NASA, ESA and ISRO Satellites and Rovers observe Mars atmosphere and Comet Siding Spring

This artist's concept illustration depicts the Comet Siding Spring (2013 A1) flyby Mars and illustrates some of the NASA, ESA and ISRO satellites positioned to record the event.

Credit: Nasa, ESA

A comet the size of a small mountain is about to skim past Mars, and NASA hopes its spacecraft will be able to photograph the once-in-a-million-years encounter.

This March 27, 2014 image provided by NASA, ESA, and J.-Y. Li shows comet C/2013 A1, also known as Siding Spring, as captured by Wide Field Camera 3 on NASA's Hubble Space Telescope. 

Credit: AP Photo /NASA, ESA, J.-Y. Li

The comet, known as Siding Spring (C/2013 A1), is set to hurtle past Mars at a close distance of about 88,000 miles (141,600 kilometers).

The closest pass is expected to happen Sunday at 2:27 pm (1827 GMT).

Astronomers do not expect it will come any where near colliding with Mars, but they do hope it will be close enough to reveal clues about the origins of the solar system.

That is because the comet is believed to have originated billions of years ago in the Oort Cloud, a distant region of space at the outskirts of the solar system.

"Comets such as C/2013 A1 are essentially dirty icy snowballs with rocks and dust embedded in frozen gasses," said Dan Brown, an astronomy expert at Nottingham Trent University.

"It is on its first run towards the center of our solar system and its material is virtually unchanged by the rays of the sun and can give us an insight to the material composition of our early solar system 4.6 billion years ago."

Fast and powdery
The comet is flying through space at a breakneck speed of 122,400 miles per hour.

Another interesting thing about the comet, about a mile wide in diameter, is that it is only about as solid as a pile of talcum powder.

Illustration of the trajectory of Siding Spring, which will come close to Mars on Sunday.

NASA has manuevered its Mars orbiters to the far side of the planet so they won't be damaged by the comet's high-speed debris.

Even as the Mars Reconnaissance Orbiter, Mars Odyssey and MAVEN have been repositioned to avoid hazardous dust, scientists hope they will be able to capture a trove of data about the flyby for Earthlings to study.

NASA's two rovers, Curiosity and Opportunity, will turn their cameras skyward and send back pictures of the comet's pass in the coming days, weeks and months, the US space agency said.

"The orbiters will keep a close eye on the show," said Rebecca Johnson, editor of StarDate magazine.

"They'll study the comet itself, which is a small chunk of ice and rock. They'll also study the cloud of gas and dust around the comet, as well as its long tail," she said.

"And they'll measure how the gas and dust interact with the Martian atmosphere."

The comet has traveled more than one million years to make its first pass by Mars, and will not return for another million years, after it completes its next long loop around the sun.

The comet was discovered by Robert McNaught at ANU's Siding Spring Observatory in January 2013.

Its flyby of Mars is not likely to be visible to sky watchers on Earth.

But the encounter is of great interest to scientists, particularly since there are so many spacecraft on and around Mars to record it.

"As it zips toward the sun, it gives scientists a chance to see a relic from the distant past, a snowball that preserves the same ingredients that gave birth to our own world," said Johnson.

This image shows just how many satellites and probes humanity has sent to Mars. Some more successful than others, and we still have much to learn about our near neighbour.

NASA Science Fleet: Comet Siding Spring C/2013 A1

Credit: NASA

NASA's extensive fleet of science assets, particularly those orbiting and roving Mars, have front row seats to image and study a once-in-a-lifetime comet flyby on Sunday, Oct. 19.

Comet C/2013 A1, also known as comet Siding Spring, will pass within about 87,000 miles (139,500 kilometers) of the Red Planet, less than half the distance between Earth and our moon and less than one-tenth the distance of any known comet flyby of Earth.

Siding Spring's nucleus will come closest to Mars around 2:27 p.m. EDT, hurtling at about 126,000 mph (56 kilometers per second).

This proximity will provide an unprecedented opportunity for researchers to gather data on both the comet and its effect on the Martian atmosphere.

"This is a cosmic science gift that could potentially keep on giving, and the agency's diverse science missions will be in full receive mode," said John Grunsfeld, astronaut and associate administrator for NASA's Science Mission Directorate in Washington.

