President Johnson has requested $17.6 million for Cambridge's National Aeronautics and Space Administration electronics research center in the fiscal 1965 budget.

Ten million dollars would go towards construction of the center--and if approved by Congress--would bring to almost $24 million the money available to build the laboratory in Kendall Square near M.I.T.

NASA officials expect to begin construction sometime this summer, a spokesman said yesterday. Completion of the $61 million complex is scheduled for sometime in 1967.

Seven million dollars is alloted for salaries. Approximately 125 people are already working in Cambridge in temporary offices and the number is expected to rise to 250 by July.

The research center will be built on a site in Kendall Square, but businessmen who presently occupy the area are fighting to prevent NASA from dislocating them.

They claim that the cost of relocating will drive many of them out of business because federal relocation allowances, which run to a maximum of $25,000, are unrealistically small.

An appeal pending in the Massachusetts State Judicial Court challenges the right of Cambridge to take the Kendall Square site under urban renewal laws and then resell to NASA.

Officials of the Cambridge Redevelopment Authority claim that the area is blighted and clearly falls under the laws. The businessmen claim that renewal is only being used as a vehicle to rob them of their land.

If the courts uphold Cambridge's position, the City would receive federal urban renewal funds to clear the 42 acres in Kendall Square--29 for NASA and 13 for an adjoining private development.

The Court challenge seems to present a problem beyond mere legality, however. Opponents of the Kendall Square project claim that their case is strong enough to go all the way to the U.S. Supreme Court. If they are right and they choose to press the issue, the legal battle could take years.

NASA, it is believed, wants to begin construction immediately and would be prevented from doing so by any drawn out legal fight. If the court struggle proves to be too long, some observers believe that the agency might begin looking for another site.