Radar sounding is opening up the third dimension for planetary exploration. First tried on Mars, the technique’s success is prompting scientists to think of all the other places in the Solar System where they would like to use radar sounders.

Credits: Jason Craig/JPL

17 April 2008
ESA’s Mars Express radar sounder, MARSIS, has looked beneath the martian surface and opened up the third dimension for planetary exploration. The technique’s success is prompting scientists to think of all the other places in the Solar System where they would like to use radar sounders.

No matter how accurate a camera is, it can only map a planet’s surface. To retrieve information about the underground realm, planetary scientists in the past would have thought it necessary to land on the surface and start digging.

But that would only be good for a single spot on a large planet and the first few decimetres of the surface. To get the global picture of the subsurface they need a radar sounder, such as the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS), to find the best spots for the future landers to go and dig.

MARSIS is built to map the distribution of liquid and solid water in the upper portions of martian crust. If reservoirs of water are detected, it will help us understand the hydrological, geological, climatic and possibly biological evolution of Mars. The radar experiment works because every time a radar wave crosses a boundary between different substances, it generates an echo that the orbiter detects.

A successful experiment

South polar layered deposit (SPLD) on Mars.

The Mars Express radar experiment, MARSIS, was designed to penetrate deep and it has delivered on its promise. The above figure shows the base of the SPLD at the deepest recorded point of 3.7 km. In contrast, The Shallow Subsurface Radar (SHARAD) on NASA’s Mars Reconnaissance Orbiter designed as a high-resolution radar for a maximum penetration of 1 km has difficulty detecting the SPLD base. The two complementary instruments work together to discover hidden martian secrets.

Credits: MARSIS: ESA/NASA/ASI/JPL-Caltech/University of Rome; SHARAD: NASA/JPL-Caltech/ASI/University of Rome/Washington Universtiy in St. Louis

MARSIS was an experiment in every sense of the word. “It was a leap into the unknown,” says Ali Safaeinili, MARSIS co-investigator at the Jet Propulsion Laboratory (JPL), California, USA.

No one had ever used a radar sounder from orbit on another planet before. So the team could not even be sure whether it would work as planned. The subsurface of the planet might have been too opaque to the radar waves or the upper levels of martian atmosphere (ionosphere) might have distorted the signal too much to be useful. Thankfully, none of this happened.

“We have demonstrated that the polar caps at Mars are mostly water ice, and produced an inventory so now we know exactly how much water there is,” says Roberto Orosei, MARSIS Deputy Principal Investigator, IASF-INAF, Italy.

While MARSIS is still collecting data, a follow-up instrument is already operating at Mars. The Shallow Subsurface Radar (SHARAD) on NASA’s Mars Reconnaissance Orbiter works at higher frequencies than MARSIS and can see more details in the signals it receives from the underground layers, at the cost of shallower penetration.

Elsewhere in the Solar System...

Armed with a better understanding of how planetary radar sounders work, the MARSIS team is beginning to look further afield in the Solar System, to other bodies that might benefit from radar investigation. One obvious target is Jupiter’s icy moon, Europa.

A MARSIS-type experiment in orbit around Europa could probe its icy crust to help understand the puzzling features we see on the surface. It may even see the interface at the bottom of the ice where an ocean is expected to begin. “At the south pole of Mars, we are seeing through ice 3.7 km thick. A small calculation shows that we could see through ice down to 20 km or more thick at Mars,” says Safaeinili.

At Saturn’s moon, Titan, penetrating radar could be used to measure the depths of the hydrocarbon lakes that the Cassini spacecraft has detected. It could also probe the structure beneath the enigmatic geysers that Cassini has observed on another one of Saturn’s satellites, Enceladus. “Radar sounders are very well suited to exploring icy worlds,” says Orosei.

This is an impression of the completely deployed MARSIS experiment on board ESA's Mars Express orbiter. Its two 20-metre booms and the 7-metre booms are sprung out and locked into place.

The MARSIS experiment will map the Martian sub-surface structure to a depth of a few kilometres. The instrument's 40-metre long antenna booms will send low frequency radio waves towards the planet, which will be reflected from any surface they encounter.

