The planned $430 million modernization of Hartsfield-Jackson International will challenge airport officials and contractors to renovate the terminal and concourses while also keeping the world’s busiest airport humming.

For example, a canopy will be added to cover the curbside area, and keeping the curbside open during the improvements will be “one of our early challenges,” said airport assistant director of project management Todd McClendon at a meeting Tuesday for contractors interested in the project.

Gate areas on concourses will also have to be updated without closing gates, McClendon said. That will require working at night and cleaning up before flights restart each morning.

“We’re an airport first, and a construction site second,” McClendon said.

As part of the broader renovation, the domestic terminal atrium will be redone with a "park-like setting," he said. "It's going to be a pretty big change. I think its time has passed. It needs to be updated." More glass will be added to bring natural light into the terminal.

The renovation will give the airport atrium a more modern look, as well as add amenities like more charging outlets. With many gate areas on concourses now offering charging outlets at seats, the in-demand amenity will be added to the domestic terminal atrium as part of the renovation project, McClendon said.

“There’s a huge demand. Everyone’s got a cell phone and a laptop,” McClendon said.

And because main checkpoint security lines at the busiest times back up into the atrium and all the way to the meet-and-greet area for arriving passengers, the airport plans to expand the switchback queuing area. Signs throughout the airport will also be replaced.

The modernization is “the most important project at the airport” currently, McClendon said. “It’s going to be a pretty big facelift, from the time the customer checks in at the curb to the time they go through the checkpoint.”

The airport is inviting contractors to compete for the work and plans to complete the modernization by the end of 2017.