This is a Dust Avalanche on Mars

HiRISE Spots Slope Streaks Fanning Out on Mars Image Credit: NASA/JPL-Caltech/UArizona

For decades, scientists have observed dark landslides called slope streaks on Mars. First seen by the Viking orbiters in the 1970s, every orbiter mission since has observed them, but the mechanism behind the slope streaks has been hotly debated: could they be caused by water activity on the Red Planet, or are they the result of some sort of dry mechanics?

Turns out, the leading candidate is “dry.” But scientists with the Mars Odyssey mission have verified an additional culprit behind the slope streaks: carbon dioxide frost.

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Eight Missions are Getting Extensions, Most Exciting: OSIRIS-REx is Going to Asteroid Apophis

An artist's illustration of NASA's OSIRIS-REx spacecraft approaching asteroid Bennu with its sampling instrument extended. Image Credit: NASA/Goddard/University of Arizona

NASA has granted mission extensions to eight different planetary missions, citing the continued excellent operations of the spacecraft, but more importantly, the sustained scientific productivity of these missions, “and the potential to deepen our knowledge and understanding of the solar system and beyond.” Each mission will be extended for three more years.

One of the most exciting extensions gives a new mission to the OSIRIS-REx spacecraft, sending it to one of the most infamous asteroids of them all, the potentially hazardous asteroid Apophis.

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Mars has Seasons, and They Might Have Revealed Where it’s Hiding its Water

The search for water on Mars has consumed a lot of data collection and research time.  Underground lakes have been found and then discounted again.  Melted ice has been proposed and then dismissed again.  All this attention focuses on one of the most important resources available to any future Martian explorers.  Water is critical to human life and can also be split into two crucial components for rocket fuel.  So finding an easily accessible cache of it is a prerequisite to any serious human mission to the red planet that expects to return its crew back home.

A team from the Lunar and Planetary Institute (LPI) thinks they might have found easily accessible reservoirs of water ice at much more temperate latitudes than had been traditionally thought.  Finding any significant water source near the equator would be cause for celebration, as most large known water deposits are located near the poles, which is even more inhospitable to human exploration than the rest of the planet.  

Continue reading “Mars has Seasons, and They Might Have Revealed Where it’s Hiding its Water”

When Martian Storms Really Get Going, they Create Towers of Dust 80 Kilometers High

The yellow-white cloud in the bottom-center of this image is a Mars "dust tower" - a concentrated cloud of dust that can be lofted dozens of miles above the surface. The blue-white plumes are water vapor clouds. This image was taken on Nov. 30, 2010, by NASA's Mars Reconnaissance Orbiter. Credit: NASA/JPL-Caltech/MSSS

When a huge dust storm on Mars—like the one in 2018—reaches its full power, it can turn into a globe-bestriding colossus. This happens regularly on Mars, and these storms usually start out as a series of smaller, runaway storms. NASA scientists say that these storms can spawn massive towers of Martian dust that reach 80 km high.

And that phenomenon might help explain how Mars lost its water.

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Mars Odyssey Reveals Phobos Using THEMIS

Phobos in three different phases (from left: half, crescent and full) as captured by 2001 Mars Odyssey's THEMIS imager. Credit: NASA/JPL-Caltech/ASU/SSI

Welcome to the moons of Mars, as you’ve never seen them.

NASA’s aging 2001 Mars Odyssey orbiter recently snapped some unique views of the twin moons Phobos and Deimos, in an effort to better understand their texture and surface composition. The images are courtesy of the spacecraft’s THEMIS (the Thermal Emission Imaging System) heat sensitive instrument, and show the thermal gradient across the surface of the moons in color. Odyssey has been studying the moons of Mars since September 2017. The recent images of Phobos taken on April 24, 2019 are especially intriguing, as they occurred during full illumination phase.

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Uh oh, Mars Doesn’t Have Enough Carbon Dioxide to be Terraformed

Artist's conception of a terraformed Mars. Credit: Ittiz/Wikimedia Commons

For almost a century now, the concept of terraforming has been explored at length by both science fiction writers and scientists alike. Much like setting foot on another planet or traveling to the nearest star, the idea of altering an uninhabitable planet to make it suitable for humans is a dream many hope to see accomplished someday. At present, much of that hope and speculation is aimed at our neighboring planet, Mars.