Credits: ESA

But not just for icy moons. Asteroids and comets could be thoroughly scanned by a radar sounder, producing three-dimensional maps of their interior– perhaps exactly the data we will need if, one day, we have to nudge one out of Earth’s way.

MARSIS has served as an excellent example of international collaboration between Europe and America. Increasingly, such collaborations are set to become a positive feature of our joint exploration of space.

Likewise, radar sounding will become an essential component of future planetary missions. In the near term, planetary scientists can look forward to more results from MARSIS. “The analysis is not concluded yet,” says Orosei. In fact, while MARSIS is still collecting data, everyone concerned expects more surprises.


Notes:

Mars Express has been orbiting the red planet since December 2003. It carries seven scientific experiments, including MARSIS. The primary purpose of MARSIS is to investigate the subsurface of Mars up to a depth of 5 km in order to detect buried materials, such as water ice or liquid. It is the first instrument ever designed to actually look below the surface of Mars.

MARSIS was developed jointly by the Italian Space Agency and NASA, under the scientific supervision of the University of Rome 'La Sapienza', in partnership with JPL and the University of Iowa, USA. The Shallow Subsurface Radar on NASA's Mars Reconnaissance Orbiter was provided by the Italian Space Agency (ASI). Its operations are led by the University of Rome and its data is analysed by a joint U.S.-Italian science team.

For more information:

Ali Safaeinili, MARSIS Co-Investigator, Jet Propulsion Laboratory, USA
Email: Ali.Safaeinili @ jpl.nasa.gov

Roberto Orosei, Deputy Principal Investigator, IASF-INAF, Italy
Email: Roberto.Orosei @ iasf-roma.inaf.it

Agustin Chicarro, ESA Mars Express Project Scientist
E-mail: Agustin.Chicarro @ esa.int

Source: ESA - Mars Express

25 April 2008

The High Resolution Stereo Camera on board ESA’s Mars Express orbiter imaged Nepenthes Mensae, a river delta on Mars, on 22 January 2008.

The data was acquired in the region lying at approximately 3° north and 121° east with a ground resolution of 15 m/pixel.

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

The High Resolution Stereo Camera on board ESA’s Mars Express orbiter imaged the region of Nepenthes Mensae, a river delta on Mars, on 22 January 2008. The region is located in the eastern hemisphere of Mars, close to the boundary between the northern lowlands and the southern highlands.

The data was acquired in the region lying at approximately 3° north and 121° east with a ground resolution of 15 m/pixel.

Context map of Nepenthes Mensae, lying at approximately 3° north and 121° east on Mars.

Credits: FU Berlin/ MOLA

The southern part of the image shows a structure reminiscent of a river delta on Earth whose material was eroded from a valley, about 30 km long and up to 1000 m deep. This formed a fan-shaped deposit at the mouth of the valley. The rim of the deposit stands roughly 300 m above the floor of the depression.

The High Resolution Stereo Camera on board ESA’s Mars Express orbiter imaged Nepenthes Mensae, a river delta on Mars, on 22 January 2008.

The data was acquired in the region lying at approximately 3° north and 121° east with a ground resolution of 15 m/pixel.

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

The resemblance of the structure to river deltas on Earth suggests that it was formed by a similar mechanism. Scientists believe that sediment transported by water was deposited as the flow of the water slowed down where the channel widened and met the mouth of the river.

This is an ortho-image of Nepenthes Mensae. The image is overlaid with elevation data from an HRSC-derived high-resolution digital terrain model (DTM).

In an ortho-image, the projecting rays are perpendicular to the plane of projection. This corrects any deformations introduced by an imaging camera. Such an image can be fitted directly on to a map.

The High Resolution Stereo Camera on board ESA’s Mars Express orbiter imaged Nepenthes Mensae, a river delta on Mars, on 22 January 2008.

The data was acquired in the region lying at approximately 3° north and 121° east with a ground resolution of 15 m/pixel.

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

The pictures show that the region was affected by two episodes of flooding. The first episode left behind a cone-shaped deposit, reaching far out into the lowlands. The second episode formed the fan with the distinct margin. This margin could indicate the location where sediments flowed into a standing body of water or ice.

The High Resolution Stereo Camera on board ESA’s Mars Express orbiter imaged Nepenthes Mensae, a river delta on Mars, on 22 January 2008.

