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By Daniel Fischer Every page present in Europe & the U.S.!
| Ahead | Awards 
The latest issue!
| A German companion! (SuW version) Current mission news: MGS (latest pictures!) + Cassini + Galileo + NEAR |
a picture, a JPL Press Release and stories from Fla. Today, Space.com, AP.
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NASA to launch a rover - or two! - to Mars in 2003It was a very tough decision, even delayed by some days, but NASA is now positive that it wants to launch a sophisticated rover to Mars in the 2003 launch window - and perhaps even two rovers to two different destinations. Most importantly, the spacecraft will go down with the same airbag technology that was so successful in 1997 with the Mars Pathfinder. The mission, called Mars Exploration Program Rover, was chosen over an orbiter alternative (see Update #189 story 2): With far greater mobility and scientific capability than the 1997 Sojourner rover, this new robotic explorer will be able to trek up to 100 meters across the surface each Martian day.The Mars rover will carry a sophisticated set of instruments that will allow it to search for evidence of liquid water that may have been present in the planet's past, as well as study the geologic building blocks on the surface. "This mission will give us the first ever robot field geologist on Mars," says Scott Hubbard, Mars program director at NASA Headquarters: "It not only has the potential for breakthrough scientific discoveries, but also gives us necessary experience in full-scale surface science operations which will benefit all future missions." Whether there are to be 1 or 2 rovers is to be decided within weeks. After launch on top a Delta II rocket and a cruise of seven and a half months, the spacecraft will enter the Martian atmosphere January 20, 2004. In a landing similar to that of the Pathfinder spacecraft, a parachute will deploy to slow the spacecraft down, and airbags will inflate to cushion the landing. Where the Pathfinder mission consisted of a lander, with science instruments and camera, as well as the small Sojourner rover, the Mars 2003 mission features a design that is dramatically different: This new spacecraft will consist entirely of the large, long-range rover, which comes to the surface inside a Pathfinder landing system, making it essentially a mobile scientific lander. |
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Nucleus of comet LINEAR disrupts, finishing its mixed performanceHyped comet had disappointed visual observers, delighted photographers and thrilled Hubble and Chandra scientists - and then the nucleus disintegrated just before perihelionWhile the brightness of the much anticipated - if not hyped - comet C/1999 S4 (LINEAR) stayed even below the worst-case predictions eventually, never much exceeding 6.5 magnitudes, the comet's quickly changing plasma tail was a delight for experienced astrophotographers. And just when the Hubble Space Telescope was turned towards the faint object, it underwent a rare violent outburst. The eruption on July 5 spewed a great deal of dust into space, which reflected sunlight and dramatically increased the comet's brightness over several hours (though ground-based telescopes did not clearly pick up the brief eruption). And then the nucleus acted up again on June 23rd - this time with apparently fatal results for the comet which is since fading rapidly.Hubble's Space Telescope Imaging Spectrograph had tracked the comet from July 5 to 7, capturing a leap in brightness and discovering the castaway chunk of material sailing along its tail. When the HST first spied the comet, it watched the icy object's brightness rise by about 50 percent in less than four hours. By the next day, the comet was a third less luminous than it had been the previous day. On the final day, the comet was back to normal - one-seventh less bright than at peak level. During the outburst's peak the comet apparently jettisoned the piece of its crust seen days later in the tail. The renegade fragment moved away from the core's weak gravitational grasp at an average speed of about 10 km/h. Did the nucleus just disappear?Much more dramatic things happened around July 24th, however, this time monitored from the ground: The nucleus of the comet seems to have disintegrated completely! According to observations with the Jacobus Kapteyn Telescope on La Palma, Canary Islands, "the central condensation was highly condensed and showed the typical 'teardrop' form in the evening of July 23rd and July 24th, although its