Mars Archives

December 4, 2009December 24, 2015 by Fraser Cain

Mars Global Surveyor

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The Mars Global Surveyor was a spacecraft sent to Mars in 1996. It arrived at Mars and studied the planet for 10 years, until it broke down in 2006, and controllers on Earth lost contact with it. But while it was operating, the spacecraft took thousands of images, and made some major discoveries about Mars.

Mars Global Surveyor was launched on November 7, 1996, and made its orbital insertion on September 11, 1997. It used a technique called aerobraking to reduce its orbit and bring it into an orbit that brought it to an average distance of 378 km from the surface of Mars. It circled the planet in a polar orbit once every 117 minutes, which allowed it to photograph the entire Martian surface.

The spacecraft was equipped with 5 major scientific instruments: Mars Orbiter Camera, Mars Orbiter Laser Altimeter, Thermal Emission Spectrometer, Magnetometer and electron reflectometer and the Ultrastable Oscillator for Doppler measurements. These instruments allowed the spacecraft to study the atmosphere and surface composition of Mars. But it also sent back the highest resolution photographs ever seen of Mars. The newer Mars Reconnaissance Orbiter has returned better images with its larger telescope, but when the first MGS images first came back from Mars, they were stunning.

It made some incredible discoveries about Mars. Thanks to the observations from MGS, astronomers determined that Mars had a layered crust that was more than 10 km thick. It found ancient craters that had been buried and then later exposed by erosion, and it found evidence of ancient lava flows.

But perhaps the biggest discovery was made in 2006, which researchers announced that they had uncovered evidence of recent water activity on Mars. Images from the Mars Global Surveyor showed gullies on Mars which looked like they’d been formed by water. It’s possible that water had erupted out of an underground aquifer and spilled down the slope of a hill before evaporating in the pressure of the Martian atmosphere.

After a decade of service, Mars Global Surveyor went silent on November 2, 2006. It went into safe mode after being issued commands to change the orientation of its solar panels, and it stopped communicating. NASA said that it was, “battery failure caused by a complex sequence of events involving the onboard computer memory and ground commands.” But we’ll never really know what happened to it.

We’ve written many articles about the Mars Global Surveyor for Universe Today. Here’s an article about how we lost contact with the Mars Global Surveyor, and here’s a picture of Earth taken by MGS.

If you’d like more info, check out the Mars Global Surveyor homepage.

Source: NASA

December 3, 2009December 24, 2015 by John Carl Villanueva

How Big is Mars?

[/caption]Planet Mars’ Olympus Mons holds the record for the tallest known peak in the entire Solar System. Having a height three times taller than Mount Everest’s and a base wide enough to prevent an observer at the base from seeing the top, you would have expected Mars to be on a relatively big planet. But did you know that Mars is much smaller than Earth? So how big is Mars?

The radius of Mars is only about half that of the Earth’s radius; roughly 3,396 km at the equator and 3,376 km at the poles. For comparison, the earth’s equatorial radius is 6,378 km, while its polar radius is 6,357 km.

These radii give Mars a surface area roughly only 28.4% of Earth’s or 144,798,500 km². The Pacific Ocean is even larger, with an area of roughly 169,200,000 km².

The dimensions of Mars also gives it a volume approximately equal to 1.6318×10¹¹ km² and a mass approximately equal to 6.4185×10²³ kg. That’s only about 15.1% and 10.7% that of the Earth’s, respectively.

Despite its noticeably smaller size than the Earth, Mars has more majestic geographical features.

For instance, there’s Valles Marineris, a 4,000 km-long and 7 km-deep canyon that spans about one-fifth of the entire planet’s circumference. It is so long that it’s even longer than the length of Europe. If you compare the Grand Canyon to it, Colorado’s pride and joy won’t look so grand anymore.

Want to know how long the Grand Canyon is? 446 km. That’s very long, yes. But that’s only a little over 10% the length of Valles Marineris.

