Tag Archives: martian atmosphere

Mars then and Now. The Red Planet has been stripped of water for billions of years, but the main mechanism of water loss is different now than it was a billion years ago (NASA)

Water stripped from Mars’ upper atmosphere may explain how it became a barren Red Planet

A new study has revealed the detection of water in the upper atmosphere of Mars for the first time. The discovery gives scientists a good idea of the mechanism that is currently stripping the Red Planet of its water. 

The surface of Mars is cold and dry —bereft of liquid water — but this wasn’t always the case. Studies of the Martian surface have discovered the tell-tale tracks of long dry ancient rivers and sedimentary deposits that indicate lake beds into which water once flowed. This poses the question of how the Red Planet lost its liquid water?

A study published in the journal Science suggests a new mechanism that could have driven Mars’ water loss. A team of astronomers has used data collected from Mars’ atmosphere by NASA’s Neutral Gas and Ion Mass Spectrometer on the Mars Atmosphere and Volatile Evolution spacecraft (MAVEN) to discover water in the planet’s upper atmosphere. 

“For the first time, we have seen water in the upper atmosphere of Mars, at around 150 km above the surface. Other scientists have previously observed water in the middle atmosphere,” Shane Wesley Stone, a PhD. Candidate in Planetary Sciences at the Lunar and Planetary Laboratory, University of Arizona, and one of the paper’s authors tells ZME Science. “Water in the upper atmosphere is quickly destroyed and can escape to space, which is why our observations of water in the upper atmosphere are significant.”

Mars then and Now. The Red Planet has been stripped of water for billions of years, but the main mechanism of water loss is different now than it was a billion years ago (NASA)
Mars then and Now. The Red Planet has been stripped of water for billions of years, but the main mechanism of water loss is different now than it was a billion years ago (NASA)

Water transported to the upper atmosphere of Mars is converted to atomic hydrogen, which is then so-light that it is lost to space. This process could have been driving Mars’ water loss for billions of years. Water had previously been detected in the lower atmosphere, where scientists believed it was confined, but this is the first detection of water in the upper atmosphere, which caught the team by surprise. 

“We did not know that water makes it all the way to the upper atmosphere, so we did not know how important this upward transport of water is to the escape of hydrogen to space and thus to water lost from Mars,” Stone says, explaining that water higher in the atmosphere would be broken down much more rapidly than happens closer to the martian surface. “Water which makes it to the upper atmosphere is destroyed in about 4 hours. This destruction of water would be ten times slower in the middle atmosphere, where most of the products of this destruction would be transported downward back toward the surface.”

Rising Damp: How Does Water Make its Way to Mars’ Upper Atmosphere?

Stone explains that the team is not yet certain what processes are lifting water to Mars’ upper atmosphere, but their study has yielded some good clues as to what may be the major players in this phenomenon. 

“We see a seasonal trend in the upper atmospheric water abundance,” says the planetary chemist. “During summer in the southern hemisphere, the water abundance in the upper atmosphere is largest. During summer in the northern hemisphere, the water abundance in the upper atmosphere is smallest but is still significant.”

Stone explains that this seasonal trend is caused by two things. Firstly, during southern summer, Mars is closer to the Sun than it is during the rest of the Martian year. Secondly, this is also the season of dust storms on Mars. He adds: “Relatively close proximity to the Sun and dust storms both lead to heating in the atmosphere, which leads to greater transport of water to the upper atmosphere.”

The researcher points to a massive Martian dust storm that occurred in 2018 as being a major contributing factor to water in the upper atmosphere. The storm was first spotted by NASA’s Mars Reconnaissance Orbiter (MRO) on May 30th 2018 and by June of that year, it had grown to a planet encompassing event. 

Rotating globes from May 28 and July 1 show a global dust storm completely obscuring the surface of Mars. (NASA)

“Dust storms lead to a sudden splash of water into the upper atmosphere: during the global dust storm of 2018, the water abundance in the upper atmosphere increases by 20x relative to the nominal seasonal abundance,” Stone says. “Smaller surges of water are observed during regional dust storms that occur every Mars year of 687 days. Global storms occur about once every 10 Earth years.”