But is it actually possible to terraform Mars using our current technology? According to a new NASA-sponsored study by a pair of scientists who have worked on many NASA missions, the answer is no. Put simply, they argue that there is not enough carbon dioxide gas (CO2) that could practically be put back into Mars’ atmosphere in order to warm Mars, a crucial step in any proposed terraforming process.

The study, titled “Inventory of CO2 available for terraforming Mars“, recently appeared in the journal Nature Astronomy. The study was conducted by Bruce Jakosky – a professor of geological sciences and the associate director of the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado, Boulder – and Christopher S. Edwards, an assistant professor of planetary science at Northern Arizona University and the leader of the Edwards Research Group.

The study was supported in part by NASA through the Mars Atmospheric and Volatile EvolutioN (MAVEN) and Mars Odyssey THEMIS (Thermal Emission Imaging System) projects. Whereas Professor Jakosky was the Principal Investigator on the MAVEN mission, Professor Edwards is a participating scientist on the Mars Science Laboratory Curiosity Rover (MSL), and worked on the Mars Odyssey THEMIS mission (among other Mars missions).

As we explored in a previous article, “How Do We Terraform Mars?“, many methods have been suggested for turning the Red Planet green. Many of these methods call for warming the surface in order to melt the polar ice caps, which would release an abundant amount of CO2 to thicken the atmosphere and trigger a greenhouse effect. This would in turn cause additional CO2 to be released from the soil and minerals, reinforcing the cycle further.

According to many proposals, this would be followed by the introduction of photosynthetic organisms such as cyanobacteria, which would slowly convert the atmospheric CO2 into oxygen gas and elemental carbon. This very method was suggested in a 1976 NASA study, titled “On the Habitability of Mars: An Approach to Planetary Ecosynthesis“. Since that time, multiple studies and even student teams have proposed using cyanobacteria to terraform Mars.

However, after conducting their analysis, Professors Jakosky and Edwards concluded that triggering a greenhouse effect on Mars would not be as simple as all that. For the sake of their study, Jakosky and Edwards relied on about 20 years of data accumulated by multiple spacecraft observations of Mars. As Edwards indicated in a recent NASA press release:

“These data have provided substantial new information on the history of easily vaporized (volatile) materials like CO2 and H2O on the planet, the abundance of volatiles locked up on and below the surface, and the loss of gas from the atmosphere to space.”

Scientists were able to gauge the rate of water loss on Mars by measuring the ratio of water and HDO from today and 4.3 billion years ago. Credit: Kevin Gill

To determine if Mars had enough gases for a greenhouse effect, Jakosky and Edwards analyzed data from NASA’s Mars Reconnaissance Orbiter (MRO) and Mars Odyssey spacecraft to determine the abundance of carbon-bearing minerals in Martian soil and CO2 in polar ice caps. They they used data from NASA’s MAVEN mission to determine the loss of the Martian atmosphere to space. As Prof. Jakosky explained:

“Carbon dioxide (CO2) and water vapor (H2O) are the only greenhouse gases that are likely to be present on Mars in sufficient abundance to provide any significant greenhouse warming… Our results suggest that there is not enough CO2 remaining on Mars to provide significant greenhouse warming were the gas to be put into the atmosphere; in addition, most of the COgas is not accessible and could not be readily mobilized. As a result, terraforming Mars is not possible using present-day technology.”

Although Mars has significant quantities of water ice, previous analyses have shown that water vapor would not be able to sustain a greenhouse effect by itself. In essence, the planet is too cold and the atmosphere too thin for the water to remain in a vaporous or liquid state for very long. According to the team, this means that significant warming would need to take place involving CO2 first.

However, Mars atmospheric pressure averages at about 0.636 kPA, which is the equivalent of about 0.6% of Earth’s air pressure at sea level. Since Mars is also roughly 52% further away from the Sun than Earth (1.523 AUs compared to 1 AU), researchers estimate that a CO2 pressure similar to Earth’s total atmospheric pressure would be needed to raise temperatures enough to allow for water to exist in a liquid state.

Artist’s rendering of a solar storm hitting Mars and stripping ions from the planet’s upper atmosphere. Credits: NASA/GSFC

According to the team’s analysis, melting the polar ice caps (which is the most accessible source of carbon dioxide) would only contribute enough CO2 to double the Martian atmospheric pressure to 1.2% that of Earth’s. Another source is the dust particles in Martian soil, which the researchers estimate would provide up to 4% of the needed pressure. Other possible sources of carbon dioxide are those that are locked in mineral deposits and water-ice molecule structures known as “clathrates”.