brightness decreased by a factor of about 3 between the two nights," says Mark Kidger from the IAC: "In the evening of July 25th something very odd was happening to the comet: the central condensation was seen to be strongly elongated, with a very flat brightness distribution.The condensation's brightness faded further and its length increased on the following nights. On July 27 there was no evidence of any local brightness peaks that would indicate the presence of sub-nuclei." In other words, the nucleus does not appear to have broken into individual fragments in the way that Comet Shoemaker-Levy 9 did in 1993. Instead, it has completely blown apart! The expansion velocity of the condensation is about 40 m/s, indicating that it is solid particles and not gas. The gas tail, which virtually disappeared between July 23rd and 24th, has reformed as an extension of the major axis of the central condensation. Telltale X-rays prove popular modelA less dramatic but crucial observation of LINEAR was also performed by the Chandra X-ray satellite, which on July 14 imaged the comet and detected X-rays from oxygen and nitrogen ions. This strong X-ray signal clinches the case for the production of X-rays due to the exchange of electrons in collisions between nitrogen and oxygen ions in the solar wind and electrically neutral elements (predominantly hydrogen) in the comet's atmosphere (see Update # 55). "This observation solves one mystery. It proves how comets produce X-rays," says Carey Lisse of the STScI who led the observations: "With an instrument like Chandra, we can now study the chemistry of the solar wind and observe the X-ray glow of the atmosphere of comets, as well as other planets such as Venus." |
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New target asteroid for Japanese sample return mission"As a result of a tight launch schedule, the Japanese MUSES-C project has announced that their target asteroid has been switched from 10302 (1989 ML) to 1998 SF36," the NASA project scientist of the small attached lander MUSES-CN, Don Yeomans, has announced: "The new mission time line is: Launch: Nov. - Dec. 2002 / Earth Swingby: May 2004 / Asteroid arrival: Sept. 2005 / Asteroid departure: Jan. 2006 / Earth sample return: June 2007." 1998 SF36 has a diameter of roughly one kilometer and is classified as a "Potentially Hazardous Object" since its orbit approaches that of the Earth to within 0.05 AU (less than 7.5 million km).The orbit (perihelion distance: 0.95 AU, aphelion distance: 1.70 AU, semi-major axis: 1.32 AU, orbital period: 1.53 years, eccentricity: 0.28) is still uncertain since it is based upon a data interval of 46 days only. The next two Earth close approaches are in 2001 and 2004, when the asteroid will reach 14th and 13th magnitude, respectively: "Before, during, and after these Earth close approaches, we hope that observers will make an effort to characterize this asteroid's rotation rate, rotation pole direction, albedo, thermal properties, size, shape, and spectral classification," says Yeomans: "Astrometric observations will also be necessary to update its orbit." |
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NEAR back at 50 km, preparing for the final adventuresNEAR Shoemaker returned to familiar territory on July 31, after a minute-long engine burn settled the spacecraft in a circular orbit 50 km from asteroid Eros. The burn wrapped up a busy month for the NEAR mission team - 4 maneuvers in all, dipping the spacecraft to an orbit 35 km from the asteroid's center before pulling it back to its latest position. Since meeting up with Eros on Feb. 14, NEAR Shoemaker has spent more time at 50 km - the ideal altitude for the spacecraft's scientific instruments - than any other distance. Higher orbits over the next three months will allow the spacecraft to gather images and data on sections of the asteroid hidden in shadows during the early months of the mission.However, NEAR team members are currently sifting through the collection of detailed, high-resolution images snapped during the past few weeks, when NEAR Shoemaker came as low as 18 km from the tips of the long, peanut-shaped space rock. "The images show a lot of things we just couldn't see before, like linear features inside the craters," says NEAR imaging team member Louise Prockter: "You can also see small-scale detail on features such as the boulders." NEAR's next maneuver will be on August 8, a thruster burn that will just shift the inclination of its orbit. A few weeks later NEAR will be put into a 100-km orbit to do more global mapping of the asteroid, particularly of the southern hemisphere hidden in shadow earlier in the year. |
