The Discovery space-shuttle that blasted off recently was supposed to be the safest launch ever. But two years and hundreds of millions after the disastrous Columbia holocaust that took the lives of all aboard, the same broken-tile cause of Columbia's catastrophe occurred again as Discovery took off.

NASA knew that the loosened tile problem had not been cleared up when Discovery was launched, but they considered that it constituted an "acceptable" risk. However, now that it faces another possible disaster from frictional incineration when Discovery re-enters the atmosphere, NASA has grounded all future shuttle fights until the tile problem is resolved.

But why wasn't this sensible step taken before Discovery was allowed to take off? What is the rush? Does the international space-station really have to be completed by 2010 when it is projected for abandonment in 2016? Was the Discovery trip undertaken for political reasons rather than for scientific ones? What comprises an 'acceptable' risk, anyway? Why gamble with astronauts' lives for ambiguous reasons?

Columbia was not the first shuttle tragedy that resulted in the death of the spacecraft's entire crew. In 1986, the Challenger shuttle explosion killed everyone on board, including a high school teacher who had been slated to teach a high school lesson from space.

Except for the 1960s' Apollo program that resulted in the magnificent historic event of humans reaching the moon for the first time, I have consistently opposed manned space flight as being premature, hazardous, unnecessary, unproductive, and unconscionably expensive. Almost all of the significant discoveries in space were made from Earth or from unmanned spacecraft monitored and controlled from Earth. Most of the costs for manned space flight are to provide an inhabitable environment for the humans aboard. Such an environment is actually damaging and corrosive to the equipment and instruments which function better when the moisture and gasses associated with life are not present.

Furthermore, as I maintained in a Newsday article published on Feb. 8, 1986 shortly after the Challenger catastrophic explosion, manned space flights were not merely unnecessary, they would be counterproductive to the goals of obtaining the needed scientific information that would some day make further human space travel safe and productive. Subsequently, during a debate on the future of human participation in space exploration that was arranged between NASA people and myself, I reiterated my support of NASA's unmanned space exploration activities (the data of which I had used in the 1960s to discover volcanic features on the moon - and in the 1970s to discover ancient glacial features on Mars), but that I opposed manned space flight for at least many decades until technological advances had made it safe and until there would be clear and unambiguous reasons for undertaking such inherently dangerous activities.

I still endorse those views in 2005.