In the past, glaciers may have existed on the surface of Mars, providing meltwater during the summer to create the features we see today. Credit: NASA/Caltech/JPL/UTA/UA/MSSS/ESA/DLR Eric M. De Jong, Ali Safaeinili, Jason Craig, Mike Stetson, Koji Kuramura, John W. Holt
Thanks to decades of exploration using robotic orbiter missions, landers and rovers, scientists are certain that billions of years ago, liquid water flowed on the surface of Mars. Beyond that, many questions have remained, which include whether or not the waterflow was intermittent or regular. In other words, was Mars truly a “warm and wet” environment billions of years ago, or was it more along the lines of “cold and icy”?
These questions have persisted due to the nature of Mars’ surface and atmosphere, which offer conflicitng answers. According to a new study from Brown University, it appears that both could be the case. Basically, early Mars could have had significant amounts of surface ice which experienced periodic melting, producing enough liquid water to carve out the ancient valleys and lakebeds seen on the planet today.
Extensive valley networks spidering through the southern highlands of Mars suggest that the planet was once warmer and wetter. Credit: NASA/JPL-Caltech/Arizona State University
For the sake of their study, Palumbo and her colleagues sought to find the bridge between Mars’ geology (which suggests the planet was once warm and wet) and its atmospheric models, which suggest it was cold and icy. As they demonstrated, it’s plausible that during the past, Mars was generally frozen over with glaciers. During peak daily temperatures in the summer, these glaciers would melt at the edges to produce flowing water.
After many years, they concluded, these small deposits of meltwater would have been enough to carve the features observed on the surface today. Most notably, they could have carved the kinds of valley networks that have been observed on Mars southern highlands. As Palumbo explained in a Brown University press release, their study was inspired by similar climate dynamics that take place here on Earth:
“We see this in the Antarctic Dry Valleys, where seasonal temperature variation is sufficient to form and sustain lakes even though mean annual temperature is well below freezing. We wanted to see if something similar might be possible for ancient Mars.”
To determine the link between the atmospheric models and geological evidence, Palumbo and her team began with a state-of-the-art climate model for Mars. This model assumed that 4 billion years ago, the atmosphere was primarily composed of carbon dioxide (as it is today) and that the Sun’s output was much weaker than it is now. From this model, they determined that Mars was generally cold and icy during its earlier days.
Nanedi Valles, a roughly 800-kilometre valley extending southwest-northeast and lying in the region of Xanthe Terra, southwest of Chryse Planitia. Credit: ESA/DLR/FU Berlin (G. Neukum)
However, they also included a number of variables which may have also been present on Mars 4 billion years ago. These include the presence of a thicker atmosphere, which would have allowed for a more significant greenhouse effect. Since scientists cannot agree how dense Mars’ atmosphere was between 4.2 and 3.7 billion years ago, Palumbo and her team ran the models to take into account various plausible levels of atmospheric density.
They also considered variations in Mars’ orbit that could have existed 4 billion years ago, which has also been subject to some guesswork. Here too, they tested a wide range of plausible scenarios, which included differences in axial tilt and different degrees of eccentricity. This would have affected how much sunlight is received by one hemisphere over another and led to more significant seasonal variations in temperature.
In the end, the model produced scenarios in which ice covered regions near the location of the valley networks in the southern highlands. While the planet’s mean annual temperature in these scenarios was well below freezing, it also produced peak summertime temperatures in the region that rose above freezing. The only thing that remained was to demonstrate that the volume of water produced would be enough to carve those valleys.
Luckily, back in 2015, Professor Jim Head and Eliot Rosenberg (an undergraduate with Brown at the time) created a study which estimated the minimum amount of water required to produce the largest of these valleys. Using these estimates, along with other studies that provided estimates of necessary runoff rates and the duration of valley network formation, Palumbo and her colleagues found a model-derived scenario that worked.
Was Mars warm and watery (i.e. a blue planet?) or an ice ball that occasionally experienced melting? Credit: Kevin Gill
Basically, they found that if Mars had an eccentricity of 0.17 (compared to it’s current eccentricity of 0.0934) an axial tilt of 25° (compared to 25.19° today), and an atmospheric pressure of 600 mbar (100 times what it is today) then it would have taken about 33,000 to 1,083,000 years to produce enough meltwater to form the valley networks. But assuming for a circular orbit, an axial tile of 25°, and an atmosphere of 1000 mbar, it would have taken about 21,000 to 550,000 years.
The degrees of eccentricity and axial tilt required in these scenarios are well within the range of possible orbits for Mars 4 billion years ago. And as Head indicated, this study could reconcile the atmospheric and geological evidence that has been at odds in the past:
“This work adds a plausible hypothesis to explain the way in which liquid water could have formed on early Mars, in a manner similar to the seasonal melting that produces the streams and lakes we observe during our field work in the Antarctic McMurdo Dry Valleys. We are currently exploring additional candidate warming mechanisms, including volcanism and impact cratering, that might also contribute to melting of a cold and icy early Mars.”
It is also significant in that it demonstrates that Mars climate was subject to variations that also happen regularly here on Earth. This provides yet another indication of how our two plane’s are similar in some ways, and how research of one can help advance our understanding of the other. Last, but not least, it offers some synthesis to a subject that has produced a fair share of disagreement.
The subject of how Mars could have experienced warm, flowing water on its surface – and at a time when the Sun’s output was much weaker than it is today – has remained the subject of much debate. In recent years, researchers have advanced various suggestions as to how the planet could have been warmed, ranging from cirrus clouds to periodic bursts of methane gas from beneath the surface.
While this latest study has not quite settled the debate between the “warm and watery” and the “cold and icy” camps, it does offer compelling evidence that the two may not be mutually exclusive. The study was also the subject of a presentation made at the 48th Lunar and Planetary Science Conference, which took place from March 20th to 24th in The Woodland, Texas.
Artist's conception of a terraformed Mars. Credit: Ittiz/Wikimedia Commons
As part of our continuing “Definitive Guide To Terraforming” series, Universe Today is happy to present our guide to terraforming Mars. At present, there are several plans to put astronauts and ever settlers on the Red Planet. But if we really want to live there someday, we’re going to need to do a complete planetary renovation. What will it take?
Despite having a very cold and very dry climate – not to mention little atmosphere to speak of – Earth and Mars have a lot in common. These include similarities in size, inclination, structure, composition, and even the presence of water on their surfaces. Because of this, Mars is considered a prime candidate for human settlement; a prospect that includes transforming the environment to be suitable to human needs (aka. terraforming).
That being said, there are also a lot of key differences that would make living on Mars, a growing preoccupation among many humans (looking at you, Elon Musk and Bas Lansdorp!), a significant challenge. If we were to live on the planet, we would have to depend rather heavily on our technology. And if we were going to alter the planet through ecological engineering, it would take a lot of time, effort, and megatons of resources!
The challenges of living on Mars are quite numerous. For starters, there is the extremely thin and unbreathable atmosphere. Whereas Earth’s atmosphere is composed of 78% nitrogen, 21% oxygen, and trace amounts of other gases, Mars’ atmosphere is made up of 96% carbon dioxide, 1.93% argon and 1.89% nitrogen, along with trace amounts of oxygen and water.
Artist’s impression of the terraforming of Mars, from its current state to a livable world. Credit: Daein Ballard
Mars’ atmospheric pressure also ranges from 0.4 – 0.87 kPa, which is the equivalent of about 1% of Earth’s at sea level. The thin atmosphere and greater distance from the Sun also contributes to Mars’ cold environment, where surface temperatures average 210 K (-63 °C/-81.4 °F). Add to this the fact that Mars’ lacks a magnetosphere, and you can see why the surface is exposed to significantly more radiation than Earth’s.
On the Martian surface, the average dose of radiation is about 0.67 millisieverts (mSv) per day, which is about a fifth of what people are exposed to here on Earth in the course of a year. Hence, if humans wanted to live on Mars without the need for radiation shielding, pressurized domes, bottled oxygen, and protective suits, some serious changes would need to be made. Basically, we would have to warm the planet, thicken the atmosphere, and alter the composition of said atmosphere.
Examples In Fiction:
In 1951, Arthur C. Clarke wrote the first novel in which the terraforming of Mars was presented in fiction. Titled The Sands of Mars, the story involves Martian settlers heating up the planet by converting Mars’ moon Phobos into a second sun, and growing plants that break down the Martians sands in order to release oxygen.
In 1984, James Lovelock and Michael Allaby wrote what is considered by many to be one of the most influential books on terraforming. Titled The Greening of Mars, the novel explores the formation and evolution of planets, the origin of life, and Earth’s biosphere. The terraforming models presented in the book actually foreshadowed future debates regarding the goals of terraforming.
