe OSIRIS-REx will attempt a quick touchdown on the asteroid Bennu to grab some tiny particles, all smaller than 0.8 inches across.

Bennu is what scientists have described as a “rubble-pile” asteroid. They use that name because it is simply a conglomeration of a lot of rocks, pebbles, boulders, and stones, all jagged and of all sizes. The overall gravity has never been strong enough to squeeze them together, at least as far as we can see, and so they are piled up loosely across the asteroid’s surface wherever we look.

I think a better name for this asteroid would a floating gravel pile, since the material on it, as clearly shown in the image to the right (reduced and rotated to post here), more resembles the tailings one finds at a mine or quarry. This photo was taken by OSIRIS-REx on May 26, 2020 during its first dress rehearsal over its back-up touch-and-go sample grab site, Osprey. As the release caption notes,

The field of view is 12 ft (3.8 m). For reference, the bright rock [near] the tip of the boulder is 1 ft (0.3 m) across, which is about the size of a loaf of bread.

I have rotated the image 90 degrees so that east is up, because the full mosaic of the entire Osprey landing site, shown below, is oriented that way, and by rotating it to match it is easier to locate this image within it.
» Read more

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A bunch of new contracts for smallsat rocket companies

9:12 am

Capitalism in space: Two news stories outlined today a bunch of new launch contracts for a number of smallsat rocket companies, with Rocket Lab getting the biggest share.

In the first award, the six companies were Rocket Lab, Aevum, Astra, X-Bow, Space Vector and VOX Space, of which only Rocket Lab is presently operational. The deal calls for the launch within the next 24 months of two cubesats from each company The money was authorized under the March Wuhan flu stimulus bill, and is apparently meant as reimbursement for each company’s losses because of the lock downs. No contract amount however was provided,

The second award to Rocket Lab came from the National Reconnaissance Office (NRO), and is likely a reward for the company’s successful launch of three NRO satellites on June 12th. It also might involve two almost simultaneous launches on two different launchpads.

In a demonstration of its responsive launch capabilities, Rocket Lab said in a statement announcing the contract that the two launches will take place “within weeks” of each other. However, in an interview, Rocket Lab Chief Executive Peter Beck said he hopes the time between the two launches is much less than that. “We’re looking forward to having two vehicles sitting on two pads simultaneously, and we’ll see how close together we can actually get them to launch,” he said. “We’re planning internally to see how close we can get those two together.

The company is also hoping in the fall to attempt their first recovery of a first stage.

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Two new multi-wavelength Hubble images of planetary nebulae

11:05 am

Hubble images of the Butterfly and Jewel Bug planetary nebulae
Click for full image.

Cool images from Hubble! Astronomers have used the Hubble Space Telescope’s entire suite of instruments to produce spectacular new multi-wavelength images of two planetary nebulae, stars that for some reasons not yet entirely understood are surrounded by breath-taking jets and cloud-formations of all shapes and sizes.

The two images are to the right, cropped and reduced to post here.

Planetary nebulas, whose stars shed their layers over thousands of years, can turn into crazy whirligigs while puffing off shells and jets of hot gas. New images from the Hubble Space Telescope have helped researchers identify rapid changes in material blasting off stars at the centers of two nebulas — causing them to reconsider what is happening at their cores.

In the case of NGC 6302, dubbed the Butterfly Nebula, two S-shaped streams indicate its most recent ejections and may be the result of two stars interacting at the nebula’s core. In NGC 7027, a new cloverleaf pattern — with bullets of material shooting out in specific directions — may also point to the interactions of two central stars. Both nebulas are splitting themselves apart on extremely short timescales, allowing researchers to measure changes in their structures over only a few decades.

This is the first time both nebulas have been studied from near-ultraviolet to near-infrared light, a complex, multi-wavelength view only possible with Hubble.

The press release suggests that the most likely and popular explanation for the formation of planetary nebula is the interaction of two closely orbiting stars. While this might be true, it remains only one theory among many, all of which explain some of what we see and none of which explain everything. As I noted in my November 2014 cover story about planetary nebulae for Sky & Telescope:
» Read more

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Three Starship prototypes in line for testing

9:14 am

Capitalism in space: SpaceX’s assembly line for building Starship prototypes is heating up, with three such ships completed or under construction in Boca Chica, Texas.

