From: Peiser Benny <[EMAIL PROTECTED]> To: cambridge-conference <[EMAIL PROTECTED]> Subject: CCNet, 13 February 2001: RELAUNCH OF NEAR SHOEMAKER TOMORROW? Date: Tue, 13 Feb 2001 10:49:15 -0000 CCNet 25/2001 - 13 February 2001: NEAR-SHOEMAKER SPECIAL III ------------------------------------------------------------ "I am happy to report that the NEAR has touched down. We are still getting signals. It is still transmitting from the surface." --Robert Farquhar, NEAR Mission Director, 12 February 2001 "Engineers at APL are looking at the prospects for relaunching the NEAR Shoemaker spacecraft from the surface of asteroid Eros. A command is already built into the probe as it rests upon the space rock's surface. The liftoff from the asteroid is on tap for this Wednesday, roughly 2:00 p.m. Eastern time, according to David Dunham, NEAR's mission designer at APL. The launch from Eros would be after nine rotations of the asteroid following today's NEAR Shoemaker landing, Dunham said." --Leonard David, Space.com, 12 February 2001 (1) MISSION TEAM CONSIDER RELAUNCHING NEAR SHOEMAKER FROM EROS Space.com, 12 February 2001 (2) NEAR SHOEMAKER MAKES HISTORIC TOUCHDOWN ON ASTEROID EROS Ron Baalke <[EMAIL PROTECTED]> (3) AMERICAN CRAFT LANDS ON ASTEROID Spaceprogramme News, 13 February 2001 (4) NEAR SHOEMAKER SURVIVES ASTEROID LANDING Spaceflight Now <[EMAIL PROTECTED]] (5) SPACECRAFT MAKES IMPROBABLE LANDING ON ASTEROID CNN, 12 February 2001 (6) METEORITES HARDER TO TRACE THAN FAMILY TREES Ron Baalke <[EMAIL PROTECTED]> (7) CATASTOPHE/APOCALYPSE COURSE AT BARD COLLEGE Benny J Peiser <[EMAIL PROTECTED]> (8) NEO DEFLECTION BY NEO COLLISION/FLY-BY Christian Gritzner <[EMAIL PROTECTED]> ============= (1) MISSION TEAM CONSIDER RELAUNCHING NEAR SHOEMAKER FROM EROS >From Space.com, 12 February 2001 http://www.space.com/missionlaunches/missions/nearlanding_preview_010212.htm l By Leonard David Senior Space Writer LAUREL, MARYLAND - What goes down, may come back up again. Engineers at APL are looking at the prospects for relaunching the NEAR Shoemaker spacecraft from the surface of asteroid Eros. A command is already built into the probe as it rests upon the space rock's surface. The liftoff from the asteroid is on tap for this Wednesday, roughly 2:00 p.m. Eastern time, according to David Dunham, NEAR's mission designer at APL. The launch from Eros would be after nine rotations of the asteroid following today's NEAR Shoemaker landing, Dunham said. "Since we've got a lock on the signal, it's got to be pretty much in the right position" for the liftoff, said Dunham. Dunham said the probe may rise upwards well over 1,300 feet (400 meters) above Eros. "It could sit in the dirt and wiggle a little bit before liftoff. These are weaker thrusters on the spacecraft," he said. Some thought has been given to sequencing a double boost of thrust from the asteroid, hurtling it perhaps as high as a kilometer above the asteroid. Dunham said that if the camera has not been damaged in the first landing, more images above the asteroid could be taken. However, pictures of the first landing spot on Eros are not likely to come into view, he said. The spacecraft would then settle down to a new landing spot. "The whole thing is just more icing on the cake," Dunham said. The NASA probe had already happily surprised scientists earlier today, when it made space history with a successful landing atop an asteroid more than 196 million miles (316 million kilometers) from Earth. "I'm happy to report the near spacecraft has touched down on the surface of Eros. We're still getting some signals, so evidently it's still transmitting from the surface itself. This is the first time that any spacecraft has landed on a small body," said Robert Farquhar, NEAR mission director at The Johns Hopkins University Applied Physics (APL) Laboratory in Laurel, Maryland. NASA Administrator Dan Goldin was among the first to congratulate the team. "I'm just overwhelmed with the courage and talent it took to get to this point," Goldin said shortly after the landing. The car-sized NEAR Shoemaker probe has been orbiting Eros since February 14, 2000. Since it began looping the tumbling space rock almost a year ago -- at a range of high and low-altitudes over