Mars Express Blog

Mars Express Blog http://webservices.esa.int/blog/blog/7 Mars Express is Europe’s first planetary mission. At launch, the mission consisted of an orbiter carrying seven instruments for remote sensing observations of the planet, and a lander (Beagle 2) for on-the-spot measurements of Martian rock and soil. Mars Express started science observations at the Red Planet in January 2004, and since then it has been delivering an incredible amount of scientific results. The ‘Express’ part of the name highlights the fact that the spacecraft was built more quickly than any other comparable planetary mission. In fact, it took only five years from mission approval to launch. In addition to global studies of the surface, subsurface and atmosphere of Mars with unprecedented spatial and spectral resolution, the unifying theme of the Mars Express mission from orbit is the search for water in its various states, everywhere on the planet by all its seven instruments using different techniques. danielscuka 2012-02-10T10:29:11Z Phobos slips past Jupiter http://webservices.esa.int/blog/post/7/1349 <a id="res_20358" href="http://webservices.esa.int/blog/gallery/7/004-2-20110610-9463-Phobos-GeomericalRelationship_H1.jpg"> <div style="text-align: center"> <img src="http://webservices.esa.int/blog/gallery/7/previews-med/004-2-20110610-9463-Phobos-GeomericalRelationship_H1.gif" border="0" alt="The trajectories of Phobos and Mars Express at the time of the conjunction with Jupiter on 1 June 2011. The graphic was created using Celestia software. The letter ‘S’ denotes the South Pole of Mars. Credit: ESA" /> </div> </a>Earlier this month, ESA’s Mars Express performed a special manoeuvre to observe an unusual alignment of Jupiter and the martian moon Phobos. The impressive images have now been processed into a movie of this rare event.   At the moment when Mars Express, Phobos, and Jupiter aligned on 1 June 2011, there was a distance of 11 389 km between the spacecraft and Phobos, and a further 529 million km to Jupiter. <a href="http://www.esa.int/SPECIALS/Operations/SEMJ53E1XOG_0.html" target="_blank">Full article via ESA</a>. General Orbits Science Operations 2011-06-17T18:44:44Z danielscuka Mars Express all set for autonomous Phobos flyby http://webservices.esa.int/blog/post/7/1304 A quick final update on spacecraft activity for the next few days, provided by Mars Express Spacecraft Operations Engineer Hannes Griebel here at ESOC: <ul> <li>The final pre-flyby orbit determination was concluded earlier this week; this precise calculation of the Mars Express orbit was used to generate the commands for the flyby </li> <li>These commands include all necessary pointing and instrument instructions so that the flyby and science observations can be conducted automatically</li> <li>They were uploaded to the spacecraft this morning during a ground station pass at 07:00 UT (08:00 CET)</li> <li>Mars Express is now in an orbit with respect to Mars ranging from approximately 400 km to 10 000 km; it will pass by the centre of Phobos on Sunday at just 111 km</li> <li>On Sunday, 9 January, Mars Express will automatically slew to point instruments toward the expected direction of Phobos starting at 13:55 UT (14:55 CET) - it will stay in this pointing mode for 5 minutes and 46 seconds</li> <li>Closest approach occurs at 14:06:30.016 UT (15:06:30.016 CET)</li> <li>A few minutes later, after closest approach, it will slew back to Earth pointing and the next ground station pass, via ESA's 35m DSA-2 deep space station at Cebreros, Spain, will begin at 14:57 UT (15:57 CET). Data will be downloaded progressively over the following days(see "When can we expect first images" below)</li> </ul> At this time, the one-way signal travel time is 19 mins:47.4 seconds and Mars Express is 355 959 424 km from Earth. Mars Express Spacecraft Operations Manager Michel Denis added: <blockquote> "The simple fact that this flyby is being done automatically and with little human activity on the days around and during closest approach hides the large amount of work done by the operations team, the flight dynamics team, the mission scientists and the principle investigators to get ready. We are looking forward to a smooth flyby and some very interesting results." </blockquote> Overall, it's a quiet but nonetheless exciting phase of the mission that promises to provide some excellent and valuable Phobos images and data from close up! We'll update you on Monday as soon as we hear any word from the team at ESOC.  -- Daniel     General Orbits Phobos Fly-by 2011 2011-01-07T17:14:46Z danielscuka Why the Mars Express orbit swings like a hula hoop http://webservices.esa.int/blog/post/7/1301 <a href="http://webservices.esa.int/videostreaming/esoc/blog-embed_video1_16x9.php" target="_blank"><img src="http://webservices.esa.int/blog/gallery/7/vlcsnap-2011-01-04-14h48m17s158.gif" align="left" /></a>Our long-time colleague Emily Lakdawalla over at the Planetary Society blog sent in a Twitter query last night: "Would love to see a blog entry explaining more details of how the MEX orbit shifts with time." Her question, while general, is directly related to this week's Phobos fly-by activity as precise knowledge of the spacecraft's orbit is vital for planning observations (Mars Express will zip by tiny Phobos is just a few seconds - see my earlier post below). I passed her query to the Mars Express operations team here at ESOC, and received the following reply from Spacecraft Operations Engineer Hannes Griebel. His colleague Thomas Ormston, who also works on the <a href="http://webservices.esa.int/blog/blog/6" target="_blank">Mars Webcam Blog</a>, additionally took some time to generate a fantastic animation showing how the Mars Express orbit changes over time. First, from Hannes: <blockquote> Mars Express is on a <a href="http://www.esa.int/SPECIALS/Mars_Express/SEMNS75V9ED_0.html" target="_blank">highly eccentric, polar orbit around Mars</a>. This means that our spacecraft flies over the poles during each orbit, as can be seen in this <a href="http://webservices.esa.int/blog/post/6/1185" target="_blank">full-orbit movie captured in May 2010</a>. However, due to perturbation forces, resulting chiefly from Mars' inhomogeneous gravity field as well as gravity from other celestial bodies and also from light and solar wind pressure, the orbit rotates slightly so that periapsis (point of closest approach to the planet) drifts around Mars. This is actually a big plus, because over the course of several months, the spacecraft gets a close-up view of all regions - from the snow-covered poles over the windswept plains of the north to the heavily cratered highlands of the south. In other words, as Mars rotates beneath our 7-hour orbit, we get full close-up coverage of virtually the entire surface over time. And, once in a while, our orbit intersects that of Phobos. The Flight Control and Flight Dynamics teams always take great care to ensure that whenever this happens, Mars Express and Phobos are never at that point of intersection at the same time (this would be sub-optimal -- Ed. :-)). But, when the geometry is favourable and the two are going to pass close by, a carefully timed manoeuvre, provided by firing the thrusters, can bring our satellite close enough to Phobos to take pictures and other measurements of this extremely interesting moon. More info available here: <a href="http://webservices.esa.int/blog/post/7/1084">http://webservices.esa.int/blog/post/7/1084</a> </blockquote> Next, Thomas produced an excellent animation (click on image above or scroll down for links): <blockquote> Hi Daniel, all, Please find attached an animation of the Mars Express orbit progression over time. The video runs from the middle of our first year at Mars, 2004, all the way through to 2011... sped up 10,000,000 times! You can see the red path of the Mars Express orbit as it swings around Mars throughout the Martian year (Earth dates are in the top right corner). Every few months this intersects with the orbit of Phobos (the inner green ring, the outer one is Deimos), giving us an opportunity for a Phobos flyby. The lines don't always display in the correct order on this video, so sometimes it looks like we also cross the orbit of Deimos; this is just an optical illusion on the video (in reality, it orbits too far out from Mars for a close encounter with Mars Express). </blockquote> Thomas, Hannes: Thanks for the excellent update! ACCESS VIDEO <a href="http://webservices.esa.int/videostreaming/esoc/blog-embed_video1_16x9.php" target="_blank">Watch the animation in your browser here</a>, or <a href="http://download.esa.int/esoc/esa_mars_express_orbit_2004-2011.avi" target="_blank">Download original file (AVI) here</a>, or <a href="http://www.facebook.com/EuropeanSpaceAgency?v=app_2392950137#!