STORY WRITTEN FOR & USED WITH PERMISSIONPosted: January 14, 2005Robert Mitchell, NASA's Cassini program manager at the Jet Propulsion Laboratory in Pasadena, Calif., says the loss of one telemetry stream from the Huygens Titan probe appears to be the result of an actual problem of some sort on board the spacecraft."The evidence we have a problem on chain A is pretty clear," he said. "I don't think the continuing playback (of Huygens data from Cassini) is going to resolve that problem. We just need to sort out what happened with it."Engineers at the European Space Agency's Space Operations Center in Germany are receiving data from Huygens on chain, or channel, B but not from chain A. Both systems are identical and scientists should receive almost all of the desired data from chain B, Mitchell said."The way the probe system works, there are two transmitters on the probe and there are two separate receivers on the orbiter so we have two separate, distinct data links between the probe and the orbiter," he said. "These data links were deigned to be largely redundant, not 100 percent, but nearly so."The way we sit now, it's clear that the B channel is coming in loud and clear and up to this point, we haven't missed a single data packet. Now on the A channel, we do have a problem and we're still sorting out what happened thre. But this, I think, will be only a minor lien on the significance of the success that's been accomplished here just because of the redundancy between the two sides."Of course, the reason you put redundancy in the design to begin with is to make yourself resilient to whatever may have happened here," Mitchell said. "So we're still sorting out exactly what happened to the A chain, but we've got at least most of the data we expected to get."Video coverage for subscribers only:VIDEO:STATUS REPORT DURING DESCENT AUDIO:TODAY'S STATUS REPORT DURING DESCENT VIDEO:HUYGENS PRE-ARRIVAL NEWS BRIEFING AUDIO:HUYGENS PRE-ARRIVAL NEWS BRIEFING VIDEO:OVERVIEW OF HUYGENS PROBE'S SCIENCE OBJECTIVES VIDEO:JULY NEWS BRIEFING ON CASSINI'S PICTURES OF TITAN VIDEO:PICTURES SHOWING TITAN SURFACE FROM OCT. FLYBY VIDEO:WHAT'S KNOWN ABOUT TITAN BEFORE THE FIRST FLYBY VIDEO:NARRATED MOVIE OF CLOUDS MOVING NEAR SOUTH POLE VIDEO:OCT. BRIEFING ON RADAR IMAGES OF TITAN SURFACE Ares 1-X PatchThe official embroidered patch for the Ares 1-X rocket test flight, is available for purchase.Apollo CollageThis beautiful one piece set features the Apollo program emblem surrounded by the individual mission logos.Expedition 21The official embroidered patch for the International Space Station Expedition 21 crew is now available from our stores.Hubble PatchThe official embroidered patch for mission STS-125, the space shuttle's last planned service call to the Hubble Space Telescope, is available for purchase. | | | | 2014 Spaceflight Now Inc.Out from the shadows: Two new Saturnian moons CASSINI PHOTO RELEASEPosted: August 16, 2004With eyes sharper than any that have peered at Saturn before, the Cassini spacecraft has uncovered two moons, which may be the smallest bodies so far seen around the ringed planet. This image shows the tiny 'worldlet,' temporarily dubbed S/2004 S1, as it makes its way around the planet. A white box frames the moon's location in the image. Credit: NASA/JPL/Space Science InstituteThe moons are approximately 3 kilometers (2 miles) and 4kilometers (2.5 miles) across -- smaller than the city ofBoulder, Colorado. The moons, located 194,000 kilometers(120,000 miles) and 211,000 kilometers (131,000 miles) from theplanet's center, are between the orbits of two other saturnianmoons, Mimas and Enceladus. They are provisionally namedS/2004 S1 and S/2004 S2. One of them, S/2004 S1, may be anobject spotted in a single image taken by NASA's Voyagerspacecraft 23 years ago, called at that time S/1981 S14."One of our major objectives in returning to Saturn was tosurvey the entire system for new bodies," said Dr. CarolynPorco, imaging team leader, Space Science Institute, Boulder,Colo. Porco planned the imaging sequences. "So, it's reallygratifying to know that among all the other fantasticdiscoveries we will make over the next four years, we can nowadd the confirmation of two new moons, skipping unnoticedaround Saturn for billions of years until just now.?The moons were first seen by Dr. Sebastien Charnoz, a planetarydynamicist working with Dr. Andre Brahic, imaging team memberat the University of Paris. "Discovering these faintsatellites was an exciting experience, especially the feelingof being the first person to see a new body of our solarsystem," said Charnoz. "I had looked for such objects forweeks while at my office in Paris, but it was only once onholiday, using my laptop, that my code eventually detectedthem. This tells me I should take more holidays."The smallest previously known moons around Saturn are about 20kilometers (12 miles) across. Scientists expected that moonsas small as S/2004 S1 and S/2004 S2 might be found within gapsin the rings and perhaps near the F ring, so they weresurprised these small bodies are between two major moons. Smallcomets careening around the outer solar system would beexpected to collide with small moons and break them to bits. This shows the second new 'worldlet,' temporarily dubbed S/2004 S2. Credit: NASA/JPL/Space Science InstituteThe fact that these moons exist where they do might providelimits on the number of small