The MPL team has this morning run out of 'silver bullets,' as they put it: All scenarios in which only one major system onboard has failed have now been played through. Either the spacecraft has been destroyed during entry or landing or several systems have broken after touchdown. There are plans now to image the likely landing area with the hi-res camera of the Mars Global Surveyor, but the preparations will take several weeks and success, if ever, might be a month or more away. While the lander would be about 1 pixel in size, the parachute might or heat shield might be easier to spot - if the descent sequence worked as planned. To be sure of that (or to find out that an accident already struck here) makes the MGS effort worthwile which even calls for the orbiter to look off-nadir at a slanted angle.

Until we find out whether the cruise stage did separate from the lander (there has been speculation for days that the responsible pyrotechnics might have failed, but in the past they always worked), there is no telling about the fate of the two microprobes either. The enormous work that went into their design and testing on Earth from 1996 to 1998 was not completely in vain, fortunately: A lot was learned about how to make electronics survive extreme g forces, and future space missions will certainly learn from this experience - even if we will never know whether the concept has worked on Mars as well...

• What will happen next? The two now-famous scientists who predicted the time but not the strength of the storm have recently met at Armagh Observatory in Northern Ireland. David Asher told the Cosmic Mirror that he feels "reasonably confident that [the outbursts of] 1833, 1866, 1867, 1869, 1966 and 1999 could be made quite consistent with sensible adjustments [...] to the 19th century peak ZHRs." The times of possible future storms in the table in Update # 157 stay put while "the rates may need revising. But even if the 15000-25000 ZHRs are adjusted, it's obvious that they're going to remain storm level (and higher than the 1999 storm). The ZHR values (with question marks) for 2000 Nov 18, at this stage it's hard to know - they could be just very little outbursts or we could be lucky and get something like [the] 1999 storm level."
• Why did NASA report a maximum value of the ZHR in 1999 that was too low? Bill Cooke from NASA's MSFC told the Cosmic Mirror that the big Leonids monitoring program the agency was coordinating had been "tasked with delivering to satellite operators (on the U.S. side) flux information, of which the ZHR was only a part. The requirement was that the fluxes be accurate to an order of magnitude, and that was accomplished." Regarding the factor of 3 underestimation of the max. ZHR Cooke adds that NASA's "low ZHR values resulted from the fact that procedures and algorithms for the integration of these various data types proved to be less than desirable" - but that "the hours of video, radar and visual observations will yield an accurate and much better picture of the 1999 Leonids than we have now" during the upcoming detailled analysis.
• How big were the particles that made the flashes on the Moon? By now six cases are known where short flashes of light on the Moon's dark side were noted by either two video cameras or by video and visual observation. In a recent circular David Dunham writes that "the objects that caused the brightest flashes that we observed were probably a few hundred kilograms [...] since very little of the impact energy is converted into light." This assessment is based on opinions voiced by several impact experts such as Jay Melosh - who also calculates that the impacts should have left craters in the 10 meters range.

• The detection of molecular hydrogen in an HVC between us and the Large Magellanic Cloud, by the ORFEUS freeflyer supports the 'galactic fountain' hypothesis, because the formation of H2 requires the presence og dust and heavy elements in general. In this picture gas bubbles are ejected from the Milky Way and rain back as HVCs. There is also substantial iron in the cloud investigated, further supporting the view (Richter & al., Nature Nov. 25, 1999, p. 386-7)
• On the other hand, observations with Hubble's GHRS of another HVC have shown very low metallicity (of only 9% of the solar value): This gas cloud seems to be primordial, coming from deep between the galaxies, where it never encountered evolved stars. The infall of such primitive clouds into the Milky Way is actually required by models of its chemical evolution. (Wakker & al., ibid. p. 388-90)