That’s not the only large geographical feature on Mars. Ma’adim Vallis, is another canyon on Mars that’s larger then the Grand Canyon, with a length of 700 km. Then there’s an impact crater that’s been found to be larger than the combined surface area of the continents of Asia, Europe, and Australia.

Now that you know about these extremely majestic geographical features on Mars, the next time someone asks you, “How big is Mars?” you can tell them how it is much smaller than the Earth … but you can also add the salient features that make the Red Planet much more interesting when it comes to a discussion on sizes.

We’ve got more articles about the Planet Mars here on Universe Today. Click on that link or read about interesting facts about the Planet Mars.

Here are two episodes at Astronomy Cast that you might want to check out as well:
Stellar Roche Limits, Seeing Black Holes, and Water on Mars
The Search for Extraterrestrial Intelligence

Reference:
NASA

December 1, 2009December 24, 2015 by Nicholos Wethington

Mars Odyssey Goes into Safe Mode

An artist's impression of the Odyssey orbiter around Mars. . Image Credit: NASA

The Mars Odyssey orbiter went into safe mode on Saturday, November 28th because of a glitch in the “memory error external bus” of the satellite. Odyssey will remain in safe mode at least until the end of the week, effectively slowing down communication with the two rovers, Spirit and Opportunity.

Odyssey is still operating at normal temperatures and communicating with the control team back on Earth. It stayed in safe mode over the weekend. After a full reboot today, the craft is on the mend and expected to be fully operational later this week.

“This event is a type we have seen before, so we have a known and tested path to resuming normal operations,” said Odyssey Project Manager Philip Varghese of NASA’s Jet Propulsion Laboratory in a press release.

Odyssey has been orbiting Mars since January 2002, mapping the surface and taking global measurements of the planet. Odyssey has also been the link to the Earth for the two rovers since 2004, acting as a communications relay that speeds up the transference of signals between the robots and the control team. Though Spirit and Oppy have their own antennae for communication, Odyssey can communicate with the Earth at 10 times the speed and with a fraction of the energy usage.

This glitch is really nothing new for the satellite – it’s much like having to reboot your laptop when it freezes up. The Mars Reconnaisance Orbiter would be the obvious backup for Odyssey, but the MRO has been in safe mode since August 26th. The MRO rebooted itself four times in 2009, and after the last reboot the spacecraft has stayed in safe mode to prevent any catastrophic damage to its memory.

NASA had planned to uplink files to the MRO to restore it sometime this week, but the uplink and recalibration of the satellite would take over a week, meaning that if Odyssey isn’t back up by the end of the week Spirit and Opportunity are on their own for a little while longer.

Odyssey is a key player in the efforts to free the Spirit rover, which has been stuck in a sand trap since May 1st of this year but is making progress. Because of a wheel stall problem that the control team thinks may be internal, an extrication attempt made on November 28th wasn’t successful. The Spirit control team hadn’t planned on making any more maneuvers to free the rover this week, as they are still analyzing the recent attempts to plan for future efforts at freeing its wheel.

Hopefully, by the end of next week we’ll be seeing two fully-functioning orbiters and a freewheelin’ Spirit.

Source: NASA press release

December 1, 2009May 11, 2015 by Fraser Cain

Mars Video

Here’s a cool Mars video.

This is a Mars video that shows you how you can use Google Mars to explore the red planet.

This is a video of the Mars Exploration Rover program. It shows an animation of the rovers launching and landing on the surface of Mars.

Here’s a cool animation of the Mars Science Laboratory, renamed to the Curiosity Rover.

And this is an animation of the Phoenix Mars Lander which successfully touched down on the surface of Mars in 2008.

We’ve written many articles about Mars for Universe Today. Here’s an article about why Mars is red, and here’s an article about the gravity on Mars.

If you’d like more info on Mars, check out Hubblesite’s News Releases about Mars, and here’s a link to the NASA Mars Exploration home page.