"This particular comet has never before entered the inner solar system, so it will provide a fresh source of clues to our solar system's earliest days."

Siding Spring came from the Oort Cloud, a spherical region of space surrounding our sun and occupying space at a distance between 5,000 and 100,000 astronomical units.

It is a giant swarm of icy objects believed to be material left over from the formation of the solar system.

Siding Spring will be the first comet from the Oort Cloud to be studied up close by spacecraft, giving scientists an invaluable opportunity to learn more about the materials, including water and carbon compounds, that existed during the formation of the solar system 4.6 billion years ago.

Some of the best and most revealing images and science data will come from assets orbiting and roving the surface of Mars.

Mars Atmosphere and Volatile EvolutioN (MAVEN)

In preparation for the comet flyby, NASA maneuvered its Mars Odyssey orbiter, Mars Reconnaissance Orbiter (MRO), and the newest member of the Mars fleet, Mars Atmosphere and Volatile EvolutioN (MAVEN), to reduce the risk of impact with high-velocity dust particles coming off the comet.

The period of greatest risk to orbiting spacecraft will start about 90 minutes after the closest approach of the comet's nucleus and will last about 20 minutes, when Mars will come closest to the center of the widening trail of dust flying from the comet's nucleus.

"The hazard is not an impact of the comet nucleus itself, but the trail of debris coming from it. Using constraints provided by Earth-based observations, the modeling results indicate that the hazard is not as great as first anticipated."

"Mars will be right at the edge of the debris cloud, so it might encounter some of the particles, or it might not," said Rich Zurek, chief scientist for the Mars Exploration Program at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California.

The atmosphere of Mars, though much thinner that Earth's, will shield NASA Mars rovers Opportunity and Curiosity from comet dust, if any reaches the planet. Both rovers are scheduled to make observations of the comet.

NASA's Mars orbiters will gather information before, during and after the flyby about the size, rotation and activity of the comet's nucleus, the variability and gas composition of the coma around the nucleus, and the size and distribution of dust particles in the comet's tail.

Observations of the Martian atmosphere are designed to check for possible meteor trails, changes in distribution of neutral and charged particles, and effects of the comet on air temperature and clouds.

MAVEN will have a particularly good opportunity to study the comet, and how its tenuous atmosphere, or coma, interacts with Mars' upper atmosphere.

Earth-based and space telescopes, including NASA and ESA's iconic Hubble Space Telescope, also will be in position to observe the unique celestial object.

The agency's astrophysics space observatories, Kepler, Swift, Spitzer, Chandra, and the ground-based Infrared Telescope Facility on Mauna Kea, Hawaii, also will be tracking the event.

NASA's asteroid hunter, the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE), has been imaging, and will continue to image, the comet as part of its operations, and the agency's two Heliophysics spacecraft, Solar TErrestrial RElations Observatory (STEREO) and Solar and Heliophysics Observatory (SOHO), also will image the comet.

The agency's Balloon Observation Platform for Planetary Science (BOPPS), a sub-orbital balloon-carried telescope, already has provided observations of the comet in the lead-up to the close encounter with Mars.

Images and updates will be posted online before and after the comet flyby. Several pre-flyby images of Siding Spring, as well as information about the comet and NASA's planned observations of the event, are available online.

NASA Mars 2020 Rover: SHERLOC to micro-map Mars minerals and carbon rings

This diagram shows components of the investigations payload for NASA's Mars 2020 rover mission. 

Mars 2020 is a mission concept that NASA announced in late 2012 to re-use the basic engineering of Mars Science Laboratory to send a different rover to Mars, with new objectives and instruments, launching in 2020.

Credit: NASA

An ultraviolet-light instrument on the robotic arm of NASA's Mars 2020 rover will use two types of ultraviolet-light spectroscopy, plus a versatile camera, to help meet the mission's ambitious goals, including a search for signs of past life on Mars and selection of rock samples for possible return to Earth.

It is called SHERLOC, for Scanning Habitable Environments with Raman & Luminescence for Organics and Chemicals.

"This instrument uses two distinct detection strategies," said its principal investigator, Luther Beegle of NASA's Jet Propulsion Laboratory in Pasadena, California.