comets in the outer solar system,a quantity essential for understanding the Kuiper Belt ofcomets beyond Neptune, and the cratering histories of the moonsof the giant planets."A comet striking an inner moon of Saturn moves many timesfaster than a speeding bullet," said Dr. Luke Dones, an imagingteam member from the Southwest Research Institute in Boulder,Colo. "If small, house-sized comets are common, these moonsshould have been blown apart many times by cometary impactsduring the history of the solar system. The disrupted moonwould form a ring, and then most of the material wouldeventually gather back together into a moon. However, if smallcomets are rare, as they seem to be in the Jupiter system, thenew moons might have survived since the early days of the solarsystem."Moons surrounding the giant planets generally are not foundwhere they originally formed because tidal forces from theplanet can cause them to drift from their original locations.In drifting, they may sweep through locations where other moonsdisturb them, making their orbits eccentric or inclinedrelative to the planet's equator. One of the new moons mighthave undergone such an evolution.Upcoming imaging sequences will scour the gaps in Saturn'srings in search of moons believed to be there. Meanwhile,Cassini scientists are eager to get a closer look, if at allpossible, at their new finds. Porco said, "We are at this verymoment looking to see what the best times are for retargeting.Hopefully, we haven't seen the last of them."The Cassini-Huygens mission is a cooperative project of NASA,the European Space Agency and the Italian Space Agency. The JetPropulsion Laboratory, a division of the California Instituteof Technology in Pasadena, manages the Cassini-Huygens missionfor NASA's Science Mission Directorate, Washington, D.C. TheCassini orbiter and its two onboard cameras were designed,developed and assembled at JPL. The imaging team is based atthe Space Science Institute, Boulder, Colo.Ares 1-X PatchThe official embroidered patch for the Ares 1-X rocket test flight, is available for purchase.Apollo CollageThis beautiful one piece set features the Apollo program emblem surrounded by the individual mission logos.Expedition 21The official embroidered patch for the International Space Station Expedition 21 crew is now available from our stores.Hubble PatchThe official embroidered patch for mission STS-125, the space shuttle's last planned service call to the Hubble Space Telescope, is available for purchase. | | | | 2014 Spaceflight Now Inc.Phoebe's surface gives scientists clues to its origin CASSINI PHOTO RELEASEPosted: June 14, 2004Images collected during Cassini's close flyby of Saturn's moon, Phoebe, have yielded strong evidence that the tiny object may contain ice-rich material, overlain with a thin layer of darker material perhaps 300 to 500 meters (980 to 1,600 feet) thick. The surface of Phoebe is also heavily potholed with large and small craters. Images revealbright streaks in the ramparts of the largest craters, bright rays which emanate from smaller craters, and uninterrupted grooves across the face of the body."The imaging team is in hot debate at the moment on the interpretations of our findings," said Dr. Carolyn Porco, Cassini imaging team leader at the Space Science Institute in Boulder, Colo. "Based on our images, some of us are leaning towards the view that has been promoted recently, that Phoebe is probably ice-rich and may be an object originating in the outer solar system, more related to comets and Kuiper Belt objects than to asteroids."In ascertaining Phoebe's origin, imaging scientists are noting important differences between the surface of Phoebe and that of rocky asteroids which have been seen at comparable resolution. "Asteroids seen up close, like Ida, Mathilde, and Eros, and the small martian satellites do not have the bright 'speckling' associated with the small craters that are seen on Phoebe," said Dr. Peter Thomas, an imaging team member from Cornell University, Ithaca, N.Y.The landforms observed in the highest resolution images also contain clues to the internal structure of Phoebe. Dr. Alfred McEwen, an imaging team member from the University of Arizona, Tucson, said, "Phoebe is a world of dramatic landforms, with craters everywhere, landslides, and linear structures such as grooves, ridges, and chains of pits. These are clues to the internal properties of Phoebe, which we'll be looking at very closely in order to understand Phoebe's origin and evolution.""I think these images are showing us an ancient remnant of the bodies that formed over four billion years ago in the outer reaches of the solar system," said Dr. Torrence Johnson, an imaging team member from NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Battered and beat-up as it is, it is still giving us clues to its origin and history."Phoebe may be an icy interloper from the distant outer solar system which found itself captured by giant Saturn in its earliest, formative years. Final conclusions on Phoebe's origins await a combination of the results on Phoebe's surface structures, mass and composition gathered from all 11 instruments, which collected data during the flyby on June 11, 2004."This has been an impressive whirlwind flyby and it's only a curtain raiser on the events about to begin," said Porco. Credit: NASA/JPL/Space Science InstituteDownload larger image version FIRST IMAGE: