Tag: science

The aging data relay spacecraft orbiting Mars

9:40 am

By the 2020s, NASA and other space agencies sending landers and rovers to Mars will be faced with a data-relay crisis, as the orbiters they presently use to provide communications with the Martian surface are aging, and no replacements are presently planned.

The venerable Mars Global Surveyor (MGS) and Mars Odyssey spacecraft were the first to employ data relay capabilities in the modern era of Mars exploration. They operated as relays for the twin Mars Exploration Rover missions until the arrival of the Mars Reconnaissance Orbiter (MRO) in 2006.

MGS entered into a safe mode in November 2006 and NASA later declared the mission over in January 2007 after the space agency failed to reestablish contact with the aging orbiter. The 12-year-old MRO and 17-year-old Odyssey have served as the primary data relays for Mars surface missions since.

More important, funding for a dedicated communications satellite called NEMO, planned for launch in 2022, has disappeared.

However, funding for NeMO has been largely phased out in favor of directing limited funds towards the development of the Mars Sample Return mission. Mars Sample Return has the primary objective of fetching samples that scientists plan to collect and cache using the Mars 2020 rover currently under development. The current Planetary Science Decadal Survey has listed the flagship sample return mission as the primary objective for NASA’s Mars program in the 2020s, along with requisite funding. The existing fleet of orbiting spacecraft at Mars, while aging, are in generally good health meaning the postponement of a new orbiter will require careful management of existing orbital assets into the next decade.

One of the reasons there is no funding for NEMO is that NASA has had to steal money from its planetary program to fund the cost overruns on the James Webb Telescope. Though this was never admitted publicly, the cuts that the Obama administration imposed on the planetary program were partly to pay for Webb. Thus, not only has that telescope killed almost all of NASA’s entire astrophysics program, it has damaged the planetary program as well.

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Sunspot update for April 2018: Heading into solar minimum

9:00 am

On Sunday NOAA posted its monthly update of the solar cycle, covering sunspot activity for April 2018. Below is my annotated version of that graph.

While there was an uptick in sunspots in April, compared to the almost complete inactivity in March (the least active month for sunspots in a decade), the uptick did little to change the general trend. Sunspot activity is now comparable to what we saw in early 2008 (as indicated by the yellow line). This was just before the arrival of the previous solar minimum, which happened to also be one of the longest and deepest on record.

» Read more

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Volcano or Impact?

11:34 am

Elliptical crater with flow features

Cool image time! Yesterday the Mars Reconnaissance Orbiter (MRO) team released its monthly image dump of more than 500 new photographs, taken by the spacecraft’s high resolution camera. As I have started to do in the past few months, I am reviewing this collection and plan to post a few of the more interesting images over the next month. On the right is the first of this series. I have cropped and reduced the resolution to show here, but you can see the full resolution version if you click on the image.

The MRO team labels this image an “elliptical crater with flow features.” The first impression one gets from the image is that the impact that caused the crater came from the side and hit the ground obliquely, creating the crater’s oval shape and the lava-type flow features in the crater’s floor.

As is almost always the case with Martian geology, beware of first impressions. You need to give any feature both a more detailed look as well as a broader view to have any chance at understanding its context and geology.
» Read more

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More problems uncovered during testing of the James Webb Space Telescope

8:42 am

During ground tests of the James Webb Space Telescope engineers have discovered an additional quite astonishing problem that will certainly delay the project again.

In a presentation at a meeting of the National Academies’ Space Studies Board here May 3, Greg Robinson, the JWST program director at NASA Headquarters, said some “screws and washers” appear to have come off the spacecraft during recent environmental testing at a Northrop Grumman facility in Southern California.

Technicians found the items after the spacecraft element of JWST, which includes the bus and sunshield but not its optics and instruments, was moved last weekend from one chamber for acoustics tests to another to prepare for vibration testing.

“Right now we believe that all of this hardware — we’re talking screws and washers here — come from the sunshield cover,” he said. “We’re looking at what this really means and what is the recovery plan.” The problem, he said, was only a couple of days old, and he had few additional details about the problem. “It’s not terrible news, but it’s not good news, either,” he said. [emphasis mine]

The absurd spin expressed by the program director above is garbage. This is unbelievable and entirely unacceptable. On spacecraft, especially those that are not planned for in-space maintenance like Webb, screws are routinely sealed with some form of glue so that they will not unscrew themselves during the vibrations of launch. This is standard space engineering and has been for more than a half century.

That some screws came off Webb during testing suggests a quality control problem at Northrop Grumman that is beyond comprehension.

