THE B-2 is dead - for now. "Star wars" is a big winner. And Pentagon personnel will be on the lookout for brown tree snakes from Guam.The defense budget season is finally all but over on Capitol Hill, with its blows and boosts to major weapon systems and innumerable small provisions the Pentagon must now interpret. The House this week wrapped up work on both the fiscal 1992 military authorization and appropriations bills. The Senate is scheduled to follow suit in days, and presidential signatures for both seem assured. More on the snakes later. First the big issue: B-2. With defense spending ceilings set by last year's overall budget agreement ($291 billion for fiscal 1992 defense budget authority), all the partisan passion usually expended on money totals seemed to spill onto the issue of whether to buy any more B-2 Stealth bombers. The Air Force did its best to invoke the Gulf war success of the F-117 Stealth fighter in selling the program, but the more recent collapse of the Soviet Union proved a larger influence on the House-Senate authorization conference committee that determined the bomber's future. Following the more negative House position on the issue, Congress has decided no new B-2 bombers will be authorized next year - with some conditions. Some $1.8 billion will be spent to keep the Northrup B-2 production line open. And another $1 billion will be set aside to fund a new plane if the secretary of defense certifies that the B-2 has passed all its radar-avoidance tests, and if Congress passes a new bill specifically allowing it. Considering the opposition to the B-2 in the House, there's little chance of a new B-2 getting built with 1992 money. With the program held at the 15 planes already built, its momentum broken, and its primary mission of deterring the Soviet Union largely irrelevant, the program may well be all but over. Many critics certainly see it that way. But by keeping the production line open Congress has ensured that the issue will come up in some form next year. And B-2 supporters such as Sen. Sam Nunn (D) of Geo rgia, the Senate Armed Services Committee chairman, insist that the program is alive, but not completely healthy. Is the B-2 dead? "I wouldn't use that word," says an aide to a key member of Congress who opposes the bomber. Defenses against ballistic missiles, on the other hand, were a clear winner this year. Largely adopting language put forward by Senator Nunn, House-Senate authorization conferees agreed that "it is a goal of the United States to ... deploy an antiballistic missile system," according to the published conference report. A ground-based defense system, small enough to stay within the bounds of the ABM Treaty, should be ready to erect by 1996 at the latest, according to the report. Furthermore, the House and Senate agreed to urge the opening of discussions with the Soviets about the feasibility of amending the ABM Treaty, so that more extensive defenses can legally be installed. Rep. Les Aspin (D) of Wisconsin, House Armed Services panel chief, said the move reflected a growing consensus in Congress that missile defenses are necessary to help deal with the threat of nuclear warhead and missile technology proliferation. "Enormous changes in the military dangers we face are forcing a basic realignment in the way we think about defenses," said Aspin on the House floor earlier this month. As always, the defense bills are among the most complex pieces of legislation Congress passes all year, filled with arcane provisions. This is where the tree snake thing comes up. Section 348 of the authorization bill is titled "Prevention of the Transportation of Brown Tree Snakes on Aircraft and Vessels of the Department of Defense." It orders the Pentagon to take such actions as necessary to prevent inadvertent introduction of said reptiles to Hawaii, where there are as yet none, from Guam, where there are zillions. Extensive US military installations in both places mean there's a steady traffic of Pentagon planes and ships back and forth. Specifically mentioned snake-guarding tools include "sniffer or tracking dogs" and traps. Other seemingly small matters addressed by our nation's legislators include a clarification of whether a parachute jump qualifies for hazardous-duty pay. (It must involve "military free-fall operations ... without the use of a static line.") Congress also authorized use of military personnel to help out at the 1993 World University Games in New York, and the 1996 Olympics, to be held in Atlanta.