NASA is launching a test rocket from Virginia tonight. Ordinarily, that’s not something most Baltimoreans would pay attention to… but this is no ordinary test rocket.

According to NASA, shortly after launch the rocket will deploy “four sub-payloads containing mixtures of barium and strontium will be released, creating a cloud that is blue-green and red in color.” In other words, something a little like this:

via NASA
via NASA

The rocket is part of a larger project testing sub-payload ejection technologies before they’re incorporated into future space missions. These vapor clouds also help NASA scientists study wind and ionosphere conditions 100 miles above earth.

Keep an eye out for the rainbow cloud between 7-9 PM tonight — unless it’s cloudy, in which case the launch might be postponed until tomorrow. You can also follow updates via Twitter.