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NASA tests new small fission power plant for future space missions

10:08 am

NASA has successfully completed a full test of a new small fission power plant that it hopes to use in future space missions.

The prototype power system uses a solid, cast uranium-235 reactor core, about the size of a paper towel roll. Passive sodium heat pipes transfer reactor heat to high-efficiency Stirling engines, which convert the heat to electricity.

According to David Poston, the chief reactor designer at NNSA’s Los Alamos National Laboratory, the purpose of the recent experiment in Nevada was two-fold: to demonstrate that the system can create electricity with fission power, and to show the system is stable and safe no matter what environment it encounters. “We threw everything we could at this reactor, in terms of nominal and off-normal operating scenarios and KRUSTY passed with flying colors,” said Poston.

The Kilopower team conducted the experiment in four phases. The first two phases, conducted without power, confirmed that each component of the system behaved as expected. During the third phase, the team increased power to heat the core incrementally before moving on to the final phase. The experiment culminated with a 28-hour, full-power test that simulated a mission, including reactor startup, ramp to full power, steady operation and shutdown.

Throughout the experiment, the team simulated power reduction, failed engines and failed heat pipes, showing that the system could continue to operate and successfully handle multiple failures.

This power plant appears similar in concept to the fission RTG nuclear fuel systems that have been used routinely for decades on unmanned planetary probes such as the two Voyager spacecraft, New Horizons, and on Curiosity. This new system however provides significantly more power, as much as ten kilowatts compared to the approximate two hundred watts provided by RTGs.

Such a system will be essential for future bases on both Mars and the Moon, where solar power is not the best option. I should also add that such a system might possibly have applications here on Earth. Developed properly, it could provide a practical power source for out-of-the-way locations not on the grid. If made cheap enough, it might also provide electrical customers a cheaper and competitive alternative that will allow them to remove themselves from the grid entirely.

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Hubble detects helium in exoplanet atmosphere

2:57 pm

Using the Hubble Space Telescope astronomers have for the first time detected helium in the atmosphere of an exoplanet.

The team made the detection by analysing the infrared spectrum of the atmosphere of WASP-107b [1]. Previous detections of extended exoplanet atmospheres have been made by studying the spectrum at ultraviolet and optical wavelengths; this detection therefore demonstrates that exoplanet atmospheres can also be studied at longer wavelengths.

…WASP-107b is one of the lowest density planets known: While the planet is about the same size as Jupiter, it has only 12% of Jupiter’s mass. The exoplanet is about 200 light-years from Earth and takes less than six days to orbit its host star.

The amount of helium detected in the atmosphere of WASP-107b is so large that its upper atmosphere must extend tens of thousands of kilometres out into space. This also makes it the first time that an extended atmosphere has been discovered at infrared wavelengths. Since its atmosphere is so extended, the planet is losing a significant amount of its atmospheric gases into space — between ~0.1-4% of its atmosphere’s total mass every billion years

The important aspect of this detection is the use of infrared, which gives astronomers another tool to study exoplanets.

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Scientists claim Earth’s magnetic field not about to flip

8:29 am

The uncertainty of science: Using computer models and data from the past two changes in the Earth’s magnetic field, some scientists now claim that the weakening of the magnetic field in the past two centuries does not herald an upcoming flip in polarity.

To calculate the likelihood of a full field switch, Holme and his colleagues looked at the magnetic alignment of rock particles deposited in and before the two most recent excursions – the Laschamp event, approximately 41,000 years ago, and the Lake Mono event, which occurred 34,000 years ago.

The scientists found that the strength of the Earth’s magnetic field several thousand years before the two wobbles – at 49,000 and 46,000 years ago – were pretty much the same as they are now. However, they were accompanied by SAA-style weak areas of much greater magnitude.

This, suggests Holme’s teams, considerably reduces the chances of anything drastic happening now. “There has been speculation that we are about to experience a magnetic polar reversal or excursion,” says Holmes. “However, by studying the two most recent excursion events, we show that neither bear resemblance to current changes in the geomagnetic field and therefore it is probably unlikely that such an event is about to happen.

“Our research suggests instead that the current weakened field will recover without such an extreme event, and therefore is unlikely to reverse.”

Can I express my skepticism? This research is interesting, but there is no way it could provide enough data for anyone to trust such a prediction. We have zero knowledge of the behavior of the magnetic field during a polarity switch, and to claim that this data gives us enough information to say that we do understand that behavior is an overstatement of stupendous proportions.