Eros -- the craft has amassed an asteroid photo gallery made up of 150,000 snapshots. Touchdown took place shortly after 3:05 p.m. Eastern time. The spacecraft fell onto the dust-laden, cratered, and rock-piled surface of Eros. While the vehicle is a fully equipped science spacecraft, NEAR Shoemaker is without landing legs or airbag. "We're right on the money," cried out mission controllers as the craft drifted closer and closer to Eros. Images relayed on the way down to the surface showed what appears to be ancient craters buried below the thick, dusty face of Eros. "We're seeing things really well," said Joseph Veverka, NEAR's imaging team leader from Cornell University in Ithaca, New York. "The pictures are absolutely fantastic. This is a great experience to just sit here and accompany a spacecraft down to the surface." In one image, a giant boulder could be clearly seen fractured in at least six pieces. As one image after another reached Earth, the spacecraft appeared to be headed toward a smooth landing surface. For over four-and-a-half hours, as engineers and scientists here at The Johns Hopkins University Applied Physics Laboratory (APL) cheered close-up images the probe sent back during its descent, the probe drifted down toward the rock of ages. APL built and managed the NEAR mission for NASA, one of the Discovery-class of probes that signals a cheaper, better, faster approach to space exploration. Price tag for this long-term survey of an asteroid by the econo-class spacecraft: $223 million. NEAR's mission control at The Johns Hopkins University's Applied Physics Laboratory reported the craft blasted its hydrazine-fueled motors for 20 second starting at 10:31 a.m. Eastern time. The burst of rocket thrust moved the NASA probe out of its current orbit 22-miles (35-kilometers) above Eros. The spacecraft immediately began dropping toward Eros. In the next four-and-a-half hours, a series of braking maneuvers led to the spacecraft making contact with Eros. Small body, big hopes The craft has relayed a bounty of scientific data about the asteroid, including some 160,000 images that covered all of the 21-mile-long (34-kilometers) asteroid's surface. Eros is moving in a clockwise direction as it spins on its axis. NEAR Shoemaker drifted onto the surface of Eros, softly touching down in an area bordering Himeros - a distinctive saddle-shaped depression. On the way down to the landing zone, the highest-resolution images ever taken of Eros' boulder-strewn, cratered terrain were transmitted to Earth. NEAR Shoemaker was not designed specifically for the touchdown, with the daring dive called for as the mission drew to a successful close on February 14. "It's a very nice way to end this mission," Louise Prockter, a member of the NEAR imaging team at the Applied Physics Laboratory (APL) told SPACE.com. "At least we'll know exactly where the spacecraft is and what happened to it. So if there's a future mission out that way, we'll be able to look for it," Prockter said. Remaining fuel a question When the spacecraft was launched February 17, 1996, its fuel tanks were filled with 715 pounds (325 kilograms) of fuel. After five years, exactly how much propellant remains is unknown. Precious bursts of fuel were needed to prod NEAR Shoemaker lower and lower to the surface of Eros and mission director Robert Farquhar was not sure the probe would have enough gas to the end. "The primary thing is to get high-resolution images. The closer we get the more success we have," Farquhar said. After plopping down on Eros, the spacecraft was healthy enough to transmit science data. Over the next two days, ground stations on Earth will keep an active ear to transmissions from NEAR Shoemaker. Roundtrip communications time between NEAR and Earth is 35 minutes. At Goldstone, California, a Jet Propulsion Laboratory (JPL) Deep Space Network antenna is to keep a lock on NEAR, with another big dish in Madrid, Spain also at the ready. Landing on an asteroid is no cakewalk, Farquhar said, particularly when the spacecraft is not built for such a task. Any number of things could have gone wrong. Engines could misfire; the camera could be pointed the wrong way; or the landing site terrain could have proved impossible