The data was acquired in the region lying at approximately 3° north and 121° east with a ground resolution of 15 m/pixel.

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

Numerous hills and flat-topped mountains visible in the central part of the depression are remnants of the material that was present in the area. The material was then eroded forming the depression, leaving behind the elevations visible today.

The High Resolution Stereo Camera on board ESA’s Mars Express orbiter imaged Nepenthes Mensae, a river delta on Mars, on 22 January 2008.

The data was acquired in the region lying at approximately 3° north and 121° east with a ground resolution of 15 m/pixel.

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

The colour scenes have been derived from the three HRSC-colour channels and the nadir channel. The perspective views have been calculated from the digital terrain model derived from the stereo channels.

The High Resolution Stereo Camera on board ESA’s Mars Express orbiter imaged Nepenthes Mensae, a river delta on Mars, on 22 January 2008.

The data was acquired in the region lying at approximately 3° north and 121° east with a ground resolution of 15 m/pixel.

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

The anaglyph (3D) image was calculated from the nadir and one stereo channel.

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

The black and white high-resolution images were derived from the nadir channel which provides the highest detail of all channels.

The High Resolution Stereo Camera on board ESA’s Mars Express orbiter imaged Nepenthes Mensae, a river delta on Mars, on 22 January 2008.

The data was acquired in the region lying at approximately 3° north and 121° east with a ground resolution of 15 m/pixel.

The southern part of the image shows a structure reminiscent of a river delta on Earth (1) whose material was eroded from a valley, about 30 km long and upto 1000 m deep (2). This formed a fan-shaped deposit at the mouth of the valley. The rim of the deposit stands roughly 300 m above the floor of the depression.

The resemblance of the structure to river deltas on Earth suggests that it was formed by a similar mechanism. Scientists believe that sediment transported by water was deposited as the flow of the water slowed down where the channel widened and met the mouth of the river.

The pictures show that the region was affected by two episodes of flooding. The first left a cone-shaped deposit, reaching far out into the lowland. The second episode formed the fan with the distinct margin. This margin could indicate the location where sediments flowed into a standing body of water or ice.

Numerous hills and flat-topped mountains visible in the central part of the depression (3) are remnants of the material that was present in the area. The material was then eroded forming the depression, leaving behind the elevations visible today.

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

For more information on Mars Express HRSC images, please read ESA's updated FAQ (frequently asked questions).

Source: ESA - Space Science - Mars Express

Mars Express left Earth for Mars on a six-month journey in June 2003, when the positions of the two planets made for the shortest possible route, a condition that occurs once every twenty-six months. The intrepid spacecraft was launched from the Baikonur Cosmodrome in Kazakhstan onboard a Russian Soyuz/Fregat launcher. It completed the interplanetary cruise, achieving a velocity of 10 800 km/h relative to Earth, in December 2003. Five days before arrival, Mars Express released the Beagle 2 lander, which was subsequently lost. Since entering its operational, near-polar orbit, Mars Express has operated perfectly, delivering some of the most spectacular and scientifically valuable results ever received from the Red Planet.

Credits: ESA - Illustration by Medialab

29 April 2008
Artificial intelligence (AI) being used at the European Space Operations Centre is giving a powerful boost to ESA's Mars Express as it searches for signs of past or present life on the Red Planet.

Since January 2004, Mars Express has been using its sophisticated instruments to study the atmosphere, surface and subsurface of Mars, confirming the presence of water and looking for other signatures of life on and below the Red Planet's rocky terrain.

The spacecraft generates huge volumes of scientific data, which must be downloaded to Earth at the right time and in the correct sequence, otherwise data packets can be permanently lost when the limited on-board memory is overwritten by newly collected data.

Traditionally, data downloading was managed using human-operated scheduling software to generate command sequences sent to Mars Express, telling it when to dump specific data packets. "This is tedious, time-consuming and never really eliminated the occasional loss - forever - of valuable science data," says Alessandro Donati, Head of the Advanced Mission Concepts and Technologies Office at ESA's Space Operations Centre (ESOC), Darmstadt, Germany.

