The small staff of the World Trade Center Memorial Museum faces a few challenges as it prepares to commemorate the fifth anniversary of the terror attacks of September 11, 2001. The museum has no gallery space and little storage area. It has barely even started collecting. Still, it has a public mission to help Americans remember. “We have this conundrum — we are not a museum yet, but we have to start acting like one,” the chief curator, Jan Ramirez, said.

In fact, progress is under way. Construction recently began on the 142 “footings” of the memorial and museum, slated to open in the fall of 2009. And this week, the museum will open its first exhibition: a series of largescale photographs that will be installed on the chain-link fence on east side of the World Trade Center site. The images are from the “here is new york” collection, an exhibit that arose spontaneously in a SoHo storefront after the September 11 attacks.

This exhibit, and a second exhibit of photographs by Jonathan Hyman that will open September 8 in World Trade Center 7, are intended to commemorate the fifth anniversary. But, on a larger scale, they will help the museum establish the credibility it needs to attract both financial donations and the gifts of personal objects required to build an emotionally resonant collection.

The groundbreaking caps a turbulent planning process. In May, the World Trade Center Memorial Foundation announced that the full cost of building the memorial area — including the museum and memorial, as well as a cooling plant, sidewalks, roadways, and foundation walls — would be almost $1 billion. The public, Mayor Bloomberg, and members of the foundation board found the amount unreasonable. Mayor Bloomberg and Governor Pataki called in the construction executive, Frank Sciame, to review the plans and bring the budget under $500 million. In the meantime, the foundation halted fund-raising, and its president, Gretchen Dykstra, resigned.

After Mr. Sciame’s review, the budget for the memorial area was reduced to $740 million, with $510 million for the memorial and museum. Of that sum, the Lower Manhattan Development Corporation will provide $250 million; the foundation is responsible for raising $260 million and will raise an additional $40 million for operations and programming until the opening. So far, they’ve raised $131 million.

Additionally, Sciame recommended that the Port Authority, rather than the foundation, oversee the physical construction. The foundation is still responsible for finishing the design and operating the memorial and museum.

Although the Sciame review resulted in reduced square footage for the galleries, the museum’s director, Alice Greenwald, and the acting president of the foundation, Joseph Daniels, both said the outcome was purely positive. “What we and our donors had been missing was a clear definition of roles and responsibilities, a clear cap on the costs, and a basic design finality,” Mr. Daniels said. “Those three elements are all now achieved.”

Once the new plans were in place, the foundation resumed fundraising. “Our board is engaged in recontacting the major donors who have been waiting to see clarity return to this project,” Mr. Daniels said.

So far, donors to the project are both major givers and concerned Americans who want to help. Two anonymous donors have given more than $10 million, and corporations including Deutsche Bank and Goldman Sachs have signed on. But then there are remarkable, small contributions, like that of a group of Ohio high school students who have so far raised $10,000 in a walkathon.

With space and funding on the way, now the big questions about the museum’s purpose and programming need to be resolved. To stimulate discussion, Ms. Greenwald, who was previously the director of museum programs at the United States Holocaust Memorial Museum in Washington, organized a series of five seminars with experts on museums, memory, trauma, and historical narrative. She invited both the foundation staff and selected members of the community — representatives of the police and fire departments, survivors, family members, and Lower Manhattan residents.

“I felt that a lot of good work had been done, but it focused pretty much exclusively on the ‘What?’ of what had to be told, not on the ‘So what?'” Ms. Greenwald said. “There wasn’t a moment when people had stepped back and said: ‘Why are we doing this? Who are we doing this for? What are we hoping to get out of it?'”

The seminars galvanized the museum and foundation staff, Ms. Greenwald said. “We have a really strong team and now, with the Sciame design in place and fund-raising beginning and construction starting, the momentum is here. We’re ready to hit the ground running and do the conceptual schematic planning for the museum.”

In terms of collecting, the museum is at a slight disadvantage, having missed out on the first four and a half years of gathering materials and being available as a repository. The Museum of the City of New York, for example, was asked by the city to dismantle and conserve the construction wall outside Bellevue Hospital that became a site for missing person posters and a public shrine.

And even though acquisitions have been made, the museum can’t overwhelm itself with material before it has significant storage space. Right now, it has some donated storage space at 1 Liberty Plaza, where its offices are located.

The museum has been collecting oral histories, which are available as podcasts on its Web site. Some of the individuals who have given oral histories have also donated artifacts from the day of the attacks. One of those is Tom Canavan, who worked on the 47th floor of the north tower and was in the underground mall when the south tower collapsed. He and another man with him crawled out of the wreckage.

“He said, ‘Oh you probably wouldn’t be interested in this.'” Ms. Ramirez said. “And out he pulls, in a baggie, the damaged wristwatch he was wearing, the dollar bills he had in his pocket, his cell phone, completely” — she made a smashing gesture with her hands. “He had been carrying this material around for years, not being comfortable having it at home because he has young kids, not knowing what to do with it.”

A retired firefighter, Mickey Kross, who survived the north tower’s collapse in stairwell B, donated his leather fire helmet, covered with scrapes and dents. When Mr. Kross extricated himself from the collapsed building, Ms. Ramirez said, he found a fire command station on West Street, where he crossed his name off a list of presumed dead. Then he went to his girlfriend’s apartment on Greenwich and Duane streets. Her building had been evacuated, so he found a piece of paper and left a note on her door: “Christine: I’m okay. Talk to you later. Luv, Mickey.” Christine recently donated the note to the museum. The paper it was written on turned out to be a piece of Election Day information. “So it’s a double historical document,” Ms. Ramirez said.

Building a collection will take time, she cautioned. “These are precious keepsakes; people aren’t ready to part with them,” she said. But “as time goes on, people will make the decision that their personal memory, as powerful as it is, needs to be passed on.”

As much as the physical construction of the museum, building the collection will be a slow process — a fact that Ms. Ramirez accepts. “We aren’t a World’s Fair that’s going to open and close in seven months,” she said, “so there’s not a rush to have it perfect the day we open.”