"It can detect an important class of carbon molecules with high sensitivity, and it also identifies minerals that provide information about ancient aqueous environments."

SHERLOC will shine a tiny dot of ultraviolet laser light at a target. This causes two different spectral phenomena to occur, which the instrument captures for analysis.

The first is a distinctive fluorescence, or glow, from molecules that contain rings of carbon atoms. Such molecules may be clues to whether evidence of past life has been preserved.

The second is an effect called Raman scattering, which can identify certain minerals, including ones formed from evaporation of salty water, and organic compounds.

This dual use enables powerful analysis of many different compounds on the identical spot.

A moving mirror in the instrument will shift pointing of the ultraviolet laser beam in a scanning pattern to provide a map of the ingredients at a microscopic scale.

The laser beam has a diameter of 50 microns; about half the thickness of a piece of paper. It will provide information on that scale within a target area about half the breadth of a dime.

This illustration depicts the mechanism and conceptual research targets for an instrument named Scanning Habitable Environments with Raman & Luminescence for Organics and Chemicals, or SHERLOC. 

This instrument has been selected as one of seven investigations for the payload of NASA's Mars 2020 rover mission. 

SHERLOC will be a spectrometer that will provide fine-scale imaging and use an ultraviolet laser to determine fine-scale mineralogy and detect organic compounds. 

NASA's Mars 2020 rover is a mission concept that NASA announced in late 2012 to re-use the basic engineering of Mars Science Laboratory to send a different rover to Mars, with new objectives and instruments, launching in 2020. 

Credit: NASA/JPL-Caltech

Mars Hand Lens Imager (MAHLI) camera

In addition, the instrument will include a contextual camera utilizing hardware originally developed by Malin Space Science Systems, San Diego, for the Mars Hand Lens Imager (MAHLI) camera on NASA's Curiosity Mars rover.

This context imager will enable researchers to correlate the composition information with visible features in the target, resulting in more information than composition alone.

Beegle said, "We'll be able not just to detect these chemicals and minerals with high sensitivity, but we will produce powerful chemical maps."

"For example, we can see whether organics are clumped together or diffuse, and we can correlate minerals with visible veins or grains in the rock."

"This also allows us to integrate our results with the other instruments for even more informational content on the samples."

NASA announced selection of SHERLOC and six other investigations for the Mars 2020 rover's payload on July 31, 2014.

Mars 2020 is a mission concept that NASA announced in late 2012 to re-use the basic engineering of Mars Science Laboratory to send a different rover to Mars, with new objectives and instruments, launching in 2020. 

Credit: NASA/JPL-Caltech

The NASA's Mars 2020 rover mission will be based on the design of the highly successful Mars Science Laboratory rover, Curiosity, which landed almost two years ago, and currently is operating on Mars.

The new rover will carry more sophisticated, upgraded hardware and new instruments to conduct geological assessments of the rover's landing site, determine the potential habitability of the environment, and directly search for signs of ancient Martian life.

Scientists will use the Mars 2020 rover to identify and select a collection of rock and soil samples that will be stored for potential return to Earth by a future mission.

The Mars 2020 mission is responsive to the science objectives recommended by the National Research Council's 2011 Planetary Science Decadal Survey.

The Mars 2020 rover also will help advance our knowledge of how future human explorers could use natural resources available on the surface of the Red Planet.

An ability to live off the Martian land would transform future exploration of the planet. Designers of future human expeditions can use this mission to understand the hazards posed by Martian dust and demonstrate technology to process carbon dioxide from the atmosphere to produce oxygen.

These experiments will help engineers learn how to use Martian resources to produce oxygen for human respiration and potentially for use as an oxidizer for rocket fuel.

NASA MSL: Ancient streambed found on surface of Mars

This set of images compares the Link outcrop of rocks on Mars (left) with similar rocks seen on Earth (right). Credit: NASA

Rounded pebbles on the surface of Mars indicate that a stream once flowed on the red planet, according to a new study by a team of scientists from NASA's Curiosity rover mission, including a University of California, Davis, geologist.

The study will be published in the May 31 issue of the journal Science.

Rounded pebbles of this size are known to form only when transported through water over long distances.

They were discovered between the north rim of the planet's Gale Crater and the base of Mount Sharp, a mountain inside the crater.