Just as we don’t really understand the mechanics of the Sun’s magnetic field, causing it to flip polarity every 11 years, we certainly don’t understand the Earth’s either. The Earth’s magnetic field is going to do what it is going to do, and when it does, we will then maybe get an inkling as to why it does it.

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Alien world

9:21 am

Meridiani Planum
So what is it we are looking at in the image above? I have reduced the resolution slightly to fit it here, but you can see the full resolution image by clicking on the picture.

Is it a marble or granite kitchen counter? Nah, the surface is too rough.

Maybe it’s a modern abstract painting that we can find hanging in the Museum of Modern Art in New York. Nah, it has too much style and depth. Abstract art is much more shallow and empty of content.

Could it be a close-up of a just-opened container of berry-vanilla ice cream, the different flavors swirling and intertwined to enhance the eating experience? No, somehow it looks too gritty for ice cream.
» Read more

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The thin dense crust of Mercury

12:24 pm

Using data gathered by the MESSENGER spacecraft while it was in orbit around Mercury, scientists now estimate that the planet’s crust is thinner than previously believed, 16 miles thick rather than 22 miles.

The crust is also as dense as aluminum. It is also the thinnest crust, relative to the planet’s core, of any rocky planet in the solar system.

Mercury’s core is believed to occupy 60 percent of the planet’s entire volume. For comparison, Earth’s core takes up roughly 15 percent of its volume. Why is Mercury’s core so large?

“Maybe it formed closer to a normal planet and maybe a lot of the crust and mantle got stripped away by giant impacts,” Sori said. “Another idea is that maybe, when you’re forming so close to the sun, the solar winds blow away a lot of the rock and you get a large core size very early on. There’s not an answer that everyone agrees to yet.”

There appears to be a great deal of uncertainty to these conclusions, and I would not be surprised if these conclusions change with the arrival of more data.

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Big earthquake in South Korea linked to geothermal power plant

8:45 am

South Korea’s second largest earthquake has now been linked by two different studies to the injection of water deep below the surface at a new geothermal power plant.

Perched on South Korea’s southeast coast and far from grinding tectonic plates, Pohang is an unlikely spot for a big earthquake. Before the geothermal plant’s two wells were drilled, there had never been an earthquake there of any significance, says Kwanghee Kim, a seismologist at Pusan National University in Busan, South Korea, and lead author of one study. But while Kim was monitoring the aftermath of an unrelated earthquake in 2016, he began to detect rumbles from Pohang. That prompted his lab to deploy eight temporary seismic sensors at the site, which were finally in place on 10 November 2017. He expected any quakes to be small—after all, the largest previous quake tied to enhanced geothermal power, in Basel, Switzerland, was just 3.4 in magnitude.

It took only 5 days to be proved wrong. “The Pohang earthquake was larger than any predicted by existing theories,” Kim says. Although some initial measures placed the source of the quake several kilometers away from the plant, Kim’s network revealed that the earthquake, and several of its foreshocks, all began right below the 4-kilometer-deep well used to inject water into the subsurface to create the plant’s heating reservoir. Indeed, it appears likely that the well’s high-pressure water lubricated an unknown fault in the rock, causing it to slip and triggering the quake, Kim says.

A second paper, by European scientists who used regional seismic data, reinforces the South Korean team’s results, in particular its shallow depth. That study also points out that an earlier 3.1-magnitude earthquake also took place near the well bottom, increasing the odds of a common source. Satellite measures of shifts in the surface after the November 2017 quake support that idea, says Stefan Wiemer, the second study’s lead author and director of the Swiss Seismological Service in Zurich. It’s clear the locked fault was storing energy that was waiting to be released, Wiemer says. “If that fault would have gone next Tuesday or 50 years from now, we’ll never know.”

The article notes that scientists had previously concluded that injecting water underground for geothermal purposes was okay (since it reduced use of fossil fuels) while doing the same for fracking (to obtain and use fossil fuels) was bad.. The data here actually suggests just the reverse, since fracking has never produced an earthquake as large as the 5.5 magnitude Pohang quake.

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Trace Gas Orbiter releases its first image

8:21 am

Trace Gas Orbiter's first released image of Korolev Crater

Europe’s Trace Gas Orbiter has released its first image after reaching its planned science orbit.

The image is posted above, reduced in resolution to show here. It shows a portion of the rim of Korolev Crater, a rare large crater located in the vast northern plains of Mars. Because it is so far north, it has ice on the rim which looks almost like glacial flows in this image.

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Trump administration considering reinstating fees to purchase Landsat images

9:31 am

The Trump administration is considering reinstating the fee system to purchase Landsat images that existed prior to 2008.