Initially numbered 5 through 7, the goal of the first two will be to do the first full scale vertical hops, flying as high as 7.5 miles.. #7 however has a different purpose:

While stouter than an actual Starship-class methane or oxygen tank, this particular test tank is maybe only 25% shorter than the methane tanks installed on Starship prototypes. According to Musk and effectively confirmed by writing all over the prototype, this particular test tank – formerly Starship SN7 – was built to determine if a different kind of steel could be preferable for future ships.

Shortly after the June 15th test began to wind down, Musk announced that the new material (304L stainless steel) had performed quite well, reaching 7.6 bar (110 psi) before it sprung a leak. The fact alone that it sprung a leak instead of violently depressurizing is already a major sign that 304L is preferable to 301L, as it means that Starships built out of it could fail much more gracefully in the event of a leak instead of collapsing or violently exploding. A step further, SpaceX has already managed to repair the leak on SN7 and will likely test the tank again in the next few days.

SpaceX is once again demonstrating how to properly do this kind of cutting edge development. You test, you fix or, you change, based on what your tests tell you. You don’t lock down design in the early stages, because at that point you really don’t know enough to do so.

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Astra schedules next launch attempt

9:01 am

Capitalism in space: The smallsat rocket company Astra has scheduled its next launch attempt for July 20.

The company tried twice to launch in March, with the second attempt destroying the rocket and launchpad. They have now rebuilt, though they also admit that this first launch might also fail, and that it is part of a three launch program. By the third launch they expect to reach orbit for sure.

If Astra succeeds, they will leap ahead of Virgin Orbit as the second smallsat rocket company, following Rocket Lab, to become operational.

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Enigmatic layering and chasms on Mars

2:27 pm

Enigmatic layering and chasms
Click for full image.

Overview map

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on April 28, 2020 by the high resolution camera on Mars Reconnaissance Orbiter. (MRO). The science team entitled it “Enigmatic Uplifts in Echus Montes,” indicating a sense of bafflement on their part about this geology.

The features here are certainly somewhat puzzling. At first glance the terrain is reminiscent of Martian chaos terrain, mesas cut by canyons in an almost random pattern. As I explained at the link,

Chaos terrain is typically a collection of mesas separated by straight-lined canyons. It is found in many places on Mars, most often in the transition zone between the southern highlands and the northern lowlands where an intermittent ocean might once have existed. It is believed to form by erosion, possibly caused by either flowing water or ice, moving along fault lines. As the erosion widened the faults, they turned into canyons separating closely packed mesas. With time, the canyons widened and the mesas turned into a collection of hills.

What makes this particular image puzzling however is that there seem to be multiple layers of mesas and canyons. Look at the top of the rectangular mesa in the upper middle of the image. It appears to have its own miniature chaos terrain on its plateau. Somehow that first layer of chaos was abandoned when the more prominent larger canyons started to form around it.

The location of this feature is indicated by the black cross on the overview map to the right. It is in the middle of the large and wide northward trending part of the giant valley dubbed Kasei Valles. And as usual, knowing the location helps explain what we are seeing.
» Read more

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SpaceX hiring engineers for building floating Starship spaceport

10:04 am

Capitalism in space: SpaceX has issued advertisements looking for two engineers to help build an offshore floating spaceport for launching its Starship/Super Heavy reusable rocket.

This plan is not really a surprise, as Musk from his first description of Starship said that it would likely launch and land on floating platforms. The rocket is big, so putting its launch and landing in the ocean reduces the risk to populated areas, while giving the company some flexibility about where it will land. The latter point reinforces the company’s stated goal of using this rocket not only to make interplanetary travel affordable but to also provide point-to-point transportation on Earth.

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Yutu-2 to resume travels after day of rest

9:58 am

The new colonial movement: After lunar day of no activity, China has reactivated its Yutu-2 rover on its 19th lunar day on the far side of the Moon.

