People claim spots on the lawn in front of the Hatch Memorial Shell for the spectacular fireworks display. (Libby O'Neill/Boston Herald)

Needham native Suni Williams was supposed to be home from the International Space Station by now, but even though she was still in orbit, the NASA astronaut reported early to the Esplanade for the 4th spacewalk.

“Hi everyone! I'm so happy to be here,” Williams said in a phone call with Boston Pops conductor Keith Lockhart. “On the Fourth of July, Boston is the best place for it. This is where it all started.”

The call came around 12:45 p.m., less than an hour after the gates opened for the 50th Boston Pops Fireworks Spectacular.

Thousands of people from near and far, dressed in the colors of America, streamed in throughout the day, filling the oval in front of the Hatch Shell and the banks of the Charles River hours before the patriotic concert and performance.

Williams called Lockhart and her five crew members – all Americans – on the ISS. And above the atmosphere, July 4th also had a special meaning for the astronauts.

“We have a lot of fun and we get to sleep in a little bit because it's a holiday. We're all Americans, so…” Williams said before the crew sang America the Beautiful.

According to Boeing, Williams and crew member Butch Wilmore boarded the Starliner at the ISS on Tuesday and worked with flight controllers and engineers during the spacecraft's boot-up.

This week marks Williams and Wilmore's fourth time in orbit. The pair launched on June 5 for a test ride in Boeing's new capsule and expected to fly home from the ISS in about a week.

However, equipment problems and helium leaks occurred en route, which meant that three possible landing dates had to be cancelled and the return flight had to be postponed.

“I want to make it very clear that Butch and Suni are not stranded in space,” Steve Stich, NASA's commercial crew program manager, said last week.

Williams and Wilmore can remain docked to the ISS until the end of July while Boeing continues to test the Starliner.

Despite the potentially awkward situation, Williams and her crewmates were in good spirits Thursday, and the Needham native was excited to find out if she could see the fireworks from space.

“This is my first Fourth of July in space, so I'm looking forward to staying up a little later, taking a nap… and trying to see them.”

A crew member added: “Everything up here looks like fireworks.”

Lockhart told reporters it was a “great responsibility and a great honor” to conduct the Boston Pops on the 4th. This will be his 29th year conducting the show.

Although Lockhart said he wanted to “keep traditions alive,” such as Tchaikovsky's 1812 Overture, slight changes are made to the concert each year.

“We're trying to make the day kind of a reflection of America,” he said, “which is difficult this year because America is in a very strange position. … But we're trying to keep it lighthearted and hopeful and looking for common ground, and that's what this day is about.”

Lou Spelios showed up at 3 a.m., nine hours before the gates opened at noon – a tradition for the Back Bay resident. Having read about the annual celebration since childhood and watched it on television, he learned that you have to show up before dawn to get a nearby seat.

“I love this concert,” Spelios told the Herald. “I love what it represents – freedom of choice and our ability to act independently. That's what we're celebrating, just the ability to control our own destiny.”

After wet and stormy weather interrupted last year's celebrations for several hours before skies cleared, Thursday saw similarly sultry conditions with oppressive humidity.

Chilean native Camilla Erices and her boyfriend Adam Provost of Springfield came to the Esplanade for their first Fourth of July.