The finding represents the first on-site evidence of sustained water flows on the Mars landscape, and supports prospects that the planet could once have been able to host life.

As a co-investigator for NASA's Mars Science Laboratory team, UC Davis geologist and study co-author Dawn Sumner played a key role in choosing Gale Crater as the landing site for Curiosity.

Finding the rounded pebbles, which were deposited more than 2 billion years ago, was a matter of landing in the right place, she said.

"The main reason we chose Gale Crater as a landing site was to look at the layered rocks at the base of Mount Sharp, about five miles away," she said.

"We knew there was an alluvial fan in the landing area, a cone-shaped deposit of sediment that requires flowing water to form. These sorts of pebbles are likely because of that environment. So while we didn't choose Gale Crater for this purpose, we were hoping to find something like this."

The finding comes from Curiosity's exploration of the Mars surface during its first 100 sols (102.7 days on Earth), or Martian days.

During that time, the rover traveled about a quarter mile from its landing site, examining multiple outcrops of pebble-rich slabs.

Curiosity took high-resolution images of these pebbles at three locations known as Goulburn, Link and Hottah.

The grain size, roundness and other characteristics of the pebbles led the researchers to conclude they had been transported by water.

Sumner said the discovery involves some of the most basic principles of geology.

The study area, which has been named 'Hottah', is by all accounts the remains of sediments from the bottom of an ancient stream, which had a relatively strong current. Credit: Malin Space Science Systems

"On the first day of my sedimentary class, I have the students measure grain size and the rounding," Sumner said. "It's simple, and it's important."

Sumner's work in South Africa and Australia studying signs of past microbial life in rocks and her work on living microbial communities in Antarctica helped land her the spot on the Mars Science Laboratory team.

NASA recognized her skills could be critical to the mission's goal: to determine whether there ever could have been life on Mars.

As part of the MSL team, Sumner helped coordinate the first scientific interpretations of what was seen during Curiosity's first few days on Mars, helps direct the rover, via computer, to shoot photographs of the planet, and continues to work on the mission from UC Davis.

NASA Mars Curiosity 3D Stereo View from 'John Klein' to Mount Sharp

Left and right eyes of the Navigation Camera (Navcam) in NASA's Curiosity Mars rover took the dozens of images combined into this stereo scene of the rover and its surroundings. 

The component images were taken during the 166th, 168th and 169th Martian days, or sols, of Curiosity's work on Mars (Jan. 23, 25 and 26, 2013). 

The scene appears three dimensional when viewed through red-blue glasses with the red lens on the left. It spans 360 degrees, with Mount Sharp on the southern horizon.

In the center foreground, the rover's arm holds the tool turret above a target called "Wernecke" on the "John Klein" patch of pale-veined mudstone. 

On Sol 169, Curiosity used its dust-removing brush and Mars Hand Lens Imager (MAHLI) on Wernecke. 

About two weeks later, Curiosity used its drill at a point about 1 foot (30 centimeters) to the right of Wernecke to collect the first drilled sample from the interior of a rock on Mars. 

This anaglyph was made with the images as captured by the Curiosity. Another version with the seams in the sky eliminated and cropped for optimal 3-D viewing can be seen at PIA16925.

Separate left-eye and right-eye mosaics are combined into the stereo view.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Science Laboratory Project for NASA's Science Mission Directorate, Washington. JPL designed and built the project's Curiosity rover and the rover's Navcam.

› Full view

Image credit: NASA/JPL-Caltech

NASA's Mars Curiosity Rover: Discovers Weird 'Hood Ornament'

A close-up of a shiny, wind-sculpted rock photographed by NASA's Mars rover Curiosity on Jan. 30, 2013. 

CREDIT: NASA/JPL-Caltech/Malin Space Science Systems

NASA's Mars rover Curiosity has photographed a shiny, metallic-looking object that bears a passing resemblance to a door handle or a hood ornament.

However, the Curiosity rover has not stumbled onto evidence of an ancient civilization that took the family van to Olympus Mons for vacation.

The object is simply a rock that the wind has sculpted into an interesting shape, scientists said.

Curiosity scientists stated that "The shiny surface suggests that this rock has a fine grain and is relatively hard."

