UARS

As many of you may have heard about the Upper Atmosphere Research Satellite (UARS) re-entering into the earth's atmosphere because of no gas and battery supplies. UARS was launched in 1991 and finished its mission in 2005, but it's been orbiting the earth for 20 years. Since it was built long time ago, scientists did not put the technology to control it when it is out of fuel and bring it safe on the earth surface as most of the new satellites work. NASA has predicted the time at which it will hit the surface during Saturday, which cannot be determined accurately because of its velocity, drag forces on it, and orientation. Solar activity was one of the drag force which could have affected the speed of the satellite, but since it passed the thermosphere already, it will not be affected by solar activity. Solar activity is when sun's flares affect changes in the earth's thermosphere. One other drag force which is included and will affect the UARS is caused by the air molecules in the atmosphere. Above all NASA did succeed in changing UARS's orientation and slowed it down. Now we can just wait and watch about what happens next. You can comment about your thoughts on this news.