'Smart' solution to complex delivery problem

The MEXAR2 tool in use in the Mars Express mission planning room at ESA's Space Operations Centre (ESOC), in Darmstadt, Germany. MEXAR2 uses artificial intelligence techniques to optimise data downloading from Mars Express, reducing workload by over 50% and largely eliminating data loss.

Credits: ESA

But since 2005, AI researchers at Italy's Institute for Cognitive Science and Technology (ISTC-CNR) led by Dr Amedeo Cesta and mission planners and computer scientists at ESOC have been developing a solution to the complex Mars Express scheduling problem by applying artificial intelligence (AI) techniques to the problem.

The result of this work is a new 'smart' tool, dubbed MEXAR2 ('Mars Express AI Tool'), which is now an integral part of the Mars Express mission planning system.

MEXAR2 works by intelligently projecting which on-board data packets might be later lost due to memory conflicts, optimising the data download schedule and generating the commands needed to implement the download. "With MEXAR2, any loss of stored data packets has largely been eliminated," says Fred Jansen, ESA's mission manager for Mars Express.

ESA's Perth station is located 20 kilometres north of Perth (Australia) on the campus of the Perth International Telecommunications Centre (PITC), which is owned by Telstra, and operated by Xantic.

Credits: ESA

MEXAR2 has reduced the mission planning team's workload considerably - by 50 percent compared to the old manual method - for generating workable downlink plans. "And because it optimises bandwidth used to receive data on Earth, we have been able to free expensive ground station time for other missions," says Michel Denis, Mars Express Spacecraft Operations Manager at ESOC.

MEXAR2 recently won the 'best application' award at ICAPS 2007, a benchmark international conference for AI planning & scheduling technology.

Europe's first deep-space mission to fly with AI

AI provides solutions for complex problems, and has now entered the space mission operations field as a value-adding technology. "Mars Express is the first European deep-space exploration mission to fly using an AI tool on the ground, and the technology is boosting science return while reducing time and resource costs," adds Donati.

EThe ExoMars rover will be ESA's field biologist on Mars. Its aim is to further characterise the biological environment on Mars in preparation for robotic missions and then human exploration.

This mission calls for the development of a Mars orbiter, a descent module and a Mars rover. The Mars orbiter will have to be capable of reaching Mars and putting itself into orbit around the planet. On board will be a Mars rover within a descent module.

The Mars descent module will deliver the rover to a specific location by using an inflatable braking device or parachute system.

Using conventional solar arrays to generate electricity, the Rover will be able to travel a few kilometres over the rocky orange-red surface of Mars. The vehicle will be capable of operating autonomously by using onboard software and will navigate by using optical sensors. Included in its approximately 40 kg exobiology payload will be a lightweight drilling system, a sampling and handling device, and a set of scientific instruments to search for signs of past or present life.

Credits: ESA

With MEXAR2's proven success, scientists at both ESOC and ISTC-CNR are working to apply the current AI technology to other problems.

Successful recent work includes the reverse problem of how to optimise the upload of commands to Mars Express, in a project dubbed - somewhat tongue-in-cheek - as 'RAXEM' - for the 'reverse of MEXAR'.

ESA-developed AI technology will also be applied to the 'Advanced Planning & Scheduling Initiative', which is designed to provide AI benefits to other areas and missions, including long term observation planning for ESA's Integral, space-borne gamma-ray observatory.

"It's possible to apply the same AI concepts to future missions, like ExoMars, Europe's first planetary rover mission to the Red Planet," says Donati, adding, "Today's achievement is the starting point for implementing new on-board autonomy concepts for ESA's challenging missions of the future."

Source: ESA - Mars Express

16 May 2008

The High-Resolution Stereo Camera (HRSC) onboard the ESA spacecraft Mars Express obtained images focusing on a depression that displays a crater at the end of the long, winding valley, Mamers Valles.

The data was obtained on 5 August 2006 with a ground resolution of approximately 14 m/per pixel. The image is centred at approximately 39° north and 17° east on the planet.

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

The High-Resolution Stereo Camera (HRSC) onboard the ESA spacecraft Mars Express obtained images of a region at the end of Mamers Valles, a long, winding valley. The focus is on a circular depression that contains a crater.

The High-Resolution Stereo Camera (HRSC) onboard the ESA spacecraft Mars Express obtained images focusing on a depression that displays a crater at the end of the long, winding valley, Mamers Valles.