Kim Stanley Robinson’s Red Mars Trilogy. Credit: variety.com
In 1992, author Frederik Pohl released Mining The Oort, a science fiction story where Mars is being terraformed using comets diverted from the Oort Cloud. Throughout the 1990s, Kim Stanley Robinson released his famous Mars Trilogy – Red Mars, Green Mars, Blue Mars – which centers on the transformation of Mars over the course of many generations into a thriving human civilization.
In 2011, Yu Sasuga and Kenichi Tachibana produced the manga series Terra Formars, a series that takes place in the 21st century where scientists are attempting to slowly warm Mars. And in 2012, Kim Stanley Robinson released 2312, a story that takes place in a Solar System where multiple planets have been terraformed – which includes Mars (which has oceans).
Proposed Methods:
Over the past few decades, several proposals have been made for how Mars could be altered to suit human colonists. In 1964, Dandridge M. Cole released “Islands in Space: The Challenge of the Planetoids, the Pioneering Work“, in which he advocated triggering a greenhouse effect on Mars. This consisted of importing ammonia ices from the outer Solar System and then impacting them on the surface.
Since ammonia (NH³) is a powerful greenhouse gas, its introduction into the Martian atmosphere would have the effect of thickening the atmosphere and raising global temperatures. As ammonia is mostly nitrogen by weight, it could also provide the necessary buffer gas which, when combined with oxygen gas, would create a breathable atmosphere for humans.
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
Another method has to do with albedo reduction, where the surface of Mars would be coated with dark materials in order to increase the amount of sunlight it absorbs. This could be anything from dust from Phobos and Deimos (two of the darkest bodies in the Solar System) to extremophile lichens and plants that are dark in color. One of the greatest proponents for this was famed author and scientist, Carl Sagan.
In 1973, Sagan published an article in the journal Icarus titled “Planetary Engineering on Mars“, where he proposed two scenarios for darkening the surface of Mars. These included transporting low albedo material and/or planting dark plants on the polar ice caps to ensure they absorbed more heat, melted, and converted the planet to more “Earth-like conditions”.
In 1976, NASA officially addressed the issue of planetary engineering in a study titled “On the Habitability of Mars: An Approach to Planetary Ecosynthesis“. The study concluded that photosynthetic organisms, the melting of the polar ice caps, and the introduction of greenhouse gases could all be used to create a warmer, oxygen and ozone-rich atmosphere.
In 1982, Planetologist Christopher McKay wrote “Terraforming Mars”, a paper for the Journal of the British Interplanetary Society. In it, McKay discussed the prospects of a self-regulating Martian biosphere, which included both the required methods for doing so and ethics of it. This was the first time that the word terraforming was used in the title of a published article, and would henceforth become the preferred term.
This was followed in 1984 by James Lovelock and Michael Allaby’s book, The Greening of Mars. In it, Lovelock and Allaby described how Mars could be warmed by importing chlorofluorocarbons (CFCs) to trigger global warming.
Artist’s concept of a possible Mars terraforming plant, warming the planet through the introduction of hydrocarbons. Credit: nationalgeographic.com
In 1993, Mars Society founder Dr. Robert M. Zubrin and Christopher P. McKay of the NASA Ames Research Center co-wrote “Technological Requirements for Terraforming Mars“. In it, they proposed using orbital mirrors to warm the Martian surface directly. Positioned near the poles, these mirrors would be able to sublimate the CO2 ice sheet and contribute to global warming.
In the same paper, they argued the possibility of using asteroids harvested from the Solar System, which would be redirected to impact the surface, kicking up dust and warming the atmosphere. In both scenarios, they advocate for the use of nuclear-electrical or nuclear-thermal rockets to haul all the necessary materials/asteroids into orbit.
The use of fluorine compounds – “super-greenhouse gases” that produce a greenhouse effect thousands of times stronger than CO² – has also been recommended as a long term climate stabilizer. In 2001, a team of scientists from the Division of Geological and Planetary Sciences at Caltech made these recommendations in the “Keeping Mars warm with new super greenhouse gases“.
Where this study indicated that the initial payloads of fluorine would have to come from Earth (and be replenished regularly), it claimed that fluorine-containing minerals could also be mined on Mars. This is based on the assumption that such minerals are just as common on Mars (being a terrestrial planet) which would allow for a self-sustaining process once colonies were established.
NASA’s Curiosity Mars rover has detected fluctuations in methane concentration in the atmosphere, implying that it is added and removed all the time. (Image Credit: NASA/JPL-Caltech/SAM-GSFC/Univ. of Michigan)
Importing methane and other hydrocarbons from the outer Solar System – which are plentiful on Saturn’s moon Titan – has also been suggested. There is also the possibility of in-situ resource utilization (ISRU), thanks to the Curiosity rover’s discovery of a “tenfold spike” of methane that pointed to a subterranean source. If these sources could be mined, methane might not even need to be imported.
More recent proposals include the creation of sealed biodomes that would employ colonies of oxygen-producing cyanobacteria and algae on Martian soil. In 2014, the NASA Institute for Advanced Concepts (NAIC) program and Techshot Inc. began work on this concept, which was named the “Mars Ecopoiesis Test Bed“. In the future, the project intends to send small canisters of extremophile photosynthetic algae and cyanobacteria aboard a rover mission to test the process in a Martian environment.
If this proves successful, NASA and Techshot intend to build several large biodomes to produce and harvest oxygen for future human missions to Mars – which would cut costs and extend missions by reducing the amount of oxygen that has to be transported. While these plans do not constitute ecological or planetary engineering, Eugene Boland (chief scientist of Techshot Inc.) has stated that it is a step in that direction:
“Ecopoiesis is the concept of initiating life in a new place; more precisely, the creation of an ecosystem capable of supporting life. It is the concept of initiating “terraforming” using physical, chemical and biological means including the introduction of ecosystem-building pioneer organisms… This will be the first major leap from laboratory studies into the implementation of experimental (as opposed to analytical) planetary in situ research of greatest interest to planetary biology, ecopoiesis and terraforming.”
The “greening of Mars” would be a multi-tiered process, involving the importation of gases and terrestrial organisms to convert the planet over the course of many generations. Credit: nationalgeographic.com
Potential Benefits:
Beyond the prospect for adventure and the idea of humanity once again embarking on an era of bold space exploration, there are several reasons why terraforming Mars is being proposed. For starters, there is concern that humanity’s impact on planet Earth is unsustainable, and that we will need to expand and create a “backup location” if we intend to survive in the long run.
Other reasons emphasize how Mars lies within our Sun’s “Goldilocks Zone” (aka. “habitable zone), and was once a habitable planet. Over the past few decades, surface missions like NASA’s Mars Science Laboratory (MSL) and its Curiosityrover have uncovered a wealth of evidence that points to flowing water existing on Mars in the deep past (as well as the existence of organic molecules).
Project Nomad, a concept for the 2013 Skyscraper Competition that involved mobile factory-skyscrapers terraforming Mars. Credit: evolo.com/A.A. Sainz/J.R. Nuñez/K.T. Rial
Ergo, if Mars was once habitable and “Earth-like”, it is possible that it could be again one day. And if indeed humanity is looking for a new world to settle on, it only makes sense that it be on one that has as much in common with Earth as possible. In addition, it has also been argued that our experience with altering the climate of our own planet could be put to good use on Mars.
For centuries, our reliance on industrial machinery, coal and fossil fuels has had a measurable effect Earth’s environment. And whereas this has been an unintended consequence of modernization and development here on Earth; on Mars, the burning of fossil fuels and the regular release of pollution into the air would have a positive effect.
Infographic showing a cost-estimate and time frame for the terraforming of Mars. Credit: NASA/National Geographic Channel/Discovery Channel
Other reasons include expanding our resources base and becoming a “post-scarcity” society. A colony on Mars could allow for mining operations on the Red Planet, where both minerals and water ice are abundant and could be harvested. A base on Mars could also act as a gateway to the Asteroid Belt, which would provide us with access to enough minerals to last us indefinitely.
Challenges:
Without a doubt, the prospect of terraforming Mars comes with its share of problems, all of which are particularly daunting. For starters, there is the sheer amount of resources it would take to convert Mars’ environment into something sustainable for humans. Second, there is the concern that any measure undertaken could have unintended consequences. And third, there is the amount of time it would take.
For example, when it comes to concepts that call for the introduction of greenhouse gases to trigger warming, the quantities required are quite staggering. The 2001 Caltech study, which called for the introduction of fluorine compounds, indicated that sublimating the south polar CO² glaciers would require the introduction of approximately 39 million metric tons of CFCs into Mars’ atmosphere – which is three times the amounts produced on Earth between 1972 and 1992.
