The Cosmic Mirrorof News events across the Universe |
Compiled and written by Daniel Fischer, Skyweek - older "Mirrors" in the Archive - and find out what the future might bring! The latest issue! |
Current mission news: MGS (science!) + Cassini + Galileo + Prospector |
WIRE satellite struggles for survivalShortly after its Pegasus launch on March 4th NASA's small Wide-Field Infrared Explorer (WIRE) satellite has run into deep trouble. While rescue attempts continue it is already clear that WIRE will not be able to complete its 4 month mission. Things began to go awry when a telescope cover inadvertantly popped off after the craft reached its orbit. Heat streaming into the spacecraft probably caused the frozen hydrogen coolant to sublimate at a much more rapid pace than planned. Engineers think pent-up hydrogen gas then began shooting out of spacecraft vents, sending the craft into a tumble.The spacecraft continues to spin, but the rate of spin has now stabilized at about 60 revolutions per minute. Controllers had sent commands to the spacecraft to see if the telescope could be gently moved in order to reduce solar input. However, imparting even the extremely light magnetic countering force on the rotating spacecraft caused the spacecraft's solar arrays to begin oscillating and the maneuver was stopped. The efforts proved that a different scheme was necessary. The WIRE team is now devising a new plan which will involve building a software program that would use the spacecraft's onboard attitude control system to "de-spin" the spacecraft; that will take several days. Otherwise WIRE's subsystems are in good shape. The solar arrays are generating power and the battery is fully charged. There is plenty of power to effect a recovery. But the loss of the hydrogen coolant means that the astronomical observations will have to be shortened in any case. (Based on a GSFC Status Report of March 6th etc.) |
Homepage and Science Homepage of WIRE. Fla. Today coverage. Stories on the launch from SpaceViews and BBC. Stories on the problems from BBC and SpaceViews. |
Shuttle visit to Hubble likely this OctoberIt now seems all but certain that the Hubble Space Telescope will get its next visit much sooner than planned: As Florida Today has learned NASA is committed to a special Servicing Mission ahead of time, in order to replace several broken gyroscopes: "The mission likely would fly on shuttle Discovery, and the work would be done by four spacewalkers who already busy preparing for the effort." Two of Hubble's six gyros are already dead and the third is "on the blink" since January and also considered a loss.The remaining three gyros are the minimum number needed to keep the telescope pointed: "Should a fourth break, Hubble would automatically shut itself down and the most powerful space telescope ever launched would be temporarily out of business. Officials say there is a high probably that could happen because the gyros are old. Two of the working units have been onboard the telescope since its April 1990 launch. The third was installed in 1993. The telescope 'would be perfectly safe' if it shut down, said David Leckrone, senior Hubble scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. 'It's just that science observations could not continue. Needless to say, we don't like the idea of Hubble being (shut) down in terms of scientific operations.'" It had been planned all along to replace the old gyro assemblies, but during the next scheduled Servicing Mission on June 8, 2000 - the same mission when the Advanced Camera for Surveys will be installed. 6 EVA's were planned for that complex mission which will now be "cut in half": The gyros and several other minor components will be exchanged this October while the ACS and new solar panels will come next summer - those items won't be ready to fly in 1999. The preparation time for the special mission is short, but the spacewalkers are in training since last August, and many other missions aspects have already been worked on. (Fla. Today March 7) |
The need for an extra mission: a CBS story More news from Hubble: HST views GRB 990123 - the picture, more details and still more. Water on Mars: Press Release. Proxima Cen and an asteroid: Press Release. Galactic cannibalism in NGC 1316: Press Release. |
Chromosphere, corona sighted during narrow annular eclipse in AustraliaWho needs total eclipses of the Sun? During the solar eclipse of Feb. 16, an annular one with the angular diameter of the Moon at 99% of the Sun's, it was astonishingly easy to detect the bright red chromosphere and even traces of the inner corona. Outstandingly clear skies over the West coast of Australia helped these experiments by several amateur astronomers (including yours truly). The chromosphere could not only be photographed with ease - e.g. with 1000 mm focal length f/20 at 1/1000 sec on 100 ISO, no filters - but also be seen in the view finder. And it was even possible to record it on video.The nearby brilliant crescent of the Sun was heavily overexposed in all these cases, of course, but was not at all able to drown out the chromosphere as well as some minor prominences. And when the Moon covered the chromosphere as well, even traces of the inner corona became evident in photographs: There was something behind the dark moon, outlining its limb. For the naked eye, though, nothing of this was evident: The narrow ring in the sky was still too bright to even look at directly. But OTOH the Sun's light was dimmed enough for the planets Venus and Jupiter to appear in the deep blue sky. The few thousand eclipse chasers who had come to Australia last month got something for their effort! |
A most detailled Report from O. Staiger. Another report (with chromosphere pictures!), another page on the eclipse and yet another one. Collected pictures and more pictures. News coverage from CNN and AP. Advance coverage from BBC. Eclipse details |
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Compiled and written by Daniel Fischer