The Yutu 2 rover had remained stationary during lunar day 18 (May 16-29), while teams back on Earth upgraded ground stations in preparation for the Tianwen-1 Mars mission, due to launch in late July or early August. Upgrades to the tracking and command facilities at Jiamusi, northeast China, and Kashi in the northwest were completed June 13 according to CLEP, meaning normal roving service can now resume.

While the rover has been stationary, the Yutu 2 science team have identified a nearby crater for examination. The 4-foot-wide (1.3 meters), 8-inch-deep (20 centimeters) crater contains reflective material which may be similar in nature to suspected impact melt glass the rover discovered last year. After checking out the crater, Yutu 2 will continue its journey northwest from the Chang’e 4 landing site. Yutu 2 has driven a total of 1,469 feet (447.68 meters) since setting down on the far side of the moon in January 2019.

Generally Yutu-2 has averaged about a hundred feet for each lunar day of actual travel.

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NOAA awards contract to private company for solar observatory

9:22 am

Capitalism in space: NOAA today awarded a contract to the private company Xplore to study development of a commercial solar observatory at the Earth-Sun L1 point.

The press release at the link is somewhat vague about the contract. It appears to be a study to see if Xplore’s proposed Xcraft spacecraft can be used as platform for such a solar observatory, not an actual contract to build the observatory.

Regardless, this award is a strong indicator that the Trump administration is applying pressure at NOAA to get it out of the business of building weather satellites and instead be a customer buying such satellites from the private sector. The weather agency has been, like NASA earlier this decade, resistant to this concept, with its bureaucracy wanting to retain control over everything. Maybe the success of SpaceX at NASA is now helping to fuel the change at NOAA.

Let us hope so. NOAA’s present fleet of solar observatories in space is years past their due date, with no sign of a replacement fleet. The agency just can’t seem to get its act together to build these satellites. For example, NOAA has been trying and failing to build a new solar observatory to monitor sunspot activity now for more than a decade.

Maybe, like NASA, giving the job to private enterprise might get things going.

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The coming final flight of the shuttle’s solid rocket booster segments

8:55 am

Link here. As NASA begins the assembly process for its first long-delayed SLS launch sometime in the next year. the article at the link outlines in detail the space shuttle history of the many reused segments used to build the rocket’s two solid rocket boosters.

All together, the Artemis I solid rocket booster segments previously helped launch 40 space shuttle missions dating back 30 years.

The oldest cylinder, which will fly as part of the booster mounted on the right side of the SLS core stage, first lifted off on the STS-31 mission with the Hubble Space Telescope on April 24, 1990. It was then used for six more shuttle flights, including Endeavour’s debut on STS-49 in 1992 and STS-95 in 1998, which lifted off with Mercury astronaut and senator John Glenn as part of its crew.

Other notable missions that are part of the Artemis 1 boosters’ legacy include: STS-71, which marked the first shuttle docking with the Russian space station Mir in 1995; STS-93, which deployed the Chandra X-ray Observatory and marked the first spaceflight commanded by a woman, Eileen Collins, in 1999; STS-114, the return to flight after the loss of the space shuttle Columbia in 2005; and STS-133, the final launch of the space shuttle Discovery in 2011.

The hardware also includes new components, including the two forward domes, two cylinders and four stiffeners.

This first SLS launch however will be the last time these segments will fly. Unlike the shuttle, NASA is making no effort to recover and reuse these boosters.

The shuttle effort to reuse these booster segments was never really very cost effective, so not reusing them on SLS might actually save money. Those savings however are chicken feed when compared to SLS’s overall cost. The problem really is with SLS’s fundamental design: cumbersome, slow, expensive, and difficult to use.

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SpaceX recovers both reused fairings from most recent launch

8:44 am

Capitalism in space: SpaceX has successfully recovered both of the reused fairings that were used in its June 13th Starlink launch.

