Sunspot update Sept 2019:
The blankest Sun in decades

With the release yesterday by NOAA of its September update of its graph showing the long term sunspot activity of the Sun, we find ourselves in what might be the longest stretch of sunspot inactivity in decades, part of what might become the most inactive solar minimum in centuries.

In the last four months the Sun has produced practically no sunspots. There were two in June, two in July, and one in August. The September graph, posted below with additional annotations by me to give it context, shows that the past month was as weak as August, with only one sunspot again.

September 2019 sunspot activity

The graph above has been modified to show the predictions of the solar science community for the previous solar maximum. The green curves show the community’s two original predictions from April 2007, with half the scientists predicting a very strong maximum and half predicting a weak one. The red curve is their revised May 2009 prediction, extended in November 2018 four years into the future.

The 2008-2009 solar minimum was one of the deepest and longest ever recorded. Yet, it never produced a stretch of four months with so few sunspots, as shown in the graph above. Moreover, during that minimum the Sun was blank 71% of the time in 2008 and 73% of the time in 2009 (a record). Right now, with almost three months to go in 2019, the Sun has already been blank 73% of time, with every indication that it will top that number before the year is out.

Furthermore, the trend continues to suggest we are heading for a period of very few sunspots. Though one of the six sunspots seen since June 1 had a polarity that belonged to the next solar cycle, we have seen no further such next-cycle sunspots since July. There was one active region on October 6 with a next solar cycle polarity, but it was never able to gather enough magnetic energy to mature into a sunspot.

As I noted in my July 8 sunspot update,
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Astronomers find 20 more moons orbiting Saturn

Astronomers have discovered an additional twenty moons orbiting Saturn, bringing the total known to 82, three more than the 79 moons known to circle Jupiter.

Each of the newly discovered moons is about five kilometers, or three miles, in diameter. Seventeen of them orbit the planet backwards, or in a retrograde direction, meaning their movement is opposite of the planet’s rotation around its axis. The other three moons orbit in the prograde—the same direction as Saturn rotates.

Two of the prograde moons are closer to the planet and take about two years to travel once around Saturn. The more-distant retrograde moons and one of the prograde moons each take more than three years to complete an orbit.

The astronomers have also created a contest allowing the public to help name these new moons.

I will make one prediction: They are going to find many more.

In fact, Saturn’s rings and its numerous moons raise the question of what defines a moon. At present, a moon is defined as any object orbiting a planet, regardless of size. With Saturn’s rings however we have millions of objects orbiting that planet, many very tiny. It seems we have never put a size limit on the definition of a moon, and really need to.

The drying out of Mars

Edge of wash
The Murray formation as seen in 2017

A new paper based on data gathered by the rover Curiosity in 2017 when it was lower on the slopes of Mount Sharp, as well as data obtained more recently at higher elevations, has confirmed that the past Martian environment of Gale Crater was wetter, and that deeper lakes formed lower down, as one would expect.

In 2017 Curiosity was traveling through a geological layer dubbed the Murray formation. It has since climbed upward through the hematite formation forming a ridge the scientists dubbed Vera Rubin Ridge to reach the clay formation, where the rover presently sits. Above it lies the sulfate-bearing unit, where the terrain begins to be get steeper with many very dramatic geological formations.

Looking across the entirety of Curiosity’s journey, which began in 2012, the science team sees a cycle of wet to dry across long timescales on Mars. “As we climb Mount Sharp, we see an overall trend from a wet landscape to a drier one,” said Curiosity Project Scientist Ashwin Vasavada of NASA’s Jet Propulsion Laboratory in Pasadena, California. JPL leads the Mars Science Laboratory mission that Curiosity is a part of. “But that trend didn’t necessarily occur in a linear fashion. More likely, it was messy, including drier periods, like what we’re seeing at Sutton Island, followed by wetter periods, like what we’re seeing in the ‘clay-bearing unit’ that Curiosity is exploring today.”

