[meteorite-list] SMART-1 Impact Simulated In A Laboratory Sandbox
11 September 2006 SMART-1 impact simulated in a laboratory sand-box European Space Agency 11 September 2006 Laboratory simulations of the SMART-1 impact performed at the University of Kent, United Kingdom, suggest that the impact may have caused a clearly elongated lunar crater, and produced a high-speed rebounding for the spacecraft. This may help explain some properties of the dust cloud observed just after the actual impact of SMART-1 on the Moon. The simulations were performed by M.J. Burchell and M.J.Cole at the University of Kent. For the test, they used a high-speed, two-stage light gas gun to shoot at 2 kilometres per second a 2-millimitre aluminium sphere that simulated the SMART-1 spacecraft. The target was a tray of sand, similar to lunar soil. We called for such laboratory simulations and numerical modelling of the SMART-1 impact as a crucial test to understand the processes at work in space-bound and artificial impacts, said Bernard Foing, ESA SMART-1 Project Scientist. Data from a previous project, in which Burchell and Cole made use of coarse grained sand, had shown that for an impact at a 10-degree incidence the fastest ejected material travelled forward (within about plus or minus 5 degree angle with respect to the impact direction) at 120 percent of the impact speed -- a higher value than the impacting projectile had. However, at that 10-degree incidence angle only one percent of the material excavated by the impact went forwards and the percentage decreased as the angle got shallower. Out of that one percent, about 75 percent was at an angle to the surface greater than 10 degrees. To reproduce the SMART-1 scenario we simulated an impact at two degrees incidence. The result was a nice non-circular crater, said Mark Burchell. According to the test's results, the fine grained dust of the lunar surface was to raise a cloud of ejected material, which would have spread out sideways, as well as in a forward direction. Based solely on the results and ignoring scaling issues, Burchell and Cole predicted the size for the SMART-1 impact crater, expected to be 7 metres long and 4.5 metres wide. This was compatible with ESA's scaling-law predictions on the size of the SMART-1 crater. Burchell and Cole also observed a 'ricochet-projectile' phenomenon, suggesting a bounce like that of a single object that had undergone some deformation, with a slight 20 percent loss of speed during the impact. Based on the latest topography analysis, SMART-1 touched down with a very grazing incidence not higher than a few degrees, said Foing. Therefore it might have bounced in a similar way to the flying bullet in the sand box, like a stone skipping on water. The result of these simulations may explain some of the properties of the clouds detected by the Canada-France-Hawaii telescope (CFHT) up to 100 seconds after the flash, added Pascale Ehrenfreund, coordinator of the SMART-1 impact ground-based observation campaign. These were spread at some tens of kilometres downstream from impact, she concluded. For more information Bernard Foing, ESA SMART-1 Project Scientist Email: bernard.foing @ esa.int Mark Burchell, University of Kent, United Kingdom Email: M.J.Burchell @ kent.ac.uk Pascale Ehrenfreund, SMART-1 ground-based impact campaign coordinator, Leiden University, The Netherlands Email: pascale @ strw.leidenuniv.nl [NOTE: Image supporting this release are available at http://www.esa.int/SPECIALS/SMART-1/SEM8SH7LURE_1.html ] __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] SMART-1 Impact Flash and Debris: Crash Scene Investigation
http://smart.esa.int/science-e/www/object/index.cfm?fobjectid=39969 SMART-1 impact flash and debris: crash scene investigation European Space Agency 7 September 2006 The SMART-1 observation campaign latest results bring new evidences on SMART-1 impact: timing, location, detection of flash and ejecta, and a firework. The successful capture of the SMART-1 impact from Earth raised a substantial interest in the amateur and professional astronomical community. They started to reanalyse the available data, to repeat observations of the impact site and to share the results worldwide as a family, says Pascale Ehrenfreund, coordinator of the SMART-1 impact ground observation campaign. Where did SMART-1 impact the Moon? From the various observations and models, we try to reconstruct the 'movie' of what happened to the spacecraft and to the Moon surface, says ESA SMART-1 Project scientist Bernard Foing. For this lunar 'Crash Scene Investigation', we need all possible Earth witnesses and observational facts. The actual SMART-1 impact took place on 3 September 2006 in the course of the spacecrafts 2890th orbit around the Moon. SMART-1 sent its last signals to Earth at 07:42:21:759 CEST (05:42:21:759 UT), and the JIVE radio telescope from Hobart, Tasmania, measured a loss of signal a few moments later, at 07:42:22.394 