Pros of space exploration include that it broadens knowledge about outer space and Earth; often leads to spin-off technologies useful in other endeavors, such as GPS technology and storm tracking; and that it leads to increased global cooperation. Cons include that it is costly and draws funding away from urgent needs on Earth, spawns technology that can be used in warfare and that it is dangerous to people in space and on Earth.
Many technologies developed by NASA and other space exploration agencies have found uses on Earth. Since 1973, NASA has published more than 1,800 reports highlighting technologies it has created or helped to develop. Today, satellite technology provides the backbone for GPS navigation systems, weather prediction, storm tracking and much of the world's communications network. However, private enterprise might have developed these technologies and launched satellites at less cost to taxpayers.
More than 20 astronauts have been killed during spaceflight missions, while others were killed performing related work on the ground. However, the number of lives lost during space exploration has been relatively low compared to other less extensive ventures on Earth that have spun off fewer overall gains in technology and knowledge. Falling space junk poses a threat to humans on Earth. So far, however, such debris has burned up in the atmosphere, fallen into the ocean or crashed in remote areas without doing harm.