for NEAR to navigate successfully. >From a distance Scientists are delighted that the spacecraft relayed high-quality, close-up images of Eros. The telescopic camera, built for remote distance viewing, stayed in focus down to an altitude of about 0.3 mile (0.5 kilometer) above the surface. "The camera should reveal things on the surface, down to as small as a tea cup," said Clark Chapman, member of the NEAR Shoemaker science team from Southwest Research Institute in Boulder, Colorado. "The close-up images are what we're after," said Lucy McFadden, NEAR science team member from the University of Maryland in College Park. "We're going to microscopic views relative to where we started. It's just tremendous." Prockter said the spacecraft's last in-focus snapshots may help quell considerable debate between scientists working on the project. The nature of the regolith -- broken up bits of rock and dirt that cover the asteroid -- as well as how deep and how much is there, and the origin of that material, are all questions being argued. "Looking close up might help us answer some of those questions," Prockter said. Chapman said a head-scratcher for him is understanding why so many giant boulders populate Eros. "We've been arguing between ourselves about what it means geologically," Chapman said. "Why is it so different than the Moon? I've just got to believe that the higher resolution images are going to give us a whole bunch of additional clues as to what's really going on. There's lots of speculation." Survivor for science? Now that the craft has touched down on the surface of Eros, hopes run high that NEAR's onboard magnetometer can relay measurements directly from the asteroid. To date, the magnetometer has not seen anything that can be attributed to Eros. Why that's the case is a little puzzling, said Andrew Cheng, NEAR project scientist, because most of the meteorites that are thought to be related to Eros are magnetized. But whether or not the magnetometer ever picks up data from Eros, researchers are still constrained by finances. Money for mission operations runs out on February 14, 2001. Prior to the landing, McFadden was wistful. "It's really sad the whole thing is going to end Monday," she said. Copyright 2001, Space.com ========= (2) NEAR SHOEMAKER MAKES HISTORIC TOUCHDOWN ON ASTEROID EROS >From Ron Baalke <[EMAIL PROTECTED]> http://near.jhuapl.edu/news/flash/01feb12_8.html For Immediate Release Feb. 12, 2001 Media Contact: Helen Worth (240) 228-5113 [EMAIL PROTECTED] Mike Buckley (240) 228-7536 [EMAIL PROTECTED] NEAR Shoemaker Makes Historic Touchdown on Asteroid Eros Today, at 3:02:10 EST, NASA's NEAR Shoemaker spacecraft traveled its last mile, cruising to the surface of asteroid Eros at a gentle 4 mph (1.9 meters per second)-finally coming to rest after its 2-million-mile journey. Cheers and congratulations filled the Mission Operations Center at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., which built the spacecraft and manages the mission for NASA, when NEAR Mission Director Robert Farquhar announced, "I'm happy to say the spacecraft is safely on the surface of Eros." The last image snapped by NEAR Shoemaker was a mere 394 feet (120 meters) from the asteroid's surface and covered a 20-foot (6-meter) area. As NEAR Shoemaker touched down it began sending a beacon, assuring the team that the small spacecraft had landed gently. The signal was identified by radar science data, and about an hour later was locked onto by NASA's Deep Space Network antennas, which will monitor the spacecraft until Feb. 14. NEAR Shoemaker's final descent started with an engine burn at 10:31 a.m. (EST) that nudged the spacecraft toward Eros from about 16 miles (26 kilometers) away. Then four breaking maneuvers brought the spacecraft to rest on the asteroid's surface in an area just outside a saddle-shaped depression, Himeros. When it touched down, NEAR Shoemaker became the first spacecraft ever to land, or even attempt to land on an asteroid. The success was sweetened by the fact that NEAR Shoemaker was not designed as a lander. The spacecraft spent the last year in a close-orbit study of asteroid 433 Eros, a near-Earth asteroid that is currently 196 million miles (316 million