Question: does there be much accidents in nasa like space shuttles blowing up ? why when a space shuttle takes off a while after you hear something comeing back through the atmospher

Sara Imari Walker answered on 22 Jun 2011:

Hello bradley! Shuttles are fascinating aren’t they? Their haven’t been that many accidents though. In the entire history of the shuttle program their have been only two fatal disasters, where we lost shuttle and crew. Of the five original shuttles in the program – Columbia, Challenger, Discovery, Atlantis and Endeavour – Challenger and Columbia were both lost to diaster: Challenger in 1986 and Columbia in 2003. Considering Discovery, Atlantis and Endeavour are running right up to retirement – thirty years after they were first built – I think we are doing pretty well. These shuttles we send to space are older than most cars people drive!!!

As far as why we hear something after the shuttle launch. Well the shuttle has to be accelerated to extremely high velocity to escape the gravity of Earth. To escape the Earth’s gravity we have to get up to about 25,000 miles/hr. The speed of sound in our atmosphere is about 770 miles/hr. When the shuttle crosses this threshold speed, it breaks the sound barrier creating a sonic boom. I think that is probably the noise you are referring. Check out this cool article for more info on crossing the sound barrier: http://www.scientificamerican.com/article.cfm?id=what-happens-when-an-airc

Great question!! I love the shuttle program. I am so sad it will retire soon!