Up until now, the rover has encountered lots of flat sediment layers that had been gently deposited at the bottom of a lake [the Murray Formation]. Team member Chris Fedo, who specializes in the study of sedimentary layers at the University of Tennessee, noted that Curiosity is currently running across large rock structures [Vera Rubin Ridge and the clay formation] that could have formed only in a higher-energy environment such as a windswept area or flowing streams.

Wind or flowing water piles sediment into layers that gradually incline. When they harden into rock, they become large structures similar to “Teal Ridge,” which Curiosity investigated this past summer [in the clay formation]. “Finding inclined layers represents a major change, where the landscape isn’t completely underwater anymore,” said Fedo. “We may have left the era of deep lakes behind.”

Curiosity has already spied more inclined layers in the distant sulfate-bearing unit. The science team plans to drive there in the next couple years and investigate its many rock structures. If they formed in drier conditions that persisted for a long period, that might mean that the clay-bearing unit represents an in-between stage – a gateway to a different era in Gale Crater’s watery history.

None of these results are really surprising. You would expect lakes in the flatter lower elevations and high-energy streams and flows in the steeper higher elevations. Confirming this geology however is a big deal, especially because they are beginning to map out in detail the nature of these geological processes on Mars, an alien world with a different make-up and gravity from Earth.

Below the fold is the Curiosity science teams overall map, released in May 2019, showing the rover’s future route up to that sulfate unit, with additional annotations by me and reduced to post here.
» Read more

Capsule and booster for SpaceX launch abort test arrives in Florida

Capitalism in space: The Dragon capsule and Falcon 9 first booster for SpaceX’s launch abort test have both arrived in Florida and are being readied for flight.

SpaceX’s launch license suggests this test will occur no earlier than November 1, so it looks like the company is getting close. However, don’t hold your breath about the manned launch. It appears that NASA is still hassling SpaceX “with certification and safety reviews,” which in plain language is mostly paperwork and filling out forms that NASA’s safety panel can then rubber stamp.

Protests in Iraq

Three days of protests in Iraq have now resulted in the deaths of 60 demonstrators, many shot by sniper fire.

The violence is the worst since Iraq put down an insurgency by Islamic State two years ago. The protests arose in the south, heartland of the Shi’ite majority, but quickly spread, with no formal leadership.

Security and medical sources gave a death toll on Friday of 60 killed across Iraq in three days of unrest, the vast majority of the deaths in the last 24 hours as the violence accelerated.

“It is sorrowful that there have been so many deaths, casualties and destruction,” Iraq’s most influential cleric, Grand Ayatollah Ali al-Sistani, said in a letter read out by his representative during a sermon. “The government and political sides have not answered the demands of the people to fight corruption or achieved anything on the ground,” said Sistani, who stays out of day-to-day politics but whose word is law for Iraq’s Shi’ites. “Parliament holds the biggest responsibility for what is happening.”

Populist cleric Moqtada al-Sadr, who leads the largest opposition bloc in parliament, ordered his lawmakers to suspend participation in the legislature until the government introduces a program that would serve all Iraqis.

Many government officials and lawmakers are widely accused of siphoning off public money, unfairly awarding contracts in state institutions and other forms of corruption.

It is suggested that the demonstrators are protesting government corruption. This could easily be true, since bribery, payoffs, embezzlement, etc, are very normal in Arab culture. At the same time, the factionalism that divides Iraq has not gone away, and these demonstrations could be a tactic by the opposition to damage the ruling party. Moqtada al-Sadr (who had been nicknamed “Mookie” by U.S. troops) has a long history of using force for his own political gain. I wouldn’t be surprised if he is behind these protests.

Chinese head in Hong Kong invokes emergency powers

Escalation: Carrie Lam, the Chinese-appointed chief executive in Hong Kong, today invoked emergency powers in her effort to stem the anti-Chinese demonstrations that have been on-going now for four months.