However, using the recent NASA spacecraft observations of mineral deposits, Jakosky and Edwards estimate that these would likely yield less than 5% of the require pressure each. What’s more, accessing even the closest minerals to the surface would require significant strip mining, and accessing all the CO2 attached to dust particles would require strip mining the entire planet to a depth of around 90 meters (100 yards).

Accessing carbon-bearing minerals deep in the Martian crust could be a possible solution, but the depth of these deposits is currently unknown. In addition, recovering them with current technology would be incredibly expensive and energy-intensive, making extraction highly impractical. Other methods have been suggested, however, which include importing flourine-based compounds and volatiles like ammonia.

The former was proposed in 1984 by James Lovelock and Michael Allaby in their book, The Greening of Mars. In it, Lovelock and Allaby described how Mars could be warmed by importing chlorofluorocarbons (CFCs) to trigger global warming. While very effective at triggering a greenhouse effect, these compounds are short-lived and would need to be introduced in significant amounts (hence why the team did not consider them).

NASA’s MAVEN spacecraft is depicted in orbit around an artistic rendition of planet Mars, which is shown in transition from its ancient, water-covered past, to the cold, dry, dusty world that it has become today. Credit: NASA

The idea of importing volatiles like ammonia is an even more time-honored concept, and was proposed by Dandridge M. Cole and Donald Cox in their 1964 book, “Islands in Space: The Challenge of the Planetoids, the Pioneering Work“. Here, Cole and Cox indicated how ammonia ices could be transported from the outer Solar System (in the form of iceteroids and comets) and then impacted on the surface.

However, Jakosky and Edwards’ calculations reveal that many thousands of these icy objects would be required, and the sheer distance involved in transporting them make this an impractical solution using today’s technology. Last, but not least, the team considered how atmospheric loss could be prevented (which could be done using a magnetic shield). This would allow for the atmosphere to build up naturally due to outgassing and geologic activity.

Unfortunately, the team estimates that at the current rate at which outgassing occurs, it would take about 10 million years just to double Mars’ current atmosphere. In the end, it appears that any effort to terraform Mars will have to wait for the development of future technologies and more practical methods.

These technologies would most likely involve more cost-effective means for conducting deep-space missions, like nuclear-thermal or nuclear-electric propulsion. The establishment of permanent outposts on Mars would also be an important first step, which could be dedicated to thickening the atmosphere by producing greenhouse gases – something humans have already proven to be very good at here on Earth!

Project Nomad, a concept for terraforming Mars using mobile, factory-skyscrapers from the 2013 Skyscraper Competition. Credit: Ares Sainz, Joaquin Rodriguez Nuñez, Konstantino Tousidonis Rial

There’s also the possibility of importing methane gas from the outer Solar System, another super-greenhouse gas, which is also indigenous to Mars. While it constitutes only a tiny percentage of the atmosphere, significant plumes have been detected in the past during the summer months. This includes the “tenfold spike” detected by the Curiosity rover in 2014, which pointed to a subterranean source. If these sources could be mined, methane gas might not even need to be imported.

For some time, scientists have known that Mars was not always the cold, dry, and inhospitable place that it is today. As evidenced by the presence of dry riverbeds and mineral deposits that only form in the presence of liquid water, scientists have concluded that billions of years ago, Mars was a warmer, wetter place. However, between 4.2 and 3.7 billion years ago, Mars’ atmosphere was slowly stripped away by solar wind.

This discovery has led to renewed interest in the colonizing and terraforming of Mars. And while transforming the Red Planet to make it suitable for human needs may not be doable in the near-future, it may be possible to get the process started in just a few decades’ time. It may not happen in our lifetime, but that does not mean that the dream of one-day making “Earth’s Twin” truly live up to its name won’t come true.

Further Reading: NASA

Old Mars Odyssey Data Indicates Presence of Ice Around Martian Equator

A new paper suggests hydrogen-possibly water ice-in the Medusa Fossae area of Mars, which is in an equatorial region of the planet to the lower left in this view. Image Credit: Steve Lee (University of Colorado), Jim Bell (Cornell University), Mike Wolff (Space Science Institute), and NASA

Finding a source of Martian water – one that is not confined to Mars’ frozen polar regions – has been an ongoing challenge for space agencies and astronomers alike. Between NASA, SpaceX, and every other public and private space venture hoping to conduct crewed mission to Mars in the future, an accessible source of ice would mean the ability to manufacture rocket fuel on sight and provide drinking water for an outpost.