Not surprisingly, the Nature article is completely hostile to this idea. The quote below gives a flavor.

Since the USGS made the data freely available, the rate at which users download it has jumped 100-fold. The images have enabled groundbreaking studies of changes in forests, surface water, and cities, among other topics. Searching Google Scholar for “Landsat” turns up nearly 100,000 papers published since 2008.

A USGS survey of Landsat users released in 2013 found that the free distribution of Landsat imagery generates more than US$2 billion of economic benefit annually — dwarfing the programme’s current annual budget of roughly $80 million. More than half of the nearly 13,500 survey respondents were academics, and the majority lived outside the United States. [emphasis mine]

Why should scientists, a majority of which are not even Americans, have a free ride?

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Gaia releases 3D map of galaxy

8:17 am

The science team for the space telescope Gaia, designed to map the positions of billions of stars, have released the probe’s second catalog, producing a 3D map of 1.7 billion stars in the Milky Way

The new data release, which covers the period between 25 July 2014 and 23 May 2016, pins down the positions of nearly 1.7 billion stars, and with a much greater precision. For some of the brightest stars in the survey, the level of precision equates to Earth-bound observers being able to spot a Euro coin lying on the surface of the Moon.

With these accurate measurements it is possible to separate the parallax of stars – an apparent shift on the sky caused by Earth’s yearly orbit around the Sun – from their true movements through the Galaxy. The new catalogue lists the parallax and velocity across the sky, or proper motion, for more than 1.3 billion stars. From the most accurate parallax measurements, about ten per cent of the total, astronomers can directly estimate distances to individual stars.

The catalog provides much more information than this. For example:

As well as positions, the data include brightness information of all surveyed stars and colour measurements of nearly all, plus information on how the brightness and colour of half a million variable stars change over time. It also contains the velocities along the line of sight of a subset of seven million stars, the surface temperatures of about a hundred million and the effect of interstellar dust on 87 million.

Gaia also observes objects in our Solar System: the second data release comprises the positions of more than 14 000 known asteroids, which allows precise determination of their orbits. A much larger asteroid sample will be compiled in Gaia’s future releases.

Further afield, Gaia closed in on the positions of half a million distant quasars, bright galaxies powered by the activity of the supermassive black holes at their cores. These sources are used to define a reference frame for the celestial coordinates of all objects in the Gaia catalogue, something that is routinely done in radio waves but now for the first time is also available at optical wavelengths.

I guarantee that many theories about specific strange stars, such as the plethora of different types of variable stars, are going to change drastically with this new and precise information. At the article they describe just one example relating to white dwarf stars.

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How to blow up a star

8:29 am

Link here. The story details the new supercomputer simulation work attempting to model the internal processes inside a dying star that cause it to explode as a supernova.

For more than half a century, physicists have suspected that the heat produced by elusive particles called neutrinos, created in the core of a star, could generate a blast that radiates more energy in a single second than the Sun will in its lifetime. But they have had trouble proving that hypothesis. The detonation process is so complex — incorporating general relativity, fluid dynamics, nuclear and other physics — that computers have struggled to mimic the mechanism in silico. And that poses a problem. “If you can’t reproduce it,” Janka says, “that means you don’t understand it.”

Now, improvements in raw computing power, along with efforts to capture the stellar physics in acute detail, have enabled substantial progress. Janka’s simulation marked the first time that physicists had been able to get a realistic 3D model of the most common type of supernova to explode. Just months later, a competing group based at Oak Ridge National Laboratory in Tennessee repeated the feat with a heavier, more complex star. The field is now buzzing, with more than half a dozen teams currently working on exploding stars in 3D.

They have apparently solved one problem, figuring out how the neutrino blast wave gets enough energy to blast free from the star’s core. A close read of the article indicates that, while progress has been made, they still have many gaps of their understanding.

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Zooming in on a Martian surprise

1:55 pm

Global map of Mars

Let’s take a journey. Above is a global map of Mars, showing its largest and well known geological features. While far smaller than Earth, its lack of oceans means that Mars’ actual dry surface has about the same square footage as the continents of Earth. It is a vast place. Getting a close look at every spot is going to take many decades of work, and probably won’t be finished until humans are actually walking its surface.

Let’s pick a spot, zoom in and find out what’s there.
» Read more

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SpaceX successfully launches NASA new exoplanet telescope

4:41 pm

Capitalism in space: SpaceX today successfully placed NASA’s new explanet space telescope, TESS, into orbit.

