Tag: science

Sublimating scallops on Mars

2:05 pm

Giant scallop on Mars
Click for full image.

Today’s cool image, shown in a rotated, cropped, and reduced version to the right, gives us a close-up look at one of the giant scallops found in the high mid-latitudes of the northern lowland plains of Mars, specifically in Utopia Basin north of the landing sites of both Perseverance and Zhurong. In fact, this particular image is only a few miles north of one of my previous cool images, Giant scallops on Mars, posted in December 2019.

The image was taken on February 3, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). While such scallops are not unusual in the mid-latitudes, their formation process is not well understood. As I noted in the 2019 post, ” scientists believe [pdf] the formation process is related to the sublimation of underground ice.”

According to [one hypothesis] scallop formation should be ongoing at the present time. Sublimation of interstitial ice could induce a collapse of material, initially as a small pit, then growing [away from the equator] because of greater solar heating on [that] side. Nearby scallops would coalesce together as can be seen to have occurred.

This hypothesis is not proven, and today’s cool image raises questions about it. Though the bright material at its center suggests exposed ice, supporting the idea that sublimation of ice near the surface created the scallop, the scallop scarps seem more extended and distinct to the south, not the north as this hypothesis proposes. Sunlight should hit the northern scarps more, which suggests they should retreat more instead of the southern scarp.

The overview map below provides the context.
» Read more

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First images from Ingenuity’s 9th flight today

10:20 am

Ingenuity landing, July 5, 2021

Ingenuity has apparently completed its 9th flight on Mars, its most challenging yet attempted. Based on the six images so far released from that flight, all taking during its landing, it appears the flight was successful. Or at least, the helicopter landed without incident or damage.

The photo to the right was the last picture taken just before touch down. From the caption:

NASA’s Ingenuity Mars Helicopter acquired this image using its navigation camera. This camera is mounted in the helicopter’s fuselage and pointed directly downward to track the ground during flight.

The dark shadow of the helicopter is clearly visible. If you want to see the entire sequence of six images, go to the Ingenuity raw image website and pick the “latest images” filter in the right column. At present it shows this sequence, though I am certain as the day passes images from the entire flight will start appearing.

As noted at the first link above, the flight was to be more than twice as long as any previous flight while flying over the roughest terrain. There was the real risk that its software would become confused by that terrain.

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Sun unleashes strongest solar flare since last solar maximum

9:54 am

X1 solar flare as seen by Solar Dynamics Observatory

On July 3, 2021 the Sun emitted the first X-class solar flare of the rising present solar maximum, the first such flare since September 2017 during the previous maximum.

This flare is classified as an X1.5-class flare. X-class denotes the most intense flares, while the number provides more information about its strength. An X2 is twice as intense as an X1, an X3 is three times as intense, etc.

The image to the right was taken by the orbiting Solar Dynamics Observatory (SDO), designed to monitor the Sun continuously and catch such events.

More information here. The flare caused some disturbances to various radio instruments, though nothing that resulted in any serious consequences.

What the flare did demonstrate is that the Sun is definitely ramping up to solar maximum. In fact, the Sun has not been blank, with no sunspots on its facing hemisphere, since May 6th, the longest such stretch since the last solar maximum.

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Sunspot update: The hot streak continues

8:01 am

This past weekend NOAA released its monthly update of its graph showing the Sun’s sunspot activity, with the new update covering the period through the end of June 2021. As I have done since I began this website eleven years ago, I post that monthly graph below, annotated to show the previous solar cycle predictions and thus provide context.

In June the hot streak of sunspot activity exceeding the prediction of NOAA’s solar science panel continued, with activity rising again after a tiny dip in May. Except for two months, since 2019 the number of sunspots each month has consistently exceeded the prediction. Furthermore, the ramp up of activity has been faster than expected.
» Read more

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Next Ingenuity flight to push envelope significantly

11:20 am

Ingenuity's 9th flight plan
Click for full image.

The engineers running the Mars helicopter Ingenuity revealed today that they will be attempting their most ambitious flight for the helicopter’s ninth flight, presently scheduled for no earlier than July 4th.

I have annotated the map to the right to show Ingenuity’s present position and its approximate landing area.

Without question this flight will be the riskiest taken by Ingenuity so far, more than doubling the flight distance achieved on any previous flight. More important, it will be flying over terrain far rougher than it was initially designed for.
» Read more

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More parachute problems for Europe’s Franklin Mars rover

10:11 am

During a parachute drop test in late June, following a redesign of the parachute with U.S. help, engineers for the ExoMars Rosalind Franklin Mars rover found the chute still experienced problems that tore it during deployment.

They actually performed two drop tests, a day apart, using two different parachutes, with the first test apparently going off without a hitch. However, according to the press release:

“The performance of the second main parachute was not perfect but much improved thanks to the adjustments made to the bag and canopy. After a smooth extraction from the bag, we experienced an unexpected detachment of the pilot chute during final inflation. This likely means that the main parachute canopy suffered extra pressure in certain parts. This created a tear that was contained by a Kevlar reinforcement ring. Despite that, it fulfilled its expected deceleration and the descent module was recovered in good state.”

