Why Will There be no More Space Shuttle Flights from NASA?

[Jay Anderson]

 

According to a New York Times article found here http://www.nytimes.com/2011/07/04/science/space/04nasa.html?_r=1&am... the following: "At the direction of the Obama administration and Congress, NASA is instead developing a large new rocket to send deep into space."  Also, "Supply missions to the ISS will be launched on Russian and European Space Agency rockets until NASA's new Ares launch vehicle begins flying in 2015."according to this page: http://www.spacetoday.org/SpcShtls/FinalShuttleFlights.html 

But my question is this, why is NASA ending shuttle missions?  Another question is what will these deep space missions be taken on if shuttles are not to be used?  Also, how deep into space are these missions planning to go?