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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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Discovery in orbit after numerous delaysMinor technical issues, bad weather and a metal pin forgotten on the launch pad had delayed the 100th shuttle mission by 6 days, but late on October 11th Discovery finally made it - and caused a rare sky show as the upper part of the SRBs' exhaust plume was illuminated bright red by sunlight propagating through the atmosphere. Less than nine minutes after liftoff, Discovery's astronauts went to work to prepare the shuttle's systems for their planned 11-day mission. With the successful launch behind them, they have now turned their attention to their chase of the International Space Station, performing several firings of the ship's jet thrusters to set up a docking with the outpost on October 13 at 17:43 UTC.Over the course of the next week, through four space walks and the use of the shuttle's robot arm, the crew will install both the Z1 truss assembly and Pressurized Mating Adapter-3 to the Unity module of the Station. That adapter is a new docking port for the ISS. The Z1 truss provides a structural backbone for the Station, with four Control Moment Gyroscopes that will be used to maintain the Station's attitude or orientation in space. The truss also houses key communications gear. The truss assembly will support the large solar arrays that will be delivered during the next Shuttle mission, STS-97. The current assembly mission is the most complex ISS visit to date. The Station itself continues to orbit the Earth every 90 minutes in good shape with the exception of two sets of batteries in the Zvezda Service Module which have been disconnected from the module's electrical system because of suspected problems with voltage converters. Battery component spares are expected to be launched on the next unmanned Progress resupply ship to the ISS in November for installation by the first resident crew. Meanwhile, Zvezda is operating normally on six healthy batteries with more than enough electrical power for ISS systems. |
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News of Mir's imminent downing prematureThe Russian news agency Interfax has reported that experts had voted to end the life of the ageing space station, but a representative of the Energia Aerospace Corporation, which owns Mir, says that Mir could theoretically continue work for several years, and MirCorp, the international group that has the commercial rights to exploit the station's business potential, says it was pressing ahead with its plans to fund further flights to the platform in 2001. And MirCorp has also made official its plans of an Initial Public Offering on leading exchanges worldwide to raise $117 million in financing for Mir's long-term commercial operations. |
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New GRB satellite reaches orbitAfter a 48-hour delay caused by communications and ground support problems, a Pegasus booster has successfully launched NASA's new gamma-ray science satellite HETE-2 (High Energy Transient Explorer 2) early on Oct. 9. 12 minutes later the Pegasus placed the spacecraft into an orbit 590 x 650 km high with 2 degrees of inclination. HETE-2, a replacement for a nearly identical satellite lost in 1996 due to a Pegasus malfunction, is the first satellite dedicated to the study of Gamma-Ray Bursts (GRBs): It is expected to not only detect a large sample of these bursts, but also to relay the accurate location of each burst in real time to ground-based optical and radio observatories. Within seconds of detecting a burst, HETE-2 will calculate relatively precise coordinates of the event and transmit its calculations to the nearest of 12 receiving stations girdling the planet, immediately allowing ground-based observers to gather detailed observations of the initial phases of GRBs.The satellite uses a low-rate VHF transmitter to continuously broadcast the burst information; on the ground, the array of listen-only burst alert stations (BAS) receives the data and transmits them to the MIT Control Center. Once received at MIT, burst information is immediately relayed to the GRB Coordinate Distribution Network (GCN) at Goddard Space Flight Center in Greenbelt, MD, for wide distribution through the Internet. Ground-based optical and radio observatories, as well as space telescopes such as Chandra and Hubble, can then follow up with a closer look. News of a burst will reach the astronomy community in approximately 10-20 seconds, as opposed to hours or days in the past - routinely, HETE-2 will provide astronomers with a good chance of seeing a burst while it is still going on. Also, HETE-2 will determine the location and environment of short bursts, a class of bursts about which little is known. |
