Tag: science

Apollo: When Americans last did some real exploring

1:02 pm

The journey of Apollo 15 on the Moon
Click for full image.

Today is the fiftieth anniversary of the landing of Apollo 15 on the Moon. To commemorate that event the science team for Lunar Reconnaissance Orbiter (LRO) today published some orbital images that capture the astronauts’ travels while on the Moon. The picture to the right, reduced to post here, outlines in oblique view their various excusions to the edge of Hadley Rille and the foot of a mountain dubbed Hadley Delta. As they note,

While Apollo 15 was the fourth mission to land a crew successfully on the lunar surface, it still pioneered many new technologies and had many firsts.

Some of the technologies developed for Apollo 15 included new suits, which were more flexible and had longer life support capabilities, as well as the Lunar Roving Vehicle (LRV), a rover capable of speeds up to 15 km / hour. With these advancements, astronauts Commander David (Dave) Scott and Lunar Module Pilot James (Jim) Irwin were able to travel more than eight times the distance traveled during the previous mission, for a total of over 25 km.

All told, astronauts Dave Scott and Jim Irwin spent more than 18 hours exploring the lunar surface on three scouting trips, covering 15.5 miles. During all those excursions their only protection from the harsh lunar environment was that thin spacesuit. In addition, if their rover broke down a walk back to the lunar module would become a race against suffocation.

And even then, they still had to get that lunar module off the ground, rendezvous and dock with the Apollo 15 command module, and then get that module back to Earth safely.
» Read more

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Apollo 11 lunar ascent stage might still be in orbit around the Moon

10:10 am

New data about the Moon’s interior and gravitational field suggest that the Apollo 11 lunar ascent stage, the part of the LM that carried the astronauts back from the Moon, might still be in orbit around the Moon, rather than have crashed into its surface as long assumed.

Using the GRAIL gravity model and the General Mission Analysis Tool (GMAT) simulator, Meador expected to find the LM’s orbit destabilizing very quickly. What he found – and was verified by a third party using different methods – was that the Ascent Stage had a feedback mechanism that caused the orbit to stabilize itself over a period of every 24 days. When he ran the simulation forward, the orbit remained stable until the present day.

The upshot of this is that the Ascent Stage may still be in orbit now and could be observed when it is in the right position in relation to the Earth and the Sun. However, Meador emphasizes that the LM was never intended to be very robust. Designed to operate for only about 10 days, it was also filled with batteries and fuel tanks, which could have exploded years ago, either destroying the craft or sending it off on a new trajectory.

If the stage is in lunar orbit, than it probably is one the most valuable and quickly reachable artifacts from one of space’s most historic missions. While the Apollo artifacts left on the Moon should be left where they are, this piece could be recaptured and returned to Earth for both study and exhibition.

In fact, if it is still in orbit it should be recovered, to preserve it.

This data also suggests that other Apollo ascent stages as well as other past lunar orbiters might also still be in lunar orbit, and should be located.

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The view of Jezero Crater, from both Ingenuity and Perseverance

1:10 pm

The view from Ingenuity during 10th flight
Click for full image.

Cool image time! Today the Perseverance science team released the 200 images that Ingeniuty took during its 10th flight on July 24, 2021.

The photo to the right was taken about 25 seconds before the helicopter landed, and looks to the southwest. In the foreground can be seen the ridge of rocks and pebbles that the scientists sent Ingeniuty to photograph. In the distance can be seen the rim of Jezero Crater, about 7.5 miles away, with some rounded hills that sit in the crater floor about 5.5 miles away.

The white box indicates the area covered by two high resolution images taken by Perseverance on July 28th that I have combined into the panorama below.
» Read more

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Atomic oxygen in Mars’ atmosphere, as seen by Al-Amal

12:06 pm

Oxygen distribution on Mars

The UAE’s Al-Amal Mars orbiter on July 19, 2021 released a new spectroscopic image, showing the global distribution of atomic oxygen in the Martian upper atmosphere.

The Emirates Ultraviolet Spectrometer (EMUS) mapped the distribution of atomic oxygen in the planet’s upper atmosphere, showing a dense patch emerging from the nightside into the new day.

The photo to the right, cropped and reduced to post here, shows this.

Over the next two years, covering one single Martian year, Al-Amal will monitor the distribution of this oxygen to see how it fluctuations from season to season, as well as from day to day. Gather this information will help the theorists untangle the past atmospheric history of Mars.

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For the first time astronomers measure the rotation of exoplanets

10:10 am

The uncertainty of science: Using the Keck Telescope in Hawaii astronomers for the first time have measured the rotation of several exoplanets orbiting the star HR8799, about 129 light years away.