/video/video.php?v=1705250145570" target="_blank">Watch it in the 'Friends of ESA' page in Facebook here</a>, or  See it in the Planetary Society YouTube channel:    <div style="text-align: center"> <object type="application/x-shockwave-flash" width="450" height="350" data="http://www.youtube.com/v/aPy5x9r7kfM" id="ltVideoYouTube"> <param name="movie" value="http://www.youtube.com/v/aPy5x9r7kfM" /> <param name="wmode" value="transparent" /> <param name="allowScriptAcess" value="sameDomain" /> <param name="quality" value="best" /> <param name="bgcolor" value="#FFFFFF" /> <param name="FlashVars" value="playerMode=embedded" /> </object> </div>     General Orbits Phobos Fly-by 2011 2011-01-04T15:58:54Z danielscuka Plotting a path past Phobos http://webservices.esa.int/blog/post/7/1299 <a id="res_12825" href="http://webservices.esa.int/blog/gallery/7/Mars-Express_Phobos_orbits.jpg"> <div style="text-align: center"> <img src="http://webservices.esa.int/blog/gallery/7/previews-med/Mars-Express_Phobos_orbits.gif" border="0" alt="Date: 15 Feb 2010 Satellite: Mars Express Depicts: Diagram of the Mars Express and Phobos orbits Copyright: ESA On 3 March 2010, Mars Express performs its closest flyby ever of Mars' innermost moon Phobos. This diagram shows the orbits of Phobos and Mars Express around Mars, with the point where the orbits cross indicated at top left. The orbit of Phobos lies virtually in Mars' equatorial plane and is indicated in yellow. Mars Express is in a polar orbit. Several revolutions are depicted here, with the colour indicating the parts that are over the northern hemisphere (white) and the southern hemisphere (blue) of Mars. Because the orbit of Mars Express evolves, with the line of apsides drifting, sequential revolutions do not overlap." /> </div> </a> Click for larger view For the teams working on the Mars Express mission, one of the most important activities during the current fly-by phase is generating and refining estimates of the spacecraft's orbit, which must be as accurate as possible. This is mandated by the fact that Phobos is really not that big - its mean radius is just 11 km - and the fly-by at closest approach happens rather quickly. It will be over in just a few moments as Mars Express zips by at around 3 km/second. As a result, the camera and other instruments on board the spacecraft - and indeed the spacecraft itself - must be pointed in precisely the correct direction at precisely the correct time in order to get any useful results at all. These pointings and timings, in turn, depend on knowing the spacecraft's trajectory very accurately - and estimating this is at least as much an art as it is a science. The trajectory estimates make use of astrophysical data including the gravity of Mars and Phobos as well as data from the star trackers on board Mars Express (which provide a picture, literally, of the background star field) and radiometric data provided by the ground tracking stations that communicate with the spacecraft, currently ESA's giant 35m station at Cebreros, Spain. Fixing the orbit is also very much a team effort involving experts from the flight dynamics team here at ESOC, the scientists who operate the instruments (including the HRSC camera and the MARSIS radar), and the flight operations team. The next set of orbit calculations for closest approach on 9 January will be generated later today, and will be refined later in the week. -- Daniel General Orbits Phobos Fly-by 2011 2011-01-04T14:55:44Z danielscuka Phobos flyby animation in YouTube http://webservices.esa.int/blog/post/7/1059 A very effective animation showing Phobos flyby on 3 March created by the <a href="http://boxx.over-blog.com/article-survol-phobos-mars-express-45426323.html" target="_blank">team at the Boxx blog</a> (audio in French). <div style="text-align: center"> <object type="application/x-shockwave-flash" width="450" height="350" data="http://www.youtube.com/v/9xLRYJtuVEg" id="ltVideoYouTube"> <param name="movie" value="http://www.youtube.com/v/9xLRYJtuVEg" /> <param name="wmode" value="transparent" /> <param name="allowScriptAcess" value="sameDomain" /> <param name="quality" value="best" /> <param name="bgcolor" value="#FFFFFF" /> <param name="FlashVars" value="playerMode=embedded" /> </object> </div>   This animation shows the Mars Express orbit very well. The animation uses our original, slightly closer approach (50km instead of the actual 67km) because that's what is in the Celestia files that we posted earlier (unfortunately, we haven't yet had time to upload the 'real' files after measuring the effects of the engine burn earlier in the week - we will do so soon!). The orientation of the spacecraft isn't quite correct