We’ve also recorded several episodes of Astronomy Cast about Mars. Listen here, Episode 52: Mars.

December 1, 2009December 24, 2015 by Fraser Cain

Mars and Venus

Mars and Venus are the two terrestrial planets most similar to Earth. One orbits closer to the Sun, and one orbits more distant to the Sun. But both are visible with the unaided eye, and two of the brightest objects in the night sky.

Venus orbits at an average distance of only 108 million km from the Sun, while Mars is an average of 228 million km. Venus gets as close to Earth as 38 million km, and Mars gets as close as 55.7 million km.

In terms of size, Venus is almost a twin planet of Earth. Its diameter is 12,104 km, which is 95% the diameter of Earth. Mars is much smaller, with a diameter of only 6,792 km. And again, in terms of mass, Venus is almost Earth’s twin. It has 81% the mass of Earth, while Mars only has 10% the mass of Earth.

The climates of Mars and Venus are very different, and very different from Earth as well. Temperatures on the surface of Venus average 461 °C across the entire planet. That’s hot enough to melt lead. While the average temperature on Mars is a chilly -46 °C. This temperature difference comes from the fact that Venus is closer to the Sun, but also because it has a thick atmosphere of heat trapping carbon dioxide. The atmosphere on Venus is nearly 100 times thicker than Earth’s atmosphere at sea level, while the atmosphere on Mars is 1% the thickness of Earth.

Mars is the most studied planet in the Solar System (after the Earth). There have been dozens of missions sent to Mars, including orbiters and rovers. Although many missions have been lost, there have been several that have successfully orbited the planet and several that have landed on the surface. Missions have also been sent to Venus, and you might be surprised to know that the Soviets sent a series of landers called Venera that actually reached the surface of Venus and survived long enough to send back a few photographs.

Mars has two moons, Phobos and Deimos, while Venus has no moons. And neither planet has rings.

We’ve written many articles about Mars and Venus for Universe Today. Here’s an article about how the atmospheres of Mars and Venus leak into space, and a look at Venus wet past.

If you’d like more information on those two planets, here’s a link to NASA’s Solar System Exploration Guide on Venus, and Hubblesite’s News Releases about Mars.

We’ve also recorded several episodes of Astronomy Cast about the planets. Listen here, Episode 50: Venus and Episode 52: Mars.

Reference:
NASA

December 1, 2009December 24, 2015 by Fraser Cain

Mars Pathfinder

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Mars Pathfinder was NASA mission to Mars, which launched on December 4th, 1996 and landed on the surface of Mars on July 4, 1997. Unlike the missions that went before it, the Pathfinder lander was also equipped with a tiny rover called Sojourner, which could venture away from the lander, crawl around the surface of Mars and study rocks up close. It was a relatively inexpensive mission that tested out many of the technologies build into later missions, like the Mars Exploration rovers Spirit and Opportunity.

The purpose of Pathfinder was to prove that the concept of “faster, better and cheaper” missions would work. Pathfinder only cost $150 million and was developed in under 3 years. It was also sent to study the surface of Mars, including the geochemistry of the rocks, the magnetic properties of the surface and the structure of the planet’s atmosphere.

When the Pathfinder mission arrived at Mars, it entered the atmosphere and deployed a parachute. Instead of using retrorockets to land gently on the surface, however, Pathfinder used an airbag system. This allowed it to save fuel; instead of landing gently, it was dropped from an altitude of about 100 meters onto the Martian surface. It bounced several times and came to a rest before opening up like the petals of a flower. Once everything checked out, the tiny Sojourner Rover was deployed onto the surface of Mars.

The area around the Pathfinder site had many rocks, large and small, and the NASA scientists gave them unique names like “Barnacle Bill” and “Yogi”. Sojourner was able to crawl around and study these rocks up close. It was able to study the chemical makeup of the rocks, and confirmed that they formed from past volcanic activity. Over the course of the entire mission, Pathfinder and Sojourner returned 16,500 images and made millions of measurements of the Martian atmosphere.