[P]rotesters here can now face criminal penalties of up to than $3,000 and a year’s imprisonment simply for wearing the masks they have used to defend themselves against tear gas and the possibility of arrest.

And, having invoked emergency powers, Lam is now in a position to do almost anything. As the New York Times sums it up: “Under the emergency powers, Mrs. Lam has a wide discretion to create new criminal laws and amend existing laws — all without going through the legislative process.” Newspapers can be censored or shuttered, web sites closed down, property seized, searches carried out galore, and so forth.

It appears that China is beginning the process of cracking down, and will likely do it incrementally, in the hope this will defuse the response, both by the Hong Kong population and the international community.

Astronomers photograph baby binary system

Baby binary stars dance in joint accretion disk
Click for full image.

Using the Atacama Large Millimetre/submillimetre Array (ALMA), astronomers have obtained the first high resolution image of a baby binary system, its two young stars dancing within a joint accretion disk.

Most stars in the universe come in the form of pairs – binaries – or even multiple star systems. Now, the formation of such a binary star system has been observed for the first time with high-resolution ALMA (Atacama Large Millimetre/submillimetre Array) images. An international team of astronomers led by the Max Planck Institute for Extraterrestrial Physics targeted the system [BHB2007] 11, the youngest member of a small cluster of young stellar objects in the Barnard 59 core in the Pipe nebula molecular cloud. While previous observations showed an accretion envelope surrounding a circum-binary disk, the new observations now also reveal its inner structure.

“We see two compact sources, that we interpret as circum-stellar disks around the two young stars,” explains Felipe Alves from MPE, who led the study. “The size of each of these disks is similar to the asteroid belt in our Solar System and their separation is 28 times the distance between the Sun and the Earth.” Both proto-stars are surrounded by a circum-binary disk with a total mass of about 80 Jupiter masses, which contains a complex network of dust structures distributed in spiral shapes. The shape of the filaments suggests streamers of in-falling material, which is confirmed by the observation of molecular emission lines.

Why most stars form as binary systems is as yet not understood. This data is a major first step towards figuring this out.

Weird glacial features in Martian crater

weird glacial feature in crater on Mars
Click for full image.

Cool image time! In reviewing today’s October release of new images from the high resolution camera of Mars Reconnaissance Orbiter (MRO), I came across the strange geology shown in the image to the right, rotated, cropped, and reduced to post here.

The uncaptioned image calls these “glacial features within crater.” The crater is located at 35 degrees north latitude in Arabia Terra, one of the more extensive regions of the transition zone between the northern lowlands and the southern highlands. It is also located within the northern band from 30 to 60 degrees latitude where most of the buried Martian glaciers are found.

The most abundant type of buried glaciers are called concentric crater fill (CCF) because they are found inside craters, and often show decay in a concentric manner. This weird feature likely falls into that category, though I would hardly call these glacier features concentric.

I’m not even sure if this is an impact crater. If it is, its rim has been heavily obscured, making it look instead like an irregular depression with one outlet to the south. In fact, I suspect it is possibly one of the lakes that scientists believe pepper this part of Arabia Terra and might have contained liquid water two to three billion years ago. That water would have later frozen, and possibly become covered by dust and debris to protect it.

According to present theories, Mars is presently in a period where its mid-latitude glaciers are shrinking, the water sublimating away and being transported back to its poles. The weird formations here suggest this process. Imagine what happens when you spray warm water on a big block of ice. It dissolves, but randomly to form weird shapes.

In this case the glacier is shrinking randomly where the ice has gotten exposed. In the thin Martian atmosphere, it transitions directly from a solid to a gas, sublimating into the atmosphere to leave these inexplicable shapes.

Italy buys tickets on Virgin Galactic’s suborbital VSS Unity

Capitalism in space: Italy yesterday announced that it has purchased seats on Virgin Galactic’s suborbital VSS Unity for a research flight sometime in 2020.