Artist’s conception of a terraformed Mars. Credit: Ittiz/Wikimedia Commons
Photolysis would also begin to break down the CFCs the moment they were introduced, which would necessitate the addition of 170 kilotons every year to replenish the losses. And last, the introduction of CFCs would also destroy any ozone that was produced, which would undermine efforts to shield to surface from radiation.
Also, the 1976 NASA feasibility study indicated that while terraforming Mars would be possible using terrestrial organisms, it also recognized that the time-frames called for would be considerable. As it states in the study:
“No fundamental, insuperable limitation of the ability of Mars to support a terrestrial ecology is identified. The lack of an oxygen-containing atmosphere would prevent the unaided habitation of Mars by man. The present strong ultraviolet surface irradiation is an additional major barrier. The creation of an adequate oxygen and ozone-containing atmosphere on Mars may be feasible through the use of photosynthetic organisms. The time needed to generate such an atmosphere, however, might be several millions of years.”
The study goes on to state that this could be drastically reduced by creating extremophile organisms specifically adapted for the harsh Martian environment, creating a greenhouse effect and melting the polar ice caps. However, the amount of time it would take to transform Mars would still likely be on the order of centuries or millennia.
Artist’s concept for a NASA manned-mission to Mars (Human Exploration of Mars Design Reference Architecture 5.0, Feb 2009). Credit: NASA
And of course, there is the problem of infrastructure. Harvesting resources from other planets or moons in the Solar System would require a large fleet of space haulers, and they would need to be equipped with advanced drive systems to make the trip in a reasonable amount of time. Currently, no such drive systems exist, and conventional methods – ranging from ion engines to chemical propellants – are neither fast or economical enough.
To illustrate, NASA’s New Horizons mission took more than 11 years to get make its historic rendezvous with Pluto in the Kuiper Belt, using conventional rockets and the gravity-assist method. Meanwhile, the Dawn mission, which relied relied on ionic propulsion, took almost four years to reach Vesta in the Asteroid Belt. Neither method is practical for making repeated trips to the Kuiper Belt and hauling back icy comets and asteroids, and humanity has nowhere near the number of ships we would need to do this.
On the other hand, going the in-situ route – which would involve factories or mining operations on the surface to release CO², methane or CFC-containing minerals into the air – would require several heavy-payload rockets to get all the machinery to the Red Planet. The cost of this would dwarf all space programs to date. And once they were assembled on the surface (either by robotic or human workers), these operations would have to be run continuously for centuries.
There is also several questions about the ethics of terraforming. Basically, altering other planets in order to make them more suitable to human needs raises the natural question of what would happen to any lifeforms already living there. If in fact Mars does have indigenous microbial life (or more complex lifeforms), which many scientists suspect, then altering the ecology could impact or even wipe out these lifeforms. In short, future colonists and terrestrial engineers would effectively be committing genocide.
NASA’s Journey to Mars. NASA is developing the capabilities needed to send humans to an asteroid by 2025 and Mars in the 2030s. Credit: NASA/JPL
Given all of these arguments, one has to wonder what the benefits of terraforming Mars would be. While the idea of utilizing the resources of the Solar System makes sense in the long-run, the short-term gains are far less tangible. Basically, harvested resources from other worlds is not economically viable when you can extract them here at home for much less. And given the danger, who would want to go?
But as ventures like MarsOne have shown, there are plenty of human beings who are willing to make a one-way trip to Mars and act as Earth’s “first-wave” of intrepid explorers. In addition, NASA and other space agencies have been very vocal about their desire to explore the Red Planet, which includes manned missions by the 2030s. And as various polls show, public support is behind these endeavors, even if it means drastically increased budgets.
So why do it? Why terraform Mars for human use? Because it is there? Sure. But more importantly, because we might need to. And the drive and the desire to colonize it is also there. And despite the difficulty inherent in each, there is no shortage of proposed methods that have been weighed and determined feasible.In the end, all that’s needed is a lot of time, a lot of commitment, a lot of resources, and a lot of care to make sure we are not irrevocably harming life forms that are already there.
But of course, should our worst predictions come to pass, we may find in the end that we have little choice but to make a home somewhere else in the Solar System. As this century progresses, it may very well be Mars or bust!
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At one time, astronomers believed the surface of Mars was crisscrossed by canal systems. This in turn gave rise to speculation that Mars was very much like Earth, capable of supporting life and home to a native civilization. But as human satellites and rovers began to conduct flybys and surveys of the planet, this vision of Mars quickly dissolved, replaced by one in which the Red Planet was a cold, desiccated and lifeless world.
However, over the past few decades, scientists have come to learn a great deal about the history of Mars that has altered this view as well. We now know that though Mars may currently be very cold, very dry, and very inhospitable, this wasn’t always the case. What’s more, we have come to see that even in its current form, Mars and Earth actually have a lot in common.
Between the two planets, there are similarities in size, inclination, structure, composition, and even the presence of water on their surfaces. That being said, they also have a lot of key differences that would make living on Mars, a growing preoccupation among many humans (looking at you, Elon Musk and Bas Lansdorp!), a significant challenge. Let’s go over these similarities and the difference in an orderly fashion, shall we?
Sizes, Masses and Orbits:
In terms of their size and mass, Earth and Mars are quite different. With a mean radius of 6371 km and a mass of 5.97×1024 kg, Earth is the fifth largest and fifth most-massive planet in the Solar System, and the largest of the terrestrial planets. Mars, meanwhile, has a radius of approximately 3,396 km at its equator (3,376 km at its polar regions), which is the equivalent of roughly 0.53 Earths. However, it’s mass is just 6.4185 x 10²³ kg, which is around 10.7% that of Earth’s.
Artistic representation of the orbits of Earth and Mars. Credit: NASA
Similarly, Earth’s volume is a hefty 1.08321 x 1012 km3, which works out 1,083 billion cubic kilometers. By comparison, Mars has a volume of 1.6318 x 10¹¹ km³ (163 billion cubic kilometers) which is the equivalent of 0.151 Earths. Between this difference in size, mass, and volume, Mars’s surface gravity is 3.711 m/s², which works out to 37.6% of Earths (0.376 g).
In terms of their orbits, Earth and Mars are also quite different. For instance, Earth orbits the Sun at an average distance (aka. semi-major axis) of 149,598,261 km – or one Astronomical Unit (AU). This orbit has a very minor eccentricity (approx. 0.0167), which means its orbit ranges from 147,095,000 km (0.983 AU) at perihelion to 151,930,000 km (1.015 AU) at aphelion.
At its greatest distance from the Sun (aphelion), Mars orbits at a distance of approximately 249,200,000 km (1.666 AU). At perihelion, when it is closest to the Sun, it orbits at a distance of approximately 206,700,000 km (1.3814 AU). At these distances, the Earth has an orbital period of 365.25 days (1.000017 Julian years) while Mars has an orbital period of 686.971 days (1.88 Earth years).
However, in terms of their sidereal rotation (time it takes for the planet to complete a single rotation on its axis) Earth and Mars are again in the same boat. While Earth takes precisely 23h 56m and 4 s to complete a single sidereal rotation (0.997 Earth days), Mars does the same in about 24 hours and 40 minutes. This means that one Martian day (aka. Sol) is very close to single day on Earth.
Earth’s axial tilt (or obliquity) and its relation to the rotation axis and plane of orbit. Credit: Wikipedia Commons
Mars’s axial tilt is very similar to Earth’s, being inclined 25.19° to its orbital plane (whereas Earth’s axial tilt is just over 23°). This means that Mars also experiences seasons and temperature variations similar to that of Earth (see below).
Structure and Composition:
Earth and Mars are similar when it comes to their basic makeups, given that they are both terrestrial planets. This means that both are differentiated between a dense metallic core and an overlying mantle and crust composed of less dense materials (like silicate rock). However, Earth’s density is higher than that of Mars – 5.514 g/cm3 compared to 3.93 g/cm³ (or 0.71 Earths) – which indicates that Mars’ core region contains more lighter elements than Earth’s.
Earth’s core region is made up of a solid inner core that has a radius of about 1,220 km and a liquid outer core that extends to a radius of about 3,400 km. Both the inner and outer cores are composed of iron and nickel, with trace amounts of lighter elements, and together, they add to a radius that is as large as Mars itself. Current models of Mars’ interior suggest that its core region is roughly 1,794 ± 65 kilometers (1,115 ± 40 mi) in radius, and is composed primarily of iron and nickel with about 16-17% sulfur.