Images like this one, showing bright wispy streaks thought to be ice revealed by subsidence of crater walls, are leading to the view that Phoebe is an ice-rich body overlain with a thin layer of dark material. Obvious down slope motion of material occurring along the walls of the major craters in this image is the cause for the bright streaks, which are over-exposed here. Significant slumping has occurred along the crater wall at top left. The slumping of material might have occurred by a small projectile punching into the steep slope of the wall of a pre-existing larger crater. Another possibility is that the material collapsed when triggered by another impact elsewhere on Phoebe. Note that the bright, exposed areas of ice are not very uniform along the wall. Small craters are exposing bright material on the hummocky floor of the larger crater. Elsewhere on this image, there are local areas of outcropping along the larger crater wall where denser, more resistant material is located. Whether these outcrops are large blocks being exhumed by landslides or actual 'bedrock' is not currently understood. The crater on the left, with most of the bright streamers, is about 45 kilometers (28 miles) in diameter, front to back as viewed. The larger depression in which the crater sits is on the order of 100 kilometers (62 miles) across. The slopes from the rim down to the hummocky floor are approximately 20 kilometers (12 miles) long; many of the bright streamers on the crater wall are on the order of 10 kilometers (6 miles) long. A future project for Cassini image scientists will be to work out the chronology of slumping events in this scene. This image was obtained at a phase, or Sun-Phoebe-spacecraft, angle of 78 degrees, and from a distance of 11,918 kilometers (7,407 miles). The image scale is approximately 70 meters (230 feet) per pixel. No enhancement was performed on this image. Credit: NASA/JPL/Space Science InstituteDownload larger image version SECOND IMAGE: A mosaic of two images of Saturn's moon Phoebe taken shortly after Cassini's flyby on June 11, 2004, gives a close-up view of a region near its South Pole. The view, taken about 13,000 kilometers (8,000 miles) from Phoebe, is about 120 kilometers (74 miles) across and shows a region battered by craters. Brighter material, likely to be ice, is exposed by small craters and streams down the slopes of large craters. The skyline is a combination of Phoebe's shape and the formation of impact craters. Walls of some of the larger craters are more than 4 kilometers (2.5 miles) high. The image scale is 80 meters (264 feet) per pixel. Credit: NASA/JPL/Space Science InstituteDownload larger image version THIRD IMAGE: Shown here is a mosaic of seven of the sharpest, highest resolution images taken of Phoebe during Cassini's close flyby of the tiny moon. The image scales range from 27 to 13 meters (90 to 43 feet) per pixel. Smaller and smaller craters can be resolved as resolution increases from left to right. The number of blocks, or bumps on the surface also increases to the right. The Sun is coming from the right, so the bright-dark pattern is reversed between blocks and small craters. Grooves or chains of pits are seen on the left portion of the mosaic, which may mark fractures or faults induced by large impact events. Many of the small craters have bright rays, similar to recent craters on the Moon. There are also bright streaks on steep slopes, perhaps where loose material slid downhill during the seismic shaking of impact events. There are also places where especially dark materials are present, perhaps rich in carbon compounds. Credit: NASA/JPL/Space Science InstituteDownload larger image version FOURTH IMAGE: On June 11, 2004, during its closest approach to Phoebe, Cassini obtained this extremely high resolution view of a dark, desolate landscape. Regions of different reflectivity are clearly visible on what appears to be a gently rolling surface. Notable are several bright-rayed impact craters, lots of small craters with bright-colored floors and light-colored streaks across the landscape. Note also the several sharply defined craters -- probably fairly young features -- near the upper left corner. This high-resolution image was obtained at a phase, or Sun-Phoebe-spacecraft, angle of 30.7 degrees, and from a distance of approximately 2,365 kilometers (1,470 miles). The image scale is approximately 14 meters (46 feet) per pixel. The image was high-pass filtered to bring out small scale features and then enhanced in contrast. Fallen Heroes special patchThis special 12-inch embroidered patch commemorates the U.S. astronauts who made the ultimate sacrifice, honoring the crews of Apollo 1, Challenger and Columbia.Choose your store: - - - Moon RushThis book examines how the exploration of space, specifically a commercial base on the Moon and Mars would transform our economies on the Earth as surely as the discovery of the New World transformed the old world of Europe.Choose your store: - - - Apollo 11 special patchSpecial collectors' patch marking the 35th anniversary of the historic Apollo 11 moon landing is now available.Choose your store: - - - Get inside Apollo!Full color drawings reveal like never before the details of the Apollo Command and Service Modules .Choose your store: - - - | | | | 2014 Spaceflight Now Inc.Pictures show active world shaped by cryogenic liquids BY WILLIAM HARWOOD