kilometers) from Earth. During that time it collected 10 times more data than originally planned and completed all its science goals before attempting its descent to the asteroid. Details of NEAR Shoemaker's landing will be discussed at a post-landing press conference that will be held at APL's Kossiakoff Center at 1 p.m., Wednesday, Feb. 14. Panelists will be: Jay Bergstralh, Acting Director, Solar System Exploration, NASA Hq., Washington, D.C. Robert Farquhar, NEAR Mission Director, APL Bobby Williams, Navigation, NASA's Jet Propulsion Laboratory, Pasadena, Calif. Joseph Veverka, Imaging Team Leader, Cornell University, Ithaca, N.Y. Thomas Coughlin, NEAR Project Manager, APL The press conference will be telecast live on a Ku band satellite at: Telstar K5 97 degrees West Longitude Transponder 12 Downlink Frequency 11936 MHz Horizontal Polarity Audio 6.2 & 6.8 Media wishing to follow the press conference on the Internet can contact NASA Hq. (202-358-1727) or APL Public Affairs (240-228-5113) for access instructions and passwords. To register for the press conference visit the NEAR Web site at http://near.jhuapl.edu and go to News Center - Upcoming Events. Images are also available on the Web site. ============= (3) AMERICAN CRAFT LANDS ON ASTEROID >From Spaceprogramme News, 13 February 2001 http://www.spaceprogramme.com/?action=display&article=5731206&template=space /index.txt&index=recent COLUMBIA, Md. (AP) - NEAR, the spacecraft that became the first manmade object to land on an asteroid, may continue sending its signal for months, but after Wednesday nobody will be listening. The spacecraft, which was designed for orbiting and not landing, astounded even the experts on Monday by touching down so gently on the asteroid Eros that its radio beacon continued to send a strong signal to Earth. Mission director Robert Farquhar said that if the craft's solar panels continue to generate electricity, the signal could last at least three months. But on Wednesday, Valentine's Day, the five-year mission officially ends, said Farquhar, and NASA's Deep Space Network will no longer relay signals from Eros, some 196 million miles away. ``We could still speak to it, but we won't be able to,'' he said. And, in any case, NEAR will eventually be silenced when the craft's landing point on Eros moves out of sunlight and the solar panels can no longer make electricity. The craft's signal then would slowly fade as its batteries died. NEAR's signal carries almost no information, so there is little likelihood of getting new scientific data from the spacecraft, which had been orbiting Eros for the past year and relaying photos and other information to Earth, officials said. The signal is little more than a hum that lets mission control known that NEAR is still alive - not of a quality high enough to send data or photos. The featherlight landing of the 1,100-pound NEAR - for Near Earth Asteroid Rendezvous - surprised even the most optimistic of mission officials. ``I just figured something had to go wrong, but it didn't,'' said Farquhar, the official who had first proposed the landing. He had estimated that the odds of NEAR being able to send a signal after landing was less than 1 percent. Some NASA officials even warned that it would be ``a controlled crash'' and not a landing on Eros, a potato-shaped object about 21 miles long. Instead, NEAR precisely fired its rockets to drop from a 15-mile orbit over the asteroid and then drifted down, slowed by four more rocket firings. It hit the asteroid, with rockets still firing, and bounced back up, before alighting firmly on the surface. Some engineers said the bounce may have carried NEAR more than 300 feet up in the low gravity of Eros, where an object dropped from six feet could take seconds to fall. ``This was a landing, not an impact,'' said Farquhar. He said the landing speed, relative to the surface of Eros, was about 3.5 miles an hour, a fast walk. The mission was controlled by the Johns Hopkins University Applied Physics Laboratory and funded by the National Aeronautics and Space Administration. ``They made a spacecraft that was only designed to orbit and then they put it down on an asteroid and it's still working,'' said Ed Weiler, NASA's chief