The deal marks the first time a government has bought a ride on a private, suborbital space mission to conduct any kind of human-led experiments. The first research flight could take place as early as next year, the company said. “We’re delighted to work with the Italian Air Force to further space-based research and technology development through this historic mission,” Virgin’s chief executive, George Whitesides, said in a news release.

The contract announcement, plus the 2020 mission date, both lend some weight to Virgin Galactic’s recent claims that it will begin commercial operations next year. However, forgive me if I remain skeptical. Virgin Galactic and Richard Branson have been making promises like this for more than a decade, with none ever coming true.

Right now I will only believe it when they actually do it.

Astronomers roughly map out Andromeda’s history

The uncertainty of science: Astronomers have now roughly mapped out the history of the Andromeda galaxy, identifying two major events whereby it had absorbed nearby dwarf galaxies.

“It’s been known for 10 to 15 years that Andromeda has a vigorous history of accumulating and destroying its neighbours,” Mackey says. In fact, he says, “It seems to have a much more intense history of that than the Milky Way.”

…[New data] “tells us there were two main events that formed the halo of Andromeda,” Mackey says. “One occurred very long ago. The other must have happened relatively recently.”

Not that Andromeda couldn’t also have eaten innumerable smaller galaxies. ”We can’t trace them with galactic clusters, because they didn’t have any to begin with,” Mackey says.

Most of the news reports about this new research have been very overwrought (Andromeda is “violent” and is going to “eat us!”) and very unaware that the assimilation of nearby small galaxies by Andromeda is not really news. Astronomers have known for years that big galaxies like Andromeda and the Milky Way absorb the dwarf galaxies around them. All this story does is postulate a more detailed though very rough timeline.

Blue Origin hints at the New Shepard ticket price

Capitalism in space: For the first time a Blue Origin official has provided a very rough estimate of what the company will charge per ticket for someone to take a flight in its suborbital New Shepard spacecraft.

But today, Blue Origin CEO Bob Smith hinted at a ballpark figure. “It’s going to not be cheap,” Smith said at TechCrunch’s Disrupt SF conference.

Although he stressed that the price for passengers hasn’t yet been published, he indicated that Blue Origin now has a price range in mind. “Any new technology is never cheap, whether you’re talking about the first IBM computers or what we actually see today,” Smith said. “But it’ll be actually in the hundreds of thousands of dollars for people to go, initially.”

Smith added that over time, “we’re going to get this down to the point where middle-class people” can afford a ticket to space. [emphasis mine]

This price sounds somewhat comparable to the prices being offered by Virgin Galactic. For the first people who had been willing to put down a deposit years ago they will pay $250K. Future buyers will pay more, at least at first.

Of course, neither company appears ready to put passengers on board, though both seem finally close and aiming for commercial flights no later than 2021. (Having said that, please don’t quote me, as I don’t really believe it, based on the endless delays coming from both companies.)

InSight robot arm to help mole dig

Mole in hole, with robot arm and scoop above
Click for full image.

In their effort to solve the issues that have prevented InSight’s mole from penetrating more than fourteen inches into the ground on Mars, engineers now plan to use the scoop on the robot arm to “pin” the mole up against one wall of the hole so that it will have the friction necessary to drill downward.

The image to the right, cropped and reduced to post here, illustrates what they have been doing and what they will do. Previously the hole was much larger, which prevented the mole from moving downward because it needed the friction from the material around it to hold it in place after each hammer action. (Think of pounding a nail into a wooden board: The nail is gripped tightly by the wood around it as it goes down, so that after each hit it goes further in.)

Since June they have been using the arm and scoop to fill in the hole around the mole. Now I think they intend to bring the scoop around to the mole’s left side, as shown in the image, and pin it upright against the right wall of the hole. When it resumes hammer-drilling they hope both the wall and the scoop will provide enough friction for the mole to drill downward.

