A sailorless submarine from Prince George's County is setting forth from Baltimore today in search of the space shuttle Columbia's two reusable booster rockets, which sank off the Florida coast after the shuttle's launch June 27.

The tiny, remote-controlled submarine, Scarab 2, operated by East Port International of Lanham, will grope for the lost rockets in 3,500 feet of water 100 miles off Florida, where the $24 million boosters are believed to have sunk.

The boosters, designed to splash down softly and float, sank after they were jettisoned from Columbia and their main parachutes failed to open.

The sci-fi looking Scarab is equipped with sonar sensing devices, three television cameras and mechanical arms. The submarine, known in deep sea jargon as an "underwater tethered vehicle," is attached to its mother ship by an umbilical cord that powers the craft's electric motors, controls direction and manipulates arms and cameras.

Sonar transponders on the boosters, called "pingers," will help the submarine locate the 150-foot-long, 80-ton rocket motors on the ocean floor.

Once the boosters are found, the Scarab's cameras will send pictures to the surface to help scientists determine why the boosters sank. Searchers also hope to find flight recorders, which carry information about the two boosters' unexpectedly short lives.

Craig Mullen, president of East Port, said yesterday that Scarab was designed to repair underwater telephone cables. Scarab is an acronym for Submersible Craft Assisting Cable Repair.

The submarine has also been used by the U.S. Navy to assist the Netherlands in recovering a military aircraft, which sank in the Atlantic. East Port has a Navy contract to provide an emergency underwater recovery service.

Scarab is 13 feet long, 8 feet high and 7 feet wide. Made almost entirely of aluminum, the submarine weighs 6,200 pounds. Two pressure housings provide the craft's buoyancy control and are attached to an aluminum frame, along with the cameras and mechanical arms.

Mullen, who will lead a team of 10 on the search mission, said the Scarab is capable of operating in up to 6,000 feet of water and its umbilical tether can be stretched to 10,000 feet.

The submarine is not big enough to haul the booster rockets to the surface if NASA decides to bring them up, he said. Scarab could, however, attach a cable to the rockets if the space agency elects to raise them from the ocean bottom.

East Port's Scarab will be transported to the Florida coast by the Freedom, a ship owned by United Space Boosters Inc., a division of United Technologies. United Space Boosters built the shuttle rockets and is under contract with NASA to recover and refurbish them for reuse.

But when the boosters sank two weeks ago, United Space asked East Port to assist in finding the rockets with Scarab.

East Port International was set up in 1968 under the name Ocean Search Inc. through a joint venture between the Aluminum Company of America and the Washington-based firm Ocean Science and Engineering.

In 1979 Alcoa sold the company to the firm's management. East Port is now involved with a series of marine business operations. It designs and builds electronic instrumentation for use in the ocean. About 50 percent of the firm's work is done for the government and much of it is classified.

According to a spokesman, the company had sales last year of more than $5 million.