In another surprising twist in U.S.-Soviet diplomacy, Soviet Foreign Minister Eduard Shevardnadze is flying here for meetings Friday aimed at putting a Washington summit meeting by Soviet leader Mikhail Gorbachev back on track after last week's sudden derailment, administration officials said last night.

U.S. sources said new signals from Moscow and elsewhere suggested yesterday that Shevardnadze will say the Soviet Union is imposing "no preconditions" for a summit meeting here later this year, and that Gorbachev will not insist in advance on more than a full discussion with President Reagan about possible limitations on antimissile weapons in space such as Reagan's Strategic Defense Initiative.

If Shevardnadze delivers this message, it would be a reversal of the position Gorbachev took during last Friday's Kremlin talks with Secretary of State George P. Shultz. At that time, Gorbachev refused to set a date for a summit this fall after hearing from Shultz and national security adviser Frank C. Carlucci that there was little prospect that Reagan is ready to accept "key provisions" limiting his SDI program.

A Soviet Foreign Ministry spokesman in Moscow, meanwhile, said Gorbachev could come to Washington "in the near future" and appeared to soften the objections to a summit meeting stated by Gorbachev last week. {Details, Page A23}.

The main purpose of a Washington summit, which may include visits by Gorbachev to other areas of the country, is to sign an intermediate-range nuclear forces (INF) treaty, which would be the first U.S.-Soviet arms-control agreement of the Reagan administration and the first to eliminate an entire class of offensive weapons.

Shultz told a briefing for members of the Senate late yesterday that the INF agreement is "98 percent complete," according to Senate Foreign Relations Committee Chairman Claiborne Pell (D-R.I.). Pell said that in the negotiations, the United States obtained "just about everything we asked."

Pell said that Shultz believes there will be a summit meeting to sign the accord, although he "remains open" about when it will take place.

The Shevardnadze mission is scheduled to be formally announced in Washington and Moscow this morning, several hours before Reagan is to speak at the U.S. Military Academy about U.S.-Soviet relations and arms-control prospects beyond the INF treaty.

State Department sources said the first word of the new Soviet maneuver came when Shevardnadze called in U.S. Ambassador Jack F. Matlock yesterday morning in Moscow to suggest flying to Washington to continue work on the INF treaty and arrangements for a summit meeting. After Matlock reported to Washington on Shevardnadze's desire to come, he was called back to the Soviet Foreign Ministry for a second session which, sources said, mainly concerned logistical details of the mission.

The sources said Shevardnadze is expected to bring Reagan the letter that Gorbachev promised last Friday at the end of the Kremlin meeting with Shultz.

It is anticipated that the date and duration of the Gorbachev visit to Washington will be set in the discussions with Shevardnadze Friday, officials said. They said there is no concrete information about what the Soviet minister will propose along these lines.

A speech by Soviet U.N. Ambassador Alexander Belonogov in the U.N. General Assembly political committee yesterday indicated that a U.S.-Soviet accord on "key provisions" of strategic and space arms was viewed as a desirable result of the next Reagan-Gorbachev summit, rather than a condition of holding that meeting.

At a news conference following his address, Belonogov said that "although at this stage, there has not yet been final agreement on the date for the next summit meeting, the possibility of holding it this year still exists." He said that what happened in Moscow last week was that "a short pause, an interval, is taken to let the Americans talk over ideas" and enable negotiators in Geneva to discuss the Antiballistic Missile Treaty.

Staff writer Helen Dewar and special correspondent Michael Berlin contributed to this report.