The data was obtained on 5 August 2006 with a ground resolution of approximately 14 m/per pixel. The images are centred at approximately 39° north and 17° east on the planet.

Credits: FU Berlin/ MOLA

The data was obtained on 5 August 2006 with a ground resolution of approximately 14 m/pixel. The images are centred at approximately 39° north and 17° east on the planet.

The High-Resolution Stereo Camera (HRSC) onboard the ESA spacecraft Mars Express obtained images focusing on a depression that displays a crater at the end of the long, winding valley, Mamers Valles.

The data was obtained on 5 August 2006 with a ground resolution of approximately 14 m/per pixel. The image is centred at approximately 39° north and 17° east on the planet.

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

The circular depression seen in the images is approximately 30 km wide and 1400 m deep. It lies at the south-eastern end of Mamers Valles.

The High-Resolution Stereo Camera (HRSC) onboard the ESA spacecraft Mars Express obtained images focusing on a depression that displays a crater at the end of the long, winding valley, Mamers Valles.

The data was obtained on 5 August 2006 with a ground resolution of approximately 14 m/per pixel. The image is centred at approximately 39° north and 17° east on the planet.

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


The valley of Mamers Valles is approximately 1000 km long, running along the boundary between the northern lowlands and southern highlands in the region of Deuteronilus Mensae.

The High-Resolution Stereo Camera (HRSC) onboard the ESA spacecraft Mars Express obtained images focusing on a depression that displays a crater at the end of the long, winding valley, Mamers Valles.

The data was obtained on 5 August 2006 with a ground resolution of approximately 14 m/per pixel. The image is centred at approximately 39° north and 17° east on the planet.

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

Scientists term a region such as Mamers Valles ‘fretted terrain’ because it shows numerous deep and wide labyrinth-like valleys and circular depressions. The depressions often show structures formed by liquid flowing on the floor.

This is an ortho-image of Mamers Valles.

The HRSC onboard the ESA spacecraft Mars Express obtained images focusing on a depression that displays a crater at the end of the long, winding valley, Mamers Valles. The data was obtained on 5 August 2006 with a ground resolution of approximately 14 m/per pixel. The image is centred at approximately 39° north and 17° east on the planet.

The ortho-image was rectified using elevation data derived from an High-Resolution Stereo Camera (HRSC) -derived high-resolution Digital Terrain Model (DTM) so that distortions introduced during imaging are corrected. Such an image can be used to derive maps. Elevation data from the DTM has been colour-coded and overlain on the ortho-image so that elevation data and the image itself are displayed in a single scene.

The scale is in metres.

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

The structures formed by the flows are thought to be ice-rich debris flows. They show some resemblance to block glaciers seen on Earth

The High-Resolution Stereo Camera (HRSC) onboard the ESA spacecraft Mars Express obtained images focusing on a depression that displays a crater at the end of the long, winding valley, Mamers Valles.

The data was obtained on 5 August 2006 with a ground resolution of approximately 14 m/pixel. The image is centred at approximately 39° north and 17° east on the planet.

The valley of Mamers Valles is approximately 1000 km long, running along the boundary between the northern lowlands and southern highlands in the region of Deuteronilus Mensae.

Scientists term a region such as Mamers Valles ‘fretted terrain’ because it shows numerous deep and wide labyrinth-like valleys and circular depressions which often show structures formed by flowing liquid on their even floors.

The structures formed by the flows are thought to be ice-rich debris flows. They show some resemblance to block glaciers seen on Earth.

The patches of rock at the centre of the depression are thought to be remnants of rock detached from the flanks of the depression and transported into its centre (2).

The wrinkle ridges (3), as the name indicates, are formed by compressive forces acting on the surface. The dark coloured material inside the crater (4) could have formed formed in-situ or was transported by the wind.

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

The patches of rock at the centre of the depression are thought to be remnants of rock that were detached from the flanks of the depression and transported to the centre.

The High-Resolution Stereo Camera (HRSC) onboard the ESA spacecraft Mars Express obtained images focusing on a depression that displays a crater at the end of the long, winding valley, Mamers Valles.

The data was obtained on 5 August 2006 with a ground resolution of approximately 14 m/per pixel. The image is centred at approximately 39° north and 17° east on the planet.

