For most of its early years, the Mann Center used its concert shed and ample lawn primarily for an equally ample helping of Philadelphia Orchestra concerts – 18 evenings of Berlioz, Dvorak, Mahler, and Shostakovich with big-name classical soloists and conductors.

The programming mix has obviously changed, with the majority of the schedule given over to popular draws like Diana Ross and, on the smaller Skyline Stage, rising singers and bands. The Philadelphia Orchestra has become a more minor presence – just a half-dozen concerts this summer, and still no sign that its music director, Yannick Nézet-Séguin, will ever debut beneath the stars in Fairmount Park.

The bigger evolution, however, is going on beneath the headliners. The Mann, for instance, is commissioning new works, most recently Nolan Williams Jr.'s astronaut-inspired Hold Fast to Dreams, set to premiere Tuesday.

On the one hand, this is a Philadelphia Orchestra concert. On the other, Hold Fast to Dreams and the space-themed program built around it — including the themes to E.T. and 2001: A Space Odyssey — exemplify the Mann's new direction.

It's about the music, of course, but it's also about being in tune with as many distinct audiences simultaneously as possible: friends and relatives of members of the four choirs performing; children who have been taking part in related school projects; followers of venerable Franklin Institute astronomer Derrick Pitts, who is narrating; and anyone who might feel pride in Guion Bluford Jr., the Philadelphia-born astronaut and the first African American in space, to whom the piece pays tribute.

Steadily and surely over the last few years, the Mann has become much more than just a venue. In addition to making new commissions, it has gone a long way toward realizing its educational potential with master classes and a months-long schedule of projects in partnership with schools, and has discovered its neighbors in West Parkside.

"We are really focusing on getting the Mann out of the Mann, and I think we've developed some genuine traction and some partnerships and collaborations that are a two-way street," says Mann president and CEO Catherine M. Cahill, who has brought in Williams not only as composer, but also as artistic director of what has become a regular festival around a different theme each year.

Williams was also the force behind festivals in years past such as Liberty Unplugged, which used music, poetry, and a "Twitter Town Hall" to explore the work of Frederick Douglass, the Rev. Dr. Martin Luther King Jr., and Nelson Mandela; and a Firebird production imported from South Africa that stretched well beyond one night with multimedia events across the city. Hold Fast to Dreams continues that path.

"We've found ways to connect with the community, and in many respects these are persons with whom historically the Mann hasn't had the kind of connection that we would have wanted to have," Williams says. "Part of what we've learned is that people do receive outreach when they perceive that the outreach is real and genuine, and they respond even more when they get the sense that it's not a one-off. And we've been real intentional in showing the community that this is a core part of who the Mann is."

This year's theme is space. Williams' song cycle includes texts by poets and writers on dreams — dreams internal and celestial, dreams soaring and deferred — but also Bluford's own words. Cristian Măcelaru will conduct Tuesday's space-themed works, ending with jollity, as in "Jupiter" from Holst's The Planets.

On Aug. 19, in anticipation of the Aug. 21 solar eclipse, the Mann will host a free day of astronomy exhibits and performances, ending with a free screening of Hidden Figures.

Hooked on (movie) classics

The pop acts that have such a big presence have not saved the Mann's bacon. Pop artists might bring in crowds, but they also come with big fees. The Mann, a nonprofit with little endowment and a relatively weak tradition of philanthropy, still struggles to end in the black each year. A recent structural analysis of the pavilion — the building opened in 1976 — led to renovations this spring that will continue into 2018 and may cost $2.5 million to $3 million.

But the Mann is not giving up on orchestras, even if they don't have the presence they once did. Falla's Nights in the Gardens of Spain has given way to music from Hogwarts and the Forbidden Forest, and the long-ago Mahler cycle from the Charles Dutoit era has become the score from La La Land. Last summer's Harry Potter and the Sorcerer's Stone managed to be both a popular and a critical success, beautifully showing a record crowd of more than 10,000 just how powerfully orchestral music can advance story, fine-tune emotion, and quicken the pulse.

This season, the Mann likes to say it programmed four of Philadelphia's orchestras: the Philadelphia Orchestra, which will perform the score to Harry Potter and the Chamber of Secrets on Friday; Philly Pops on Memorial Day weekend; Chamber Orchestra of Philadelphia, playing live Aug. 17 to the screening of La La Land; and a Curtis Institute of Music orchestra concert that opened the season (even if it had to be moved to Curtis, because of a cold spring rain, and heard only as an online experience).

Can the Mann be something more? A summer venue can dream, and the Mann is having some ambitious visions. Several trends are converging. Commercial music presenters have come into the Philadelphia market in a big way, giving the Mann some competition. "Philly has become this rock-and-roll destination like nobody's business," Cahill says. "It's crazy."

At the same time, arts education has become a bigger priority for arts groups and funders, and the Mann, sitting in the middle of a neighborhood, is beginning to imagine becoming a bigger player in education, perhaps even morphing into an urban Tanglewood, with a resident professional orchestra atop a pyramid of training ensembles and master classes.

The Mann may be uniquely positioned to take on a summer institute role, especially with the right partners. Summer for music students means unusually concentrated time for practicing, studying, and listening, often allowing a quantum leap in skills in a couple of months.

A new study being commissioned by the Mann on arts education and community outreach promises some answers.

"We may shift and go in a really dynamic direction," Cahill says. "The Mann has its eye on the ball and on the future." Among the questions: What is the Mann's part in the city's larger arts education scene? Should it have an off-season presence in schools? Are these themed festivals the right way to go?

"Maybe we only own summer," she says. "We have to find out what the community needs and wants."

Cahill is encouraged by concerts like last summer's Firebird project, which culminated in a concert by South Africa's Ladysmith Black Mambazo and Handspring Puppet Company, where the audience was 20 percent African American. The norm for Mann orchestral concerts is about 2 percent, she says.

"I think there's no question that, historically, the Mann was not always perceived to be the most welcoming for all constituencies, and we are trying to change that."

Williams himself answers the puzzle of mission aptly, if more poetically, in his song cycle, where he adapts a line from Max Ehrmann's Desiderata:

You are a child of the universe,
no less than the trees and the stars;
you have a right to be here.

What new study for a shed, a lawn, and a city could say it any better?

Orchestra shows at the Mann this summer

Hold Fast to Dreams debuts at the Mann Center, 52nd and Parkside Ave., Tuesday at 8 p.m. The program, with the Philadelphia Orchestra plus vocal soloists and four choirs led by Cristian Măcelaru, also includes works of John Williams, Bernstein, Puccini, Dvorak, and others.

Other Mann orchestral concerts this summer:

Saturday, July 22, at 7:30 p.m., the Philadelphia Orchestra plays live to Jurassic Park.

The "People's Choice" concert July 26 at 8 p.m. features the Philadelphia Orchestra in great standard repertoire with unusually low ticket prices — $12 to $27.

On July 28 at 7:30 p.m., the Philadelphia Orchestra plays live to a screening of Harry Potter and the Chamber of Secrets.

The Chamber Orchestra of Philadelphia performs live to La La Land Aug. 17 at 7:30 p.m., 800-745-3000.