December 4, 1993

New debate is swirling over the degree of danger posed by the space shuttle's solid-fueled rocket boosters, despite the successful launching this week of Endeavour on its mission to repair the Hubble Space Telescope. The boosters are like giant, complex Roman candles -- 15-story tubes packed with rubbery, highly explosive fuel that once ignited cannot be extinguished. A pair of boosters, mounted on either side of the shuttle, assists the spacecraft into orbit on each flight. After falling away from the speeding shuttle and parachuting into the ocean, they are recovered and repacked with fuel for another flight.

In what analysts called clinching proof of economic speed-up, the nation's unemployment rate fell four-tenths of a point in November, to 6.4 percent, the biggest monthly improvement in 10 years. The unexpected decline resulted mainly from strong job creation that removed 534,000 people from the unemployment ranks, according to a survey of the nation's households. Many of those people returned to jobs from which they had been laid off. Adult men were the principal beneficiaries.

Nearly two years after Russia began its great economic experiment, freeing prices as it moved toward a market economy, industrial production seems to have stopped falling and the ruble has become relatively stable against the dollar. Together with the privatization of important parts of state industry, these are considerable achievements as the Government of President Boris N. Yeltsin approaches a crucial parliamentary election and constitutional referendum on Dec. 12. They mean that most Russians still have jobs, that their salaries are worth more in dollars, and that there are goods in the shops to buy, though often at prices that make Russians blanch.

Three years ago, Melody Fairchild of Boulder, Colo., then a feathery 5-foot-2-inch, 95-pound runner, was heralded as the greatest female distance-running prospect since a teen-aged Mary Decker first appeared on the track scene nearly 20 years before. Fairchild, of Boulder High, won two national high school cross-country titles, broke many records in track and cross-country and became the first American girl to break 10 minutes for the two-mile run, clocking 9 minutes 55.92 seconds on an indoor track.

Scientists have detected two cases in which the AIDS virus has been transmitted from one child and one adolescent to others but apparently not by the usual routes. The most likely cause is believed to be that infected blood from one entered the other through a cut or disease that broke the skin. Such a mode of transmission has rarely, if ever, been documented before. Although the cases can be expected to raise questions about the current policy of admitting infected children to schools and day care centers, experts familiar with the two cases say they strongly believe that there is no reason to change public policy because of the rarity of such transmission.