So far, attempt to locate an equatorial source of water ice have failed. But after consulting old data from the longest-running mission to Mars in history – NASA’s Mars Odyssey spacecraft – a team of researchers from the John Hopkins University Applied Physics Laboratory (JHUAPL) announced that they may have found evidence of a source of water ice in the Medusae Fossae region of Mars.

This region of Mars, which is located in the equatorial region, is situated between the highland-lowland boundary near the Tharsis and Elysium volcanic areas. This area is known for its formation of the same name, which is a soft deposit of easily-erodible material that extends for about 5000 km (3,109 mi) along the equator of Mars. Until now, it was believed to be impossible for water ice to exist there.

Artist’s conception of the Mars Odyssey spacecraft. Credit: NASA/JPL

However, a team led by Jack Wilson – a post-doctoral researcher at the JHUAPL – recently reprocessed data from the Mars Odyssey spacecraft that showed unexpected signals. This data was collected between 2002 and 2009 by the mission’s neutron spectrometer instrument. After reprocessing the lower-resolution compositional data to bring it into sharper focus, the team found that it contained unexpectedly high signals of hydrogen.

To bring the information into higher-resolution, Wilson and his team applied image-reconstruction techniques that are typically used to reduce blurring and remove noise from medical and spacecraft imaging data. In so doing, the team was able to improve the data’s spatial resolution from about 520 km (320 mi) to 290 km (180 mi). Ordinarily, this kind of improvement could only be achieved by getting the spacecraft much closer to the surface.

“It was as if we’d cut the spacecraft’s orbital altitude in half,” said Wilson, “and it gave us a much better view of what’s happening on the surface.” And while the neutron spectrometer did not detect water directly, the high abundance of neutrons detected by the spectrometer allowed the research team to calculate the abundance of hydrogen. At high latitudes on Mars, this is considered to be a telltale sign of water ice.

The first time the Mars Odyssey spacecraft detected abundant hydrogen was in 2002, which appeared to be coming from subsurface deposits at high latitudes around Mars. These findings were confirmed in 2008, when NASA’s Phoenix Lander confirmed that the hydrogen took the form of water ice. However, scientists have been operating under the assumption that at lower latitudes, temperatures are too high for water ice to exist.

This artist’s concept of the Mars Reconnaissance Orbiter highlights the spacecraft’s radar capability. Credit: NASA/JPL

In the past, the detection of hydrogen in the equatorial region was thought to be due to the presence of hydrated minerals (i.e. past water). In addition, the Mars Reconnaissance Orbiter (MRO) and the ESA’s Mars Express orbiter have both conducted radar-sounding scans of the area, using their Shallow Subsurface Radar (SHARAD) and Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instruments, respectively.

These scans have suggested that there was either low-density volcanic deposits or water ice below the surface, though the results seemed more consistent with their being no water ice to speak of. As Wilson indicated, their results lend themselves to more than one possible explanation, but seem to indicate that water ice could part of the subsurface’s makeup:

“[I]f the detected hydrogen were buried ice within the top meter of the surface. there would be more than would fit into pore space in soil… Perhaps the signature could be explained in terms of extensive deposits of hydrated salts, but how these hydrated salts came to be in the formation is also difficult to explain. So for now, the signature remains a mystery worthy of further study, and Mars continues to surprise us.”

Given Mars’ thin atmosphere and the temperature ranges that are common around the equator – which get as high as 308 K (35 °C; 95 °F) by midday during the summer – it is a mystery how water ice could be preserved there. The leading theory though is that a mixture of ice and dust was deposited from the polar regions in the past. This could have happened back when Mars’ axial tilt was greater than it is today.

The MARSIS instrument on the Mars Express is a ground penetrating radar sounder used to look for subsurface water and ice. Credit: ESA

However, those conditions have not been present on Mars for hundreds of thousands or even millions of years. As such, any subsurface ice that was deposited there should be long gone by now. There is also the possibility that subsurface ice could be shielded by layers of hardened dust, but this too is insufficient to explain how water ice could have survived on the timescales involved.

In the end, the presence of abundant hydrogen in the Medusae Fossae region is just another mystery that will require further investigation. The same is true for deposits of water ice in general around the equatorial region of Mars. Such deposits mean that future missions would have a source of water for manufacturing rocket fuel.