The team believe that water is moving upward past what planetary scientists call the hygropause — a cold layer in the atmosphere at which water condenses from vapour to liquid, forming clouds. “This because, as we and other scientists have found, the Martian hygropause is not as efficient at trapping water close to the surface as the hygropause on Earth,” Stone says. “The hygropause on Mars is not as efficient because it is too warm: when Mars is closest to the Sun and when dust storms occur, heating caused by these processes warms the hygropause, allowing water to move upward.”

The mechanism their finding reveals is currently the main way that Mars loses water, but Stone points out that this likely wasn’t always the case.

The Changing Picture of Water Loss on Mars

Water transported to Mars’ upper atmosphere by seasonal effects and dust storms where it is broken down to hydrogen and then lost to space is currently the predominant mechanism of water loss on Mars, but the team says this is only because of the Red Planet’s current environment. The water loss mechanisms that have proceeded for billions of years were likely different in the past in terms of both dominance and the speed at which they proceed.

“This process we describe is an important factor in Martian water loss today. However, this water could only be transported to the upper atmosphere relatively recently, over the last billion years or so,” Stone says. “Much of Mars’ atmosphere was lost to space before this time, leading to the weak hygropause which allows water into the upper atmosphere. All escape processes we observe today were likely faster in the past.”

NASA scientists have determined that a primitive ocean on Mars held more water than Earth's Arctic Ocean and that the Red Planet has lost 87 percent of that water to space. Credits: NASA/GSFC
NASA scientists have determined that a primitive ocean on Mars held more water than Earth’s Arctic Ocean and that the Red Planet has lost 87 per cent of that water to space. Credits: NASA/GSFC

The team reached this conclusion due to the fact that when all the water loss rates of the present-day escape processes are summed, their current escape rate is too slow to explain all the water loss that scientists know must have occurred over the last few billion years. 

“We know that over 4 billion years, Mars lost about 66% of its atmosphere to space,” Stone explains. “If we talk about water specifically, Mars has lost 10s to 100s of meters of a ‘global equivalent layer’ of water — equivalent to spreading all of the water lost by Mars over its surface to form an even layer and then reporting how deep this layer would be.”

The process the team describe is responsible for the loss of 44 cm of H2O over the last billion years, and global dust storms are responsible for the loss of an additional 17 cm on top of this over the last billion years.

“In the present epoch, during most of the Martian year, this process we describe is just as important as the ‘classical process’ — the basic process scientists thought responsible for the transport of hydrogen to the upper atmosphere since the first work on this topic in the early 1970s,” Stone says. “During global storms, this water which makes it to the upper atmosphere produces 10x more escaping hydrogen than does the classical process.”

Big Surprises and Future Investigations

Stone describes that the next steps for this research involve figuring out exactly how important this new water loss mechanism has been throughout the history of Mars. 

“Extrapolating back over billions of years is extremely difficult and doing it correctly takes time. We still need to understand better the specific transport processes responsible for delivering this water to the upper atmosphere,” he says, adding that the team’s findings came as something as a shock even to them. “The entire project was a huge surprise to us: we were surprised to see water this high in the atmosphere, we were surprised to see the seasonal trend in the water abundance, and we were surprised by just how big an effect the global dust storm has on the upper atmospheric water abundance.” 

Comparing the atmospheres of earth and Mars could help scientists determine the chances of liquid water existing on exxoplanets. (ESA)

Researching water loss from Mars is likely to be an important step in understanding how abundant water is throughout the Universe, as Dimitra Atri, a researcher from the Space Science at NYU Abu Dhabi (NYUAD), recently told ZME Science: “Since it is extremely difficult to observe the escape process in exoplanets, we are planning to study this phenomenon in great detail on Mars with the UAE’s Hope mission.”

Thus, this type of study could tell us how unique Earth is in terms of the possession of liquid water in the Universe. Something that could, in turn, tell us about the chances of life on exoplanets. 