Both planets have a silicate mantle surrounding their cores and a surface crust of solid material. Earth’s mantle – consisting of an upper mantle of slightly viscous material and a lower mantle that is more solid – is roughly 2,890 km (1,790 mi) thick and is composed of silicate rocks that are rich in iron and magnesium. The Earth’s crust is on average 40 km (25 mi) thick, and is composed of rocks that are rich in iron and magnesium (i.e. igneous rocks) and granite (rich in sodium, potassium, and aluminum).
Artist’s impression of the interior of Mars. Credit: NASA/JPL
Comparatively, Mars’ mantle is quite thin, measuring some 1,300 to 1,800 kilometers (800 – 1,100 mi) in thickness. Like Earth, this mantle is believed to be composed of silicate rock that are rich in minerals compared to the crust, and to be partially viscous (resulting in convection currents which shaped the surface). The crust, meanwhile, averages about 50 km (31 mi) in thickness, with a maximum of 125 km (78 mi). This makes it about three times as hick as Earth’s crust, relative to the sizes of the two planets.
Ergo, the two planets are similar in composition, owing to their common status as terrestrial planets. And while they are both differentiated between a metallic core and layers of less dense material, there is some variance in terms of how proportionately thick their respective layers are.
Surface Features:
When it comes to the surfaces of Earth and Mars, things once again become a case of contrasts. Naturally, it is the differences that are most apparent when comparing Blue Earth to the Red Planet – as the nicknames would suggest. Unlike other planet’s in our Solar System, the vast majority of Earth is covered in liquid water, about 70% of the surface – or 361.132 million km² (139.43 million sq mi) to be exact.
The surface of Mars is dry, dusty, and covered in dirt that is rich iron oxide (aka. rust, leading to its reddish appearance). However, large concentrations of ice water are known to exist within the polar ice caps – Planum Boreum and Planum Australe. In addition, a permafrost mantle stretches from the pole to latitudes of about 60°, meaning that ice water exists beneath much of the Martian surface. Radar data and soil samples have confirmed the presence of shallow subsurface water at the middle latitudes as well.
As for the similarities, Earth and Mars’ both have terrains that varies considerably from place to place. On Earth, both above and below sea level, there are mountainous features, volcanoes, scarps (trenches), canyons, plateaus, and abyssal plains. The remaining portions of the surface are covered by mountains, deserts, plains, plateaus, and other landforms.
Mars is quite similar, with a surface covered by mountain ranges, sandy plains, and even some of the largest sand dunes in the Solar System. It also has the largest mountain in the Solar System, the shield volcano Olympus Mons, and the longest, deepest chasm in the Solar System: Valles Marineris.
Earth and Mars have also experienced many impacts from asteroids and meteors over the years. However, Mars’ own impact craters are far better preserved, with many dating back billions of years. The reason for this is the low air pressure and lack of precipitation on Mars, which results in a very slow rate of erosion. However, this was not always the case.
Mars has discernible gullies and channels on its surface, and many scientists believe that liquid water used to flow through them. By comparing them to similar features on Earth, it is believed that these were were at least partially formed by water erosion. Some of these channels are quite large, reaching 2,000 kilometers in length and 100 kilometers in width.
Color mosaic of Mars’ greatest mountain, Olympus Mons, viewed from orbit. Credit NASA/JPL
So while they look quite different today, Earth and Mars were once quite similar. And similar geological processes occurred on both planets to give them the kind of varied terrain they both currently have.
Atmosphere and Temperature:
Atmospheric pressure and temperatures are another way in which Earth and Mars are quite different. Earth has a dense atmosphere composed of five main layers – the Troposphere, the Stratosphere, the Mesosphere, the Thermosphere, and the Exosphere. Mars’ is very thin by comparison, with pressure ranging from 0.4 – 0.87 kPa – which is equivalent to about 1% of Earth’s at sea level.
Earth’s atmosphere is also primarily composed of nitrogen (78%) and oxygen (21%) with trace concentrations of water vapor, carbon dioxide, and other gaseous molecules. Mars’ is composed of 96% carbon dioxide, 1.93% argon and 1.89% nitrogen along with traces of oxygen and water. Recent surveys have also noted trace amounts of methane, with an estimated concentration of about 30 parts per billion (ppb).
Because of this, there is a considerable difference between the average surface temperature on Earth and Mars. On Earth, it is approximately 14°C, with plenty of variation due to geographical region, elevation, and time of year. The hottest temperature ever recorded on Earth was 70.7°C (159°F) in the Lut Desert of Iran, while the coldest temperature was -89.2°C (-129°F) at the Soviet Vostok Station on the Antarctic Plateau.
Space Shuttle Endeavor silhouetted against the atmosphere. The orange layer is the troposphere, the white layer is the stratosphere and the blue layer the mesosphere. Credit: NASABecause of its thin atmosphere and its greater distance from the Sun, the surface temperature of Mars is much colder, averaging at -46 °C (-51 °F). However, because of its tilted axis and orbital eccentricity, Mars also experiences considerable variations in temperature. These can be seen in the form of a low temperature of -143 °C (-225.4 °F) during the winter at the poles, and a high of 35 °C (95 °F) during summer and midday at the equator.
The atmosphere of Mars is also quite dusty, containing particulates that measure 1.5 micrometers in diameter, which is what gives the Martian sky a tawny color when seen from the surface. The planet also experiences dust storms, which can turn into what resembles small tornadoes. Larger dust storms occur when the dust is blown into the atmosphere and heats up from the Sun.
So basically, Earth has a dense atmosphere that is rich in oxygen and water vapor, and which is generally warm and conducive to life. Mars, meanwhile, is generally very cold, but can become quite warm at times. It’s also quite dry and very dusty.
Magnetic Fields:
When it comes to magnetic fields, Earth and Mars are in stark contrast to each other. On Earth, the dynamo effect created by the rotation of Earth’s inner core, relative to the rotation of the planet, generates the currents which are presumed to be the source of its magnetic field. The presence of this field is of extreme importance to both Earth’s atmosphere and to life on Earth as we know it.
Map from the Mars Global Surveyor of the current magnetic fields on Mars. Credit: NASA/JPL
Essentially, Earth’s magnetosphere serves to deflect most of the solar wind’s charged particles which would otherwise strip away the ozone layer and expose Earth to harmful radiation. The field ranges in strength between approximately 25,000 and 65,000 nanoteslas (nT), or 0.25–0.65 Gauss units (G).
Today, Mars has weak magnetic fields in various regions of the planet which appear to be the remnant of a magnetosphere. These fields were first measured by the Mars Global Surveyor, which indicated fields of inconsistent strengths measuring at most 1500 nT (~16-40 times less than Earth’s). In the northern lowlands, deep impact basins, and the Tharsis volcanic province, the field strength is very low. But in the ancient southern crust, which is undisturbed by giant impacts and volcanism, the field strength is higher.
This would seem to indicate that Mars had a magnetosphere in the past, and explanations vary as to how it lost it. Some suggest that it was blown off, along with the majority of Mars’ atmosphere, by a large impact during the Late Heavy Bombardment. This impact, it is reasoned, would have also upset the heat flow in Mars’ iron core, arresting the dynamo effect that would have produced the magnetic field.
Another theory, based on NASA’s MAVEN mission to study the Martian atmosphere, has it that Mars’ lost its magnetosphere when the smaller planet cooled, causing its dynamo effect to cease some 4.2 billion years ago. During the next several hundred million years, the Sun’s powerful solar wind stripped particles away from the unprotected Martian atmosphere at a rate 100 to 1,000 times greater than that of today. This in turn is what caused Mars to lose the liquid water that existed on its surface, as the environment to become increasing cold, desiccated, and inhospitable.
Satellites:
Earth and Mars are also similar in that both have satellites that orbit them. In Earth’s case, this is none other than The Moon, our only natural satellite and the source of the Earth’s tides. It’s existence has been known of since prehistoric times, and it has played a major role in the mythological and astronomical traditions of all human cultures. In addition, its size, mass and other characteristics are used as a reference point when assessing other satellites.
The Moon is one of the largest natural satellites in the Solar System and is the second-densest satellite of those whose moons who’s densities are known (after Jupiter’s satellite Io). Its diameter, at 3,474.8 km, is one-fourth the diameter of Earth; and at 7.3477 × 1022 kg, its mass is 1.2% of the Earth’s mass. It’s mean density is 3.3464 g/cm3 , which is equivalent to roughly 0.6 that of Earth. All of this results in our Moon possessing gravity that is about 16.54% the strength of Earth’s (aka. 1.62 m/s2).
The Moon varies in orbit around Earth, going from 362,600 km at perigee to 405,400 km at apogee. And like most known satellites within our Solar System, the Moon’s sidereal rotation period (27.32 days) is the same as its orbital period. This means that the Moon is tidally locked with Earth, with one side is constantly facing towards us while the other is facing away.