The first stage, which was making its first flight, successfully landed on the drone ship in the Atlantic. They hope to reuse this booster on a future Dragon launch.

Update: TESS’s solar arrays have successfully deployed.

The leaders in the 2018 launch standings:

11 China
8 SpaceX
4 ULA
3 Japan
3 Russia
3 Europe
3 India

The U.S. is now ahead of China, 12 to 11, in the national list.

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Diamonds from space!

9:46 am

Researchers have discovered nano-sized diamonds inside a recovered meteorite that suggest a formation process deep within a planet at least the size of Mercury.

The researchers used transmission electron microscopes to determine their composition and morphology, and found that the diamonds contained inclusions (impurities) made of chromite, phosphate and iron-nickel sulfides.

These inclusions are common in diamonds formed underground here on Earth, but this marks the first time they’ve been found in alien rocks. That’s interesting enough on its own, but it has much bigger implications – the team calculated that these diamonds could only have formed under pressure of more than 20 gigapascals. That means they must have been born inside a planet at least as big as Mercury, and possibly up to the size of Mars.

But there’s still more to the story. The fact these diamonds made it to Earth implies that their home planet, whatever it may have been, is no longer with us, since it would take quite a cataclysm to wrench them out of their birthplace deep underground and fling them into space. Instead, the team believes the diamonds came from a planetary embryo.

Not so fast. Though the researchers themselves, in the released paper, assume that the diamonds could only have formed from inside a now destroyed large planet, this leaves out the possibility that the diamonds formed inside one of the existing terrestrial planets, were moved upward toward the surface by later geological process (as happens to diamonds are here on Earth), and then were thrown from the planet by a later nearby impact. This scenario is just as likely.

Nonetheless, this discovery is fascinating. More than anything, it illustrates the inconceivable amount of time that has passed in creating our solar system. Any of these scenarios requires time, time in quantities that no human can really understand or conceptualize.

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How I spent my Saturday: Removing graffiti in a cave

11:40 am

Yesterday was another of my many cave adventures, but different than most. Instead of exploring and mapping newly discovered or out-of-the-way remote cave passages, I participated in a project of the Central Arizona Grotto (a chapter of the National Speleological Society and located in Phoenix) to remove years of graffiti from Peppersauce Cave. You can see pictures of yesterday’s effort here, published by the Arizona Star.

You won’t see any pictures of me. The younger cavers were far more photogenic.

Peppersauce has become what cavers call a “sacrificial cave.” It is open and ungated, relatively easy to traverse, and very well known throughout the state. Thus, many inexperienced people go there to see it, most of whom know little about caving, the ethics of protecting them, or the proper techniques for caving safely. Yesterday, while we were working to either sand-blast, chemically remove, or grind away old spray-paint (some of which was sadly obscene), I must have seen between 150 to 200 people go by. At least two thirds of them were not wearing helmets. Many clearly had never been in a cave before. Some were not wearing headlamps, carrying flashlights instead (which makes climbing harder because you don’t have use of both hands and can easily lose your light). A few even came in with no lights, depending instead on the lights their companions carried.

Because of this heavy traffic, Peppersauce has been badly trashed. On visits by experienced cavers we routinely carry out bags of trash, only to find that trash reappearing, sometime in mere hours. The walls of the cave had been covered with graffiti, some many layers deep.

Ray Keeler of Central Arizona Grotto (CAG) has organized several projects in the past to remove this graffitti over the past two decades. The effort he is leading this year is the third, and has the help of cavers from grottos throughout the state. This was the fourth clean-up weekend, and the first that I was able to attend (having missed the first three due to scheduling conflicts).

I’ve done similar things before, but never on this scale. It was quite educational using the solvent to remove some graffiti, but unfortunately many types of paint are completely resistant to removal by either sand-blasting or solvent. After awhile I got discouraged doing solvent work. Too often nothing got removed. In the afternoon I switched to our last technique, grinding, and was far more gratified with the results. The grinder, which we do not use on formations, removes only the slightest layer of material, and thus does little damage. It however is very effective in removing all paint, no matter how resistant.

The cave is now about two thirds cleaned. We are racing to finish the rest before the summer, because a typically insane reason forced upon us by the government. You see, according to a law passed by Congress, graffiti that is more than fifty years old is considered historical, and cannot be removed without a great deal of paperwork and complex bureaucracy. Spray paint was invented in the late 1960s (about fifty years ago), and so some of this ugly graffiti, no matter how obscene, is going to be protected by our government beginning later this year. Our goal is to get it removed beforehand, so that the cave can be returned to a more natural state, for future visitors to experience.

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