Pathfinder stopped communicating with Earth after 83 days on the surface of Mars. Its battery was only designed to be recharged 40 times, and once its battery stopped working, the spacecraft was unable to keep its electronics heated in the cold Martian night. After it stopped communicating, NASA decided to name the lander after Carl Sagan. It became The Carl Sagan Memorial Station.

We have written many articles abut the Mars Pathfinder mission for Universe Today. Here’s an article about photos of Mars Pathfinder taken from orbit, and research about a cold and wet early Mars.

Here’s a link to the original mission homepage for the Mars Pathfinder.

We’ve recorded several episodes of Astronomy Cast about missions to Mars. Start here, Episode 92: Missions to Mars, Part 1.

Source: NASA

November 27, 2009December 24, 2015 by Fraser Cain

Who Discovered Mars?

Mars is one of the 5 planets visible with the unaided eye. On any dark night, when Mars is in the sky, it’s easy to see with your own eyes. Ancient people knew about Mars, and long ago discovered that it moves from night to night compared to the stars. So it’s impossible to know who discovered Mars. That would have been one of the first humans.

Perhaps a better question to ask is: who realized that Mars is a planet? And that discovery happened with the idea that the Earth is a planet.

In ancient times, astronomers thought that the Earth was the center of the Universe, and the Sun, Moon, planets and stars orbited around us in a set of crystalline spheres. But the motions of the planets were hard to explain; they would sometimes speed up, stop, and even reverse their direction in the sky.

But the astronomer Nicolaus Copernicus developed the view that it was the Sun that was at the center of the Solar System, and the planets orbited around it. This view neatly explained the strange motions of the planets, since the Earth was also moving around the Sun, and these quirks were really just changes in perception.

Galileo was the first person to view Mars in a telescope, and he saw not much more than a bright disk. He did take many observations over the course of the year and realized that Mars gets closer and more distant, and so larger and smaller in his telescope. As telescopes got bigger and better, astronomers were able to make out the polar ice caps on Mars, and some astronomers incorrectly thought they saw a system of canals crisscrossing the surface of the planet.

But the best views of Mars came with the first robotic exploration of Mars. The first spacecraft to arrive at Mars was NASA’s Mariner 4, launched in 1964. The first spacecraft to go into orbit around Mars was Mariner 9, in 1971. These spacecraft helped take high resolution images that revealed craters, mountains and chasms; the red landscape of Mars that we’re so familiar with today.

We’ve written many articles about the discovery of planets for Universe Today. Here’s an article about the discovery of Uranus, and another about the discovery of Neptune.

If you’d like more information on Mars, check out Hubblesite’s News Releases about Mars, and here’s a link to the NASA Mars Exploration home page.

We’ve also recorded several episodes of Astronomy Cast about Mars. Start here, Episode 52: Mars.

References:
NASA Mars Exploration
NASA: The Mariner Missions

November 25, 2009December 24, 2015 by Nancy Atkinson

New Findings On Allen Hills Meteorite Point to Microbial Life

Scientists caused quite a stir in 1996 when they announced a meteorite had been found in Antarctica that might contain evidence for microscopic fossils of Martian bacteria. While subsequent studies of the now famous Allen Hills Meteorite shot down theories that the Mars rock held fossilized alien life, both sides debated the issue and the meteorite is still being studied. Now, Craig Covault in Spaceflightnow.com reports that a new look at ALH84001 provides “evidence that supports the existence of life on the surface of Mars, or in subsurface water pools, early in the planet’s history.” Covault says we can expect a public announcement by NASA Headquarters within a few days.

Research using a more advanced High Resolution Electron Microscopy than was in existence when the initial findings were made 13 years ago has provided the new evidence. Covault reported that the “laboratory sensors are being focused directly on carbonate discs and associated tiny magnetite crystals present inside the meteorite Allen Hills ALH 84001.” The data reveal information that counters a “wide range of opposing theories as to why the finding should not be supported as biological in origin.”