"Hard, fine-grained rocks can be polished by the wind to form very smooth surfaces."

A shiny-looking Martian rock is visible in this image taken by NASA's Mars rover Curiosity's Mast Camera (Mastcam) during the mission's 173rd Martian day, or sol (Jan. 30, 2013).

CREDIT: NASA/JPL-Caltech/Malin Space Science Systems

NASA Curiosity Rover Collects First Martian Bedrock Sample

At the center of this image from NASA's Curiosity rover is the hole in a rock called "John Klein" where the rover conducted its first sample drilling on Mars. 

The drilling took place on Feb. 8, 2013, or Sol 182, Curiosity's 182nd Martian day of operations. 

Several preparatory activities with the drill preceded this operation, including a test that produced the shallower hole on the right two days earlier, but the deeper hole resulted from the first use of the drill for rock sample collection. Image credit: NASA/JPL-Caltech/MSSS.

NASA's Curiosity rover has, for the first time, used a drill carried at the end of its robotic arm to bore into a flat, veiny rock on Mars and collect a sample from its interior. This is the first time any robot has drilled into a rock to collect a sample on Mars.

The fresh hole, about 0.63 inch (1.6 centimeters) wide and 2.5 inches (6.4 centimeters) deep in a patch of fine-grained sedimentary bedrock, can be seen in images and other data Curiosity beamed to Earth Saturday. The rock is believed to hold evidence about long-gone wet environments. In pursuit of that evidence, the rover will use its laboratory instruments to analyze rock powder collected by the drill.

"The most advanced planetary robot ever designed is now a fully operating analytical laboratory on Mars," said John Grunsfeld, NASA associate administrator for the agency's Science Mission Directorate. "This is the biggest milestone accomplishment for the Curiosity team since the sky-crane landing last August, another proud day for America."

For the next several days, ground controllers will command the rover's arm to carry out a series of steps to process the sample, ultimately delivering portions to the instruments inside.

"We commanded the first full-depth drilling, and we believe we have collected sufficient material from the rock to meet our objectives of hardware cleaning and sample drop-off," said Avi Okon, drill cognizant engineer at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Rock powder generated during drilling travels up flutes on the bit. The bit assembly has chambers to hold the powder until it can be transferred to the sample-handling mechanisms of the rover's Collection and Handling for In-Situ Martian Rock Analysis (CHIMRA) device.

Before the rock powder is analyzed, some will be used to scour traces of material that may have been deposited onto the hardware while the rover was still on Earth, despite thorough cleaning before launch.

"We'll take the powder we acquired and swish it around to scrub the internal surfaces of the drill bit assembly," said JPL's Scott McCloskey, drill systems engineer. "Then we'll use the arm to transfer the powder out of the drill into the scoop, which will be our first chance to see the acquired sample."

"Building a tool to interact forcefully with unpredictable rocks on Mars required an ambitious development and testing program," said JPL's Louise Jandura, chief engineer for Curiosity's sample system. "To get to the point of making this hole in a rock on Mars, we made eight drills and bored more than 1,200 holes in 20 types of rock on Earth."

Inside the sample-handling device, the powder will be vibrated once or twice over a sieve that screens out any particles larger than six-thousandths of an inch (150 microns) across. Small portions of the sieved sample will fall through ports on the rover deck into the Chemistry and Mineralogy (CheMin) instrument and the Sample Analysis at Mars (SAM) instrument. These instruments then will begin the much-anticipated detailed analysis.

The rock Curiosity drilled is called "John Klein" in memory of a Mars Science Laboratory deputy project manager who died in 2011. Drilling for a sample is the last new activity for NASA's Mars Science Laboratory Project, which is using the car-size Curiosity rover to investigate whether an area within Mars' Gale Crater has ever offered an environment favorable for life.

NASA MARS Curiosity: Starts Drilling

The percussion drill in the turret of tools at the end of the robotic arm of NASA's Mars rover Curiosity has been positioned in contact with the rock surface in this image from the rover's front Hazard-Avoidance Camera (Hazcam).

The drill was positioned for pre-load testing, and the Hazcam recorded this image during the 170th Martian day, or sol, of Curiosity's work on Mars (Jan. 27, 2013).>br />
CREDIT: NASA/JPL-Caltech
NASA's Mars rover Curiosity is sizing up a target rock and flexing its robotic arm ahead of its first-ever drilling activity on the Red Planet, which should take place in the coming days.