I have embedded below the fold the only video released by the European Space Agency. It is not clear whether this is from the first or second test. Near the end it appears that the pilot chute above the main chute might be separated, but the video ends before that can be confirmed.

Though ESA has apparently improved the chute’s performance significantly since its earlier failures that contributed to the delay of ExoMars from last year to 2022, they still haven’t gotten the chute completely right. Fortunately they still have time to get it fixed before that ’22 launch.
» Read more

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Perseverance’s most recent view of Jezero Crater

10:30 am

Panorama by Perseverance, Sol 130, July 2, 2021
Click for full resolution.

Overview map
Click for interactive map.

Cool image time! The panorama above, reduced to post here, is made from two navigation camera images on the Mars rover Perseverance, found here and here.

The map to the right, taken from the “Where is Perseverance?” website and annotated further by me, shows with the yellow lines what I think (but am not sure) is the area seen in the panorama.

The navigation cameras on Perseverance are more wide angle than the navigation cameras on Curiosity, in order to cover a larger area. They thus produce a slight fisheye distortion, illustrated by the curve of the horizon.

The large mountain in the center right is likely the crater rim. You can also see the knobs to the left as indicated on the overview map. The rover is now about halfway to the southernmost planned spot it is expected to reach within the floor of Jezero Crater, which is about a half to three quarters of a mile further south.

The terrain seems quite desolate and barren, which of course is no surprise, because that is what it is like on all of the surface of Mars. No plant life, just rocks and dirt. While Curiosity is now in the mountains, Perseverance remains on the crater floor, so the points of interest (from the mere tourist’s perspective) are small or far away.

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Al-Amal detects Martian aurora

10:11 am

Aurora on Mars

The United Arab Emirates Al-Amal Mars orbiter has detected evidence of a Martian aurora that would be visible at night for short periods.

The ultraviolet images to the right have been reduced slightly to post here.

These three images of atomic oxygen emission at a wavelength of 103.4 nm from the planet Mars were obtained by the Emirates Mars Ultraviolet Spectrometer instrument on 22 April, 23 April, and 06 May 2021 respectively. The full set of data collected during these observations include far and extreme ultraviolet auroral emissions which have never been imaged before at Mars. The beacons of light that stand out against the dark nightside disk are highly structured discrete aurora, which traces out where energetic particles excite the atmosphere after being funneled down by a patchy network of crustal magnetic fields that originate from minerals on the surface of Mars.

Though Mars does not have a magnetic field, it is believed that sections of the planet’s crust are magnetized, and under the right conditions can guide the charged particles from the Sun’s solar wind to the night side to hit the atmosphere where they break up and produce the aurora. Because there is no magnetic field however the particles are not guided by the field lines to the poles, but to different spots at all latitudes, depending on circumstances.

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Scientists solve methane data conflict on Mars

9:10 am

Using the methane detector on the rover Curiosity scientists now think they have solved the mystery why Curiosity has detected methane in the atmosphere near the surface while Europe’s Trace Gas Orbiter fails to detect any methane at all.

[Planetary scientist John E. Moores from York University in Toronto], as well as other Curiosity team members studying wind patterns in Gale Crater, hypothesized that the discrepancy between methane measurements comes down to the time of day they’re taken. Because it needs a lot of power, TLS [Curiosity’s methane detector] operates mostly at night when no other Curiosity instruments are working. The Martian atmosphere is calm at night, Moores noted, so the methane seeping from the ground builds up near the surface where Curiosity can detect it.

The Trace Gas Orbiter, on the other hand, requires sunlight to pinpoint methane about 3 miles, or 5 kilometers, above the surface. “Any atmosphere near a planet’s surface goes through a cycle during the day,” Moores said. Heat from the Sun churns the atmosphere as warm air rises and cool air sinks. Thus, the methane that is confined near the surface at night is mixed into the broader atmosphere during the day, which dilutes it to undetectable levels. “So I realized no instrument, especially an orbiting one, would see anything,” Moores said.

Immediately, the Curiosity team decided to test Moores’ prediction by collecting the first high-precision daytime measurements. TLS measured methane consecutively over the course of one Martian day, bracketing one nighttime measurement with two daytime ones. With each experiment, SAM sucked in Martian air for two hours, continuously removing the carbon dioxide, which makes up 95% of the planet’s atmosphere. This left a concentrated sample of methane that TLS could easily measure by passing an infrared laser beam through it many times, one that’s tuned to use a precise wavelength of light that is absorbed by methane.

“John predicted that methane should effectively go down to zero during the day, and our two daytime measurements confirmed that,” said Paul Mahaffy, the principal investigator of SAM, who’s based at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. TLS’ nighttime measurement fit neatly within the average the team had already established. “So that’s one way of putting to bed this big discrepancy,” Mahaffy said.

While this explains the data conflict, it does not yet explain where the methane is coming from. It is suspected it is coming from underground, but why and from what is still unclear. Nor do scientists yet understand why it doesn’t accumulate enough in the atmosphere for Trace Gas Orbiter to detect it. Something is causing the methane to break up sooner than expected.