This would shave billions of dollars of the costs of individual mission since spacecraft would not need to carry enough fuel for a return trip with them. As such, interplanetary spacecraft could be manufactured that would be smaller, lighter and faster. The presence of equatorial water ice could also be used to provide a steady supply of water for a future base on Mars.

Crews could be rotated in and out of this base once every two years – in a way that is similar to what we currently do with the International Space Station. Or – dare I say it? – a local source of water could be used to supply drinking, sanitation and irrigation water to eventual colonists! No matter how you slice it, finding an accessible source of Martian water is critical to the future of space exploration as we know it!

Further Reading: NASA

NASA Curiosity Rover Missing ‘Scientific Focus And Detail’ In Mars Mission: Review

NASA's Mars rover Curiosity took this self-portrait, composed of more than 50 images using its robotic arm-mounted MAHLI camera, on Feb. 3, 2013. The image shows Curiosity at the John Klein drill site. A drill hole is visible at bottom left. Credit: NASA / JPL / MSSS / Marco Di Lorenzo / Ken Kremer-

NASA’s planetary senior review panel harshly criticized the scientific return of the Curiosity rover in a report released yesterday (Sept. 3), saying the mission lacks focus and the team is taking actions that show they think the $2.5-billion mission is “too big to fail.”

While the review did recommend the mission receive more funding — along with the other six NASA extended planetary missions being scrutinized — members recommended making several changes to the mission. One of them would be reducing the distance that Curiosity drives in favor of doing more detailed investigations when it stops.

The role of the senior review, which is held every two years, is to help NASA decide what money should be allocated to its extended missions. This is important, because the agency (as with many other departments) has limited funds and tries to seek a balance between spending money on new missions and keeping older ones going strong.

Engineering acumen means that many missions are now operating well past their expiry dates, such as the Cassini orbiter at Saturn and the Opportunity rover on Mars. In examining the seven missions being reviewed, the panel did recommend keeping funding for all, but said that 4/7 are facing significant problems.

Opportunity rover’s 1st mountain climbing goal is dead ahead in this up close view of Solander Point at Endeavour Crater. Opportunity has ascended the mountain looking for clues indicative of a Martian habitable environment. This navcam panoramic mosaic was assembled from raw images taken on Sol 3385 (Aug 2, 2013).  Credit: NASA/JPL/Cornell/Marco Di Lorenzo/Ken Kremer (
Opportunity rover’s 1st mountain climbing goal is dead ahead in this up close view of Solander Point at Endeavour Crater. Opportunity has ascended the mountain looking for clues indicative of a Martian habitable environment. This navcam panoramic mosaic was assembled from raw images taken on Sol 3385 (Aug 2, 2013). Credit: NASA/JPL/Cornell/Marco Di Lorenzo/Ken Kremer (

In the case of Curiosity, the panel called out principal investigator John Grotzinger for not showing up in person on two occasions, preferring instead to interact by phone. The review also said there is a “lack of science” in its extended mission proposal with regard to “scientific questions to be answered, testable hypotheses, and proposed measurements and assessment of uncertainties and limitations.”

Other concerns were the small number of samples over the prime and extended missions (13, a “poor science return”), and a lack of clarity on how the ChemCam and Mastcam instruments will play into the extended mission. Additionally, the panel expressed concern that NASA would cut short its observations of clays (which could help answer questions of habitability) in favor of heading to Mount Sharp, the mission’s ultimate science destination.

“In summary, the Curiosity … proposal lacked scientific focus and detail,” the panel concluded, adding in its general recommendations for the reviews that principal investigators must be present to avoid confusion while answering questions. The other missions facing concern from the panel included the Lunar Reconnaissance Orbiter, Mars Express and Mars Odyssey.

Lunar Reconnaissance Orbiter
Lunar Reconnaissance Orbiter. Image Credit: NASA

LRO: Its extended mission (the second) is supposed to look at how the moon’s surface, subsurface and exosphere changes through processes such as meteorites and interaction with space. The panel was concerned with a “lack of detail” in the proposal and in answers to follow-up questions. The panel also recommended turning off certain instruments “at the end of their useful science mission”.