This sets the stage for the first reuse of a fairing for the third time. The article at the link notes this important detail about these used fairings, both of which were not caught prior to landing in the ocean:

Preventing a vast majority of seawater exposure, a catch with [the ships] Ms. Tree or Ms. Chief may always be preferable for fairing reuse but the fact remains that all three successful reuses up to this point have been achieved with fairing halves that landed in the ocean. That success means that SpaceX has found a way to fully prevent or mitigate any potential corrosion that might result from seawater immersion. Given that that problem must have been a showstopper for the ~2.5 years SpaceX was able to recover – but not reuse – intact fairings, it’s safe to say that the company’s engineers have more or less solved the problem of corrosion. [emphasis mine]

In a sense we should not be surprised that the fairings were not seriously damaged by their short exposure to salt water. As designed, the shape of the fairings is essentially that of a boat hull. By landing them controlled by parachute, SpaceX guarantees that the sensitive electronics and equipment inside the fairings remains dry and untouched by salt water.

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Trace Gas Orbiter detects oxygen layer in Martian atmosphere

8:35 am

Europe’s Trace Gas Orbiter, in orbit around Mars, has detected for the first time the green atmospheric layer in Martian atmosphere caused by the interaction of oxygen and sunlight.

From what I can tell from the press release at the link, they did not “see” this green glow, they detected it spectroscopically. So, any images you see portraying it are simply artist renditions, not the real thing.

The detection is important, nonetheless. First, it confirms that there is oxygen in Mars’ atmosphere. Second, it is the first time this has been detected in the atmosphere other than Earth. Third, the detection matched closely to their computer models, suggesting that the models are a reasonable simulation of this aspect of Mars’ atmosphere.

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Next Rocket Lab launch scheduled only three weeks after last launch

8:26 am

Capitalism in space: Rocket Lab yesterday announced that its next launch is now scheduled for July 3, less than three weeks after its previous launch, the fastest turnaround the company has attempted so far.

The July launch will place seven cubesats into orbit. The fast turnaround this time is part of the company’s attempt to complete one launch per month through the rest of the year, a pace they have been promising now since 2019 but have been as yet unable to achieve.

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Lego Antikythera Mechanism

6:01 pm

An evening pause: From the youtube webpage:

The Antikythera Mechanism is the oldest known scientific computer, built in Greece at around 100 BCE. Lost for 2000 years, it was recovered from a shipwreck in 1901. But not until a century later was its purpose understood: an astronomical clock that determines the positions of celestial bodies with extraordinary precision. In 2010, we built a fully-functional replica out of Lego.

Hat tip Shaun Karry.

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Cassini evidence suggests volcanoes on Titan

4:04 pm

Scientists are now proposing that. based on a close look at data and imagery of Titan from the Cassini mission archive, that this moon of Saturn might have volcanoes, and that they might even be active today.

Volcano-like features seen in polar regions of Saturn’s moon Titan by NASA’s Cassini spacecraft could be evidence of explosive eruptions that may continue today, according to a new paper by Planetary Science Institute Senior Scientist Charles A. Wood and coauthor Jani Radebaugh of Brigham Young University.

Morphological features such as nested collapses, elevated ramparts, halos, and islands indicate that some of the abundant small depressions in the north polar region of Titan are volcanic collapse craters, according to “Morphologic Evidence for Volcanic Craters near Titan’s North Polar Region” that appears in the Journal of Geophysical Research: Planets. A few similar depressions occur near the south pole of Titan. “The close association of the proposed volcanic craters with polar lakes is consistent with a volcanic origin through explosive eruptions followed by collapse, as either maars or calderas,” Wood said. “The apparent freshness of some craters may mean that volcanism has been relatively recently active on Titan or even continues today.”

The data being somewhat think, there is a great deal of uncertainty with this theory. Nonetheless, it makes perfect sense, and in fact it would be a surprise if some sort of volcanic activity was not occurring on Titan.

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Deciphering the strange geology of Mars — or anything!

10:03 am

Eroding Medusae Fossae Formation ash deposits
Click for full image.

Today’s cool image is for once not taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Instead, the image to the right, cropped and reduced to post here, was taken by Mars Odyssey on April 5, 2020, and shows the scouring and erosion caused by winds over many eons in a region dubbed Zephyria Planum. (Note that the image might fool your eye. Sunlight is coming from the east, and the rough terrain at the top is higher than the smooth plain at the bottom.)