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Hubble update: Engineers narrow possible failed hardware to one of two units

5:09 pm

Engineers working to pinpoint the cause of the computer hardware issue that has placed the Hubble Space Telescope in safe mode since June 13th have now narrowed the possible failed hardware to one of two units.

The source of the computer problem lies in the Science Instrument Command and Data Handling (SI C&DH) unit, where the payload computer resides. A few hardware pieces on the SI C&DH could be the culprit(s).

The team is currently scrutinizing the Command Unit/Science Data Formatter (CU/SDF), which sends and formats commands and data. They are also looking at a power regulator within the Power Control Unit, which is designed to ensure a steady voltage supply to the payload computer’s hardware. If one of these systems is determined to be the likely cause, the team must complete a more complicated operations procedure to switch to the backup units. This procedure would be more complex and riskier than those the team executed last week, which involved switching to the backup payload computer hardware and memory modules. To switch to the backup CU/SDF or power regulator, several other hardware boxes on the spacecraft must also be switched due to the way they are connected to the SI C&DH unit.

Over the next week or so, the team will review and update all of the operations procedures, commands and other related items necessary to perform the switch to backup hardware. They will then test their execution against a high-fidelity simulator.

The team performed a similar switch in 2008, which allowed Hubble to continue normal science operations after a CU/SDF module failed.

That such a switch was done successfully in the past is a very hopeful sign. However, it sounds as though they are not 100% sure they have pinpointed the actual issue, which means that this switch still might not fix the problem.

We can only wait and hope. And even if the fix works, Hubble will no longer have working backup units for these pieces of hardware. Should any of the backup that are now being activated fail, the telescope will fail, and this time it won’t be fixable with the equipment on board.

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Astronomers detect a white dwarf that is both the smallest and most massive ever found

10:04 am

Using an array of telescopes on the ground and in space, astronomers have discovered a white dwarf star that is both the smallest ever found while also being the most massive.

White dwarfs are the collapsed remnants of stars that were once about eight times the mass of our Sun or lighter. Our Sun, for example, after it first puffs up into a red giant in about 5 billion years, will ultimately slough off its outer layers and shrink down into a compact white dwarf. About 97 percent of all stars become white dwarfs.

While our Sun is alone in space without a stellar partner, many stars orbit around each other in pairs. The stars grow old together, and if they are both less than eight solar-masses, they will both evolve into white dwarfs.

The new discovery provides an example of what can happen after this phase. The pair of white dwarfs, which spiral around each other, lose energy in the form of gravitational waves and ultimately merge. If the dead stars are massive enough, they explode in what is called a type Ia supernova. But if they are below a certain mass threshold, they combine together into a new white dwarf that is heavier than either progenitor star. This process of merging boosts the magnetic field of that star and speeds up its rotation compared to that of the progenitors.

Astronomers say that the newfound tiny white dwarf, named ZTF J1901+1458, took the latter route of evolution; its progenitors merged and produced a white dwarf 1.35 times the mass of our Sun. The white dwarf has an extreme magnetic field almost 1 billion times stronger than our Sun’s and whips around on its axis at a frenzied pace of one revolution every seven minutes (the zippiest white dwarf known, called EPIC 228939929, rotates every 5.3 minutes).

Based on their present understanding of stellar evolution, single white dwarfs do not form from stars with more than 1.3 solar masses. Stars with greater masses instead become neutron stars, or black holes. To get a white dwarf of 1.35 masses thus requires a merger of two white dwarfs, but it also means that the resulting dwarf could be unstable and could collapse into a neutron star at some point. The data also suggests that this merger process might be how a large number of neutron stars actually form.

The dwarf is also the smallest ever found, with a diameter of 2,670 miles, because the larger masses squeezes it into a tighter space.

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Dust covering solar panels threatens to end InSight mission

9:52 am

The InSight science team has revealed that the amount of dust that presently covers the solar panels on the Mars lander has now reduced their available power by about 80%, and if a dust devil doesn’t soon blow the dust off they will have to shut the spacecraft down sometime in the next ten months.

“The dust accumulation on the solar arrays has been considerable. We have about 80% obscuration of the arrays,” said Bruce Banerdt, principal investigator for the InSight mission at NASA’s Jet Propulsion Laboratory (JPL) in Southern California, according to SpaceNews.

Banerdt showed the impact of the declining power levels during a June 21 meeting of NASA’s Mars Exploration Program Analysis Group. When InSight landed near the Martian equator in November 2018, he said, the robot was generating roughly 5,000 watt-hours of power. Today that level is less than 700 watt-hours.

None of this is a surprise. Both the Opportunity and Spirit rovers faced the same problems. Both however were able to recover because periodically a dust devil would fly over the rover and clear the dust from the solar panels.

InSight however has not so far been lucky. While it has seen many nearby dust devils with its camera, none has come close enough to sweep the solar panels clean.

As the power has declined they have shut off various systems in order to keep the lander’s prime instrument, its seismometer, operating continuously. Engineers have also been using the scoop on the lander’s robot arm to try to dislodge some of the dust, with only a very very limited success. If the panels are not cleared soon, however, engineers will eventually be forced to shut everything down.

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