Using the state-of-the-art Keck Planet Imager and Characterizer (KPIC) on the Keck II telescope atop Hawaiʻi Island’s Maunakea, astronomers found that the minimum rotation speeds of HR 8799 planets d and e clocked in at 10.1 km/s and 15 km/s, respectively. This translates to a length of day that could be as short as three hours or could be up to 24 hours such as on Earth depending on the axial tilts of the HR 8799 planets, which are currently undetermined. For context, one day on Jupiter lasts nearly 10 hours; its rotation speed is about 12.7 km/s.

As for the other two planets, the team was able to constrain the spin of HR 8799 c to an upper limit of less than 14 km/s; planet b’s rotation measurement was inconclusive.

These results are somewhat uncertain, as are any conclusions theorists try to draw from them. Even if confirmed, the sample is so small it doesn’t tell us anything yet about overall trends in planet formation or the expected spin rate of planets as they form.

Nonetheless, the detection appears valid and thus a scientific triumph. Astronomers have been telling me for years that figuring out ways to find out more about exoplanets is going to become the next hot subject in astronomy. This result illustrates this.

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Scientists: Clay, not liquid water, explains radar data under Martian south icecap

9:57 am

The uncertainty of science: In a new paper scientists claim that clay materials, not liquid water, better explain the radar data obtained by orbital satellites, initially hypothesized to be liquid water lakes under Mars’ south polar icecap.

Sub-glacial lakes were first reported in 2018 and caused a big stir because of the potential for habitability on Mars. Astrobiologists and non-scientists were equally attracted to the exciting news. Now, the solution to this question, with great import to the planetary science community, may be much more mundane than bodies of water on Mars.

The strength of this new study is the diversity of techniques employed. “Our study combined theoretical modeling with laboratory measurements and remote sensing observations from The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument on NASA’s Mars Reconnaissance Orbiter. All three agreed that smectites can make the reflections and that smectites are present at the south pole of Mars. It’s the trifecta: measure the material properties, show that the material properties can explain the observation, and demonstrate that the materials are present at the site of the observation,” Smith said.

This paper is only one of several recently that has popped the balloon on the liquid lake theory. Nothing is actually proven, but the weight of evidence is definitely moving away from underground liquid water under the south pole icecap.

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Nauka finally docks with ISS

9:21 am

ISS configuration with Nauka added
The configuration of the Russian portion of ISS with
Nauka and the as-yet launched docking hub.

This morning the new fullsize module to ISS, Nauka, finally docked with the station, ending a week of tension because of issues with its engines.

The docking was not without issue, with Russian cosmonauts noting that Nauka wasn’t on the correct course less than an hour before docking; however, a retro burn quickly corrected the issue. After also troubleshooting an issue with the TORU manual docking system, Nauka successfully docked in automated fashion to the Zvezda service module’s nadir port at 09:29 EDT / 13:29 UTC, marking the first major expansion to the Russian segment for over 20 years.

They will now begin a series of eleven spacewalks to outfit the module. This includes installing a new European-built robot arm and transferring an airlock and radiator on a different module that were originally built to be attached to Nauka and have been waiting eleven years for its much delayed arrival.

In November Russia will then launch a small docking hub module that will dock with Nauka and provide the docking ports that were lost when the Piers module was detached earlier this week (thus allowing Nauka to dock). This new docking hub is also critical, because it will allow Russia to limit dockings to the aft port on Zvezda, which has serious structural stress issues and must be treated gently to prevent further hull cracks and air leaks.

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The nearest hill to China’s Zhurong

3:45 pm

Pitted cone near Zhurong
Click for full image.

Cool image time! The science team for the high resolution camera on Mars Reconnaissance Orbiter (MRO) today released a pair of images the camera took on June 28, 2021 of the nearest pitted cone to China’s Zhurong rover.

The stereo anaglyph to the right, cropped and reduced to post here, allows you, with blue-red 3D glasses, to see the cone in three dimensions. Quite impressive. As noted by Alfred McEwen of the Lunar & Planetary Laboratory in Arizona in his caption,

This image completed a stereo pair of a region just west of where the Zhurong rover landed in southern Utopia Planitia.

The cutout is from a portion of the stereo anaglyph, showing an enigmatic pitted cone. Is this cone composed of sediments or volcanic materials? The sharp bright features surrounding the cone are aeolian (wind-blown) landforms.

According to McEwan, the hill itself is about 200 to 220 feet high, with the pit at its top about 60-65 feet deep.

While McEwan has told me this cone would be his primary target if he was running Zhurong, it appears the Chinese are instead heading south toward the largest nearby crater, and on the way inspecting the parachute, fairing, and heat shield discarded just prior to landing.

The mosaic below from three MRO context camera images provides a wider overview.
» Read more

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Fractured crater close to the Phoenix lander on Mars

2:37 pm

Fractured crater on Mars
Click for full image.

Cool image time! The photo to the right, cropped to post here, was taken on May 3, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a remarkably fractured crater that lies only a few miles to the southeast of where the now-inactive Phoenix lander put down back in 2008, at the very high latitude of 69 degrees north.