Mars Express: The extended mission is focusing on the ionosphere and atmosphere as well as the planet’s surface and subsurface. Concerns were raised about matters such as why funding is needed to calibrate its high-resolution stereo camera after 11 years — especially given the instrument has been rarely cited in published journal reports lately — and how people involved in the extended mission would meet the goals. The panel also saw a “lack of communication” in the team.

Mars Odyssey: If approved, the spacecraft will move to the day/night line of Mars to look at the planet’s radiation, gamma rays, distribution of water/carbon dioxide/dust in the atmosphere, and the planet’s surface. The panel, however, said there are no “convincing arguments” as to how the new science relates to the Decadal Survey objectives for planetary science. Odyssey, which is in its 11th year, may also be nearing the end of its productive lifespan given fewer publications using its data in recent years, the panel said.

The panel also weighed in on the success of the Cassini and Opportunity missions:

Artist's conception of the Mars Odyssey spacecraft. Credit: NASA/JPL
Artist’s conception of the Mars Odyssey spacecraft. Credit: NASA/JPL

Cassini received the highest rating — “Excellent” — due to its scientific merit, the only mission this time around to do so. The panel was particularly excited about seasonal changes that will be seen on Titan in the coming years, as well as measurements of Saturn’s rings and magnetosphere and its icier moons (such as Enceladus). The spacecraft is noted to be in good condition and the new mission will be a success because of “the unique aspect of the new observations.”

Opportunity, which is more than 10 years into its Mars exploration, is still “in sufficiently good condition” to do science, although the panel raised concerns about software and communication problems. The panel, however, said more time with the rover would allow it to look for evidence of past water on Mars that would not be visible from orbit — even though it’s unclear if phyllosilicates around its current location (Endeavour crater) are from the Noachian period, the earliest period in Mars’ history.

The panel is just one step along the road to figuring out how NASA chooses to spend its money in the coming years. Funding availability depends on how much money Congress allocates to the agency.

NASA Preps for Nail-biting Comet Flyby of Mars

This graphic depicts the orbit of comet C/2013 A1 Siding Spring as it swings around the sun in 2014. On Oct. 19, the comet will have a very close pass at Mars. Its nucleus will miss Mars by about 82,000 miles (132,000 kilometers). The comet's trail of dust particles shed by the nucleus might be wide enough to reach Mars or might also miss it. Credit: NASA/JPL

As Comet C/2013 A1 Siding Spring inches closer to the Red Planet, NASA’s taking steps to protect its fleet of orbiting Mars spacecraft. On October 19, the comet’s icy nucleus will miss the planet by just 82,000 miles (132,000 km). That’s 17 times closer than the closest recorded Earth-approaching comet, Lexell’s Comet in 1770. 

Comet C/2013 A1 (Siding Spring) on July 11, 2014. The comet, discovered by comet hunter Rob McNaught from Siding Spring Observatory in New South Wales, Australia on January 3, 2013, shows a bright coma and well-developed tail. Credit: Joseph Brimacombe
Comet C/2013 A1 (Siding Spring) on July 11, 2014. The comet, discovered by comet hunter Robert McNaught from Siding Spring Observatory in New South Wales, Australia on January 3, 2013, shows a bright coma and well-developed tail. Credit: Joseph Brimacombe

No one’s worried about the tiny nucleus doing any damage. It’ll zip right by. Rather it’s dust particles embedded in vaporizing ice that concern NASA planners. Dust spreads into a broad tail that could potentially brush Mars’ upper atmosphere and strike an orbiter. A single particle of debris half a millimeter across may not seem like your mortal enemy, but when it’s traveling at 35 miles (56 km) per second relative to the spacecraft, one hit could spell trouble.

This graphic depicts the orbit of comet C/2013 A1 Siding Spring as it swings around the sun in 2014. On Oct. 19, the comet will have a very close pass at Mars. Its nucleus will miss Mars by about 82,000 miles (132,000 kilometers). The comet's trail of dust particles shed by the nucleus might be wide enough to reach Mars or might also miss it. Credit: NASA/JPL
The orbit of comet C/2013 A1 Siding Spring as it swings around the sun in 2014. NASA’s already begun moving the Mars orbiters toward safe positions in preparation for the upcoming flyby. Credit: NASA/JPL

“Three expert teams have modeled this comet for NASA and provided forecasts for its flyby of Mars,” explained Rich Zurek, chief scientist for the Mars Exploration Program at NASA’s Jet Propulsion Laboratory in Pasadena, California. “The hazard is not an impact of the comet nucleus, but the trail of debris coming from it. Using constraints provided by Earth-based observations, the modeling results indicate that the hazard is not as great as first anticipated. Mars will be right at the edge of the debris cloud, so it might encounter some of the particles — or it might not.”

