In recent years, NASA officials have spoken up frequently in defense of the theory that human activity is adding too much carbon dioxide to the atmosphere and is dangerously elevating the earth’s temperatures.  But that belief is not universal in the nation or even within NASA.  That’s why a large group of former astronauts and Johnson Space Center officials are pleading with NASA Administrator Charles Bolden to stop presenting an unproven contention as settled science.  Apollo 7 astronaut Walt Cunningham says the space agency has no business wading into a politically charged debate and believes the prestige of NASA is being used to achieve political goals that are not good for America.  Cunningham also offers his thoughts on the end of manned space flights here in the U.S. and what the priorities of our space program ought to be.