SpaceX wins launch contract for NASA privately-built lunar lander

Intuitive Machines, one of the three companies awarded NASA contracts to build unmanned lunar landers, has awarded SpaceX the launch contract for its planned 2021 mission.

The Houston-based company’s first robotic Nova-C lander will carry up to 220 pounds, or 100 kilograms, of payloads to the moon’s surface. Launch and landing are scheduled for July 2021, according to Trent Martin, vice president of aerospace systems at Intuitive Machines.

Intuitive Machines previously stated plans to launch the first Nova-C mission on a SpaceX rocket, but Martin said in an interview Wednesday that the company held a “fully open competition” among multiple launch service providers before signing a contract for a Falcon 9 launch.

In a statement, Intuitive Machines said it “ultimately selected SpaceX for its proven record of reliability and outstanding value.” The company said the Nova-C mission will take off from pad 39A at NASA’s Kennedy Space Center in Florida. [emphasis mine]

That “outstanding value” almost certainly was the lowest price by far offered by any rocket company, a reality that continues to bring SpaceX business while taking market share from everyone else.

The slowly changing dunes of Mars

Map of Mars

In order to better understand the climate and geology of Mars, scientists need to study how the thin Martian atmosphere causes changes to the planet’s numerous sand dunes. To do this, they have been using the high resolution camera on Mars Reconnaissance Orbiter (MRO) to periodically snap photos of the same places repeatedly over time, to track any changes that might occur.

Recently the monthly download dump of images from MRO included one such location in the northwest quadrant of Hellas Basin, what I call the basement of Mars because it the planet’s lowest point. The uncaptioned image was taken on May 20, 2019 and was titled “Hellas Region Sand Dune Changes.” A review of past images shows that MRO has taken pictures of this location several times in the past, in 2011 and in 2017. All these images were taken during the Martian autumn season, and were taken to see if over time there were any significant changes to the dunes due to winds.

My superficial comparison of the 2011 and 2017 images does not show much obvious change. There could be small changes that my quick review did not spot, and there is also the strong possibility that the entire dune field could have shifted as a unit over those three Martian years, a change that would require a more detailed analysis beyond my technical capabilities. Click on both links, put the photographs in separate tabs, and switch quickly between them to see if you can spot any differences.

Comparing the 2011 and 2019 images however shows some significant changes, most of which I think are due to the 2018 global dust storm. Below is that comparison.
» Read more

More organics detected in Enceladus’ plumes

Using Cassini archived data scientists have detected evidence of new organic molecules in the water-ice plumes coming from the tiger stripe fissures on Saturn’s moon Enceladus.

Powerful hydrothermal vents eject material from Enceladus’ core, which mixes with water from the moon’s massive subsurface ocean before it is released into space as water vapor and ice grains. The newly discovered molecules, condensed onto the ice grains, were determined to be nitrogen- and oxygen-bearing compounds.

On Earth, similar compounds are part of chemical reactions that produce amino acids, the building blocks of life. Hydrothermal vents on the ocean floor provide the energy that fuels the reactions. Scientists believe Enceladus’ hydrothermal vents may operate in the same way, supplying energy that leads to the production of amino acids.

For clarity I should point out that I am using the term “organics” as chemists do. It refers not to life, but to any molecule that is formed using carbon.

Juno completes long engine burn to avoid Jupiter’s shadow

In order to avoid a twelve-hour plunge through Jupiter’s shadow that would have likely sucked all power from Juno’s solar powered systems and killed the spacecraft, mission engineers have successfully used its attitude thrusters to complete a 10.5 long engine burn.

Juno began the maneuver yesterday, on Sept. 30, at 7:46 p.m. EDT (4:46 p.m. PDT) and completed it early on Oct. 1. Using the spacecraft’s reaction-control thrusters, the propulsive maneuver lasted five times longer than any previous use of that system. It changed Juno’s orbital velocity by 126 mph (203 kph) and consumed about 160 pounds (73 kilograms) of fuel. Without this maneuver, Juno would have spent 12 hours in transit across Jupiter’s shadow – more than enough time to drain the spacecraft’s batteries. Without power, and with spacecraft temperatures plummeting, Juno would likely succumb to the cold and be unable to awaken upon exit.