Thanks to examinations of Moon rocks that were brought back to Earth, the predominant theory states that the Moon was created roughly 4.5 billion years ago from a collision between Earth and a Mars-sized object (known as Theia). This collision created a massive cloud of debris that began circling our planet, which eventually coalesced to form the Moon we see today.
Mars has two small satellites, Phobos and Deimos. These moons were discovered in 1877 by the astronomer Asaph Hall and were named after mythological characters. In keeping with the tradition of deriving names from classical mythology, Phobos and Deimos are the sons of Ares – the Greek god of war that inspired the Roman god Mars. Phobos represents fear while Deimos stands for terror or dread.
Phobos measures about 22 km (14 mi) in diameter, and orbits Mars at a distance of 9,234.42 km when it is at periapsis (closest to Mars) and 9,517.58 km when it is at apoapsis (farthest). At this distance, Phobos is below synchronous altitude, which means that it takes only 7 hours to orbit Mars and is gradually getting closer to the planet. Scientists estimate that in 10 to 50 million years, Phobos could crash into Mars’ surface or break up into a ring structure around the planet.
Meanwhile, Deimos measures about 12 km (7.5 mi) and orbits the planet at a distance of 23,455.5 km (periapsis) and 23,470.9 km (apoapsis). It has a longer orbital period, taking 1.26 days to complete a full rotation around the planet. Mars may have additional moons that are smaller than 50- 100 meters (160 to 330 ft) in diameter, and a dust ring is predicted between Phobos and Deimos.
Scientists believe that these two satellites were once asteroids that were captured by the planet’s gravity. The low albedo and the carboncaceous chondrite composition of both moons – which is similar to asteroids – supports this theory, and Phobos’ unstable orbit would seem to suggest a recent capture. However, both moons have circular orbits near the equator, which is unusual for captured bodies.
So while Earth has a single satellite that is quite large and dense, Mars has two satellites that are small and orbit it at a comparatively close distance. And whereas the Moon was formed from Earth’s own debris after a rather severe collision, Mars’ satellites were likely captured asteroids.
Conclusion:
Okay, let’s review. Earth and Mars have their share of similarities, but also some rather stark differences.
Mean Radius: 6,371 km 3,396 km
Mass: 59.7×1023 kg 6.42 x 10²³ kg
Volume: 10.8 x 1011 km3 1.63 x 10¹¹ km³
Semi-Major Axis: 0.983 – 1.015 AU 1.3814 – 1.666 AU
Air Pressure: 101.325 kPa 0.4 – 0.87 kPa
Gravity: 9.8 m/s² 3.711 m/s²
Avg. Temperature: 14°C (57.2 °F) -46 °C (-51 °F)
Temp. Variations: ±160 °C (278°F) ±178 °C (320°F)
Axial Tilt: 23° 25.19°
Length of Day: 24 hours 24h 40m
Length of Year: 365.25 days 686.971 days
Water: Plentiful Intermittent (mostly frozen)
Polar Ice Caps: Yep Yep
In short, compared to Earth, Mars is a pretty small, dry, cold, and dusty planet. It has comparatively low gravity, very little atmosphere and no breathable air. And the years are also mighty long, almost twice that of Earth, in fact. However, the planet does have its fair share of water (albeit mostly in ice form), has seasonal cycles similar to Earth, temperature variations that are similar, and a day that is almost as long.
All of these factors will have to be addressed if ever human beings want to live there. And whereas some can be worked with, others will have to be overcome or adapted to. And for that, we will have to lean pretty heavily on our technology (i.e. terraforming and geoengineering). Best of luck to those who would like to venture there someday, and who do not plan on coming home!
Artist’s rendering of a solar storm hitting Mars and stripping ions from the planet's upper atmosphere. Credits: NASA/GSFC
NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) orbiter mission has determined that ancient Mars suffered drastic climate change and lost its thick atmosphere and surface bodies of potentially life giving liquid water because it lost tremendous quantities of gas to space via stripping by the solar wind, based on new findings that were announced today, Nov. 5, at a NASA media briefing and in a series of scientific publications.
The process of Mars dramatic transformation from a more Earth-like world to its barren state today started about 4.2 Billion years ago as the shielding effect of the global magnetic field was lost as the planets internal dynamo cooled, Bruce Jakosky, MAVEN principal investigator at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado, Boulder, told Universe Today.
The radical transformation of ancient Mars from a warm world with significant bodies of standing water that could have supported life, to its current state as a cold, arid and desert-like world that’s rather inhospitable to life was caused by the loss of most the planet’s atmosphere as powerful streams of solar wind particles crashed into it and stripped it away due to the loss of the protective magnetic field as the planets core cooled.
“We think that the early magnetic field that Mars had would have protected the planet from direct impact by the solar wind and would have kept it from stripping gas off,” Jakosky told me.
“So it would have been the turn off of the magnetic field, that would have allowed the turn on of stripping of the atmosphere by the solar wind.”
“The evidence suggests that the magnetic field disappeared about 4.2 Billion years ago.”
The period of abundant surface water actively carving the Martian geology lasted until about 3.7 Billion years ago. The loss of the atmosphere by stripping of the solar wind took place from about 4.2 to 3.7 Billion years ago.
Billions of years ago, Mars was a very different world. Liquid water flowed in long rivers that emptied into lakes and shallow seas. A thick atmosphere blanketed the planet and kept it warm. Credit: NASA
With the release of today’s results, the MAVEN science team has accomplished the primary goal of the mission, which was to determine how and why Mars lost its early, thick atmosphere and water over the past four billion years. The atmosphere is composed mostly of carbon dioxide.
Since water is a prerequisite for life as we know it, determining its fate and longevity on Mars is crucial for determining the habitability of the Red Planet and its potential for supporting martian microbes, past of present if they ever existed.
“The NASA Mars exploration program has been focused on finding water,” said Michael Meyer, lead scientist for the Mars Exploration Program at NASA Headquarters.
“Water is the prime ingredient needed for life. It is a major factor in the climate and for shaping geology. And it is a critical resource for future human exploration.”
This NASA video shows a visualization of the solar wind striking Mars:
Video caption: Created using data from NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) mission, this visualization shows how the solar wind strips ions from the Mars’ upper atmosphere into space. Credits: NASA-GSFC/CU Boulder LASP/University of Iowa
MAVEN arrived in orbit at Mars just over one year ago on Sept. 21, 2014.
The $671 Million MAVEN spacecraft’s goal is to study Mars tenuous upper atmosphere in detail for the very first time by any spacecraft and to explore the mechanisms of how the planet lost its atmosphere and life giving water over billions of years as well as determine the rate of atmospheric loss.
The new MAVEN data have enabled researchers to measure the rate of Mars atmospheric loss of gas to space via the action of solar wind stripping as well as the erosional effect of solar storms.
Based on measurements from MAVEN’s suite of nine state-of-the-art scientific instruments, the solar wind is stripping away gas at a rate of about 100 grams (equivalent to roughly 1/4 pound) every second today, in the form of carbon dioxide and oxygen, said David Brain, MAVEN co-investigator at LASP.
“Most of the stripping [of the Martian atmosphere] by the solar wind at Mars was thought to have taken place very early in the history of the solar system when the sun was much more active and when the solar wind was more intense. So today the rate of loss at Mars is low,” Jakosky said at the briefing.
“Today’s Mars is a cold dry desert-like environment. The atmosphere is thin and it’s not capable of sustaining liquid water at the surface today, it would freeze or evaporate very quickly. However when we look at ancient Mars we see a different type of surface, one that had valleys that looked like they were carved by water and lakes that were standing for long periods of time. We see an environment that was much more able to support liquid water.”
The MAVEN results were published today in nearly four dozen scientific papers in the Nov. 5 issues of the journals Science and Geophysical Research Letters.
I asked Jakosky; How much gas would have been lost from ancient Mars and what is the rough estimate for the ancient rate of loss to arrive at Mars thin atmosphere today?
“For the amount of gas that we think you would have to have been removed – let me start with the current Mars atmosphere which has a thickness of 6 millibars, that’s just under 1% as thick as the Earth’s atmosphere,” Jakosky replied.
“So we think you would have to remove an amount of gas that is about equivalent to what’s in Earth’s atmosphere today.”
“So the rate would have to have been a factor of about 100 to 1000 times higher, than today’s loss of 100 grams per second in order to have removed the gas early in that time period, which is consistent with what the models have predicted that the loss rate would have been back then in early history.”
NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft celebrated one Earth year in orbit around Mars on Sept. 21, 2015. MAVEN was launched to Mars on Nov. 18, 2013 from Cape Canaveral Air Force Station in Florida and successfully entered Mars’ orbit on Sept. 21, 2014. Credit: NASA
What is the solar wind and how does it strip away the atmosphere?