Years ago, when I first started to rummage through the archives of images from the various Mars orbiters, I would have seen this image and posted it because I was completely baffled by what I saw, and thought that mystery made it worth showing to the public. Since then my incessant probing of research papers as well as asking a lot of questions of scientists has taught me a lot more about what scientists now surmise of the Martian geology. This greater knowledge in turn makes it possible for me to look at an image like this and immediately make a reasonable guess as to an explanation. This photo, while still containing much that is mysterious, is no longer completely baffling to me.

This willingness to ask questions and dig deeper is fundamental to all things. To have a deeper understanding and not simply guess about any subject, you always have to recognize that your assumptions are likely wrong, and that to learn anything you have to repeatedly ask what I call “the next question.” The first answer will force you to recognize that your first guesses are wrong, raise more questions, which in turn will lead to more questions, and then more questions, and so forth.

Whether I am researching Mars or early space history or politics, this rule always applies. Don’t leap to a conclusion. Think it possible you could be wrong. Ask the next question. And the next. You will repeatedly find that what you thought you knew was not correct, and in the end you will gain a deeper understanding of what is actually known about any subject, as well as what is unknown. And knowing the unknowns is probably the most important thing you can learn.

To gain a better understanding of today’s particular image, our first questions must start with context. Where is this feature on Mars? What is the surrounding history of that location? And what is already known about this place?

The location immediately reveals a great deal, as shown in the overview map below.
» Read more

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Interstellar suborbital launch ends in failure

10:28 pm

Capitalism in space: A suborbital launch attempt today by Interstellar, a private Japanese smallsat rocket company, failed one minute into flight, with the rocket falling into the sea.

It apparently failed at about 12 kilometers elevation, when it began tumbling. I have embedded the video of the launch below the fold, cued to just before liftoff.

This was their fifth launch attempt. Only the third launch reached their target altitude of 100 kilometers.
» Read more

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Successful SpaceX launch

2:38 am

Falcon 9 shortly after launch

Capitalism in space: SpaceX tonight successfully launched 58 Starlink satellites as well as three Planet earth observation satellites. The image to the right looks up at the exhaust from the nine firing Merlin engines of Falcon 9 rocket, about two minutes after launch.

That first stage also successfully landed, the third time this stage has completed a launch. The fairing halves were also reused.

The leaders in the 2020 launch race:

11 China
9 SpaceX
7 Russia
3 ULA

The U.S. now leads China 15 to 11 in the national rankings.

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Successful Rocket Lab launch

10:27 pm

Electron eleven seconds after liftoff

Capitalism in space: Rocket Lab today (June 13 in New Zealand) successfully launched five cubesats into orbit using its Electron rocket. The image to the right was taken eleven seconds after liftoff.

This was Rocket Lab’s second launch in 2020, delayed three months due to the Wuhan flu panic that shut down New Zealand. This does not put them in the leader board, but it does change the national rankings. The leaders in the 2020 launch race:

11 China
8 SpaceX
7 Russia
3 ULA

The U.S. now leads China 14 to 11 among the nations. Since SpaceX has its own Starlink launch later tonight, these numbers will likely change again before the night is over.

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Help scientists plan Curiosity’s future travels

1:27 pm

The Curiosity science team is asking the help of ordinary citizens in improving the software it uses to plan Curiosity’s future travels.

Using the online tool AI4Mars to label terrain features in pictures downloaded from the Red Planet, you can train an artificial intelligence algorithm to automatically read the landscape.

Is that a big rock to the left? Could it be sand? Or maybe it’s nice, flat bedrock. AI4Mars, which is hosted on the citizen science website Zooniverse, lets you draw boundaries around terrain and choose one of four labels. Those labels are key to sharpening the Martian terrain-classification algorithm called SPOC (Soil Property and Object Classification).

The goal is not to have citizens plan the rover’s route, but to use their judgments to refine the software that the scientists and engineers use to plan the route. This refinement will also be applicable to Perseverance when it gets to Jezero Crater in February 2021.

