MARY LOUISE KELLY, HOST:
Tonight, as it has for years, the Boston Pops will play Tchaikovsky's "1812 Overture"...
(SOUNDBITE OF BOSTON POPS ORCHESTRA PERFORMANCE OF TCHAIKOVSKY'S "1812 OVERTURE")
KELLY: ...Then an intricate fireworks show will launch from barges in the middle of the Charles River between Boston and Cambridge. A huge audience will be watching in person, on TV and streaming online. As part of our Backstage Pass series, WBUR's Jeremy Goodwin went on board the barge to preview how it will all work.
JEREMY GOODWIN, BYLINE: A crew of about a dozen workers is on three barges setting up for the big night. They're sawing planks of wood and hammering together racks for empty mortars, or metal tubes. That's where the firework shells are loaded in. When night falls, state troopers will be stationed on the barges to keep watch. No one else is allowed within a thousand feet. Fireworks by Grucci is the company that pulls off the show. Lauren Grucci is the sixth generation of her family in the business. She's writing with a black marker on strips of masking tape and carefully sticking them onto the wooden racks of mortars.
LAUREN GRUCCI: I'm labeling each one so that everybody knows which shell to put in which spot. It's all choreographed to music, so they need to know, you know, each one of these are going to go off at a very specific time. So it all needs to be numbered so that it's clear.
GOODWIN: Her father, Phil, is the creative maestro behind the fireworks show. When the time comes, he'll be running the controls inside a metal box on one of the barges. He spent hours working with Boston Pops conductor Keith Lockhart to plan out a song list, then designed a fireworks display that will boom, crackle and explode in sync with the tunes.
The basic technology behind fireworks goes back to China as far as 2,000 years ago. But the guy who's overseeing the setup out here on the barges, Ian MacKenzie, says the newest equipment onboard nowadays creates a pinpoint level of control unheard of previously.
IAN MACKENZIE: It launches a single star, these very specially refined stars, out of a long mortar tube. We can spell out letters. We can draw shapes. We can do all sorts of - we've done that in various other performances around the world.
GOODWIN: MacKenzie won't say what's in store tonight.
MACKENZIE: I'm going to leave that part as a surprise. You'll see - you'll know it when you see it (laughter).
GOODWIN: In addition to folks watching on TV and the internet, about half a million people will line both sides of the Charles River tonight to find out in person. For NPR News, I'm Jeremy Goodwin in Boston.
(SOUNDBITE OF BOSTON POPS ORCHESTRA PERFORMANCE OF JOHN PHILIP SOUSA'S "THE STARS AND STRIPES FOREVER") Transcript provided by NPR, Copyright NPR.