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By Daniel Fischer Every page present in Europe & the U.S.!
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The latest issue!
| A German companion! (SuW version) Current mission news: MGS (latest pictures!) + Cassini + Galileo + NEAR |
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GRB - supernova link strenghtened by new HST imagesThe first detailed images of a galaxy in which a gamma-ray burst has occurred, taken with one of Hubble's high-resolution cameras, reveal a barred spiral galaxy with numerous star-forming regions - and the gamma-ray burst has been located in one of them. It is the famous GRB 980425 that has raised eyebrows ever since it exploded in April, 1998, in a galaxy orders of magnitude closer than any of the other hosts where GRBs had been located before - and a galaxy where a strange supernova (SN 1998bw) was discovered just a day after the GRB. Was this a very special and extremely underluminous class of GRBs that had a link to supernovae? Or was it all just a coincidence?Several groups of astronomers have followed the development of this event closely over the last two years. On 12 June this year a group of European astronomers obtained very detailed observations of the host galaxy ESO 184-G82 for this gamma-ray burst with Hubble's STIS. They show that the host galaxy is actively star-forming and contains numerous clouds of hydrogen and regions teeming with activity from newly born hot stars. The galaxy is a spiral with loosely wound spiral arms and a large bar of gas and dust running through the center. The proximity of the host galaxy and the supernova's brilliant light has helped to pinpoint the location of the gamma-ray burst: It occurred in an active region in one of the galaxy's spiral arms. Here an underlying hydrogen gas complex is overlaid with several bright red giant stars. At the exact position of the gamma-ray burst a very compact source of emission is seen. Most of this emission is probably the last remnant of the fading light from the supernova itself, but the scientists suspect that a faint underlying star cluster may contribute as well. Most astronomers today believe that GRB 980425 and the supernova (less than 24 hours apart) did indeed arise from the same source - the probability of two such events occurring at the same place and at nearly the same time is perhaps as little as 1 in 10,000. Two other events have also indicated a link between gamma-ray bursts and supernova explosions, but the case of SN 1998bw and GRB 980425 is the strongest so far. |
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Three important Russian launches in close successionremain scheduled for mid-July: While the Zvezda module for the ISS has now a firm launch date of July 12, this decision has pushed the launch of the first two Cluster satellites back 3 days to July 15 - which is also the day when the small German CHAMP satellite will launch.
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Deep Space One restarts ion engine after navigation problem solved"Following a rescue mission of cosmic proportions," as the mission management puts it, Deep Space 1 is in powered flight again: Its advanced ion propulsion system is gently but persistently pushing the craft along as DS1 orbits the Sun - with comet Borrelly the next target. This is the result of "one of the most challenging yet one of the most successful and impressive robotic space rescues ever accomplished": Two months after the end of its extremely successful primary mission, Deep Space 1's star tracker, which was responsible for determining the probe's orientation in space, had ceased operating - but the engineers have come up with a way to restore the craft's sense of direction by writing new computer programs to use the camera instead of the star tracker.The new system that has allowed Deep Space 1 to regain full three-dimensional control and knowledge of its orientation works in part by taking pictures of a reference star. As the spacecraft rotates, the reference star appears to drift away from the center of the camera's view, so the computer programs analyze the pictures and determine how to reorient the craft to bring the star back to its intended location - this provides the means to keep the spacecraft stable. On June 21, with the spacecraft locked on a star in the view of the camera, after more than 7 months of dormancy the ion propulsion system obediently began thrusting. The attitude control system, whose on-board task of controlling the spacecraft's orientation was made so difficult when the star tracker failed, not only has to keep the spacecraft steady while the ion propulsion system is firing, but it actually uses the ion drive to stabilize the spacecraft's rotation whenever it is thrusting. After testing this in the Deep Space 1 simulators located on Earth, controllers were eager to see how well it would work on the real spacecraft. They were rewarded when data transmitted from the tremendously distant probe revealed that it was operating exactly as it was supposed to. Engineers have devised a new way to chart a course from where DS1 is now to where it will reach the comet by thrusting with just a few selected stars in the camera's view during the next year. |
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NEAR Shoemaker has Eros coveredTo NEAR Shoemaker's digital camera it was merely another sequence of images. But the photos of Eros' south pole snapped in the early hours of June 27 will give NEAR team members the last pieces of a global puzzle, covering the only ground on Eros they haven't seen since the satellite began orbiting the asteroid on Feb. 14. It's autumn in the asteroid's northern hemisphere, which means the sun is illuminating the southern regions that were shadowed through the first months of NEAR Shoemaker's orbit. Now that it has a overall view of Eros, the NEAR team can start to train the camera on specific details among the asteroid's craters, ridges, grooves, boulders and troughs.The camera couldn't "see" the areas earlier because it needs reflected light from the surface, so most of the imaging covered the northern sections. The NEAR team will get its closest look yet at those features on July 14, when the spacecraft begins a 10-day, nearly circular orbit just 35 x 37 km from the asteroid's surface. NEAR Shoemaker will start to descend from its current 50 km circular orbit on July 7 at 18:00 UTC and finally return to it by the 31st at 16:00 UTC. The spacecraft is 118 million kilometers from Earth, circling Eros at just under 11 kilometers an hour. |