The new findings were reported in the November issue of the respected journal Geochimica et Cosmochimica Acta, the journal of the Geochemical and Meteoritic Society. The authors include Kathie Thomas-Keprta, Simon Clement, David McKay (who led the original team), Everett Gibson and Susan Wentworth, all of the Johnson Space Center.

Covault said the new work centers on what is called magnetic bacteria that on Earth, and Mars as well, leave distinctively-shaped remnants in the rock. These features test with a high chemical purity more like a biological feature than geological.

For more details, read the article on Spaceflightnow.com

Exciting! Stay tuned…

November 23, 2009December 24, 2015 by Bill Dunford

Cold as Hell with a Chance of Dust Storms: Weather Movies from Mars

Caption: One frame from an animation of weather patterns around the south pole of Mars. Credit: NASA/JPL-Caltech/MSSS

If you think about it, those hypnotizing patterns of swirling clouds you see in TV weather reports are pretty amazing: satellites let us see what’s happening in the skies all over the world. But these days, that kind of global vision even goes beyond the Earth. The Mars Reconnaissance Orbiter makes daily weather observations of the Red Planet, and mission scientists regularly compile the pictures into movies that are available online. The result is that anyone can follow along as fierce dust storms rage across the plains of Mars, clouds cling to the peaks of towering volcanoes and polar ice advances and retreats.

On board the MRO is a wide-angle camera called the Mars Color Imager (MARCI) that scans the face of Mars in both visible and ultraviolet light. MARCI views Mars from pole to pole, snapping dozens of images every day that are combined into a global map with resolution comparable to weather satellites at home.

This daily weather report helps Mars explorers understand day-to-day events, as well as seasonal and annual changes on the Red Planet. Sometimes the weather watch also gives rover drivers a crucial warning when a storm might be headed in the direction of Spirit or Opportunity.

The weather images can be striking and intriguing. This animation shows the south pole of Mars during a period of about a month earlier this year, when storms raged along the retreating edge of frost in the polar cap. You can see giant, swirling clouds of dust, as well as the changing shape of the cap as it shrinks with the approach of Summer.

Malin Space Science Systems is the firm that built and operates MARCI for NASA’s Jet Propulsion Laboratory. They post weekly movies that show a spinning, global view of the most recent Martian weather. You never know what you’ll see each week, but a careful look often turns up water ice clouds, wind storms or the giant canyon Valles Marineris filled to the brim with dust.

The descriptions that Malin scientists write to accompany each movie are fascinating. They sound both as exotic as a science fiction novel–and as routine as your local weatherman’s report on the evening news. One sample:

“A large dust storm moved south down the Acidalia/Chryse/Xanthe corridor, partially spilling into eastern Valles Marineris at the beginning of the week. From there the storm moved over Thaumasia and Argyre, picking up intensity as it moved into the subtropics of Aonia and Icaria/Daedalia… Dust storms and water-ice clouds also formed in the northern mid-latitudes, with more notable activity occurring over Deuteronilus and Utopia. The increased amount of dust activity on the planet has created a haze that lingers in the atmosphere and has caused skies over both Opportunity and Spirit to be hazy during the past week.”

That’s why Mars fascinates. It’s an alien world that in some ways is tantalizing similar to home.

MARCI will be turned back on in early December after a hiatus of a few months. Previous weather movies are still online.

November 23, 2009December 24, 2015 by Nancy Atkinson

Large Ocean, Extensive River Network, Rainfall on Ancient Mars

An enhanced network of river valleys on Mars. Credit: NIU, LPI

Did Mars once have a vast network of river valleys – “canals” if you will – and an ocean that covered most of the planet’s northern hemisphere? A new computer-generated map of the Red Planet provides a more detailed look at the valley networks on Mars, and indicates the networks are more than twice as extensive as had been previously depicted in the only other planet-wide map of the valleys. “All the evidence gathered by analyzing the valley network on the new map points to a particular climate scenario on early Mars,” said Wei Luo, from Northern Illinois University (NIU). “It would have included rainfall and the existence of an ocean covering most of the northern hemisphere, or about one-third of the planet’s surface.”

