Nasa launches rockets after delays
Nasa has launched five rockets to study the upper level jet stream after several delays.
The rockets began blasting off Tuesday morning from a Nasa space centre in the US state of Virginia.
Bad weather had postponed other planned launches last week.
The Anomalous Transport Rocket Experiment will help scientists understand the jet stream, which is located 60 to 65 miles above Earth's surface.
After launching, the rockets released a chemical tracer to form white clouds that allowed scientists and the public to visualise the winds.