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Isidis Basin, on whose margin Perseverance will roam

1:20 pm

Pedestal craters in Isidis Basin
Click for full image.

Overview map

Today’s cool image to the right, cropped and reduced to post here, highlights the floor of one of Mars’ largest basins, dubbed Isidis Planitia, and located at the transition zone between the planet’s northern lowland plains and the southern cratered highlands.

The overview map below of Isidis Basin provides some context. The white box shows where this particular image is located. Jezero Crater, indicated by the red circle (which is also about the size of the crater), is where the rover Perseverance is going to land and roam come February 2021, should all go well. For scale, Isidis is about the size of the eastern half of the United States. If Chicago was located at Jezero Crater, Baltimore would be on the basin’s eastern edge, at around 4 o’clock.

This particular section of the full photo, taken on April 5, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), shows many features very typical of the floor of Isidis Basin, which also immediately reveal a great deal about its possible history.

In this small snippet we can see what at first glance appear to be pedestal craters standing up like mesas, with ordinary craters scattered about on that lower surrounding terrain. Clearly, if these are pedestal craters they had to have been created first, and then over a very long time erosion processes ate away at that plain, leaving these pedestals (which had become resistant to erosion because the impact had packed their material together and made it harder) behind as mesas.

Then, after this period of erosion was complete enough additional time was required for at least one or two rounds of cratering to occur, leaving behind the many more younger craters on the plain floor, many of which are now partly buried by dust and sand.

The problem is that these mesas are almost certainly not pedestal craters, despite their appearance. » Read more

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Marble race

6:01 pm

An evening pause: I actually would do this with my marbles as a child. All you needed was a gentle slope and a way to keep the marbles confined within the track. For me, it was a gap between the carpet and one wall in the living room of our rented apartment. The floor just happened to slope just enough.

What is amazing is how you can’t help but pick a marble and cheer for it.

Hat tip Rex Ridenoure of Ecliptic Enterprises.

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New Horizons sees stellar parallax

3:04 pm

New Horizons is now far enough away from Earth that its perspective of the universe shifts at least two nearby stars into slightly different positions than seen on Earth.

On April 22-23, the spacecraft turned its long-range telescopic camera to a pair of the closest stars, Proxima Centauri and Wolf 359, showing just how they appear in different places than we see from Earth. Scientists have long used this “parallax effect” – how a star appears to shift against its background when seen from different locations — to measure distances to stars.

An easy way to see parallax is to place one finger at arm’s length and watch it jump back and forth when you view it successively with each eye. Similarly, as Earth makes it way around the Sun, the stars shift their positions. But because even the nearest stars are hundreds of thousands of times farther away than the diameter of Earth’s orbit, the parallax shifts are tiny, and can only be measured with precise instrumentation. “No human eye can detect these shifts,” Stern said.

But when New Horizons images are paired with pictures of the same stars taken on the same dates by telescopes on Earth, the parallax shift is instantly visible. The combination yields a 3D view of the stars “floating” in front of their background star fields.

The resulting 3D image, available at the link, is very cool. Both stars clearly appear closer than the surrounding background stars, which of course is true as they are among the closest stars to the Sun.

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India’s first manned mission faces delays, caused by COVID-19

9:20 am

The new colonial movement: According to ISRO officials, India’s first manned mission, Gaganyaan, might have to be delayed because of restrictions imposed due to the Wuhan flu panic.

Bengaluru-headquartered ISRO (Indian Space Research Organisation) had earlier said it has planned two trial flights without crew ahead of Gaganyaan — the first one around December 2020 and the second around July 2021.

“…there are some disturbances because of COVID, but still nothing is confirmed (about delay). We need to see, still we have got some six months time. We are trying to see if we can reach there,” a senior ISRO official told P T I. He added: “There may be slight up and down (in the schedule), but that will be known only when we do the complete evaluation…it is premature to say anything, because the team that is working (on the project) has not indicated (about delay).”

The manned flight is presently scheduled for 2022. This might change.

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