This (3D) anaglyph image was calculated from the nadir and one stereo channel. The black and white high-resolution images were derived form the nadir channel which provides the highest level of detail.

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

The wrinkle ridges, as the name indicates, are formed by compressive forces acting on the surface. The dark coloured material inside the crater could have formed in-situ or may have been transported by the wind.

The colour scenes have been derived from the three HRSC-colour channels and the nadir channel. The perspective views have been calculated from the Digital Terrain Model derived from the stereo channels.


The anaglyph image was calculated from the nadir and one stereo channel; stereoscopic glasses are required to view it. The black-and-white high-resolution images were derived form the nadir channel, which provides the highest level of detail.

For more information on Mars Express HRSC images, please read ESA's updated FAQ (frequently asked questions).

Source: ESA - Space Science - Mars Express

14 July 2008

The High-Resolution Stereo Camera (HRSC) on board ESA’s Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet. Echus Chasma is the source region of Kasei Valles which extends 3000 km to the north. The data was acquired on 25 September 2005. The pictures are centred at about 1° north and 278° east and have a ground resolution of approximately 17 m/pixel.

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

The High-Resolution Stereo Camera (HRSC) on board ESA’s Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet.

The data was acquired on 25 September 2005. The pictures are centred at about 1° north and 278° east and have a ground resolution of approximately 17 m/pixel.

The High-Resolution Stereo Camera (HRSC) on board ESA’s Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet. Echus Chasma is the source region of Kasei Valles which extends 3000 km to the north. The data was acquired on 25 September 2005. The pictures are centred at about 1° north and 278° east and have a ground resolution of approximately 17 m/pixel.

Credits: FU Berlin/ MOLA

Echus Chasma is an approximately 100 km long and 10 km wide incision in the Lunae Planum high plateau north of Valles Marineris, the ‘Grand Canyon’ of Mars. Echus Chasma is the water source region of Kasei Valles, which extends thousands of kilometres to the north, and its southern-most part.

The High-Resolution Stereo Camera (HRSC) on board ESA’s Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet. Echus Chasma is the source region of Kasei Valles which extends 3000 km to the north.

The data was acquired on 25 September 2005. The pictures are centred at about 1° north and 278° east and have a ground resolution of approximately 17 m/pixel.

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

Echus Chasma is bounded to the west by the Echus Chasma plateau which lies about 4 km above the Echus Chasma floor. On the plateau are deeply incised valleys which connect to the Echus Chasma valley.

Ortho-image of Echus Chasma.

The High-Resolution Stereo Camera (HRSC) on board ESA’s Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet. Echus Chasma is the source region of Kasei Valles which extends 3000 km to the north. The data was acquired on 25 September 2005. The pictures are centred at about 1° north and 278° east and have a ground resolution of approximately 17 m/pixel.

The ortho-image was rectified using elevation data derived from a high-resolution Digital Terrain Model, or DTM (obtained from HRSC data), such that distortions introduced during imaging are corrected. Such an image can be used to derive maps. Elevation data from the DTM has been colour-coded and overlain on the ortho-image so that elevation data and the image itself are displayed in a single scene.

The scale is in metres.

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

The images of the Echus Chasma plateau show valleys that are about 10 km long and 1000 m deep. The main valley, Kasei Valles, is about 4 km in depth. The smaller valleys, also called sapping canyons, originate from the discharge of groundwater.

The High-Resolution Stereo Camera (HRSC) on board ESA’s Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet. Echus Chasma is the source region of Kasei Valles which extends 3000 km to the north. The data was acquired on 25 September 2005. The pictures are centred at about 1° north and 278° east and have a ground resolution of approximately 17 m/pixel.

The images show valleys that are about 10 km long and 1000 m deep (1). The main valley, Kasei Valles, is about 4 km in depth. The smaller valleys, also called sapping canyons, originate from the discharge of groundwater.

A prominent, sickle-shaped (about 25 km-long) dike is visible in the centre of the image (2). Dikes form when magma rises up through fissures in the overlying rock or penetrates existing rock layers. This indicates that the region must have been volcanically active in the past. The magmatic rock is usually quite resistant to weathering and is able to endure erosion.