scientist. ``That is amazing.'' NASA administrator Dan Goldin said Monday he first doubted NEAR's chances for a successful landing. ``I was dubious that we would ever get a signal back,'' he said. ``They pushed the boundaries. Wonderful, bold, courageous, brilliant - those are the words to come to mind.'' Goldin said he called the Mission Control Center in Houston, which is commanding the flight of space shuttle Atlantis to the International Space Station. ``I told them to tell the astronauts that we have just landed on an asteroid,'' said Goldin. After the news was relayed to the Atlantis crew, spacewalking astronaut Thomas Jones radioed back: ``I hope we'll have some astronauts following to the asteroids in just a few years.'' The United States does plan to send more robot missions to asteroids and to eventually land a craft on a comet and bring back samples. But no manned missions to an asteroid are planned. Putting a spacecraft on the asteroid was a major first for the United States. Never before had an American craft made the initial landing on an outer space body, NASA officials said. The first robot landings on the moon, Mars and Venus were all Soviet craft. Weiler said the NEAR landing taught valuable lessons that will help in future exploration of asteroids and comets. Such missions, he said, could be important if an asteroid such as Eros ever threatens the Earth. A similar space mountain is thought to have killed the dinosaurs 65 million years ago. ``This landing gives us a lot of practice,'' said Weiler. ``We'll eventually want to land on comets.'' NEAR achieved orbit of Eros, an asteroid named for the Greek god of love, on Valentine's Day last year. The landing completes a five-year, 2-billion-mile mission for NEAR and boosts the cheaper-faster-better philosophy pushed by NASA for exploring outer space. Developed by scientists at Johns Hopkins, NEAR was designed, built and launched in just 26 months, far shorter than most NASA missions. Its cost, $223 million, was less than expected. Johns Hopkins returned about $3 million to NASA, Weiler said. NEAR was launched Feb. 17, 1996, into an independent solar orbit. NEAR swung by the Earth once to pick up speed and then streaked outward toward Eros, which is in an elongated orbit that nears Mars and approaches Earth's orbit. On the Net: Mission site: http://near.jhuapl.edu Copyright 2001 Associated Press. ============= (4) NEAR SHOEMAKER SURVIVES ASTEROID LANDING >From Spaceflight Now <[EMAIL PROTECTED]] The NEAR Shoemaker probe is apparently alive and well after touching down on the surface of asteroid Eros today. The spacecraft returned remarkable close up views of the asteroid's surface as it swooped down to its historic landing. Check our home page for the latest news and pictures. http://spaceflightnow.com/ ============ (5) SPACECRAFT MAKES IMPROBABLE LANDING ON ASTEROID >From CNN, 12 February 2001 http://www.cnn.com/2001/TECH/space/02/12/near.landing.02/index.html Web posted at: 7:57 p.m. EST (0057 GMT) By Richard Stenger CNN.com Writer (CNN) -- A NASA robot ship ended a deep space odyssey by touching down on an asteroid on Monday, despite having no landing gear. Shortly after the first landing on an asteroid, excited mission managers were considering an almost unthinkable encore: coaxing the craft from its resting spot for another flight. NEAR engineers should decide within hours after landing whether to command the resilient robot to fire up its thrusters for a return to space, mission director Robert Farquhar said. "I am happy to report that the NEAR has touched down. We are still getting signals. It is still transmitting from the surface," said Farquhar as NEAR engineers cheered and clapped their hands. NEAR's landing was confirmed when mission control received a beacon signal from the craft resting on the surface of Eros, some 196 million miles from Earth. Before colliding with the space rock, the NEAR-Shoemaker spacecraft beamed back pictures with unprecedented clarity of the asteroid. NASA scientists hope to see features as small as a human hand when they process the images in the coming hours and days. Mission astronomers didn't expect the $225 million orbiter to survive the impact. It was designed to study, not