“With the success of this burn, we are on track to jump the shadow on Nov. 3,” said Scott Bolton, Juno principal investigator at the Southwest Research Institute in San Antonio.

This burn did not use the spacecraft’s main engine, which they fear has a problem that would produce a catastrophic failure if fired. Instead, they used Juno’s small attitude thrusters, which explains the length of the maneuver. In fact, this 10.5 hour burn might actually be the longest chemical engine burn in space ever. While ion engines routinely fire for this long or longer, as far as I can remember no chemical engine in space has ever fired even close to this length of time.

NASA in negotiations to buy more Russian Soyuz astronaut seats

Collusion with Russia discovered! NASA has begun negotiations with Russia’s Roscosmos space agency to buy more astronaut flights to ISS using Russia’s Soyuz rocket and capsule.

According to the story at the link, NASA’s last purchased ticket will fly in March of 2020, and these negotiations would buy flights beginning in the fall of 2020 and beyond into 2021. The story also cites statements by NASA administrator Jim Bridenstine to CNN, confirming these negotiations.

Apparently NASA thinks the manned capsules being built by Boeing and SpaceX will not be ready by the fall of 2020, and needs to buy tickets from Russia because of this.

However, the only reason those American capsules will not have been approved and flown by then will be because NASA’s timidity in approving their launch. The agency’s safety panel as well as its management have repeatedly delayed these private American capsules, sometimes for very strange reasons, including a demand that lots of paperwork be filled out, and what I consider to be an unjustified demand for perfect safety.

Had NASA adopted a reasonable criteria for launch, SpaceX’s Dragon capsule could have flown three years ago.

Meanwhile, NASA seems quite willing to put Americans on a Soyuz rocket, launched by a foreign power whose safety record in the past half decade has been spotty, at best. In that time Russia has experienced numerous quality control problems, including mistakes that led to an Soyuz abort during a launch and a Soyuz parachute failure during a landing, corruption that forced them to recall all rocket engines and freeze launches for almost a year, and sabotage where someone drilled a hole in a Soyuz capsule prior to launch, a sabotage that Russia still refuses to explain.

It is unconscionable for NASA to favor putting Americans on a Soyuz with many documented safety issues, but block the launch of Americans on American-made capsules, for imagined safety issues that have mostly made no sense. In fact, the contrast makes me wonder about the loyalty of NASA’s bureaucracy. They certainly seem to favor Russia and Roscosmos over private American companies.

Relativity raises $140 million in third funding round

Capitalism in space: The new smallsat rocket company Relativity announced yesterday that it has raised $140 million in its third funding round, providing it enough funding to complete and launch its Terran 1 rocket.

The new round brings the total raised by the Los Angeles-based company to $185 million. The new funding, Relativity executives said, will be sufficient to complete development of its Terran 1 rocket and begin commercial operations in 2021. It will support expansion of its headquarters and establishment of a factory for rocket production at the Stennis Space Center in Mississippi, where it currently tests its engines.

“That round will carry us past first flight of Terran 1,” said Jordan Noone, co-founder and chief technology officer of Relativity, in an interview. “This round is all the capital required to get to first flight, build out more of the Mississippi test site, Launch Complex 16 in Florida and expand our L.A. headquarters and manufacturing.”

That first launch, once scheduled for late 2020, is now planned for February 2021. “That original prediction for when first flight would be was made about four years ago, so moving it two months to the right here is not bad,” he said. Part of the reason for the slip is a decision to develop a larger payload fairing with twice the volume of the original one, based on feedback from prospective customers.

This all sounds very encouraging. The test will be their engineering concept to manufacture their rocket entirely by 3D printing, something no one has ever done before. If they experience any problems with this those launch dates will immediately be threatened.