“The solar wind is a stream of particles, mainly protons and electrons, flowing from the sun’s atmosphere at a speed of about one million miles per hour. The magnetic field carried by the solar wind as it flows past Mars can generate an electric field, much as a turbine on Earth can be used to generate electricity. This electric field accelerates electrically charged gas atoms, called ions, in Mars’ upper atmosphere and shoots them into space,” according to a NASA description.
MAVEN is NASA’s next Mars orbiter and is due to blastoff on Nov. 18 from Cape Canaveral, Florida. It will study the evolution of the Red Planet’s atmosphere and climate. Universe Today visited MAVEN inside the clean room at the Kennedy Space Center. With solar panels unfurled, this is exactly how MAVEN looks when flying through space and circling Mars. Credit: Ken Kremer/kenkremer.com
MAVEN is just now completing its primary mission and starts the extended mission phase on Nov. 16.
The 5,400 pound MAVEN probe carries nine sensors in three instrument suites to study why and exactly when did Mars undergo the radical climatic transformation.
MAVEN’s observations will be tied in with NASA’s ongoing Curiosity and Opportunity surface roving missions as well as MRO and Mars Odyssey to provide the most complete picture of the fourth rock from the sun that humanity has ever had.
MAVEN thundered to space on Nov. 18, 2013 following a flawless blastoff from Cape Canaveral Air Force Station’s Space Launch Complex 41 atop a powerful United Launch Alliance Atlas V rocket.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
NASA’s MAVEN Mars orbiter, chief scientist Prof. Bruce Jakosky of CU-Boulder and Ken Kremer of Universe Today inside the clean room at the Kennedy Space Center on Sept. 27, 2013. MAVEN launched to Mars on Nov. 18, 2013 from Florida. Credit: Ken Kremer/kenkremer.com
Credit: NASA/MRO/Rendering: James Dickson, Brown University
Though the surface of Mars is a dry, dessicated and bitterly cold place today, it is strongly believed that the planet once had rivers, streams, lakes, and flowing water on its surface. Thanks to a combination of spacecraft imagery, remote sensing techniques and surface investigations from landers and rovers, ample evidence has been assembled to support this theory.
However, it is hard to reconcile this view with the latest climate models of Mars which suggest that it should have been a perennially cold and icy place. But according to a new study, the presence of warm, flowing water may have been an episodic occurrence, something that happened for decades or centuries when the planet was warmed sufficiently by volcanic eruptions and greenhouse gases.
The study, which was conducted by scientists from Brown University and Israel’s Weizmann Institute of Science, suggests that warmth and water flow on ancient Mars were probably episodic, related to brief periods of volcanic activity that spewed tons of greenhouse-inducing sulfur dioxide gas into the atmosphere.
The work combines the effect of volcanism with the latest climate models of early Mars and suggests that periods of temperatures warm enough for water to flow likely lasted for only tens or hundreds of years at a time.
The notion that Mars had surface water predates the space age by centuries. Long before Percival Lowell observed what he thought were “canals” on the Martian surface in 1877, the polar ice caps and dark spots on the surface were being observed by astronomers who thought that they were indications of liquid water.
Curiosity found evidence of an ancient, flowing stream on Mars at a few sites, including the “Hottah” rock outcrop pictured here. Credit: NASA/JPL
But with all that’s been learned about Mars in recent years, the mystery of the planet’s ancient water has only deepened. The latest generation of climate models for early Mars suggests that the atmosphere was too thin to heat the planet enough for water to flow. Billions of years ago, the sun was also much dimmer than it is today, which further complicates this picture of a warmer early Mars.
“These new climate models that predict a cold and ice-covered world have been difficult to reconcile with the abundant evidence that water flowed across the surface to form streams and lakes,” said James W. Head, professor of earth, environmental and planetary sciences at Brown University and co-author of the new paper with Weizmann’s Itay Halevy. “This new analysis provides a mechanism for episodic periods of heating and melting of snow and ice that could have each lasted decades to centuries.”
Halevy and Head explored the idea that heating may have been linked to periodic volcanism. Many of the geological features that suggest water was flowing on the Martian surface have been dated to 3.7 billion years ago, a time when massive volcanoes are thought to have been active.
And whereas on Earth, widespread volcanism has often led to global dimming rather than warming – on account of sulfuric acid particles reflecting the sun’s rays – Head and Halevy think the effects may have been different in Mars’ dusty atmosphere.
To test this theory, they created a model of how sulfuric acid might react with the widespread dust in the Martian atmosphere. The work suggests that those sulfuric acid particles would have glommed onto dust particles and reduced their ability to reflect the sun’s rays. Meanwhile, sulfur dioxide gas would have produced enough greenhouse effect to warm the Martian equatorial region so that water could flow.
Image of the McMurdo Dry Valleys, Antarctica, acquired by Landsat 7’s Enhanced Thematic Mapper plus (ETM+) instrument. Credit: NASA/EO
Head has been doing fieldwork for years in Antarctica and thinks the climate on early Mars may have been very similar to what he has observed in the cold, desert-like.
“The average yearly temperature in the Antarctic Dry Valleys is way below freezing, but peak summer daytime temperatures can exceed the melting point of water, forming transient streams, which then refreeze,” Head said. “In a similar manner, we find that volcanism can bring the temperature on early Mars above the melting point for decades to centuries, causing episodic periods of stream and lake formation.”
As that early active volcanism on Mars ceased, so did the possibility of warmer temperatures and flowing water.
According to Head, this theory might also help in the ongoing search for signs that Mars once hosted life. If it ever did exist, this new research may offer clues as to where the fossilized remnants ended up.
“Life in Antarctica, in the form of algal mats, is very resistant to extremely cold and dry conditions and simply waits for the episodic infusion of water to ‘bloom’ and develop,” he said. “Thus, the ancient and currently dry and barren river and lake floors on Mars may harbor the remnants of similar primitive life, if it ever occurred on Mars.”
MAVEN's Ultraviolet Imaging Spectrograph (IUVS) uses limb scans to map the chemical makeup and vertical structure across Mars' upper atmosphere. It detected strong enhancements of magnesium and iron from ablating incandescing dust from Comet Siding Spring. Credit: NASA
NASA’s newest Mars spacecraft is “go” for at least a year — and potentially longer. After taking a time-out from commissioning to observe Comet Siding Spring whizz by the Red Planet in October, the Mars Atmosphere and Volatile Evolution (MAVEN) officially began its science mission Monday (Nov. 17). And so far things are going well.
“From the observations made both during the cruise to Mars and during the transition phase, we know that our instruments are working well,” stated principal investigator Bruce Jakosky, who is with NASA’s Goddard Space Flight Center in Maryland. “The spacecraft also is operating smoothly, with very few ‘hiccups’ so far. The science team is ready to go.”
MAVEN arrived in orbit Sept. 16 after facing down and overcoming a potential long delay for its mission. NASA and other federal government departments were in shutdown while MAVEN was in final launch preparations, but the mission received a special waiver because it is capable of communicating with the rovers on Mars. Given the current relay spacecraft are aging, MAVEN could serve as the next-generation spacecraft if those ones fail.
Three views of an escaping atmosphere, obtained by MAVEN’s Imaging Ultraviolet Spectrograph. By observing all of the products of water and carbon dioxide breakdown, MAVEN’s remote sensing team can characterize the processes that drive atmospheric loss on Mars. Image Credit: University of Colorado/NASA
But that’s providing that MAVEN can last past the next year in terms of hardware and funding. Meanwhile, its primary science mission is better understanding how the atmosphere of Mars behaves today and how it has changed since the Red Planet was formed.
“The nine science instruments will observe the energy from the Sun that hits Mars, the response of the upper atmosphere and ionosphere, and the way that the interactions lead to loss of gas from the top of the atmosphere to space,” Jakosky added.
“Our goal is to understand the processes by which escape to space occurs, and to learn enough to be able to extrapolate backwards in time and determine the total amount of gas lost to space over time. This will help us understand why the Martian climate changed over time, from an early warmer and wetter environment to the cold, dry planet we see today.”
First ever image of Earth Taken by Mars Color Camera aboard India’s Mars Orbiter Mission (MOM) spacecraft while orbiting Earth and before the Trans Mars Insertion firing on Dec. 1, 2013. Image is focused on the Indian subcontinent. Credit: ISRO
CAPE CANAVERAL, FL – MOM is looking at you, kid!
And if the spectacular new image of billions of Earth’s children captured by India’s Mars Orbiter Mission (MOM) is any indication (see above), then we can expect absolutely gorgeous scenes of the Red Planet once the groundbreaking probe arrives there in September 2014.