land, on Eros, an oddly shaped rock whose appearance has been likened to everything from a potato to a kidney bean. But somehow against all odds it survived the landing and sent a radio message back home. Mission engineers think NEAR-Shoemaker landed on its side on a sunlit landing site between the South Pole and a distinctive saddle-shaped depression. NEAR-Shoemaker began descending toward the asteroid in the morning, drifting toward its rocky companion and using its thrusters to brake several times after closing to within 3 miles (5 km) of Eros. The spacecraft snapped dozens of pictures in its final hour, the closest only several hundred yards away, NEAR scientists said. It likely smacked into the surface at about 5 mph (8 km/h), according to NEAR scientists, a speed similar to that of a parachutist hitting the ground. Its yearlong mission over, its budget exhausted, its fuel spent, NEAR-Shoemaker was sent on the deadly dive to gain "bonus science," said Farquhar. NEAR scientists have puzzled over strange surface features first spotted in images in October. They hope the close-ups taken by the spacecraft will help to answer their questions about the geology of the asteroid more than 196 million miles from Earth. 'Another door has opened' Some unexplained erosion processes seem to have taken place on Eros, according to team scientist Joseph Veverka. "Suddenly we started seeing things we didn't expect and hadn't seen on other surfaces in the solar system," the Cornell University astronomer said. "It's like another door has opened." Already the spacecraft has sent home a bonanza of data about the composition, gravity and appearance of Eros, which it zapped with 11 million laser pulses and photographed almost 200,000 times. The pictures reveal a haunting panorama with fields of craters, mysterious bright spots and boulders the size of soccer fields. Some have been turned into dramatic movies of NEAR's close-up view as it swooped near the surface of the revolving rock. The data has given scientists clues about the history of the solar system. Eros is considered a geologic relic from the infancy of the solar system, which formed about 4.5 billion years ago. It could also prevent a future catastrophe. The 21-mile-long (34-km) Eros belongs to a group of large asteroids with orbits relatively close to Earth, like the one that scientists speculate slammed into Earth and killed off the dinosaurs 67 million years ago. Scientists warn that there is a remote risk another such killer asteroid will someday hit Earth. Learning about Eros could offer them clues to prevent such a catastrophic collision. Named after famed astronomer Eugene Shoemaker, a pioneer in lunar and asteroid studies, NEAR-Shoemaker traveled about 2 billion miles (3.2 billion km) during a trek that lasted five years. It was supposed to reach Eros in 1998 but a software glitch sparked a costly engine misfire that pushed back its arrival time until February 14, 2000. Eros became only the fifth celestial body touched by a human spacecraft, following the Moon, Mars, Venus and Jupiter. Copyright 2001, CNN ============= (6) METEORITES HARDER TO TRACE THAN FAMILY TREES >From Ron Baalke <[EMAIL PROTECTED]> >From San Francisco Chronicle, 12 February 2001 http://www.sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/2001/02/12 /MN192684.DTL Meteorites Harder to Trace Than Family Trees Chemicals, radiation help determine celestial parentage of former asteroids Keay Davidson San Francisco Chronicle February 12, 2001 In a modern-day version of the legendary quest for the source of the Nile, space scientists seek the source of the heavens' gift to Earth: meteorites. These fragments of rock and metal are chips off multibillion-year-old flying mountains -- asteroids -- that hurtle through the night sky and occasionally crash to Earth. Like birds and bugs, meteorites and asteroids aren't homogeneous: rather, they come in different varieties. For decades, space scientists have debated which types of meteorites come from which types of asteroids. "This, of course, is the Holy Grail of asteroid science -- to establish parent body asteroid types for each of the major classes of meteorites," says Donald K. Yeomans, a noted space scientist