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Perhaps the most spectacular solar eclipse image everhas now been generated by Christian Viladrich from 17 individual images he took during the totality of 1998 from Guadeloupe. "I used a Fluorite 55 mm F/8 refractor on motorized equatorial mount, OM1 camera with winder," Viladrich explains: "Kodak Royal 100 negative film [was used] for better dynamic range. The film was scanned with Nikon LS2000 scanner at 2700 dpi, X16 multi-scan (for better S/N) and 12 bit per color (for better shade separation). Each color was processed separately with 16 bits resolution with Qmips (a French software) and AstroArt (an Italian software). Photoshop was used for color correction.17 images were composited : 2 x 4 s exposures, 7 x 1 s exposures, 4 x 1/30 s exposures, 4 x 1/250 exposures. The 7 x 1 s exposures were registered with respect to stars and processed with a radial mask to reduce the radial gradient brightness of the corona. The 4x1/30s and 4x1/250 s were registered with respect to prominences and inner corona, then added to the 7 x 1s composit, and processed with a non symetric radial mask to reduce the large scale brightness differences between different azimuths of the inner corona. The problem with the previous processing is that the moon surface is blurred [...]. So the last step was to register the 2x4 s and 7x1s exposures with respect to the moon disk to have a better view of lunar surface." |
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Mars headlines galoreWhile the scientific evaluation of the puzzling features in the MGS images will take months to come, there have been numerous articles on all kinds of related topics:
Throw Galileo eventually into Jupiter or onto Iobut never onto Europa (and better also not onto Ganymede or Callisto), the Space Studies Board's Committee on Planetary and Lunar Exploration (COMPLEX) has recommended - NASA should chose a trajectory that leads to a defined end of Galileo's mission, but which would also generate even more exciting science. A solution with several close Io flybys might thus be the preferred way to go: Disposal Options, a summary, coverage by Space Daily, SpaceRef, AP, SpaceViews, Discovery, SPIEGEL, Fla. Today, Space.com, Spaceflight Now.All future spacecraft to Europa must be sterilized, even if that makes the mission significantly more expensive, another study has recommended - although a minority thinks that's not necessary: NRC Study, coverage by SpaceViews. A new model for the cracks in Europa's surface has tidal forces due to Jupiter's gravity make planes of ice flow across each other in narrow zones, creating frictional heat and "warm, soft ice" - with liquid water appearing there for short intervals, perhaps long enough for primitive life to bloom: NSU, Space.com, SpaceViews. |
The first accurate ratio of deuterium to hydrogen in the Galactic Centermeasured now shows that there is almost ten times less deuterium at the center of the galaxy than in our own neighbourhood. But on the other hand, the measured abundance is 100,000 times greater than it should be, after considering the gas that has been processed through the centers of stars - this can only mean that the deuterium has fallen into the center of the galaxy from outside: Nature Science Update and Williams Press Release (EurekAlert version); coverage by BBC, Space.com, SpaceViews.First Light for INGRIDThe Isaac Newton Group Red Imaging Device (INGRID) saw its first light on the William Herschel Telescope on March 16 - it provides astronomers with the opportunity to make large field of view, deep near-infrared observations of the universe, as demonstrated by the images achieved on the first night of scientific use: ING Press Release.Meet the 747 that will once become SOFIA, the flying infrared observatory: CSM. Portugal becomes the 9th ESO member state - it will formally join the organisation on January 1, 2001: ESO Press Release. Next generation NASA communications satellite aloftNASA's most advanced communications satellite roared into space on June 30 - once deployed, the Tracking and Data Relay Satellite will become known as TDRS-8: CNN, Space.com, SpaceViews, Spaceflight Now.The most sophisticated nanosatellitelaunched so far was onboard a Russian Cosmos rocket on June 28: SNAP-1, joining Tsinghua-1 and Nadezhda-M COSPAS/SARSAT. The 6.5 kg SNAP-1 with its 'machine vision' will later try to rendezvous with Tsinghua-1 - a maneuver that could be used in future missions for orbital debris removal: Press Release, SNAP-1 and Tsinghua-1 Homepages, SpaceViews, Spaceflight Now, BBC.Did a hacker endanger astronauts during a 1997 mission?A computer hacker endangered shuttle astronauts in 1997 by overloading NASA's communication system to such an extent that it interfered with communications, the BBC has claimed - NASA denies, though, that the incident was that severe: BBC, Space.com, AP, NASA News Release, SpaceViews, ABC, AP again, AFP, CNN, Fla. Today.China's next test of the Shenzhou space capsule will probably come later this year, with the first manned use some time in 2001: AP, Space Daily, Space.com, Spaceflight Now, SpaceViews. Earlier: BBC. |
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Compiled and written by Daniel Fischer
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