“Mars used to look like Earth: warmer and wetter with a thick atmosphere and abundant liquid water on its surface,” Stone concludes. “But over the history of the solar system, Mars’ water was lost to space, leaving behind the cold, dry, red planet we see today. Regardless, Mars will be the next planet on which humans step foot.”

S.W. Stone; R.V. Yelle; D.Y. Lo, et al, [2020], ‘Hydrogen escape from Mars is driven by seasonal and dust storm transport of water,Science.

NASA using pufferfish-inspired technology to carry large payloads to Mars

A brilliant technology reaching its limits

Carrying heavier spacecraft to Mars and then safely landing it at supersonic speeds in the Martian atmosphere is no easy feat – and NASA could use any bit of help they can get. NASA’s Wallops Flight Facility is playing an integral role in solving those problems with the Low Density Supersonic Decelerator mission, or LDSD – a technology inspired from pufferfish.

In order to conduct more advance experiments on Mars, engineers need to figure out ways to carry heavier payloads. It makes sense: if you want to do more things, you need more thingss (yes, this is why I don’t work at NASA). The main problem is the landing though; in the thin Martian atmosphere, high speeds are much more dangerous than on Earth due to the lack of friction. Deceleration and landing are very hard to do in the lack of a thick atmosphere and NASA hasn’t really updated their landing technology in the past recades.The current technology for decelerating payloads dates back to NASA’s Viking Program, in 1976. This same technology safely landed the Curiosity rover in 2012.

But this technology, as brilliant as it is, is starting to reach its limit. In order to deliver more cargo to the Red Planet, NASA needs to try something else. Their solution? They borrowed a technique from the ‘o’opu hue, commonly as the Hawaiian pufferfish.

Rapid Inflation

Economists, calm down! This is the name of the technique used by the pufferfish, not an economic situation. Silly jokes aside, the pufferfish is a slow swimmer – he can’t really compete with other fish, so he needs something else to defend himself when the going gets tough. He has the capacity to fill its highly elastic stomach with large amount of water or even air to give it a shape of a balloon or ball which helps to deter predators to swallow it; this is what NASA is going for (the pufferfish is also highly poisonous, but I don’t think this is really needed for Mars exploration).

Already set for a test launch, LDSD will use a 20-foot diameter, solid rocket-powered balloon-like vessel called a Supersonic Inflatable Aerodynamic Decelerator (SIAD) to test these capabilities. To mimic the Martian atmosphere more accurately, they are testing the technology in the thin air in the Earth’s stratosphere.

To reach this altitude, the LDSD will use a helium baloon. When fully deployed, the balloon itself is over 34 million cubic feet (easily fitting a football field inside it). It’s not clear exactly when the launch will take place. NASA has identified six potential launch dates for the balloon carrying LDSD: June 3, 5, 7, 9, 11, and 14. The test can be viewed live on NASA TV beginning at 7:45 a.m. HST (1:45 p.m. EDT) or on the web at:


You can also find more information and recent updates regarding the launch here:


On Monday, June 2 at 8am HST, there will be a press conference and media teleconference held at the Pacific Missile Range Facility. We will also be taking questions from our @NASA_Technology and @NASA accounts using the hashtag #AskNASA. Want to know how much the test vehicle weighs or what is the altitude the balloon will reach? Ask us tomorrow at 8am HST (11am PDT, 1pm CDT, 2pm EDT) using #AskNASA.

Researchers make Mars clouds on Earth

Researchers at MIT have recreated Mars-like conditions within a three-story-tall cloud chamber in Germany, adjusting the temperature and humidity to match those on Mars – basically creating Martian clouds.

mars clouds

Illustration via NASA.

Judging by the images Curiosity has sent us, Martian clouds look quite similar to ours – the gauzy, high-altitude wisps look a lot like the cirrus clouds we find here on Earth. Judging by what researchers know about Martian clouds, they are probably carbon dioxide or water-based ice crystals, though it’s hard to estimate the conditions which lead to their formation.

