The main mission of SDI is to stop Soviet intercontinental ballistic missiles. An ICBM has four main phases in its flight. In the boost phase, which lasts a few minutes, the ICBM's rocket boosters propel the missile above the earth's atmosphere. In the post-boost and midcourse phases, which together last some twenty to thirty minutes, the multiple nuclear warheads of each missile are released and travel through outer space toward their separate targets. The most modern Soviet ICBMs could release ten or more warheads along with "decoys" to fool enemy defensive weaponry. In the terminal, or re-entry, phase, which lasts less than a minute, the warheads decelerate as they re-enter the earth's atmosphere, and finally they reach their targets and detonate.
The case for Star Wars begins logically: The best time to destroy a Soviet ICBM is in the boost phase. The ICBM itself has a large, fiery rocket plume, making it easy to see, and it carries large amounts of highly explosive fuel, making it potentially easy to destroy. What's more, a single U.S. shot could destroy ten Soviet bombs.
Unfortunately, the boost phase lasts a brief three to five minutes. To destroy Soviet ICBMs so quickly, the SDI Organization plans to have weapons already in space, on satellites, when the Soviet attack begins. These satellites must carry weaponry, that can aim, fire, and hit the target within a few minutes. Lieutenant General James Abrahamson, the head of the SDI Organization, told Congress last summer that the system would have only forty to a hundred seconds to decide to react after the Soviets launched their ICBMs. He maintained, nonetheless, that his research so far indicated that such a "decision timeline is feasible" and would still allow for human control over the process.
In a series of setbacks, technology after technology has been considered for this demanding mission and rejected by SDI scientists. The most significant setback concerns chemical lasers, which shoot intense beams of light traveling 186,000 miles per second. These were the most mature of all the directed-energy technologies being considered, but scientists no longer think they are promising in the near term. Nonetheless, the SDI Organization may yet propose these lasers for early deployment. Other impressive high-technology systems that once received much publicity include neutral-particle beams and the nuclear-pumped x-ray laser. However, a panel of the American Physical Society, in the most definitive study yet done on directed-energy weapons, examined all the relevant classified information and concluded unanimously:
We estimate that even in the best of circumstances, a decade or more of intensive research would be required to provide the technical knowledge needed for an informed decision about the potential effectiveness and survivability of directed energy weapon systems. In addition, the important issues of overall system integration and effectiveness depend critically upon information that, to our knowledge, does not yet exist.
The prime remaining candidate possibly available in this century for boost-phase defense is space-based chemical rockets, along the lines of the fleet of 432 rocket-launching satellites orbiting the earth proposed by the group High Frontier. However, that system was repeatedly rejected by Administration experts. In a September, 1981, memo Herbert Reynolds, then the Department of Defense's deputy director for intelligence and space policy, called the concept "one vu-graph deep" and concluded that the need to rely on "hair-trigger" computer-based reaction time "alone might be enough to reject the concept, even if the system could do the job as advertised." In 1982 Secretary of Defense Caspar Weinberger criticized the scheme after a thorough Department of Defense review concluded, "It is the unanimous opinion of the Air Force technical community that the High Frontier proposals are unrealistic regarding state of technology, cost and schedule." The President's Commission on Strategic Forces, known as the Scowcroft Commission, reported in April of 1983 that "applications of current technology offer no real promise of being able to defend the United States against massive nuclear attack in this century." The U.S. Air Force studied and abandoned a system of this type in the 1960s, in a project nicknamed BAMBI (for ballistic-missile boost interceptor), which called for rockets strikingly similar to those planned for the SDI system. Nonetheless, the SDI Organization has decided to work toward deploying the High Frontier defense early in the next decade.
Officially there has not yet been a decision to deploy the system. But Secretary of Defense Weinberger said in March of last year, "The basic decision that we want to deploy has been made long ago." When the SDI officials reported to Congress last year on these interceptor rockets—then known as space-based kinetic-kill vehicles, or SBKKVs—they focused on a "series of achievements in excess of what was expected" which proved that "a SBKKV system can be built" and that the "technical feasibility of a near term SBKKV [has been] established."
Congress wanted no part of that scheme, which would violate the ABM treaty. Last year both the House and the Senate voted to cut back the budget increase for SDI requested by the Administration and to require adherence to the traditional interpretation of the ABM treaty—thereby restricting Star Wars tests. Further, the House rejected an accelerated development and deployment schedule designed to make SDI operational by 1993, by an overwhelming vote (302-121). In last year's continuing resolution Congress barred any funds for the full-scale development and deployment of any space-based interceptor system during 1988.
But SDI officials forged ahead. The dispersal of $1 billion in contracts was timed nicely to precede the July meeting of the Department of Defense's Acquisition Board, at which the SDI program underwent its first formal Pentagon review. After intense debate, including charges that crucial information damaging to SDI was being withheld from the board, six key SDI projects were granted Milestone I approval. This meant that the program could move from concept research and development to hardware demonstration and concept "validation." Thanks to strong support from the White House and from Weinberger, the program's proponents were able to dodge hard questions as to how SDI should be shaped, how it should proceed, and how strategic defense should fit into the overall U.S. military force structure. This political pressure enabled SDI to circumvent the basic deliberative processes of the defense board.