The 1-ton Curiosity rover pressed down on the rock in four different places with its arm-mounted drill Monday (Jan. 27). These "pre-load" tests should allow mission engineers to see if the amount of force applied matches predictions, researchers said.

The six-wheeled robot won't be ready to start boring into the rock until it completes several additional hardware tests and other checks, which should keep the rover busy through at least the end of this week, they added.

NASA Mars Curiosity Night Image: White Lightning

This image of a Martian rock illuminated by white-light LEDs (light emitting diodes) is part of the first set of nighttime images taken by the Mars Hand Lens Imager (MAHLI) camera at the end of the robotic arm of NASA's Mars rover Curiosity. 

MAHLI took the images on Jan. 22, 2012 (PST)

View all NASA images here.

NASA MARS Curiosity: 'Mars Flower' Photo

This photo from the Mars rover Curiosity is a close-up of a transparent rock feature that some have dubbed a "flower." 

Researchers say that its origins are not biological. 

CREDIT: NASA/JPL-Caltech/Malin Space Science Systems

An odd flower-like feature spotted on Mars by NASA's Curiosity rover continues to perplex researchers, who nevertheless stress that its origins are not biological.

The object garnered a lot of attention after Curiosity photographed it last month, with many Internet users quickly dubbing it the "Mars flower."

The feature is actually a rounded, light-colored pebble slightly larger than a grain of sand, but determining its precise mineralogical makeup would require more information, researchers said.

"It could be a lot of things, but without some chemical information to back me up, I'd really hesitate to say what it is," Aileen Yingst, of the Planetary Science Institute in Tucson, Ariz., told reporters today (Jan. 15).

"I'm not trying to be cagey," added Yingst, the deputy principal investigator for Curiosity's Mars Hand Lens Imager, or MAHLI. "I'm just trying to be clear that a light grain could be a lot of different things."



The so-called Mars flower juts from a rock near an outcrop mission scientists have named "John Klein," in honor of a former Curiosity deputy project manager who died in 2011.

The car-size rover is preparing to use its drill for the first time in the area, boring into a John Klein rock over the next two weeks or so.

The outcrop and its environs show many signs of long-ago exposure to liquid water, including water-deposited mineral veins that fill fissures in the rock. John Klein is thus a suitable drilling target for Curiosity, whose main goal is to determine if Mars has ever been capable of supporting microbial life.

The Mars flower is not a sign of life, but it does add to the site's intrigue, researchers said.

"It does indicate that you have, you know, a relatively diverse set of grains just in this one sample," Yingst said.

NASA MARS Curiosity Rover Image

NASA Mars Curiosity: MastCam Image of Phobos moon taking a bite out of the Sun

NASA Mars Rover Curiosity's Mastcam captures the eclipse on Sol 37 (September 13, 2012). 

Credit: NASA/JPL-Caltech/Malin Space Science Systems

People often go to exotic locations to try and get the perfect view of a solar eclipse, but the Curiosity rover on Mars only had to look up to see an eclipse of a different kind.

Careful planning by the mission engineers ensured that the NASA rover had its cameras ready to capture the transit of Mars’s moon Phobos across the face of the Sun.

The partial eclipse occurred on September 13 (Sol (Martian day) 37 of Curiosity's time on the planet) and it took around 15 minutes for Phobos to graze the edge of the Sun.

The NASA Mars Rover Curiosity's MastCam camera is capable of filtering out some sunlight, meaning that it can safely look at the Sun.

Curiosity took more photos of the Mars' two moons crossing the face of the Sun on September 17.

Unlike a total solar eclipse on Earth, the moon Phobos is not large enough to completely block out the Sun’s disc.

Phobos is an irregular shaped moon measuring 27 by 22 by 18 kilometres, so it will only disrupt a portion of the Sun’s light.

In contrast, our Moon is 3,480 kilometres across, is 400 times smaller than the Sun and 400 times closer to Earth than the Sun, meaning that on Earth we can occasionally see a total solar eclipse.

Earth is the only planet in the solar system where a total solar eclipse can occur.

