A thank-you written in light

On the night of Tuesday, April 28, 2020, 136 Verge Aero drones rose 400 feet over Franklin Field in West Philadelphia. Their message was simple: thank you.

We donated and dedicated this show to the doctors, nurses and staff at the Hospital of the University of Pennsylvania and Children's Hospital of Philadelphia, and to the first responders and essential workers keeping the city running. There was no advance publicity and no ticketed crowd — just a surprise in the sky for the people who needed it most.

Why we flew it

Verge Aero is a hometown Philadelphia company, based at Penn's Pennovation Works. This spring, like everyone, we watched the city go quiet. Live events stopped. Our fleet sat grounded.

Meanwhile, health care workers were putting in impossibly long shifts. We'd seen New Yorkers cheering from their windows at shift change, and how much it meant to the people walking home from the hospital. Our team wanted to give Philadelphia's front line something like that — on a scale only a drone show can deliver.

So we coordinated with Penn, ran our test flights at Franklin Field, and planned a show that the hospital right across the street could watch. Staff could step outside or look out a window and still keep their distance. Our CEO, Nils Thorjussen, put it this way: we flew it "solely for these heroes."

Behind the scenes

Flying 136 drones beside two major hospitals, under an active helicopter flight path, takes more than a good design. Here's what went into it.

Built for a busy sky. PennSTAR's medical helicopters fly in and out of the HUP helipad around the clock. We coordinated with the hospitals' helipad teams and filed the proper NOTAMs, so every pilot in the area knew when drones would be up. If needed, one button on our ground control software could land the entire fleet instantly. During setup, a helicopter came in and our drones stayed on the ground until it was clear. Nothing we do comes before manned aircraft.

The FAA on site. Michael Bauer, an inspector with the Federal Aviation Administration, joined us to review our operation, risk assessment and documentation. As he put it, the FAA was there as a partner in safety and outreach.

Precision and security. Before every new site, we scan the radio spectrum for interference. Our RTK base station then tightens each drone's position from a few meters to about ten centimeters. The whole network is isolated from the internet — the only way to reach the drones is through that box — and it travels anywhere without outside infrastructure.

Designed by creatives. The show was built in Verge Design Studio, our in-house software. It works like a video editor: designers choose the shapes and the drones map to them automatically. That's why we flew 136 — it's exactly what Philadelphia's LOVE sign needed to look right.

Built here. We designed the drones and their electronics ourselves, with manufacturing in Johnstown, Pennsylvania. Each one of our X1 drones shines at about 900 lumens, roughly as bright as a car headlight, so the show could be seen across University City.

The show

As the sun went down, staff came out of HUP and CHOP and looked up. Firefighters and first responders gathered nearby. Then the lights came on.

The drones drew Philadelphia's story of the spring: medical symbols, a flattening curve, a waving American flag, the Liberty Bell ringing, a beating heart turning a full 360 degrees, and a very grumpy coronavirus. Then came the LOVE sign and the message "THANK U HEROES." The show was part of the citywide #PhillyShinesBlue campaign and the global #LightItBlue movement, and it flew the same day the Navy Blue Angels and Air Force Thunderbirds saluted the city's health care workers.

Linda Kocent, a Penn Nursing alum who runs a family learning center at CHOP, had just finished a long day and almost headed home. She stayed. She later told Penn Nursing it felt like fireworks, only more elaborate — synchronized swimming with drones.

That was the whole point. For a few minutes, the people carrying the heaviest load in the city got to just stand outside and watch something beautiful made for them.

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What it means for drone shows

This show changed how we think about what drone light shows are for.

A spectacle that doesn't need a crowd. Fireworks and concerts gather people together. A drone show can reach an entire neighborhood from windows, rooftops and sidewalks, with everyone keeping their distance. In a year when gathering isn't safe, that matters.

A show that travels. Most people who saw "Thank u heroes" didn't see it in person. They saw it on their phones, shared by nurses, neighbors and news outlets across the country. A drone show can be filmed and shared so its message is felt far beyond the sky it flies in.

Proof that drone shows can fly safely in busy airspaces. Flying next to two hospitals and an active helipad, with the FAA on site, showed that drone shows can work in the most demanding urban airspace — when safety comes first and everyone stays in the loop.

A medium for meaning. Drone shows are often about brands and big events. This one was about gratitude. We think there's room for much more of that.

In the press

• The Philadelphia Inquirer: A drone light show lit up the Philly skies to thank health workers
• PhillyVoice: Drone light show in West Philly honors COVID-19 front-line workers
• Tech Times: Drone Light Show Lit Up In Philadelphia To Thank Workers Amid COVID-19 Pandemic
• Penn Nursing: Lighting Up Philly to Honor Health Care Heroes

Thank you

To the University of Pennsylvania, Pennovation Works, Penn Medicine, CHOP, PennSTAR and the FAA: thank you for helping us make this happen safely.

Thank you to Nick Lang Media for producing our behind-the-scenes video for this show.

And to every nurse, doctor, technician, custodian, first responder and essential worker in Philadelphia and beyond — this one was for you. Thank you, heroes.