Phoenix was purposely sent to this high latitude to find out what the ground and atmosphere was like there. It found the following:

Phoenix’s preliminary science accomplishments advance the goal of studying whether the Martian arctic environment has ever been favorable for microbes. Additional findings include documenting a mildly alkaline soil environment unlike any found by earlier Mars missions; finding small concentrations of salts that could be nutrients for life; discovering perchlorate salt, which has implications for ice and soil properties; and finding calcium carbonate, a marker of effects of liquid water.

Phoenix findings also support the goal of learning the history of water on Mars. These findings include excavating soil above the ice table, revealing at least two distinct types of ice deposits; observing snow descending from clouds; providing a mission-long weather record, with data on temperature, pressure, humidity and wind; observations of haze, clouds, frost and whirlwinds; and coordinating with NASA’s Mars Reconnaissance Orbiter to perform simultaneous ground and orbital observations of Martian weather.

Below is an overview map showing the location of both this crater and the Phoenix lander.
» Read more

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An astrophysicist explains cosmology’s theoretical failures

8:37 am

Link here. The astrophysicist, Paul Sutter, does a very nice job of outlining the conundrum that has been causing astrophysicists to tear their hair out for the past decade-plus.

In the two decades since astronomers discovered dark energy, we’ve come upon a little hitch: Measurements of the expansion rate of the universe (and so its age) from both the CMB [cosmic microwave background] and supernovas have gotten ever more precise, but they’re starting to disagree. We’re not talking much; the two methods are separated by only 10 million or 20 million years in estimating the 13.77-billion-year history of the universe. But we’re operating at such a level of precision that it’s worth talking about.

If anything, this failure for two measurements of data spanning billions of light years — which is billions in both time and space — is a perfect illustration of the uncertainty of science. Astrophysicists are trying to come up with answers based on data that is quite thin, with many gaps in knowledge, and carries with it many assumptions. It therefore is actually surprising that these two numbers agree as well as they do.

Sutter, being in the CMB camp, puts most of the blame for this failure on the uncertainty of what we know about supernovae. He could very well be right. The assumptions about supernovae used to measure the expansion rate of the universe are many. There is also a lot of gaps in our knowledge, including a full understanding of the process that produces supernovae.

Sutter however I think puts too much faith in theoretical conclusions of the astrophysics community that have determined the age of the universe based on the CMB. The uncertainties here are as great. Good scientists should remain skeptical of this as well. Our knowledge of physics is still incomplete. Physicists really don’t know all the answers, yet.

In the end, Sutter however does pin down the biggest problem in cosmology:

The “crisis” is a good excuse to keep writing papers, because we’ve been stumped by dark energy for over two decades, with a lot of work and not much understanding. In a sense, many cosmologists want to keep the crisis going, because as long as it exists, they have something to talk about other than counting down the years to the next big mission.

In other words, the discussion now is sometimes less about science and theories and cosmology, but instead about funding and career promotion. What a shock!

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A hiker’s view from Mount Sharp

10:10 am

A hiker's view of Gale Crater, taken by Curiosity
Click for full image.

A quick cool image! The photo to the right, reduced to post here, was taken yesterday by Curiosity’s left navigation camera. It looks west across the floor of Gale Crater, at the base of a nearby butte.

The crater rim, as seen by the distant mountains, is about 25 miles away. The butte that towers above Curiosity is probably no more than 50 feet high.

Below is a panorama showing the full view to the west, with Navarro Mountain (the nearby 450-foot-high foothill at the base of Mount Sharp) on the left edge. Based on the rover’s planned route, it will travel to the right of the butte rather than climbing up onto the saddle on the left. This will take it to the western side of Navarro Mt, where it will eventually head south into the canyon Gediz Vallis.
» Read more

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1st water vapor in Ganymede’s atmosphere, detected using data from Hubble

9:06 am

Using Hubble data, astronomers have detected the first evidence of water vapor in the atmosphere of Jupiter’s largest moon, Ganymede.

Though larger than the blistering planet Mercury, the Jovian moon Ganymede is no place to go sunbathing. Located ½-billion miles from the Sun, the water ice on its surface is frozen solid in frigid temperatures as low as minus 300 degrees Fahrenheit. This makes the ice as hard as rock. Still, a rain of charged particles from the Sun is enough to turn the ice into water vapor at high noon on Ganymede.

This is the first time such evidence has been found, courtesy of the Hubble Space Telescope’s spectroscopic observations of aurora on Ganymede spanning two decades. The auroras are used to trace the presence of oxygen, which then is linked to the presence of water molecules sputtering off the surface. Ganymede has a deep ocean located an estimated 100 miles below the surface. That’s too deep for water vapor to be leaking out.

This detection has a margin of uncertainty, but it provides a baseline for the up close observations planned for Europe’s JUICE orbiter, set to launch in ’22 and arrive in Jupiter orbit in ’29. JUICE’s study focus will be the three Galilean moons that appear to have lots of ice, Ganymede, Calisto, and Europa.

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