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SPACEWATCH finds possible new moon of JupiterFirst it was thought that the object 1999 UX18 found by the SPACEWATCH asteroid-hunting telescope last fall was just another asteroid - but orbital calculations have now shown that the faint 20 to 21 magnitude body is apparently in a wide orbit around the planet Jupiter and would thus be its 17th known moon. The discovery was no coincidence, though, as the time around Jupiter's closest approach to Earth had been used for a systematic search with the old 36-inch telescope (and its modern CCD camera) for unknown satellites of Jupiter.Nobody noticed at first, however, that one of the many objects discovered during the survey and given the asteroid designation 1999 UX18 was moving in a slightly unusual manner - a manner in fact suggesting that it might be a comet, except that it didn't look like one. And the work of both SPACEWATCH and the Minor Planet Center where the orbits of all asteroids are monitored had to move on, with numerous more electronic scans by the former and the processing by the latter including night-to-night linkages of data also from observing programs that nightly cover a much greater area of sky than SPACEWATCH. Only this May, when the old data were reanalyzed while trying out a new computer program, it dawned on the MPC astronomers that 1999 UX18 was not in a heliocentric orbit but one around the giant planet. Now it is designated S/1999 J 1, but unfortunately its precise orbit isn't known yet: No earlier sightings turned up in the MPC's huge data base. But is seems clear that the new satellite belongs to a subgroup that travel around Jupiter in irregular orbits around an average distance of 25 million km from the planet and take some two years to do so. The sun's gravitational influence makes these orbits highly erratic. The satellites orbit Jupiter in the opposite direction to the other jovian satellites and have undoubtedly been captured long ago in the past from orbits about the sun. S/1999 J 1 is the first reasonably established outer satellite of Jupiter to be found since Charles Kowal discovered Jupiter XIII, a member of the other subgroup of outer satellites, in 1974. With only about 10 km in size, this moon (named Leda) is so far the smallest confirmed planetary satellite - if the circumjovian orbit of S/1999 J 1 is confirmed, it would break that record as its diameter is only about 5 km. |
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Tau neutrino detected - and more evidence for neutrino oscillationsTwo major announcements about successful neutrino experiments - one of the hardest fields of physics, given the weak interactions of these fundamental particles - have been announced in late July: At Fermilab several detections of Tau neutrinos were reported, and in Japan an experiment that shot a neutrino beam through hundreds of kilometers of rock has confirmed that neutrinos oscillate from one flavor into another, just as observations of atmospheric neutrinos had shown two years earlier (see Update # 82).The Fermilab scientists had fired an intense neutrino beam (created by directing a high-energy proton beam toward a block of high-density material like tungsten), which they expected to contain tau neutrinos, into the meter-long "DONUT" target of iron plates sandwiched with layers of emulsion, which recorded the particle interactions. In the target, one out of one million million tau neutrinos interacted with an iron nucleus and produced a tau lepton, which left its one-millimeter-long tell-tale track in the emulsion. The physicists needed about three years of painstaking work to identify the tracks revealing a tau lepton and its decay, the key to exposing the tau neutrino's secret existence, and have found 4 or 5 convincing cases. The new evidence for neutrino oscillatios comes from the K2K (KEK-to-Kamioka) Long Baseline Neutrino Oscillation Experiment in which the Super-Kamiokande detector detects artificially produced muon neutrinos fired from KEK laboratory's 12 GeV Proton Synchrotron, 250 km away. Until the end of March 2000, 17 neutrinos fired from KEK were detected inside the central 22,500 tons of the 50,000-ton water Cherenkov detector Super-K, but 29.2+3.5-3.3 neutrino events were expected - which means that null neutrino oscillation is disfavored at 2 sigma level (in other words, the hypothesis of neutrino oscillation is favored at about 95% probability). The measurements will continue until a 3 sigma level - when the discovery is really significant - is reached. |