Two impact craters with a diameter of approximately 8 km are located south-east of the dike (3). The eastern crater was partly eroded as the valley formed. A large portion of the crater collapsed into the valley and its debris was removed.

The dark material shows a network of light-coloured, incised valleys (4) that look similar to drainage networks known on Earth. It is still debated whether the valleys originate from precipitation, groundwater springs or liquid or magma flows on the surface.

An impressive cliff, up to 4000 m high, is located in the eastern part of Echus Chasma(5). Gigantic water falls may once have plunged over these cliffs on to the valley floor. The remarkably smooth valley floor was later flooded by basaltic lava.

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

One possible indication for volcanic activity in the past is be a sickle-shaped, about 25-km long dike in the centre of the image (feature 2 in the annotated image). Dikes are rock formations of volcanic origin. They are formed when magma rises up through fissures in the overlying rock or penetrates existing rock layers. The magmatic rock is usually resistant to weathering and is able to endure erosion.

The High-Resolution Stereo Camera (HRSC) on board ESA’s Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet. Echus Chasma is the source region of Kasei Valles which extends 3000 km to the north. The data was acquired on 25 September 2005. The pictures are centred at about 1° north and 278° east and have a ground resolution of approximately 17 m/pixel.

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

Two impact craters with a diameter of approximately 8 km are located south-east of the dike. The eastern crater was partly eroded as the valley formed. A large portion of the crater collapsed into the valley and its debris was removed.

The High-Resolution Stereo Camera (HRSC) on board ESA’s Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet. Echus Chasma is the source region of Kasei Valles which extends 3000 km to the north. The data was acquired on 25 September 2005. The pictures are centred at about 1° north and 278° east and have a ground resolution of approximately 17 m/pixel.

The dark material shows a network of light-coloured, incised valleys that look similar to drainage networks known on Earth. It is still debated whether the valleys originate from precipitation, groundwater springs or liquid or magma flows on the surface.

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

For more images, see page two (below)

Source: ESA - Space Science - Mars Express

14 July 2008

The High-Resolution Stereo Camera (HRSC) on board ESA’s Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet. Echus Chasma is the source region of Kasei Valles which extends 3000 km to the north. The data was acquired on 25 September 2005. The pictures are centred at about 1° north and 278° east and have a ground resolution of approximately 17 m/pixel.

An impressive cliff, up to 4000 m high, is located in the eastern part of Echus Chasma. Gigantic water falls may once have plunged over these cliffs on to the valley floor. The remarkably smooth valley floor was later flooded by basaltic lava.

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

A 4000-m-high cliff marks the edge of the source area of Kasei Valles in its western part. Gigantic water falls may have once plunged over these cliffs on to the valley floor. The original shoreline is still partially visible. The remarkably smooth valley floor was later flooded by basaltic lava.

Images acquired in different orbits were combined to create the image mosaics, the map, as well as the colour-coded elevation model.

The High-Resolution Stereo Camera (HRSC) on board ESA’s Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet. Echus Chasma is the source region of Kasei Valles which extends 3000 km to the north. The data was acquired on 25 September 2005. The pictures are centred at about 1° north and 278° east and have a ground resolution of approximately 17 m/pixel.

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

The colour scenes have been derived from the three HRSC-colour channels and the nadir channel. The perspective views have been calculated from the digital terrain model derived from the stereo channels.

The High-Resolution Stereo Camera (HRSC) on board ESA’s Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet. Echus Chasma is the source region of Kasei valles which extends 3000 km to the north.

The data was acquired on 25 September 2005. The pictures are centred at about 1° north and 278° east and have a ground resolution of approximately 17 m/pixel.

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

The anaglyph image was calculated from the nadir and one stereo channel. The black and white high resolution images were derived from the nadir channel, which provides the highest level of detail.

The High-Resolution Stereo Camera (HRSC) on board ESA’s Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet. Echus Chasma is the source region of Kasei Valles which extends 3000 km to the north. The data was acquired on 25 September 2005. The pictures are centred at about 1° north and 278° east and have a ground resolution of approximately 17 m/pixel.

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


The High-Resolution Stereo Camera (HRSC) on board ESA’s Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet. Echus Chasma is the source region of Kasei Valles which extends 3000 km to the north. The data was acquired on 25 September 2005. The pictures are centred at about 1° north and 278° east and have a ground resolution of approximately 17 m/pixel.

