East coasters should turn their gaze skywards this evening, as NASA performs a flight test that will provide a free show in the sky. Between 7 p.m. and 9 p.m., colorful vapors will be released 130 miles above Earth as a result of a rocket launch.
The sounding, or suborbital, rocket will take off from Wallops Flight Facility in Virginia. The flight’s primary objective is to test the performance of a modified Black Brant motor, launch vehicle, spacecraft systems, and sub-payload ejection technologies. The sub-payload ejections will contain mixtures of barium and strontium, which will form colorful clouds of teal and red. Residents of the mid-Atlantic region—from Long Island, N.Y. to Morehead City, N.C.—will be able to get a glimpse of the technicolor vapors.
These vapor tracers have been used by NASA since the '50s and help scientists understand the planet's near-space environment. "These materials make visible the naturally occurring flows of ionized and neutral particles either by luminescing at distinct wavelengths in the visible and infrared part of the spectrum or by scattering sunlight," NASA explains.
Tonight's event will test how effectively the rocket can launch payloads into space. If all goes well, it can be used to shuttle micro-satellites and other experiments. The vapor can also be used to study the atmosphere itself and phenomena like the aurora borealis.
Barium helps illustrate the motion of ions and neutrals in space; the strontium is added to help promote the neutral barium emissions and make it easier to see. NASA says that the chemical amounts used are much less than go into a typical July 4 fireworks display, and will pose no threat to the people below. Here is an example of what it might look like: