Navy salvage crews took advantage of calmer seas today to recover a 3,250-pound chunk of debris that may be part of Challenger's right-side solid rocket booster.

A Navy spokesman said it is not clear whether the 6-by-18 foot segment dredged from 400 feet of water 28 miles east-northeast of Cape Canaveral is from the suspect right booster, believed responsible for triggering the shuttle disaster.

The spokesman also did not say which part of the booster was found. Engineers are most interested in recovering segments where videotapes of the flight indicate a leak occurred. Investigators say they believe a tongue of flame coming from the right booster led to the Jan. 28 explosion of Challenger's large external fuel tank, killing all seven aboard.

Salvage operations have been using sonar and video cameras to identify debris on the ocean floor. But no NASA spokesman could be reached to ascertain whether parts, numbers or other means of distinguishing the right booster segments from left booster segments have been found.

Navy salvage teams also continued to work toward bringing to the surface what is left of the crew cabin and remains of the astronauts.

Meanwhile, astronaut Paul Weitz said on CBS News' "Face the Nation" that the National Aeronautics and Space Administration plan for nine shuttle missions in 1987 is overly ambitious and NASA may be "setting ourselves up" to the same scheduling pressure that could have contributed to the disaster.

"I personally feel that a schedule such as that probably would be more than we ought to start out with again," he said. "In the past . . . the system has come to succumb, probably subconsciously, to the pressures of schedule."

Weitz appeared from Houston with astronaut Henry Hartsfield Jr., who has repeatedly expressed anger that NASA failed to inform previous shuttle crews, including one he commanded, of potential safety problems. "I'm sure it won't happen again," Hartsfield said.

Both men denied there is growing "polarization" between the astronaut corps and other segments of the agency and said bickering has been overblown in news accounts.