Vapour tracers are artificial clouds that allow scientists to track the movement of particles through space.
Early Thursday morning, some may see colorful clouds as a result of a rocket launch by NASA.
Launched from NASA's Wallops Flight Facility in Virginia, the rocket flew to a height of 118 miles, NASA shared in a statement.
'The Terrier-Improved Malemute launched this morning, June 29, at 4:25 a.m.
The clouds, or vapor tracers, are formed "through the interaction of barium, strontium and cupric-oxide", according to NASA.
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The mission deployed ten soda-can-sized canisters, each containing cloud-forming vapour, roughly 100 miles above the surface just before 5 a.m. (EDT).
"The tracers will be released at altitudes 96 to 124 miles high and pose no hazard to residents along the mid-Atlantic coast". (Obviously, delaying the mission over half a dozen times was all part of the plan.) To that end, NASA was successful: According to a press release, Wallops received roughly 2,000 reports and photos of cloud signings, from NY to North Carolina.
The launch delays started on May 31, with the last attempt, on June 24, foiled by extensive cloud cover.
After a month of trying, NASA finally launched one of its small sounding rockets from the coast of Virginia, creating a delightful mix of colorful clouds in the upper atmosphere.
Sounding rockets have been used since the 1950s to study the upper atmosphere and ionosphere as part of scientists' efforts to understand the Earth's near-space environment.