CEST (05:42:22.394 UT). These times are remarkably in agreement with the last SMART-1 flight dynamics predictions of 3 September at 07:42:20 CEST (05:42:20 UT), in the location at 46.20 deg West longitude and 34.4 deg South latitude. This is also in agreement with the coordinates newly derived from the position of the infrared impact flash observed by the Canada-France-Hawaii telescope (CFHT). Extensive data processing is now going on to specify the topography of the impact site. From a preliminary analysis of the topographic stereo data available and earlier maps built with SMART-1 data, the satellite should have hit the Moon in the ascending slope of a mountain about 1.5 kilometres high, above the Lake of Excellence plain. What happened? Dust after the flash To determine what part of the flash comes from the lunar rock heated at impact or from the volatile substances released by the probe, it is important to obtain measurements in several optical and infrared wavelengths, in addition to the CFHT observations (2.12 microns). From a detailed analysis of the CFHT infrared movie of the variations after the flash, a cloud of ejected material or debris travelling some 80 kilometres in about 130 seconds has been detected by observer Christian Veillet, Principal Investigator for the SMART-1 impact observations at CFHT. It seems that some ejecta or debris made it across the mountain. This is good news to search for the ejecta blanket says Foing. We might also see the 'firework' expansion of gas and debris that has bounced after impact from the spacecraft. Some SMART-1 campaign amateurs report that they may have observed the optical flash in their own data, and a possible impact afterglow. We call for observers to search for the crater and ejecta blankets from SMART-1, in particular using visible or infrared imagery, or even to look at spectroscopic anomalies at the impact site, added Foing. We also call all observers to send us their reports, thanking them for engaging in the SMART-1 adventure. Note to editors The five radio telescopes involved in the SMART-1 observations and coordinated by the Joint Institute for VLBI (Very Long Baseline Interferometry) in Europe (JIVE), are: the Medicina (INAF) 32- metre antenna in Italy, the Fortaleza (ROEN) 14-metre antenna in Brazil, the German-Chilean TIGO (BKG) 6-metre antenna in Chile, the Mount Pleasant Observatory of the University of Tasmania (Australia) and the Australia Telescope Compact Array (CSIRO). The SMART-1 impact observation campaign involved a core of participating telescopes, including: the South African Large Telescope (SALT), the Calar Alto observatory in Andalucia, Spain, the ESA Optical Ground Station (OGS) at Tenerife, Spain, the TNG telescope in La Palma, Canary Islands, Spain, the CEA Cariri observatory in Brazil, the Argentina National Telescope, the Florida Tech Robotic telescopes at Melbourne FL and Kitt Peak, MSFC lunar meteor robotic telescopes, Houston 1m, Big Bear Solar Observatory, MDM telescopes at Kitt Peak, NASA IRTF, the Canada-France-Hawaii Telescope, the Japanese Subaru Auxiliary telescopes on Hawaii, the ODIN space observatory. We acknowledge also support from Nottingham University, and the USGS. Reports on data gathered by other observatories that joined the campaign will follow on this site. For more information: Bernard H. Foing, ESA SMART-1 Project Scientist Email: bernard.foing @ esa.int Pascale Ehrenfreund, SMART-1 ground-based impact campaign coordinator, Leiden University, The Netherlands Email: pascale @ strw.leidenuniv.nl [NOTE: Images supporting this release are available at
[meteorite-list] SMART-1 impact
Hi Doug and List, I don't know if I'm the first to notice this but the effect of the lunar impact is still visible in the Canada-France-Hawaii telescope image 15 seconds after impact. Check the frame immediately after the bright impact frame in the movie below, and you'll see a small lingering white spot centered exactly on where the impact flash was in the prior frame: http://www.cfht.hawaii.edu/News/Smart1/anim2.gif http://www.cfht.hawaii.edu/News/Smart1/anim2.gif --Rob __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] SMART-1 impact
Hi, Rob, Gee, Rob, now I know why you find things! The 11th frame has the impact. The 12th frame has a brightened patch two pixels wide and five pixels high. The 13th frame has a less bright but still over-brightened patch two pixels wide and two pixels high, which are in the same position as the upper 4 pixels of the 12th frame patch. In the 14th frame and the 11th frame, this same area is completely cool, much grayer. So, the heating effect persisted for more than 30 seconds (the frame rate was 15 seconds exposure per frame, and you have to read out the chip between frames). If anyone else wants to see the effect, load the animated gif file into Photoshop which will separate the frames as layers. I enlarged the impact point to a 2000% view in a window framed around the edges