But despite all that’s been accomplished so far, the space drama is still in its infant stages – because MOM still needs to ignite her thrusters this weekend in order to achieve escape velocity, wave good bye to Earth forever and eventually say hello to Mars!
The picture – snapped from Earth orbit – is focused on the Indian subcontinent, the probes origin.
MOM has captured the imagination of space enthusiasts worldwide.
During testing of the MOM probes payloads – while it’s still flying in a highly elliptical orbit around our Home Planet – engineers from India’s space agency turned the crafts camera homewards to capture the “First ever image of Earth Taken by Mars Color Camera,” according to the Indian Space Research Organization (ISRO).
The beautiful image was taken on Nov. 20 at around 1350 hrs (IST) from a height of almost 70,000 km above earth and has a spatial resolution of 3.5 km, said ISRO.
The image also gives a rather good approximation of what MOM’s color camera will actually see from apoapsis after reaching the Red Planet since the probe will enter a similarly highly elliptical orbit around Mars – ranging in altitude from 366 kilometers (km) x 80,000 kilometers (km).
MOM has just passed by its penultimate perigee. With this, the final orbit of MOM around Earth begins! Credit: ISRO
Following a 10 month interplanetary cruise, MOM is due to arrive in the vicinity of Mars on September 24, 2014 to study the Red Planets’ atmosphere.
At that time, the 440 Newton liquid fueled main engine must fire precisely as planned during the absolutely essential Mars orbital insertion burn to place the probe into orbit about Mars.
But before MOM can accomplish anything at Mars, she must first successfully fire her main engine – to complete the crucial departure from Earth and Trans Mars Insertion (TMI) scheduled for this Saturday!
MOM’s picture perfect Nov. 5 liftoff atop India’s highly reliable four stage Polar Satellite Launch Vehicle (PSLV) C25 from the ISRO’s Satish Dhawan Space Centre SHAR, Sriharikota, precisely injected the spacecraft into an initial elliptical Earth parking orbit of 247 x 23556 kilometers with an inclination of 19.2 degrees.
Since then the engine has fired 6 times to gradually raise the spacecrafts apogee.
The most recent orbit raising maneuver occurred at 01:27 hrs (IST) on Nov 16, 2013 with a burn time of 243.5 seconds increased the apogee from 118,642 km to 192,874 km.
The nail-biting final main engine burn of 1351 seconds is set for this weekend on Dec. 1. It will place MOM on a precise interplanetary trajectory to the Red Planet.
Graphic of MOM approaching its penultimate perigee pass on Nov 26. Credit: ISRO
If all continues to goes well, India will join an elite club of only four who have launched probes that successfully investigated the Red Planet from orbit or the surface – following the Soviet Union, the United States and the European Space Agency (ESA).
The low cost $69 Million MOM mission is the first of two new Mars orbiter science probes from Earth that flawlessly blasted off for the Red Planet this November.
Both MAVEN and MOM’s goal is to study the Martian atmosphere, unlock the mysteries of its current atmosphere and determine how, why and when the atmosphere and liquid water was lost – and how this transformed Mars climate into its cold, desiccated state of today.
The MAVEN and MOM science teams will “work together” to unlock the secrets of Mars atmosphere and climate history, MAVEN’s top scientist Prof. Bruce Jakosky told Universe Today.
Clouds on the ground ! The sky seems inverted for a moment ! Blastoff of India’s Mars Orbiter Mission (MOM) on Nov. 5, 2013 from the Indian Space Research Organization’s (ISRO) Satish Dhawan Space Centre SHAR, Sriharikota. Credit: ISRO
Stay tuned here for continuing MOM and MAVEN news and Ken’s MAVEN and SpaceX Falcon 9 launch reports from on site at the Kennedy Space Center press center and Cape Canaveral Air Force Station, Florida.
Learn more about MOM, MAVEN, Mars rovers, SpaceX, Orion and more at Ken’s upcoming presentations
Nov 28: “SpaceX launch, MAVEN & MOM Mars Launches and Curiosity Explores Mars, Orion and NASA’s Future”, Kennedy Space Center Quality Inn, Titusville, FL, 8 PM
Dec 11: “Curiosity, MAVEN, MOM and the Search for Life on Mars”, “LADEE & Antares ISS Launches from Virginia”, Rittenhouse Astronomical Society, Franklin Institute, Phila, PA, 8 PM
“MOM is in normal health,” at this time according to the Indian Space Research Organization (ISRO) – which has now scheduled a supplementary main engine firing for early Tuesday (Nov. 12) to boost the crafts orbit the missing 20,000 km required.
Monday’s engine firing only raised MOM’s apogee (farthest point to Earth) from 71,623 km to 78,276 km compared to the originally planned apogee of about 100,000 [1 lakh] km), said ISRO in a press release.
This is the first serious problem to strike MOM in space. And it seemed clear to me something might be amiss when ISRO failed to quickly announce a successful completion of the 4th firing as had been the pattern for the initial three burns.
Trajectory graphic showing new supplemental 5th Midnight Maneuver thruster firing of ISRO’s Mars Orbiter Mission Spacecraft planned for Nov. 12 (IST) following the premature main engine shutdown during 4th orbit raising engine burn on Nov. 11. Credit: ISRO
The premature shutdown of the liquid fueled 440 Newton main engine “imparted an incremental velocity of 35 metres/second as against 130 metres/second originally planned,” ISRO stated.
That’s barely a quarter of what was hoped for.
“A supplementary orbit-raising operation is planned tomorrow (November 12, 2013) at 0500 hrs IST to raise the apogee to nearly 1 lakh [100,000] km.”
A series of six absolutely essential firings of the 440 Newton main engine – dubbed “midnight maneuvers” – had been originally scheduled by Indian space engineers.
The purpose of the “midnight maneuvers” is to achieve Earth escape velocity by gradually raising MOM’s apogee over several weeks, and set her on a trans Mars trajectory to the Red Planet, following the spectacular blastoff on Nov. 5 from India’s spaceport.
Graphic showing trajectory that had been planned for the Fourth Midnight Maneuver of ISRO’s Mars Orbiter Mission Spacecraft on Nov. 11 until early shutdown of the 440N liquid fueled main engine. Credit: ISRO
MOM was due to depart Earth’s orbit on Dec. 1 after accomplishing the 6th of the originally scheduled thruster firings – and begin a 10 month long interplanetary cruise to Mars.
MOM’s picture perfect Nov. 5 liftoff atop India’s highly reliable four stage Polar Satellite Launch Vehicle (PSLV) C25 from the ISRO’s Satish Dhawan Space Centre SHAR, Sriharikota, precisely injected the spacecraft into an initial elliptical Earth parking orbit of 247 x 23556 kilometers with an inclination of 19.2 degrees.
The 1st, 2nd and 3rd thruster firings were spot on and incrementally raised MOM’s apogee from 23556 km to 28814 km, 40186 km and 71,623 km respectively.
The next firing had been slated for Nov. 16.
Here’s how ISRO described the source of the main engine shutdown:
“During the fourth orbit-raising operations held today (November 11, 2013), the redundancies built-in for the propulsion system were exercised, namely, (a) energising the primary and redundant coils of the solenoid flow control valve of 440 Newton Liquid Engine and (b) logic for thrust augmentation by the attitude control thrusters, when needed.
However, when both primary and redundant coils were energised together, as one of the planned modes, the flow to the Liquid Engine stopped. The thrust level augmentation logic, as expected, came in and the operation continued using the attitude control thrusters. This sequence resulted in reduction of the incremental velocity.”
Artists concept shows Midnight Maneuver thruster firing of the liquid engine of ISRO’s Mars Orbiter Mission Spacecraft. Credit: ISRO
It is not known at this time how or whether the requirement for a supplemental “midnight maneuver” engine firing will affect the mission’s timing at Earth and its operations and longevity at Mars.
Why are the firings called midnight maneuvers?
“Firing has to happen near the perigee and in the visibility from ISTRAC ground stations. All these orbits have argument of perigee of ~285 deg. When all these constraints are put together, firings time will almost always fall in to midnights of Indian sub continent,” said ISRO in response to a readers inquiry.
In the latest update, ISRO reports: “After achieving an apogee of around 78,000 km in last night’s Maneuver, ISRO’s Mars Orbiter Mission Spacecraft is all set to reach the apogee of One lakh km in a supplementary maneuver scheduled for 5 AM tomorrow. [Nov 12].”
MOM was to arrive in the vicinity of Mars on September 24, 2014 when the absolutely essential Mars orbital insertion firing by the 440 Newton liquid fueled main engine will slow the probe and place it into a 366 km x 80,000 km elliptical orbit.
