From faraway stars to earthly clouds The US space agency NASA early Tuesday began the countdown to
launch two satellites designed to help unlock the secrets of Earth's cloud cover.The satellites, named CloudSat and CALIPSO, will help scientists from the United States, France and Canada unlock the mysteries behind snow and rain, cold fronts and heat waves as well as many other atmospheric phenomena that still remain enigmatic.After reaching a 705-kilometre circular orbit, the new spacecraft will fly in formation with the so-
called "A-Train," a
constellation with three other Earth observatories belonging to the NASA and France.The arrival of CloudSat and CALIPSO, scientists said, will enhanced the constellation, allowing it new insight into the global distribution and evolution of clouds."The scientific knowledge gained from such observations will be used to improve models that predict Earth's weather and climate," said Ghassem Asrar, a deputy associate administrator at NASA.According to NASA, CloudSat and CALIPSO will be able provide a three-dimensional view of the clouds as well as airborne particles called aerosols and thus help answer questions about how they form and evolve.