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Zvezda - and its German computer - take control of the ISSThe International Space Station now is under computer control from its newest addition, the Zvezda service module, following a `handover' of that responsibility in late July after the successful docking of the module early on the 26th. Zvezda now is handling all attitude maneuvers of the 60-ton complex through its own Motion Control System following the automatic docking. Since then, leak checks have been performed verifying a tight seal between Zarya and Zvezda. Additionally, commanding through the Unity node's early communications system was transferred to Zvezda as well, meaning that equipment can be powered via ground commands sent from Moscow, through Houston and up to the station.Meanwhile ISS main contractor Boeing and Russia's Khrunichev State Research and Production Space Center have announced a cooperative planning effort to market a commercial space module (CSM) that could attach to the ISS as early as 2002: The CSM would be a sister module to Zarya, the first element of the ISS (it would be based on a spare module built for the case Zarya was lost). The multi-purpose module could be used to deliver propellant and cargo to ISS, and when docked to the station, provide on-orbit storage, interim crew quarters, accommodations for multimedia, scientific, and communications equipment, and waste management capabilities. External pallets could be used for Earth observation instrumentation, astrophysical research and additional external storage. |
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A Planetary Nebula in globular cluster M 15has been imaged by Hubble - the object known as Kuestner 648 was the first planetary nebula to be identified in a globular cluster: STScI Caption, CNN, Discovery, Space.com, SpaceViews.What to do with the HST after its mission is over is already being debated - bringing it back is the leading option, followed by parking it in a higher 'graveyard orbit': Fla. Today. Early results from the FUSE satellite (see also Update # 167 story 4) have eliminated the possibility that one leading suspect, molecular hydrogen, accounts for any significant portion of dark matter - now the bet is on million-degree gas: U of Chicago Press Release (Space Daily version). The most distant novae ever seenhave been spotted by the Very Large Telescope - in the Fornax galaxy cluster 70 million light years away, where no less than four novae were detected in a single giant galaxy within only 11 days: ESO Press Release, Space.com, SPIEGEL. The VLT is nearing completion: Discovery.Is Pluto Express in danger of cancellation?The bold new Mars plans (see lead story) could, as a side effect, cause to the cancellation of the 2003 or 2004 NASA mission to Pluto and the Kuiper Belt, though NASA says no decisions have been made yet: Planetary Society message, CNN, SpaceViews.Big cash for new SETI telecope arrayTechnologists Paul G. Allen and Nathan P. Myhrvold have announced $12.5 million in support for a revolutionary new telescope to advance the Search for Extra-Terrestrial Intelligence (SETI) - the new instrument to be called Allen Telescope Array (formerly known as the "one hectare telescope") will also advance other astronomical research: SETI Institute Welcome page and Press Release, coverage by San Jose Mercury News, Space.com, Discovery, Reuters, SpaceViews. |
Clusters in final orbit as 2nd launch approachesAfter one of the most complex series of manoeuvres ever carried out by Earth-orbiting spacecraft, the first Cluster pair have successfully reached their final elliptical orbit: ESA Science News, SpaceViews, RP, CSM.The 2nd launch will be on August 9 at 11:13 UTC: ESA Science News. German amateurs capture Cluster pair: Heppenheim page and ESA Science News. Cluster Project Manager looks back to a perfect launch: ESA Science News. CHAMP working fine, too, with all instruments activated since late July: JPL and GFZ Press Releases plus all the CHAMP Bulletins. SeaLaunch is back in businessafter a successful launch on July 28: Boeing Press Release, CNN, Space.com, Spacefl. Now, RP, SpaceViews. Next launch set for September: Space Daily, Space.com.MightySat II.1 is fine after its Minotaur launch - the cheap satellite will demonstrate on-orbit, high payoff space system technologies: Space Daily. Japanese mini-shuttle program on hold since it is unclear on what rocket Hope-X would be launched: Spaceflight Now.
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