because throughout the closest approach MEX stayed pointed at Earth so we could receive the radio signal. Nonetheless, the animation is still excellent, and the illustration of how our orbit crosses Phobos is excellent! Thanks to the Association Planete Mars (French section of the Mars Society) and their <a href="http://www.planete-mars.com/news/index.php?id=862" target="_blank">newly created "Atelier 3D" (free 3D for Mars exploration)</a> for an excellent job! -- Daniel Orbits Phobos Fly-By 2010 2010-03-05T14:01:24Z danielscuka Visualise Mars Express Phobos flyby: Celestia files http://webservices.esa.int/blog/post/7/1057 Kester Habermann, one of the flight dynamics team members here at ESOC, kindly sent in the data files for anyone who uses the popular (and free) <a href="http://www.shatters.net/celestia/" target="_blank">Celestia real-time, 3D visualisation software</a>. With these files, you can play back the entire flyby sequence (details and links after the jump). Thanks, Kester! -- Daniel   Kester wrote: <blockquote> Hello Daniel, Hello Stuart, Phobos was changed like this in Celestia data/solarsys.ssc:   "Phobos" "Sol/Mars" {           Mesh "phobos.cmod"           Texture "phobos.*"           Radius 13.0 # maximum semi-axis           MeshCenter [ -0.233 -0.156 -0.168 ]           SampledOrbit "phobos.xyz"           UniformRotation           {           Inclination               0.0           MeridianAngle           354.2           }           Albedo         0.07   } Note: We also used JPL DE-405 ephemerides for Mars. and Mars Express is in extras/mars_express.ssc   "Mars Express" "Sol/Mars"  {       Class "spacecraft"       Mesh "marsexpress.3ds"       Radius 0.006       Albedo 0.7       SampledOrbit "mex.xyz"   } Kind Regards, Kester </blockquote> Access the files in a ZIP archive here: <a href="http://webservices.esa.int/blog/resource/7/12449" target="_blank">http://webservices.esa.int/blog/resource/7/12449</a>     Orbits Phobos Fly-By 2010 2010-03-04T15:24:44Z danielscuka A response from a happy scientist http://webservices.esa.int/blog/post/7/1051 Martin Paetzold, Principle Investigator of the Mars Radio Science observation is smiling.  This morning, before the flyby, he admits to having been anxious.  “There was a very small probability of an occultation at closest approach,” he says.  It was a very small possibility but if it happened, Phobos would have blocked the signal with Earth at the critical moment. There is nothing to be anxious about any more.  Closest approach took place at 20:55 CET.  It took 6 minutes and 34 seconds for signals to cross the volume of space between Phobos and Earth, and be received on Earth. If the occultation had taken place, it would have created a gap in the data of five to ten minutes whilst the signal link was re-established with the spacecraft. “We would have had to extrapolate between the two data sets and that would not have been good.  Now we have continuous data,” says Paetzold. The team will receive the data on Friday, and they will begin the full analysis once they receive the precise orbit determination of Mars Express on its way into the flyby.  They hope to assess the data and the preliminary results in about two weeks time. Let the analysis begin! -- Stuart Orbits Phobos Fly-By 2010 2010-03-03T22:41:08Z stuartclark Closest approach happening now... http://webservices.esa.int/blog/post/7/1049 Waiting for signal confirmation. -- Daniel Orbits Phobos Fly-By 2010 2010-03-03T21:56:10Z danielscuka Another cool graphic... http://webservices.esa.int/blog/post/7/1048 This shows tonight's orbit orientations from an interesting angle. -- Daniel   <a href="http://www.flickr.com/photos/europeanspaceagency/4404105102/" title="Mars Express Phobos flyby by europeanspaceagency, on Flickr"><img src="http://farm5.static.flickr.com/4035/4404105102_7af75c2476.jpg" alt="Mars Express Phobos flyby" width="500" height="360" /></a> Orbits Phobos Fly-By 2010 2010-03-03T21:48:24Z danielscuka Animation showing tonight's orbits: Mars, Phobos, Deimos, Mars Express http://webservices.esa.int/blog/post/7/1043 Animation showing Mars, Phobos, Diemos and Mars Express in their relative orbits this evening is now live in ESA Flickr (click on 'HD' at bottom right of Flickr playback window to watch in high resolution): <a href="http://www.flickr.com/photos/europeanspaceagency/4403651689/" target="_blank">http://www.flickr.com/photos/europeanspaceagency/4403651689/ </a>   Orbits Phobos Fly-By 2010 2010-03-03T21:10:25Z danielscuka