Washington — On Lt. Gen. James A. Abrahamson's desk in a large but spare office are a couple of small and apparently useless objects. One is a piece of steel with two ragged holes punched through it. The others are marshmallow-size lumps of plastic with copper cores. The holes in the two-inch-thick steel were made by the two-ounce plastic projectiles, fired from an electromagnetic rail gun at nearly two kilometers per second (4,475 m.p.h.).
From such stuff, says the head of the Pentagon's Strategic Defense Initiative Office (SDIO), do the dreams of preventing nuclear war grow.
As head of the program that critics call ''star wars,'' General Abrahamson himself has become a target, of sorts. Plucked from the United States space shuttle program five months ago, he is point man for a concept that challenges not only the basis for today's nuclear deterrence but also the beliefs of many physicists, strategists, and other experts on nuclear war.
His job is to defend the notion of space-based ballistic missile defenses before audiences ranging from the US Congress to European allies to hometown groups. And he must put together a management team that is able to cut through interservice rivalries while overcoming the protective shield thrown up around other Defense Department programs threatened by SDIO.
In an interview this week, Abrahamson expressed great optimism about the effort he oversees, while stressing that the decision to deploy missile defenses in space is years off. The bottom line, he says, will be the answer to the question ''Is the world safer?''
Well experienced at giving briefings, the former test pilot and astronaut likes to talk with chalk. At the blackboard in his office, he draws missile arcs , points of possible defense, and his ''horse race'' plan for motivating defense contractors to return ''the first with the most'' in ideas for making it work.
But he seems the most thoughtful and sincere when discussing the ''moral'' basis for President Reagan's controversial decision and the ''statement of faith'' about the technological possibilities, which he likens to the US space program - especially the flights to the moon.
''It opens up a whole new regime for leverage with (arms control) negotiations,'' he says. ''And the most important thing is that it is not leverage that is going to be threatening in the sense that they are nuclear weapons to destroy the Soviet Union.''
Critics - and there are many - say that adding missile defenses to an already-huge offensive nuclear system would create at least the impression that the United States is able to launch a successful first strike. That would undermine deterrence based on each side's having sufficient retaliatory forces, they warn.
''It is in fact a very fundamental issue,'' Abrahamson says. ''And in that sense, I guess I'm not at all surprised that there are people who are clinging to the past and to the ideas that have worked reasonably well so far in the nuclear age, in that we have not had a nuclear war.''
''On the other hand,'' he adds, ''the other ideas have not been at all successful in controlling nuclear weapons. And as the world becomes a more complex one ... I'm not sure that the old ideas are going to suffice a decade from now or two decades from now.''
New ideas have been an important part of much of this affable Oregonian's career. His undergraduate studies were at the Massachusetts Institute of Technology, and he earned a graduate degree in aeronautical engineering through an Air Force program with the University of Oklahoma. He was a spacecraft project officer in a nuclear detection satellite program, served as an astronaut in the Manned Orbiting Laboratory Program, and commanded an Air Force test wing.
Three years ago he was named the National Aeronautics and Space Administrations's associate administrator for the space shuttle program. Here, he was, as he says, ''the last guy to say, 'OK, let's launch the space shuttle.' ''
This week, Abrahamson launched something that may seem less spectacular than a fiery shuttle launch but could have greater impact.
He put out the formal ''request for proposals'' to defense industries hoping to get of the new SDIO action. So far, more than 220 have signed this bidders' list.
During the first phase, about a dozen relatively small ($1 million) contracts will be let to study ''alternate architectures,'' that is, ways to intercept enemy warheads at diffent points along the missile arc. Those contractors who first come up with the best ideas will enter the second track of the ''horse race'' with $5 million contracts.
''I'm going to try to get our contractors in this project to go back to working in a garage with a team of highly creative people,'' he says. ''Obviously, that's an overstatement. But I want to get overheads down and get them to put their very best people in it ... because only if they get a really select team together will they be able to maintain the pace that we want.''
One of the toughest things for SDIO supporters to explain is how a missile defense system could help render nuclear weapons ''impotent and obsolete'' (as President Reagan called for) without having to provide a ''bubble defense'' over the whole country.
''This argument that it's got to be perfect is, I think, badly founded,'' Abrahamson says. ''Clearly, we're going to try for just as good as possible. It will probably continue to improve over a long period of time, and it may even someday be very, very, very effective.''
''What it's really supposed to do is be so effective that (the Soviets) will understand that they will never be able to achieve this military victory,'' he adds.
In conversation, General Abrahamson is a pleasant, engaging man who seems to have (as another officer in his organization says) ''that enthusiasm that makes everybody want to work for him.''
Yet he did not win his three stars by being overly optimistic or naive about what this as-yet largely theoretical business is all about, which is the possibility of nuclear war between military giants.
Flying back from a talk in Albany, Ore., the other day, he read an article about the growing number of American towns declaring themselves ''nuclear-free zones,'' that is, places where nuclear materials or weapons could not be stored or transported. It bothered him to think that communities in this country, and perhaps in Europe, might one day begin declaring their neutrality. Would this make the world a safer place? he wondered. And what does it say about the possibility of, as he put it, the ''deteriorating resolve'' in the face of ''a potential enemy who hasn't changed its course at all and whose policy is being made by 14 tough men in the Kremlin''?
As Abrahamson sees it, whatever superpower stability exists today rests largely on the United States ''relying on (Soviet) stability and their good intentions - just like we relied on them not to shoot down an airliner.''
It is a hard-edged comment that may alarm those who would like to see the US be more accommodating in its relations with the Soviet Union.
But on one thing Abrahamson and critics of the program he heads can agree: It will be these kinds of perceptions and how they are acted upon - and not the speed and accuracy of electromagnetic rail guns - that determine whether the push for missile defenses and a new strategic doctrine continues.