Forget the disaster movies of earth warming, ice melting, world awash. And stow the political arguments attending all that. We are on the way to finding out what is true about what is happening to Mother Earth, what’s doing it, and how fast.

Part of the answer is aboard a 6,500-pound satellite launched early Thursday from Vandenberg Air Force Base in California. It is called “Aura” and its job is to train four instruments on the column of material that reaches from the surface of the earth to the upper reaches of the stratosphere, a distance of some 55 miles.

“Aura’s” missions are to discover if the ozone layer in the stratosphere is recovering, how air quality is affected by nature and by man, and the processes of change. From a polar orbit 437 miles high, “Aura” is expected to be operational in October. Glitches with its Delta 2 launch rocket and the satellite itself had delayed launch from June 19th until now.

“Aura” is the caboose, actually, of a six-satellite flight of sensing satellites dubbed the “A-Train.” The financiers are the U. S., France, and Canada, with Japan, Brazil, the Netherlands and Finland contributing specific instruments. The engine, satellite “Aqua,” is already in orbit, concentrating on the study of water vapor. Since the caboose, “Aura,” must follow “Aqua’s” orbital track by 15 minutes, the timing of the Thursday launch provided a window of some 2 minutes. The intervening satellites yet to launch, “CloudSat,” “Calipso,” and “Parasol,” must also launch with split-second timing. “CloudSat” must lag “Aqua” by no more than 2 minutes, “Calipso” must be no more than 15 seconds behind “CloudSat,” and “Parasol” must be a minute behind “CloudSat.” All because “A-Train” is to act as a synergistic unit, measuring what is happening to our vital coverlet. It’ll cost $2.3 billion and foresees being part of a 47-nation effort called the Global Observing System.

There has been agreement on the ozone-depleting effects of chlorofluorocarbons, the stuff that spritzes your hairspray out of the can. This agreement has led to the Montreal Protocol restricting CFC’s in 1987, and the later Copenhagen agreement. But the question of global warming and its remedies has left the United States in disagreement and standing outside the Kyoto Protocol mandating curbs on thermal emissions. The U.S. cites lack of reliable data for refusal to take the expensive pledge.

The “A-Train” may get us past Harlem and to a consensus about what is really happening up there, why, and what should be done about it. The apolitical nature of it is best exhibited by plans for the sixth little orbiter, the OCO, or orbital carbon observatory, being worked on by NASA and the Bush administration. When launched in 2007, “OCO” will lead the A-Train by 15 minutes, a sort of scientific sidecar pumping out ahead.