at NASA's Jet Propulsion Laboratory in Pasadena. Resolving this debate is a key goal of NASA's Near Earth Asteroid Rendezvous mission to the asteroid Eros. Today, if all goes as planned, the one-ton, 9-foot-long robotic spaceship will end its five-year, highly successful journey by crashing into the asteroid surface. One of NEAR's prime goals has been to use X-ray and gamma-ray spectrometers to analyze the surface of Eros. The scientists hope to determine how well Eros' chemical composition matches that of the commonest type of meteorites, technically dubbed "ordinary chondrites." Full story here: http://www.sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/2001/02/12 /MN192684.DTL ============== (7) CATASTOPHE/APOCALYPSE COURSE AT BARD COLLEGE >From Benny J Peiser <[EMAIL PROTECTED]> "Catastrophe/Apocalypse" is a course being given every fall at Bard College by Prof. William Mullen. Bill and his students have set up a website featuring this innovative course about "cenocatastrophism" and would appreciate feedback and suggestions by CCNet readers on how the course might be improved. They would also like to hear from others involved in similar courses elsewhere. Please feel free to send your comments and suggestions to [EMAIL PROTECTED] For further details about the course, see: http://inside.bard.edu/specialproj/clas214 ============================ * LETTERS TO THE MODERATOR * ============================ (8) NEO DEFLECTION BY NEO COLLISION/FLY-BY >From Christian Gritzner <[EMAIL PROTECTED]> Dear Benny, dear Mr. Frisbee, in CCNet 12 Febr. 2001, Joseph H. Frisbee presented his ideas on NEO deflection. I just want to add that the NEO deflection concept of inter-NEO collisions was already proposed at the "Near-Earth Object Interception Workshop" in Los Alamos in 1992 (LA-12476-C conference, issued Feb. 1993, LANL, NM 87545). In chapter 6 "Assessment of current and future technologies" (pp. 227-236) the two following concepts were presented: a) "Billiards Shot" - The orbit of a small NEO will be changed in this concept in order to achieve a collision with the (larger) NEO being on collision course with Earth. This method would be capable to deflect even 10 km-class NEOs. But this requires very accurate astrodynamical capability and the impacting NEO has to be available for this manoeuvre, i.e. we need a deflection system that provides enough delta-v for this. b) "Brilliant Mountains" - This concept was proposed by T. Zuppero which requires large amounts (1,000 to 10,000 tons) of (asteroidal/cometary/lunar) material in Earth orbit. These mass packages shall be directed onto a collision course with the incoming NEO which requires only a small delta-v. It is assumed that the collision (close to the Earth) would fragment the NEO and that these fragments would miss the Earth. Such concepts cannot be realised in the near future because they require a deflection system for the small impactor NEO which is not available today... But it is worth to further analyse this concept! If we study all the alternative mitigation concepts now, we will know what to do if the next NEO on collision course with our planet is discovered. The lead time available may decide whether the mitigation mission will be successful or not - this calls for intensified NEO detection and tracking activities, and for detailed studies on mitigation systems. Best wishes, Christian Gritzner -- Technische Universitaet Dresden Institut fuer Luft- und Raumfahrttechnik Dr.-Ing. Christian Gritzner, Senior Engineer 01062 Dresden, Germany Tel.: +49-351-463-8234 (Fax: -8126) E-mail: [EMAIL PROTECTED] Homepage: www.tu-dresden.de/mw/ilr/space/space.htm -------------------------------------------------------------------- THE CAMBRIDGE-CONFERENCE NETWORK (CCNet) -------------------------------------------------------------------- The CCNet is a scholarly electronic network. To subscribe/unsubscribe, please contact the moderator Benny J Peiser <[EMAIL PROTECTED]>. Information circulated on this network is for scholarly and educational use only. The attached information may not be copied or reproduced for any other purposes without prior permission of the copyright holders. 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