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Cassini's first Jupiter images / Trouble with HuygensGood and bad news from the Saturn-bound Cassini spacecraft came on the same day: Cassini's camera has taken its first images of Jupiter, which are excellent, despite a distance of 84 million km - but it has also become known that the data link between the Huygens Titan probe and the Cassini mothership has a major design error! The bandwidth of the (European) receiver on-board Cassini is too small to cope with the Doppler effect during Huygens' short dive and not all the data generated during the descent and landing would be received properly by Cassini. Several options are currently under study, however, which would allow the science of the Huygens mission to be fully realised - by the summer of 2001 a solution should have been found.ESA's Director General has already initiated an enquiry board to ascertain why the bad link characteristics were not identified prior to launch but only during tests in February 2000 and to ensure that the Huygens science will be fully realised and that future ESA missions utilising similar hardware are alerted to the problem. The link margins are degraded due to Doppler shift on the data sub-carrier being outside the bandwidth of the receiver phase-lock loop: In essence this means that there could be up to 10dB extra loss in the link compared to that assumed for the mission. Verification before launch was achieved by a mix of analysis and ground testing, this parameter was not isolated. Potential options for recovering the situation range from a greater fly-by distance, slower orbiter approach to tracking of the probe, all of which would lead to an increased signal level with a reduced Doppler shift enabling the data signal to remain with the existing Huygens receiver phase lock loop bandwidth. Already a Jupiter image of Oct. 1st, the first in a long series of pictures and other measurements of Jupiter which Cassini will be making over the next several months as it flies by Jupiter, has clearly shown the exceptional resolving power of the imaging system even at a distance of more than 84 million km. Clouds, storms and latitudinal bands are clearly seen in the image as well as a color view. A steady stream of ever-closer color and black-and-white images will be released in the weeks ahead. "This has been our first opportunity to exercise the Cassini flight and ground systems in a mode very similar to how we expect to operate at Saturn, and I'm extremely pleased with how it is working," says Cassini program manager Bob Mitchell. The spacecraft is so steady that the images are unexpectedly sharp and clear, even in the longest exposures taken and most challenging spectral regions.
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New big optical interferometer at workAstronomers on October 4 have dedicated a new observatory in California that will enable observing the details of stars with unprecedented clarity: The CHARA array (Center for High Angular Resolution Astronomy) is one of the world's most powerful optical interferometers, able to resolve details 200 times finer than is possible with the Hubble Space Telescope. The array consists of six one-meter telescopes within a 400-meter-diameter circle and thus provides an angular resolution comparable to a telescope 400 meters in diameter: The configuration will provide high resolution interferometry in the visible spectral region as well as at near-infrared wavelengths (2.2 microns), with a limiting resolution of 0.2 milliarcsec in the visible.The Array will be applicable to problems in almost all areas of contemporary astronomy. It is particularly suited to stellar astrophysics where it will be used to measure the diameters, distances, masses, and luminosities of stars as well as to image features such as spots and flares on their surfaces. Other projects range range from detecting other planetary systems to imaging the black hole driven central engines of quasars and active galaxies. The facility is located on Mt. Wilson in the San Gabriel Mountains of California overlooking the Los Angeles basin, chosen on the basis of the excellent atmospheric stability over this coastal range, the number of clear nights available, and the infrastructure available to CHARA at this site. |
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First VLTI Delay Line integratedAnother optical interferometry milestone was reached on September 25th with the successful integration of the first Delay Line for the Very Large Telescope Inferferometer. That will be followed by the integration of the second Delay Line by the end of November and the third is scheduled for February 2001; both are now in their final development phase in Europe. "VLTI First Light" is then expected to take place soon thereafter, by means of two small special telescopes ("siderostats"). The combination of the light beams from two of the 8.2-m Unit Telescopes will happen in mid-2001. |
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Three new cases of asteroids with moonshave become known - and one out of every five Near Earth Asteroids seems to have one, according to a recent analysis of lightcurves! Two of the new asteroid moons were discovered optically and one by radar:
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Pluto mission could launch in 2009 or 2010JPL has been directed by NASA to reconfigure a planned mission to Pluto, which will result in a deferment of the launch - Doug Stetson, manager of JPL's Solar System Exploration Office, said the earliest launch date now under consideration would be either 2009 or 2010, and such a mission would not include a gravity assist at Jupiter, as did the 2004 launch plan: JPL Universe. Meanwhile a Save the Pluto-Kuiper Express! website has opened (also covered by SpaceViews).
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All other historical issues can be found in the Archive.
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Compiled and written by Daniel Fischer
(send me a mail to [email protected]!), Skyweek
