Compiled and written by Daniel Fischer, Skyweek - older "Mirrors" in the Archive - and find out what the future might bring!

During the next two weeks, QuikScat will fire its thrusters as many as 25 times to circularize and gradually fine-tune its polar orbit. Eighteen days into flight, the "SeaWinds" scatterometer, QuikScat's only science instrument, will be turned on for the first time. Members of the project engineering and science teams will spend the next 12 days performing checks of the instrument and calibrating its radar backscatter and ocean wind measurements. Although that will continue for several months, QuikScat will formally begin its primary mission of mapping ocean wind speed and direction starting about 30 days after launch. The primary mission is scheduled to continue for two years.

While monitoring the health of systems on board through Russian ground stations and the newly repaired early communications system, the controllers had been notified by the U.S. Air Force Space Command of a possible close approach of a spent Russian rocket body upper stage. While this is not a routine occurrence, it is an event that flight controllers deal with from time to time, as has been the case infrequently during the Space Shuttle program. Early predictions showed the closest approach of the debris to the ISS would be within 1 kilometer, but the actual distance at the time of its closest approach on Sunday morning was 7 kilometers.

Flight controllers planned to maneuver the station on June 12th, but the uplinked procedure for maneuvering had one of the Zarya module's engines firing longer than is permitted by the module's on board computer program. Therefore, Zarya's motion control system correctly canceled the burn automatically and the maneuver was not performed. Though the debris was ultimately not a problem, all of the procedures for debris avoidance maneuvers are being evaluated by both Russian and American flight controllers as a result. And someone will have to explain why the software of Zarya never learned about Unity and its additional mass ... (AW&ST of June 21st, p. 22, etc.)

The key was in the chemistry: Observations - using an infrared spectrometer on NASA's 3 m telescope at the Infrared Telescope Facility at the Mauna Kea Observatory in Hawaii - determined that the carbon monoxide/water ratio in the comet's original ice component was 12 percent. This is different from the value in interstellar clouds, indicating some thermal processing (as expected for a formation in the outer planetary system). Had Hale-Bopp formed in the Kuiper Belt instead, i.e. way beyond the orbit of Neptune, it would never have experienced temperatures high enough to explain the observations. (DiSanti & al., Nature of June 17th, p. 662-5)

Only with the high-sensitive Dust Detector System on board Galileo, which measures dust grains hitting a 1000 square cm gold target, could these dust clouds be detected directly: A total of 44 particles was identified during the 4 Ganymede encounters. The dust concentration is so low, though, that only one grain can be found in a cube with 20 meters on a side, on the other hand the total dust mass hovering of the moon could be around 10 tons (with a factor of 10 uncertainty). Although the cloud is very interesting scientifically, it does not cause a danger for the Galileo spacecraft, nor can it be detected optically. (Krueger & al., Nature of June 10th, p. 558-60)

But new observations by the RXTE satellite of the Soft Gamma Repeater SGR 1900+14 just do not fit: According to the current fast loss of angular momentum the neutron star would have formed less than 1000 years old - but the supernova remnant it sits in is > 10 000 years old! And even more disturbing: The spindown rate of SGR 1900+14 has suddenly changed after its last big outburst in August of 1998 (see Update # 105) which would imply a drastic increase of its magnetic field, from 570 to 820 trillion Gauss. And that makes no sense: If anything, the field should have shrunk during the outburst.

Another model thus seems to be needed to explain the fast spin-down of the neutron star, one that does not involve extremely strong magnetic fields. In a new scenario a steady wind of high energy particles is being thrown away from the neutron star-carrying away rotational energy and slowing down the star by carrying away its angular momentum. Such a wind can explain the observed spin period and rate of change of the period of SGR 1900+14 for a supernova remnant age of 15 000 years, which is consistent with the estimated age of the supernova remnant that produced the soft gamma-ray repeater. One possible explanation for the wind is that it consists of magnetic waves that are excited by starquake vibrations of the neutron star surface. (Marsden & al., Preprint astro-ph/9904244)