On any steamy afternoon, when the museums on the Mall are clogged with tourists, you can escape into the air-conditioned comfort of a different Smithsonian museum, the Anacostia Neighborhood Museum. You can see a portrait of "The Brown Bomber," boxer Joe Louis. Or of Alain Locke, who in 1907 was the first black American to win a Rhodes scholarship. Or of performer Paul Robeson, majestically attired as Othello.

But on one recent steamy afternoon, the museum was empty. Not one person for two hours.

"It slows down in the summer, when school's out," said director John Kinard, "and we also don't have parking." But, he added, "It gears back up when summer programs start, after the Fourth of July."

The Anacostia Neighborhood Museum, located on a busy part of Martin Luther King Avenue, was set up in 1967 as a bold experiment, with the aim of bringing some of the Smithsonian's resources to Washington's neighborhoods. It is housed in a 5,000-square-foot building that has been a church, a skating rink, and a theater.

"We want to stay here," said Kinard. "We just need more space" so that the museum can attract more visitors from Anacostia and beyond. "We are a community museum, but we are also local, national and international . . . The aspirations, hopes and dreams of the people of Anacostia are no different from those of the people anywhere else. Everyone can learn from the museum."

What they can learn is a varied mix: for example, this month local dancer Greg Reynolds will lead a participatory workshop, and today there will be a creative writing workshop. A "Young People's Film Festival" will play throughout July. "Believe it or not," said Kinard, "some kids today don't know who Martin Luther King was. We want to provide role models."

Children in the Anacostia neighborhood recognize the museum as an integral part of their community. "It gives me ideas so I can make reports for history," said 12-year old Tamika Green, who was strolling through the neighborhood that same hot afternoon. Charmaine Hunter, 11, added, "If you go early enough, you can see a movie. And Mr. Hammond a museum guard gives us candy every Friday." Nine-year old Daryll Anthony Price takes his museum-going seriously. "I went every day since last January. I like the statue of the old lady sitting in the rocking chair Sojourner Truth . I go by myself and I'm glad it's here."

Exhibits have ranged from the 1969 show "The Rat: Man's Invited Affliction," to the recent "Anna Julia Cooper: A Voice from the South." "We are moving from exhibits that document black achievements in isolation to exhibits that talk about an epoch and all those involved," explained Kinard. "It does us no good today to concentrate on the achievements of blacks in isolation . . . The day in which we had to prove we existed is gone."

In 1980, Kinard tried to expand the museum and focus specifically on Afro-American history. But a Smithsonian committee decided that the Anacostia museum should remain a neighborhood operation.

"The committee thought that Afro-American history was such a broad subject that they didn't want it reduced to the nomenclature of 'community museum.' But since the Smithsonian was not dealing with it Afro-American history in a major or even in a minor way, this museum needed to take it on its own back," said Kinard. "I'm operating as though that report never existed."

An annex is scheduled to open in September 1984 in Fort Stanton, a residential, wooded area a mile away where the museum's research facilities are housed. Kinard said he expects that the new location will attract more "middle-class oriented people who don't feel safe" at the present location.

Congress has not yet approved the Smithsonian's fiscal 1984 request, which includes funds for the new building. John Reinhardt, a former director of the International Communications Agency who is now acting assistant director for history and art at the Smithsonian, said he expects a decision "any time from summer to Christmas," though he is confident that the Smithsonian's testimony was well-received.

Fort Stanton is only supposed to be a temporary site. The museum plans to build a permanent home with 800 parking spaces on the Anacostia River in 1986, near the projected Anacostia stop of Metro's Green Line. "We all know what Metro stops do for a community," said Reinhardt. Kinard's enthusiasm for the new location approaches epic proportions; he said that after Metro arrives, Anacostia will "rival Georgetown in development." But plans are on hold as long as the subway construction is delayed, and that could be indefinitely. A Federal District judge in Baltimore has halted construction, and no date has been set for a final decision.

Kinard says he is content with his present relationship with the Smtihsonian. Major institutions, he noted, "are usually standing in the shadows dictating. This is not the case with the Smithsonian. If we stumble and fall, as the museum expands it's our own fault."