Clouds on the ground ! The sky seems inverted for a moment ! Blastoff of India’s Mars Orbiter Mission (MOM) on Nov. 5, 2013 from the Indian Space Research Organization’s (ISRO) Satish Dhawan Space Centre SHAR, Sriharikota. Credit: ISRO
If all goes well, India will join an elite club of only four who have launched probes that successfully investigated the Red Planet from orbit or the surface – following the Soviet Union, the United States and the European Space Agency (ESA).
The low cost $69 Million MOM mission is the first of two new Mars orbiter science probes from Earth blasting off for the Red Planet this November.
Half a world away, NASA’s $671 Million MAVEN orbiter remains on target to launch in less than one week on Nov. 18 – from Cape Canaveral, Florida.
Both MAVEN and MOM’s goal is to study the Martian atmosphere, unlock the mysteries of its current atmosphere and determine how, why and when the atmosphere and liquid water was lost – and how this transformed Mars climate into its cold, desiccated state of today.
The MAVEN and MOM science teams will “work together” to unlock the secrets of Mars atmosphere and climate history, MAVEN’s top scientist Prof. Bruce Jakosky told Universe Today.
Stay tuned here for continuing MOM and MAVEN news and Ken’s MAVEN launch reports from on site at the Kennedy Space Center press center
Learn more about MAVEN, MOM, Mars rovers, Orion and more at Ken’s upcoming presentations
Nov 14-19: “MAVEN Mars Launch and Curiosity Explores Mars, Orion and NASA’s Future”, Kennedy Space Center Quality Inn, Titusville, FL, 8 PM
Dec 11: “Curiosity, MAVEN and the Search for Life on Mars”, “LADEE & Antares ISS Launches from Virginia”, Rittenhouse Astronomical Society, Franklin Institute, Phila, PA, 8 PM
The solar panels on the MAVEN spacecraft are deployed as part of environmental testing procedures at Lockheed Martin Space Systems in Littleton, Colorado, before shipment to Florida 0on Aug. 2 and blastoff for Mars on Nov. 18, 213. Credit: Lockheed Martin
The solar panels on NASA’s MAVEN Mars orbiter are deployed as part of environmental testing procedures at Lockheed Martin Space Systems in Littleton, Colorado, before shipment to Florida on Aug. 2 and blastoff for Mars on Nov. 18, 2013. Credit: Lockheed Martin Watch cool testing videos below![/caption]
MAVEN is NASA’s next mission to Mars and in less than three days time the spacecraft ships out on a cross country trek for the first step on the long sojourn to the Red Planet.
But before all that, technicians took MAVEN for a final spin test, flexed her solar arrays and bombarded her with sound and a whole lot more.
On Aug. 2, MAVEN (Mars Atmosphere and Volatile EvolutioN Mission) journeys half a continent from its assembly facility at Lockheed Martin in Littleton, Colorado to the Kennedy Space Center and the Florida Space Coast aboard a USAF C-17.
Unlike Curiosity, which is roving across a crater floor on the Red Planet at this very moment, MAVEN is an orbiter with a first of its kind mission.
MAVEN is the first spacecraft from Earth devoted to investigating and understanding the upper atmosphere of Mars.
The goal is determining how and why Mars lost virtually all of its atmosphere billions of years ago, what effect that had on the climate and where did the atmosphere and water go?
To ensure that MAVEN is ready for launch, technicians have been busy this year with final tests of the integrated spacecraft.
Check out this video of MAVEN’s Dry Spin Balance Test
The spin balance test was conducted on the unfueled spacecraft on July 9, 2013 at Lockheed Martin Space Systems in Littleton, Colorado.
NASA says the purpose of the test “is to ensure that the fully integrated spacecraft is correctly balanced and to determine the current center of gravity. It allows the engineering team to fine-tune any necessary weight adjustments to precisely fix the center of gravity where they want it, so that it will perform as expected during the cruise to Mars.”
It was the last test to be completed on the integrated spacecraft before its shipment to Florida later this week.
This next video shows deployment tests of the two “gull-wing” solar panels at Lockheed Martin Space Systems.
Wingtip to wingtip, MAVEN measures 11.43 m (37.5 feet) in length.
In mid May, MAVEN was moved into a Thermal Vacuum Chamber at Lockheed Martin for 19 days of testing.
The TVAC test exposed MAVEN to the utterly harsh temperatures and rigors of space similar to those it will experience during its launch, cruise, and mission at Mars.
MAVEN is slated to blast off atop an Atlas V-401 rocket from Cape Canaveral Air Force Station, Florida on Nov. 18, 2013. The 2000 pound (900 kg) spacecraft will be housed inside a 4 meter payload fairing.
After a 10 month interplanetary voyage it will join NASA’s armada of four robotic spacecraft when it arrives in Mars orbit in September 2014.
Scientists hope that measurements from MAVEN will help answer critical questions like whether, when and how long the Martian atmosphere was once substantial enough to sustain liquid water on its surface and support life.
“What we’re doing is measuring the composition of the atmosphere as a measure of latitude, longitude, time of day and solar activities,” said Paul Mahaffy, of NASA’s Goddard Space Flight Center in Greenbelt, Md, and the principal investigator for MAVEN’s mass spectrometer instrument.
“We’re trying to understand over billions of years how the atmosphere has been lost.”
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Learn more about MAVEN, Cygnus, Antares, LADEE, Mars rovers and more at Ken’s upcoming lecture presentations
Aug 12: “RockSat-X Suborbital Launch, LADEE Lunar & Antares Rocket Launches from Virginia”; Rodeway Inn, Chincoteague, VA, 8 PM
Oct 3: “Curiosity and the Search for Life on Mars – (3-D)”, STAR Astronomy Club, Brookdale Community College & Monmouth Museum, Lincroft, NJ, 8 PM
NASA’s MAVEN orbiter is due to blast off for Mars on Nov. 18, 2013 atop an Atlas V rocket similar to this which launched Curiosity from Cape Canaveral on Nov. 26, 2011. Credit: Ken Kremer/kenkremer.com
[/caption]I think that one of the most interesting questions that have been posed of late is ‘what is Mar’s atmosphere made of?’ There has been a great deal of study done on this topic and interest is increasing since the discovery of methane, a possible indicator of life.
The atmosphere of Mars is over 95% carbon dioxide, 95.32% to be exact. The breakdown of gases goes like this:
Carbon dioxide 95.32%
Nitrogen 2.7%
Argon 1.6%
Oxygen 0.13%
Carbon monoxide 0.07%
Water vapor 0.03%
Nitric oxide .0013%
Trace gases(including krypton, methane, etc)
The Martian atmosphere has four main layers: lower, middle, upper, and exosphere. The lower atmosphere is a warm region(around 210 K). It is warmed by airborne dust(1.5 micrometers across) and heat radiated from the surface. This airborne dust gives the planet its ruddy brown appearance. The middle atmosphere is features a jetstream similar to Earth’s. The upper atmosphere is heated by the solar wind and the temperatures are much higher than at the surface. This heat separates the gases. The exosphere starts at about 200 km and has no clear end. It just tapers off into space.
The carbon dioxide in the atmosphere freezes for part of the year and may drop to the surface. As much as 25% of the atmospheric carbon dioxide condenses at the polar caps into solid ice(dry ice) because the Martian poles are not exposed to sunlight during the planet’s winter. When the poles are again exposed to sunlight, the ice returns to its gas form and rises back into the atmosphere. So, a significant annual variation in the atmospheric pressure and atmospheric composition around the Martian poles.
The methane mentioned earlier is used to show the possibility of life on Mars. While it is a byproduct of life, it is also a result of volcanism, geothermal process, and hydrothermal activity. Methane is an unstable gas, so there has to be a source on the planet that is constantly replenishing it. It has to be a very active source, because studies have shown that the methane is destroyed in less than on Earth year. It is thought that peroxides and perchlorates in the soil or that it condenses and evaporates seasonally from clathrates.
Now you answer ‘ what is Mar’s atmosphere made of?’ the next time it comes up. You can be sure that the methane component will continue to be studied by rovers, orbiters, and, in the future, astronauts.
We have written many articles about the atmosphere of Mars for Universe Today. Here’s an article about the air on Mars, and here’s an article about Mars’ comparison with Earth.
![Space Shuttle Endeavour sillouetted against the atmosphere. The orange layer is the troposphere, the white layer is the stratosphere and the blue layer the mesosphere.[1] (The shuttle is actually orbiting at an altitude of more than 320 km (200 mi), far above all three layers.) Credit: NASA](https://www.universetoday.com/wp-content/uploads/2012/03/Endeavour_silhouette_STS-130.jpg)