The first thing they noticed was the humidity – in order to create these clouds, they had to raise water humidity to 190 percent, far greater than cloud formation requires on Earth. The finding should help improve conventional models of the Martian atmosphere, many of which give Mars and Earth a similar humidity.

“A lot of atmospheric models for Mars are very simple,” says Dan Cziczo, the Victor P. Starr Associate Professor of Atmospheric Chemistry at MIT. “They have to make gross assumptions about how clouds form: As soon as it hits 100 percent humidity, boom, you get a cloud to form. But we found you need more to kick-start the process.”

In order to recreate the conditions, they the used Aerosol Interaction and Dynamics in the Atmosphere (AIDA) facility – a former nuclear reactor which is now being used in cloud studies. The building was initially used to study Earth clouds, but Cziczo realised that with just a little fine tuning, it could also be used for Martian clouds.

The AIDA facility.

The AIDA facility.

To do this, he first pumped all the oxygen out of the chamber, and instead filled it with inert nitrogen or carbon dioxide – which are omnipresent in the Martian atmosphere. Then they created a dust storm, of course, with the same minerals and grain sizes found on the Red Planet; this was a crucial step, because just like on our planet, these particles act as cloud seeds around which water vapor can adhere to form cloud particles. They then adjusted the temperature, trying out different temperatures commonly found on Mars as they went. By adjusting the chamber’s relative humidity under each temperature condition, the researchers were able to create clouds under warmer, Earth-like temperatures, at expected relative humidities, which gave them confidence that they are working with the right parameters as they moved on to colder, Martian temperatures.

During a week’s time, they created 10 clouds, with each cloud taking about 15 minutes to form. Since the room was perfectly insulated, they used a a system of lasers, which beam across the chamber, to detect cloud formation. Whenever clouds were formed, the light would be diffracted and this scattering is then detected and recorded by computers, which display the results – size, number and type of particles.

They plan to return next fall for even more experiments, going to lower temperatures, which are closer to the icy surface of Mars.

“If we want to understand where water goes and how it’s transported through the atmosphere on Mars, we have to understand cloud formation for that planet,” Cziczo says. “Hopefully this will move us toward the right direction.”

Curiosity takes a deep breath, analyzes Martian atmosphere

Curiosity took a break from its usual rock sampling activities and instead focused on the air, trying to figure out how Mars lost the biggest part of its atmosphere, leaving it with 100 times less than what Earth has.


Researchers believe in the distant past, Mars was a pretty different sight from what we see today, with a thick, rich atmosphere and permanent water. They’re not just throwing away a hunch on this, there’s a big chunk of evidence which points towards a wet past for Mars, but this changed a long time ago: the drought probably started some 600 million years ago.

The rover inhaled the Martian air, analyzing samples taken in the Gale crater, where Curiosity is hanging around these days. Its Sample Analysis at Mars (SAM) instruments suggest that Mars suggests that Mars lost its atmosphere through a process which favored only the retention of the heavier isotopes, with the lighter ones simply drifting off to outer space. The initial results show that the heavier isotopes of carbon in atmospheric carbon dioxide have increased by 5 per cent – a rather subtle, but meaningful change; the same thing happened with heavier argon isotopes. This suggests that the top of the atmosphere, devoid of any heavy elements was lost in outer space.

Another highlight for Curiosity’s research is methane; methane is a simple precursor to life, basically you would expect to find it everywhere you’d find living creatures. But the bad thing is, as far as Curiosity can tell, there’s extremely little methane (if any) in the Martian atmosphere.

“Methane is clearly not an abundant gas at the Gale Crater site, if it is there at all. At this point in the mission we’re just excited to be searching for it,” said SAM Tunable Laser Spectrometer lead Chris Webster. “While we determine upper limits on low values, atmospheric variability in the Martian atmosphere could yet hold surprises for us.”

Still, nothing is clear, and SAM will move on to even more interesting things: it will analyze its first solid samples, searching for organic compounds in the rocks and minerals found in Gale Crater.

Source: NASA