Mars’ moon Deimos is even smaller than Phobos, measuring 15 by 12 by 11 kilometres, and has a higher altitude, meaning that it will blot out far less of the Sun than Phobos when it transits the face of the disc.

Phobos has previously been caught in the act of eclipsing the Sun by the Opportunity rover in December 2010.

Opportunity’s twin, Spirit, also witnessed Phobos fade from the night sky as it passed within Mars’ shadow, in the equivalent of a lunar eclipse.

Phobos orbits Mars at a very low altitude of 9,400 kilometres, so it needs to travel fast in order to stop it from spiralling down towards the red planet.

This high speed means that it orbits Mars three times for every one rotation of the planet.

'Martian Triangle' Visible in Night Sky

Hours before NASA's newest rover Curiosity touches down on Mars tonight, the Red Planet will put on an impressive show in the night sky to mark the historic occasion. NASA's Curiosity rover, which is also called the Mars Science Laboratory, is scheduled to land on the surface of the Red Planet on Sunday night (Aug. 5) at 10:31 p.m. PDT (1:31 a.m. EDT Aug. 6; 0531 GMT). For those planning to stay up for the event, it might help pass the time to see the celestial meet-up in the night sky between Mars, Saturn and the bright star Spica. Spica is the brightest star in the constellation of Virgo, and if conditions are favorable on the night of Curiosity's landing, observers will be able to see it team up with the planets Saturn and Mars to form a "Martian Triangle" that will be visible from almost everywhere on Earth, according to NASA officials. The triangle between Saturn, Mars and Spica will be visible after sunset on Sunday. As the sky turns black, look west to where the setting sun slipped away. The three celestial objects will form a bright equilateral triangle, with angles of about 5 degrees on each side, NASA astronomers said in a statement. Planets Saturn and Mars and Bright Star Spica Form Martian Triangle in the Night Sky Saturn, Mars and Spica will form a "Martian Triangle" in the night sky on Aug. 5, 2012, just hours before NASA's Curiosity rover touches down on the Red Planet.

NASA - Mars Science Laboratory, the Next Mars Rover

With Mars looming ever larger in front of it, NASA's Mars Science Laboratory spacecraft and its Curiosity rover are in the final stages of preparing for entry, descent and landing on the Red Planet at 10:31 p.m. PDT Aug. 5 (1:31 a.m. EDT Aug. 6). 

Curiosity remains in good health with all systems operating as expected. Today, the flight team uplinked and confirmed commands to make minor corrections to the spacecraft's navigation reference point parameters. 

This afternoon, as part of the onboard sequence of autonomous activities leading to the landing, catalyst bed heaters are being turned on to prepare the eight Mars Lander Engines that are part of MSL's descent propulsion system. 

As of 2:25 p.m. PDT (5:25 p.m. EDT), MSL was approximately 261,000 miles (420,039 kilometers) from Mars, closing in at a little more than 8,000 mph (about 3,600 meters per second).

More info at Nasa.gov

ESA Mars Express marks the spot for Curiosity landing

Gale Crater is 154 km wide and is located at latitude 5.4 degrees south and longitude 137.9 degrees east.

This image, taken by the High Resolution Stereo Camera (HRSC) of Mars Express, has a resolution of 100 metres per pixel. It is colour-coded based on a digital terrain model derived from stereo image data.

Credits: ESA/DLR/FU Berlin (G. Neukum).

Oblique view of Mount Sharp inside Gale Crater, with the original and revised landing ellipses marked.

Credits: NASA/JPL-Caltech/ESA/DLR/FU Berlin/MSSS

This artist's concept depicts the moment that NASA's Curiosity rover touches down onto the Martian surface.

The entry, descent, and landing (EDL) phase of the Mars Science Laboratory mission begins when the spacecraft reaches the Martian atmosphere, about 81 miles (131 kilometers) above the surface of the Gale crater landing area, and ends with the rover safe and sound on the surface of Mars.

Entry, descent, and landing for the Mars Science Laboratory mission will include a combination of technologies inherited from past NASA Mars missions, as well as exciting new technologies. Instead of the familiar airbag landing systems of the past Mars missions, Mars Science Laboratory will use a guided entry and a sky crane touchdown system to land the hyper-capable, massive rover.

