Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mars Express acquires sharpest images of martian moon Phobos

31.07.2008
Mars Express closed in on the intriguing martian moon Phobos at 6:49 CEST on 23 July, flying past at 3 km/s, only 93 km from the moon. The ESA spacecraft’s fly-bys of the moon have returned its most detailed full-disc images ever, also in 3-D, using the High Resolution Stereo Camera on board.

Phobos is what scientists call a ‘small irregular body’. Measuring 27 km × 22 km × 19 km, it is one of the least reflective objects in the Solar System, thought to be a capture-asteroid or a remnant of the material that formed the planets.

The best images of Phobos ever

The HRSC images, which are still under processing, form a bounty for scientists studying Phobos. They are a result of observations carried out over several close fly-bys of the martian moon, performed over the past three weeks. At their best, the pictures have a resolution of 3.7 m/pixel and are taken in five channels (in the stereo channel) for images in 3-D and (in the photometric channels) to perform analyses of the physical properties of the surface.

The images obtained by several other spacecraft so far have either been of a lower resolution, or not available in 3D and have not covered the entire disc of Phobos. This is also the first time that portions of the far-side of the moon have been imaged in such high resolution (Phobos always faces Mars on the same side).

Scientific bounty

In observing Phobos, Mars Express benefits from its highly elliptical orbit which takes it from a closest distance of 270 km from the planet to a maximum of 10 000 km (from the centre of Mars), crossing the 9000 km orbit of the martian moon. Mars Express imaged the far-side of Phobos (with respect to Mars) for the first time after NASA’s Viking mission, by flying outside the spacecraft’s orbit around Mars.

Phobos-Grunt (Phobos soil), a Russian sample-return mission, is due to for launch in 2009. It is expected to land on the far-side of Phobos at a region between 5° south to 5° north, and 230° west to 235° west. This region was last imaged in the 1970s by the Viking orbiters.

The HRSC observations have been awaited eagerly to better assess and characterise the choice of the landing site.

The moon's remarkably grooved surface can be seen in the pictures quite clearly. The origin of these grooves is still debated. It is not known whether they are produced by ejecta thrown up from impacts on Mars, or if they result from the surface regolith, or soil, slipping into internal fissures.

In this image, at least two families of grooves with distinct orientations can be seen along with an elongated crater.

The stereo observations (resolution 3.7 m/pixel) are important for structural analysis and they will be used to derive a digital terrain model (a 3-D map of the surface that includes elevation data). The extra photometric channels (at 7.4 m/pixel) make it possible to study the properties of the Phobos regolith at micron to millimetre scales.

An operational challenge

Managing the close fly-bys was an operational challenge, made possible by spacecraft operations engineers and scientists who worked together to specially optimise Mars Express’s trajectory and obtain the best possible views.

The observation made use of a spacecraft slew, a special manoeuvre whereby the body of the spacecraft is rotated against the direction of motion, to effectively lower the speed at which the target passes in the field of view of the camera. This makes it possible to avoid blurring of the pictures despite the high fly-by velocities, whilst maintaining acceptable exposure time.

The HRSC Super Resolution Channel (SRC) also observed during this close fly-by, with a nominal resolution of 90 cm/pixel. As expected, despite the slew, some residual motion blur has crept into the image, but much detail is expected to be recovered after further processing.

In the days running up to the observation, the primary star-tracker - a navigation device that helps the spacecraft point its instruments at the target accurately - experienced some temporary difficulty in recognising the star constellations in its field of view, leaving the spacecraft operating on its secondary system. Concerned that this might affect this critical observation, the team at ESA's European Space Operations Centre (ESOC) in Darmstadt, Germany, worked intensely to recover the primary system and were able to switch back successfully two days before the fly-by.

Agustin Chicarro | alfa
Further information:
http://www.esa.int
http://www.esa.int/SPECIALS/Mars_Express/SEM5H48N9JF_0.html

More articles from Physics and Astronomy:

nachricht Study offers new theoretical approach to describing non-equilibrium phase transitions
27.04.2017 | DOE/Argonne National Laboratory

nachricht SwRI-led team discovers lull in Mars' giant impact history
26.04.2017 | Southwest Research Institute

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>