LOWELL — It was hard — impossible, even — to miss. Several people were intrigued enough to stop and stare. They pulled out their cell phones and snapped photos, filmed video clips.

Along Pawtucket Boulevard late Thursday morning was a giant bubble on a city-owned grassy lot. Inside, a dummy lay on what appeared to look like a giant cheese wedge. A crane loomed over a group of people, who fidgeted with the inflatable bubble that kind of resembled a gigantic beach ball.

“Sorry, we’re not able to talk about it,” said a woman who was part of the group on scene.

But Lowell Fire Deputy Chief Phillip Charron could.

“There’s a company there testing a new device and it’s for dropping a human being from a high altitude and having them land safely,” he told The Sun Thursday afternoon, adding that the company did pull a permit with the city. “They were doing testing at that location using a crane, which I’m sure you saw and it’s part of their preliminary testing of dropping the device from a crane up to 100 feet and they calculate the data, and that’s what they’re using to base further development of the product on.”

A woman who asked not to be named said the bubble was being dropped three times — at 25 feet, 50 feet, and 100 feet.

Though secrecy enveloped the scene late Thursday morning, theories from passerby swirled.

“As a matter of fact, I don’t know what’s going on and they don’t want to tell us, but I think that something has to do with the space,” said Hemchand Berajawala, who on his daily walk stopped to observe the bubble. “The guy is going up and he’s going to come back to the same capsule. Whatever it is called.”

Berajawala, 78, said he owns several condos in the neighboring complex. Whatever it is, he said it’s excellent.

“They should have told in the newspaper or something,” he said. “To advertise or something, so the kids will enjoy what’s going on because this is future for the kids.”

Carmen Estrada and Zully, who declined to give her last name, stopped to stare.

“I think it’s something scientific,” Zully said in Spanish.

“Maybe it’s to see if they can survive in there,” Estrada suggested. “Something like that.”

Howie Savard, of Dracut, stood on the sidewalk for a while. He noticed the bubble on his five-mile walk and, once he was done, looped back again to check it out. Savard said someone told him it was a re-entry module for astronauts.

“It’s just an interesting sight. Everybody has these, you know,” Savard said, lifting up the cell phone in his hands. “We went from insta-photography to very insta-photography.”

Follow Amaris Castillo on Twitter @AmarisCastillo.