This is a global map depicting the dissection density of valley networks on Mars, in relation to the hypothesized northern ocean. Credit: NIU, LPI

NIU and the Lunar and Planetary Institute in Houston used an innovative computer program to produce the new map that shows regions dissected by the valley networks roughly form a belt around the planet between the equator and mid-southern latitudes, consistent with a past climate scenario that included precipitation and the presence of an ocean covering a large portion of Mars’ northern hemisphere.

Scientists have previously hypothesized that a single ocean existed on ancient Mars, but the issue has been hotly debated.

Luo and Tomasz Stepinski, a staff scientist at the Lunar and Planetary Institute, publish their findings in the current issue of the Journal of Geophysical Research — Planets.

“The presence of more valleys indicates that it most likely rained on ancient Mars, while the global pattern showing this belt of valleys could be explained if there was a big northern ocean,” Stepinski said.

The researchers created an updated planet-wide map of the valley networks by using a computer algorithm that uses topographic data from NASA satellites and recognizes valleys by their U-shaped topographic signature. “The basic idea behind our method is to flag landforms having a U-shaped structure that is characteristic of the valleys,” Stepinski added. “The valleys are mapped only where they are seen by the algorithm.”

Valley networks on Mars exhibit some resemblance to river systems on Earth, suggesting the Red Planet was once warmer and wetter than present.

The networks were discovered in 1971 by the Mariner 9 spacecraft, but scientists have debated whether they were created by erosion from surface water, which would point to a climate with rainfall, or through a process of erosion known as groundwater sapping. Groundwater sapping can occur in cold, dry conditions.

The large disparity between river-network densities on Mars and Earth had provided a major argument against the idea that runoff erosion formed the valley networks. But the new mapping study reduces the disparity, indicating some regions of Mars had valley network densities more comparable to those found on Earth.

A zoomed-in area comparing the old map of valley networks and the new one. (Left) A satellite image, with color indicating elevation; (center) the old map of valley networks; (right) the new map of valley networks. Credit: Wei Luo, Northern Illinois University

“It is now difficult to argue against runoff erosion as the major mechanism of Martian valley network formation,” Luo said. “When you look at the entire planet, the density of valley dissection on Mars is significantly lower than on Earth,” he said. “However, the most densely dissected regions of Mars have densities comparable to terrestrial values. The relatively high values over extended regions indicate the valleys originated by means of precipitation-fed runoff erosion—the same process that is responsible for formation of the bulk of valleys on our planet.”

“The only other global map of the valley networks was produced in the 1990s by looking at images and drawing on top of them, so it was fairly incomplete and it was not correctly registered with current datum,” Stepinski said. “Our map was created semi-automatically, with the computer algorithm working from topographical data to extract the valley networks. It is more complete, and shows many more valley networks.”

The Martian surface is characterized by lowlands located mostly in the northern hemisphere and highlands located mostly in the southern hemisphere. Given this topography, water would accumulate in the northern hemisphere, where surface elevations are lower than the rest of the planet, thus forming an ocean, the researchers said.

“Such a single-ocean planet would have an arid continental-type climate over most of its land surfaces,” Luo said.

The northern-ocean scenario meshes with a number of other characteristics of the valley networks.

“A single ocean in the northern hemisphere would explain why there is a southern limit to the presence of valley networks,” Luo added. “The southernmost regions of Mars, located farthest from the water reservoir, would get little rainfall and would develop no valleys. This would also explain why the valleys become shallower as you go from north to south, which is the case.

“Rain would be mostly restricted to the area over the ocean and to the land surfaces in the immediate vicinity, which correlates with the belt-like pattern of valley dissection seen in our new map,” Luo said.

Source: EurekAlert