The agency’s taking a prudent approach. NASA currently operates the Mars Reconnaissance Orbiter (MRO) and Mars Odyssey spacecraft with a third orbiter, MAVEN, currently on its way to the planet and expected to settle into orbit a month before the comet flyby. Teams operating the orbiters plan to have all spacecraft positioned on the opposite side of Mars when the comet is most likely to pass by.

Already, mission planners tweaked MRO’s orbit on July 2 to move it toward a safe position with a second maneuver to follow on August 27. A similar adjustment is planned for Mars Odyssey on August 5 and October 9 for the Mars Atmosphere and Volatile Evolution (MAVEN) probe. The time of greatest risk to the spacecraft is brief – about 20 minutes – when the widest part of the comet’s tail passes closest to the planet.

Will dust shed by the comet streak as meteors in the Martian sky on October 19?  The rovers will be watching. Credit: NASA/JPL
Will dust shed by the comet streak as meteors in the Martian sky on October 19? The rovers will be watching. Credit: NASA/JPL

One question I’m always asked is whether the Mars rovers are in any danger of dust-producing meteors in the comet’s wake. While the planet might get peppered with a meteor shower, its atmosphere is thick enough to incinerate cometary dust particles before they reach the surface, not unlike what happens during a typical meteor shower here on Earth. Rover cameras may be used to photograph the comet before the flyby and to capture meteors during the comet’s closest approach.

Despite concerns about dust, NASA knows a good opportunity when it sees one. In the days before and after the flyby, all three orbiters will conduct studies on the comet.

According to a recent NASA press release, instruments on MRO and Odyssey will examine the nucleus, coma and tail and possible effects on the Martian atmosphere:

Comet Siding Spring observed by the Spitzer Space Telescope in two wavelengths of infrared light in March 2014. The hint of blue-white corresponds to dust, red-orange to gas. Credit: NASA
Comet Siding Spring observed by the Spitzer Space Telescope in two wavelengths of infrared light in March 2014. The hint of blue-white corresponds to dust, red-orange to gas. Credit: NASA/JPL-Caltech/M. Kelley (Univ. Maryland)

“Odyssey will study thermal and spectral properties of the comet’s coma and tail. MRO will monitor Mars’ atmosphere for possible temperature increases and cloud formation, as well as changes in electron density at high altitudes and MAVEN will study gases coming off the comet’s nucleus as it’s warmed by the sun. The team anticipates this event will yield detailed views of the comet’s nucleus and potentially reveal its rotation rate and surface features.”

This is Comet Siding Spring’s first trip to the inner solar system. Expect exciting news as we peer up close at pristine ices and dust that have been locked in deep freeze since the time the planets formed.

For more information on the event, check out this NASA website devoted to the comet.




Feel The Heat! New Mars Map Shows Differences Between Bedrock And Sand

An impact crater on Mars called Graterri, which is only 4.3 miles (6.9 km) in diameter, shines in a global heat map of the Red Planet produced in 2014. Credit: NASA/JPL-Caltech/Arizona State University

For years, NASA’s Mars Odyssey has been working on some night moves. It’s been taking pictures of the Red Planet during nighttime — more than 20,000 in all — to see how the planet’s heat signature looks while the sun is down.

The result is the highest-resolution map ever of the thermal properties of Mars, which you can see here. Why is this important? Researchers say it helps tell the story about things such as if an area is shrouded with dust, where bare bedrock is, and whether sediments in a crater are packed tight or floating freely.

“Darker areas in the map are cooler at night, have a lower thermal inertia and likely contain fine particles, such as dust, silt or fine sand,” stated Robin Fergason at the USGS Astrogeology Science Center in Arizona, who led the map’s creation. Brighter areas are warmer, likely yielding regions of bedrock, crust or coarse sand.

The map from Odyssey’s Thermal Emission Imaging System (THEMIS) is also used for a more practical purpose: deciding where to set down NASA’s next Mars mission.

After assisting in landing site selection for the Curiosity mission, the THEMIS data will be used to figure out where the Mars 2020 rover will be placed, Arizona State University stated.

You can check out more recent THEMIS images (updated daily) on this website.

Source: Arizona State University