For Kennedy troops it's on to New Hampshire -- and '84?

Sen. Edward M. Kennedy's campaign had been trying -- with some success -- to come to grips with the prospect of a defeat even before the first concrete hint of it surfaced in Iowa.

Despite the loss in that state's precinct caucuses Jan. 21, which Kennedy workers concede dims their candidate's prospects, the Senator's camp is showing an upbeat mood.

The week of "downtime" caused by cancellation of the Democratic presidential debate in Iowa was spent polishing Mr. Kennedy's speaking style and "prepping" him on issues. His style now is crisper. He is showing a greater sense of ease and humor on the campaign trail.

For the next five weeks before the New Hampshire primary, in his home territory, the senator plans no change in strategy or technique, says Kennedy spokesman Thomas Southwick. He will continue to try to draw President Carter out to the center of the ring "for the real debate on domestic, economic, and foreign affairs."

Because contributions will harder to come by in the wake of the Iowa defeat, cost cutting is already under way. The campaign has dropped its expensive jet airplane -- which was hurting media coverage because reporters balked at paying the high "fare" the Kennedy campaign was charging -- in favor of commercial and single-trip charter flights.

In terms of basic campaign strategy, Kennedy people concede Mr. Carter is winning because he is managing to keep the contest on his own terms -- an incumbent president acting responsibly in times of international crisis. The Kennedy challenge in the critical weeks ahead is to attempt to redefine the issues in terms of the Senator's theme that a change in policy and leadership is needed.

Events could still turn in their favor, the Kennedy people say. Iowa accounts for less than 2 percent of the delegates to the national convention. More than 20 percent are to be chosen in eight states on June 3, the last primary day.

More broadly, the Kennedy campaign seems to have taken the measure of the prospect of defeat in this year's presidential nomination contest -- and found it would not mean the end of their man's White House quest. Finishing the race in good, vigorous form would be useful.

And ahead there is 1984, when the Carter incumbency edge will have lapsed and the unusual foreign affairs circumstances are unlikely to be duplicated.

"Kennedy has been able to put himself into perspective in recent days," says Stephen J. Wayne, George Washington University presidential scholar and author of a new book, "The Road to the White House." The senator "is much more relaxed now," Mr. Wayne says. "He seems to be emerging as Carter did after his own crisis in 1966 after he lost the [Georgia] governor's race. Carter's ego seemed crushed, but he put himself into perspective and came back.

"Kennedy's putting his ambitions more into perspective makes him more acceptable as a candidate. A loss doesn't put him out of the running for 1984. To prove yourself vulnerable by losing to an incumbent president is no disgrace, " he continued.

"Proving that someone with the Kennedy name can lose may make him a more human, realistic candidate."

The lingering effect of Chappaquiddick could change, if voters come to feel that Mr. Kennedy has "paid the price" in an electoral loss, some observers speculate.

But in 1984 Senator Kennedy would not likely have the field to himself. In addition to a probable run by Vice- President Walter Mondale, other Democrats in the Senate and in governors' mansions will be interested. So in terms of campaign experience, and in finding the realistic proportions of a Ted Kennedy candidacy, this year's run -- win or lose -- will be useful, the Kennedy people reason.

And for as long as it goes -- to the convention, they hope -- the senator's troops say it might as well be enjoyed.