Most of Skylab, including the largest and heaviest pieces, fell in Australia and not in the Indian Ocean, the National Aeronautics and Space Administration said yesterday.

Conceding that its early estimates, placing the debris from the 77-ton orbiting laboratory mostly in the sea southwest of Australia, were wrong, the space agency yesterday released maps showing the path of the wreckage passing directly across the continent.

That would mean that about 20 of the estimated 26 tons of debris that survived the plunge through the atmosphere fell across the center of Australia, on a line from the city of Albany in the southwest to Somerset in the northeast. Parts also fell into the water south of Papua New Guinea.

"Skylab debris appears to have fallen across a sparsely populated area of Australia," public affairs officer William O'Donnell said yesterday at NASA headquarters in Washington, adding that fewer "than one person per square kilometer lives along that track in Australia."

No property damage and no injuries were reported along Skylab's path, but at least one farmer said the falling debris scared his sheep, and at least one fallen piece of Skylab had been found near the sheep-raising town of Rawlinna.

The discovered chunk of Skylab was described as a metal cylinder six feet long and three feet around that looked like it might weigh one ton. That fits the description of one of Skylab's oxygen tanks. There were six aboard, each weighing 2,700 pounds.

Sightings of burning Skylab debris as it fell were made by people in Perth, Esperance, Albany and Kalgoorlie, all cities near or along the path where NASA said Skylab fell Sightings were also made in Alice Springs, almost at the geographical center of the continent and one of the largest cities in the Australian outback.

No sightings were made any farther along the orbital track than Alice Springs, even though NASA says it believes that debris came down as far north as the tip of Cape York, more than 1,000 miles from Alice Springs.

NASA conceded that as many as 48 large pieces of Skylab fell on Australia, 38 that weighing more than 1,000 pounds each.

The 10 largest pieces were a 1,100-pound telescope spar, a 1,600 pound bulkhead off a fuel tank, the six oxygen tanks, a 3,900-pound lead-lined film vault and an airlock shroud 22 feet long and 5,100 pounds. Other than the one probable oxygen tank, none of these large pieces had been found as of yesterday.

NASA said it is sending a team of three of four engineers and a public affairs officer to Australia to identify and recover as many of the lost pieces of Skylab as possible. The team will come from the Marshall Space Flight Center in Huntsvill, Ala., where Skylab was designed and put together.

Although any parts of Skylab that are recovered are the property of NASA, the agency will allow finders to keep the debris.

Engineers would like to recover at least one fallen piece of debris whose metal skin had been exposed to the cosmic radiation of space over the six years Skylab was in orbit. Exposure of that duration could provide clues as to how cosmic rays affect metals in space.

NASA said it still did not know where it went wrong in predicting that all of the debris would come down in the south Atlantic and Indian oceans 1,000 miles short of Australia. Clearly, the space station stayed up and held itself together a lot longer than had been predicted.

Flight directors at the Johnson Space Center in Houston deliberately put Skylab into a tumble at an altitude of 92 miles to decrease the drag on the space station and delay its time of reentry. This was done Wednesday morning, when it appeared that Skylab might begin to break up over southern Canada and Maine.

Looking back at what happened, Skylab flight directors may have been premature in tumbling Skylab when they did. The tumble maneuver apparently delayed reentry a lot longer than had been expected.

The las radar look at the falling space station took place on Ascension Island in the Atlantic Ocean between Brazil and the West coast of Africa. Radar operated by the North American Air Defense Command (NORAD) watched as Skylab began to break up out over the south Altantic, but then lost the space station when it passed over the horizon on its way toward the south Indian Ocean.

The debris that rained down on Australia was made up of heavier pieces, which came down at the end of the fallout because their weight gave them enough forward speed to carry them further down range than the lighter pieces.