of the flash in frame 11, then switched from layer to layer to layer. Rob, if you found this with your bare eyeballs, from just watching the gif, I congratulate you. It's invisible to me at that size! A little poking around in the ESA website reveals that SMART-1 came in from the north in a polar orbit, so I will hypothesize that the top four pixels where the heat persists through two frames is the impact point itself and the six pixels below it are the splash of the low inclination impact, hot debris and ejecta being thrown out in a blanket that extends mostly to the south of the crater. You know how I like to hypothesize... As to pixel size translation to actual ground size, we can forget it -- not enough data. Instead of the megacam they talk about on the CFHT website, they used their new WIRcam, a wide angle IR sensor, so no idea of pixel-ground size. However, Lehmann C crater is 16 kilometers in diameter and is eight pixels wide in the image, so -- just a wild guess -- 2 kilometers to the pixel? Just in case anyone has a telescope big enough to search for a 10-meter crater (like a 10-meter scope in orbit, say), the ESA website has a very detailed Observing Guide to the impact site: http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=39863 The reason Rob finds things? He looks for them! Sterling K. Webb -- - Original Message - From: Matson, Robert [EMAIL PROTECTED] To: [EMAIL PROTECTED]; meteorite-list@meteoritecentral.com Sent: Monday, September 04, 2006 8:19 PM Subject: [meteorite-list] SMART-1 impact Hi Doug and List, I don't know if I'm the first to notice this but the effect of the lunar impact is still visible in the Canada-France-Hawaii telescope image 15 seconds after impact. Check the frame immediately after the bright impact frame in the movie below, and you'll see a small lingering white spot centered exactly on where the impact flash was in the prior frame: http://www.cfht.hawaii.edu/News/Smart1/anim2.gif http://www.cfht.hawaii.edu/News/Smart1/anim2.gif --Rob __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
[meteorite-list] SMART-1 Impact: Last Call For Ground Based Observations
http://www.esa.int/esaCP/SEMTU0Z7QQE_index_0.html SMART-1 impact: last call for ground based observations European Space Agency 17 August 2006 If you are a professional or amateur astronomer and want to contribute to the final phase of the SMART-1 mission, join ESA on the impact ground observation campaign. Like most of its lunar predecessors, SMART-1 will conclude its scientific observations of the Moon through a small impact on the lunar surface. This is planned to take place in the lunar Lake of Excellence, located at mid-southern latitudes. A trim manoeuvre at the end of July has determined that the impact will most likely occur on 3 September 2006 at 07:41 CEST (05:41 UT), or at 02:36 CEST (00:36 UT) on the previous orbit due to uncertainties in the detailed knowledge of the lunar topography. If impacting on 3 Sept at 07:41 CEST, SMART-1 will touch the Moon at the lunar coordinates 36.44º South and 46.25º West. If impacting on 3 September at 02:36 CEST the lunar coordinates will be 36.4º South and 43.5º West. The Lake of Excellence is very interesting from the scientific point of view â it is a volcanic plain area surrounded by highlands, but also characterised by ground mineral heterogeneities. âWe call for ground-based observations mostly to study impact physics, the release of spacecraft volatiles, and the lofted soil mineralogy,â says Bernard Foing , SMART-1 Project Scientist at ESA. âWe look for fast imaging of the impact and of the associated ejected material, and for spectroscopic analysis, for example to find hints about the mineralogy of the impact area.â âEven if the impact at 2 kilometres per second is of modest energy, the plume might be observable if it reaches sunlight, with an amateur telescope or binoculars,â continues Foing. âFor sites not covering the time of impact, we ask for context observations before and after impact to look for the ejecta blanketâ. A number of worldwide observatories have already confirmed their participation to the campaign. They include the network of VLBI Very Long Baseline Interferometry and radio observatories, the South African Large Telescope SALT, the Calar Alto observatory in Andalucia, Spain, the ESA OGS Optical Ground Station at Tenerife, Spain, the CEA Cariri observatory in Brazil, the Argentina National Telescope, the Florida Tech Robotic telescopes, NASA IRTF and Japanese telescopes at Hawaii, as well as a number of professional and amateur astronomy telescopes around the world, and the ODIN observatory from space. ESA invites the scientific community and amateur astronomers to join in the observation campaign. For more information follow this link http://sci.esa.int/smart1impact. For more information Bernard Foing, ESA SMART-1 Project Scientist Email: Bernard.Foing @ esa.int __ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