The sheer size of the Mars Science Laboratory rover (over one ton, or 900 kilograms) would preclude it from taking advantage of an airbag-assisted landing.

Instead, the Mars Science Laboratory will use the sky crane touchdown system, which will be capable of delivering a much larger rover onto the surface. It will place the rover on its wheels, ready to begin its mission after thorough post-landing checkouts.

The new entry, descent and landing architecture, with its use of guided entry, will allow for more precision. Where the Mars Exploration Rovers could have landed anywhere within their respective 93-mile by 12-mile (150 by 20 kilometer) landing ellipses, Mars Science Laboratory will land within a 12-mile (20-kilometer) ellipse!

This high-precision delivery will open up more areas of Mars for exploration and potentially allow scientists to roam "virtually" where they have not been able to before.

In the depicted scene, Curiosity is touching down onto the surface, suspended on a bridle beneath the spacecraft's descent stage as that stage controls the rate of descent with four of its eight throttle-controllable rocket engines.

The rover is connected to the descent stage by three nylon tethers and by an umbilical providing a power and communication connection.

When touchdown is detected, the bridle will be cut at the rover end, and the descent stage flies off to stay clear of the landing site.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, Calif., manages the Mars Science Laboratory Project for the NASA Science Mission Directorate, Washington.
More information about Curiosity is at http://mars.jpl.nasa.gov/msl/.

Credits: NASA/JPL-Caltech

NASA's MSL as seen from Mars Express during MSL's arrival at Mars - YouTube

Celestia animation based on forecast orbital trajectories of ESA's Mars Express, NASA's Mars Science Laboratory and Mars itself during MSL's entry, descent and landing, set for 6 August 2012.

Nasa Mars Curiosity Rover - Matthew Wallace on - YouTube

In this video from a Royal Aeronautical Society lecture on 17 July, Matt Wallace, MSL Flight System Manager, from NASA's Jet Propulsion Laboratory, describes the Mars Curiosity Rover mission.

The Rover is set to touch down on Mars on 6 August, where it will search for signs of life on the Red Planet. In this lecture, Wallace describes the technical challenges, the Rover’s design and answers questions from the informed specialist audience.

Challenges of Getting to Mars: Curiosity's Seven Minutes of Terror - YouTube

The massive, nuclear powered Mars Science Lander is due to land Curiosity on the Martian surface on August 5.

In the intervening months since MSL’s November 2011 launch, NASA engineers have had ample time to ponder in just how many ways things can go wrong.

Already, changes have been made to Curiority’s landing parameters. In a new NASA video, engineers focus on the landing mechanism itself including the novel Sky Crane slated to lower the lab gently to the surface.

These engineers anticipate those “seven minutes of terror” while MSL lands and they can do nothing but wait for word of its survival.

To see more JPL Mars Videos on YouTube, go here

NASA Mars: Simulated View from Curiosity

Curiosity's simulated view of Mars

MARS Rover Curiosity: Astrobiologists Claim Parts Of Mars May Be Habitable

Astrobiological researchers have discovered significant regions below the surface of Mars that could be habitable for Earth-based life.

“Our models tell us that if there is water present in the Martian sub-surface then it could be habitable – as an extensive region of the subsurface is at temperatures and pressures comfortable for terrestrial life,” said the lead author Eriita Jones in a press release.

Their research, which is published today in the journal Astrobiology, could serve as a guide to future Martian exploration missions that are looking for indigenous Martian life.

However, current Mars rovers don’t have the capability to dig deep enough to test the researchers’ findings.

In an earlier paper, the same researchers applied a statistical technique to the Earth to determine where life existed on Earth and where it didn’t.

They then used the techniques from that earlier study and applied them to Mars. What they found is that about 3% of the total volume of Mars is capable of supporting Earth-based lifeforms.

That may not sound like a lot – until you consider that only 1% of the Earth’s volume is inhabited.

It will be interesting to see if future generations of Martian rovers will have the capability to follow up on this research.

I’d be curious to see if the new rover, Curiosity, will be near one of the regions that these researchers uncovered. One of that rover’s goal is to look for ideal places for future rover missions to search for life.

If Curiosity is able to find any signs of life at all near regions identified in this paper, that would make it an excellent roadmap for future Martian missions.