Ukraine: The Democratic Party’s effort to overthrow the elected government

In the past two weeks the mainstream media, working for the Democratic Party, has blasted us with a new anti-Trump scandal, accusing the president of using his influence during a phone call with Ukrainian President Volodymyr Zelensky to pressure the Ukraine to instigate an investigation of Joe Biden.

As I usually do with big political stories such as this, I let them play out a bit before drawing some conclusions. I will admit that I immediately thought this was all balderdash, comparable to the same fake accusations against Trump in connection with Russian collusion. Those were never creditable, and after almost two years even Robert Mueller, the FBI hack chosen by DC insiders to frame Trump, found he had no evidence and came up empty.

The Trump-Ukraine accusations seemed at first glance to be the same garbage, but I decided to watch and wait, to see if they had substance.

Not surprisingly, they don’t.

First we have the accusation itself, coming from an anonymous whisteblower. Not only is the accuser anonymous, so are all his or her sources. All.

Even more significant, the accusation is not based on first hand knowledge. The accuser was not witness to Trump’s phone call. His claim is based entirely on hearsay and rumor, which would be laughed out of any court in the land. That anyone in the press is taking these accusations seriously based on this evidence proves they are, as Glenn Reynolds often says, merely Democratic operatives with bylines.

Second, soon after the press and the Democrats (I repeat myself) began to make a big deal about this feeble accusation, Trump went ahead and released the transcript of his conversation.

The transcript shows absolutely nothing scandalous. » Read more

Musk on Starship, engineering, and management

Several listeners have sent me the link to a fifteen minute interview with Elon Musk that took place the day of his big Starship speech on September 30.

I have embedded it below. Watch it. It reveals several very important overarching things about SpaceX and Musk.

1. Musk calls himself SpaceX’s chief engineer, and during this interview he demonstrates why. He understands this stuff at more fundamental level that I think most similar big rocket company heads. This gives him the ability to distinguish good engineering from bad, and thus shape the company’s design direction more forcefully. It also makes him more similar to the early owners of American airplane companies (Douglas, Boeing, McDonnell, Northrop, etc), all of whom were engineers first and managers second. Too often today CEOs know little about the engineering behind their company, and therefore can be easily sidetracked by bad ideas.

2. At several points in discussing his management approach, Musk clearly wants to give an example of how bad management leads to bad engineering, but it is clear he censors himself. I suspect he is thinking of SLS, but does not want to say so to avoid a controversy he doesn’t need.

3. Much of the interview revolves around the aerospike nozzle, and why SpaceX hasn’t used it. It appears Musk’s reason is that while it might make the exhaust of a rocket more efficient, it causes a loss of efficiency in combustion, and the trade-off isn’t worth it.

4. Finally, Musk’s openness to new ideas, even if they prove him wrong, is quite obvious. As he says,

If someone could show that we’re wrong, that would be great. If someone can show you a way to make your design better, this is a gift. I would be like, thank you! Wow, this is awesome. The worst thing would be that we want to do a dumb design and stick with our dumb design. That would be insane.

This is one of those moments where I think he is thinking of SLS, but doesn’t come right out and say so.

The sounds of Mars

The InSight seismometer team today issued an update of their results since the instrument began recording quakes on Mars in February.

But after the seismometer was set down by InSight’s robotic arm, Mars seemed shy. It didn’t produce its first rumbling until this past April, and this first quake turned out to be an odd duck. It had a surprisingly high-frequency seismic signal compared to what the science team has heard since then. Out of more than 100 events detected to date, about 21 are strongly considered to be quakes. The remainder could be quakes as well, but the science team hasn’t ruled out other causes.

The press release provides audio for many of these detections, including two 3.3+ earthquakes as well as a strange sequence of what they call “dinks and donks” that appear to occur each evening as the seismometer adjusts to night-time temperatures.

So far the data suggests that Mars’ interior is a relatively quiet place, compared to Earth.

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