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


The High-Resolution Stereo Camera (HRSC) on board ESA’s Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet. Echus Chasma is the source region of Kasei valles which extends 3000 km to the north.

The data was acquired on 25 September 2005. The pictures are centred at about 1° north and 278° east and have a ground resolution of approximately 17 m/pixel.

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

Source: ESA - Space Science - Mars Express

16 July 2008

An image of Phobos by the High-Resolution Stereo Camera on board Mars Express on 10 January 2007.

The larger and inner of the two martian moons is seen here floating just above the martian limb. The image has been enhanced slightly to bring out the detail on the moon.

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

Scientists and engineers are preparing ESA’s Mars Express for several close fly-bys of the Martian moon Phobos. Passing within 100 km of the surface, Mars Express will conduct some of the most detailed investigations of the moon to date.

The series of fly-bys will take place between 12 July and 3 August. During the second encounter, the spacecraft will fly within 273 km of the surface. Six days later, Mars Express will close to within just 97 km.

Although the Red Planet itself has been studied in detail, very little is known about the origins of its moons, Phobos and Deimos. It is unclear if the moons are actually asteroids that were captured by Mars’s gravity and never left its orbit. Another possibility is that Phobos and Deimos are actually surviving planetesimals, bodies which formed the planets of the Solar System. They may also be remnants of an impact of a large object on Mars.

As Mars Express closes-in on Phobos, the data gathered will help scientists answer these questions.

This image, taken by the High Resolution Stereo Camera (HRSC) on board ESA’s Mars Express spacecraft, is one of the highest-resolution pictures so far of the Martian moon Phobos.

The image shows the Mars-facing side of the moon, taken from a distance of less than 200 kilometres with a resolution of about seven metres per pixel during orbit 756, on 22 August 2004.

This colour image was calculated from the three colour channels and the nadir channel on the HRSC. Due to geometric reasons the scale bar is only valid for the centre of the image.

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

Mars Express has flown close to Phobos in the past, but this is the first time that the spacecraft will be less than 100 km from the moon. To achieve this proximity to Phobos, spacecraft operations engineers and scientists have been working together to optimise the trajectory of Mars Express to obtain optimum science results – this is not the case for routine fly-bys.

As it flies by at a distance of 97 km, Mars Express will image areas of Phobos that have never been glimpsed before. The High-Resolution Stereo Camera (HRSC) on board the orbiter will take pictures of the moon’s surface with the highest resolution possible, in colour, and in 3-D.

The data obtained will be added to a digital terrain model (DTM). This DTM will help scientists visualise what it would be like to stand on the moon’s surface by calculating its topography, or the elevation of its surface.

An image of Phobos by the High-Resolution Stereo Camera on board Mars Express on 22 January 2007.

The larger and inner of the two martian moons is seen here floating just above the martian limb. The image has been enhanced slightly to bring out the detail on the moon.

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

The camera may also capture an image of the intended landing site for Russia's Phobos-Grunt mission, due for launch in 2009. The manoeuvres required to observe this site are an operational challenge, and the activity involves close cooperation between ESA mission scientists, the flight control team and flight dynamics specialists.

The Visible and Infrared Mineralogical Mapping Spectrometer, OMEGA, the Planetary Fourier Spectrometer, PFS, and the Ultraviolet and Infrared Atmospheric Spectrometer, SPICAM, will also gather details on the surface composition, geochemistry and temperature of Phobos.

The Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) will collect information during two flybys (23 and 28 July) on the topography of the moon’s surface and on the structure of its interior.

The Energetic neutral atoms analyser, ASPERA will study the environment around Phobos, in particular the plasma that surrounds the moon and also the interaction of the moon with the solar wind.

During the second fly-by, all efforts will be concentrated on accurately determining the mass of the moon using the Mars Radio Science experiment (MaRS).



For more information:

Agustin Chicarro, ESA Mars Express Project Scientist
E-mail: Agustin.Chicarro @ esa.int

Olivier Witasse, ESA Mars Express Deputy Project Scientist
Email: Olivier.Witasse @ esa.int

Source: ESA - Space Science - Mars Express