Sometime late Saturday night, a Minuteman II intercontinental ballistic missile carrying a mock warhead and single decoy will lift off a launch pad at Vandenberg Air Force Base in California, and race across the Pacific.
About 20 minutes after this simulated target missile is launched, there will be another launch about 4,800 miles away. A prototype interceptor missile of the Bush administration's proposed missile defense system will launch from the Ronald Reagan Missile Test Facility at Kwajalein Atoll in the Republic of the Marshall Islands and head eastward.
If all goes according to plan, about 10 minutes into the flight, a "kill vehicle," having separated from the interceptor missile, will collide with the target approximately 140 miles above the central Pacific Ocean about halfway through the target missile's flight.
Pressure for an Intercept
The $100 million test flight is one of the most controversial in the long-standing effort to build a missile defense system to protect the United States from ballistic missile attack or an accidental launch of an intercontinental ballistic missile.
Bush administration officials have favored deploying the system as soon as technologically feasible. President Clinton delayed the deployment decision last year after a previous, failed test.
A controversial report prepared last year by the Pentagon's chief test evaluator found the system's effectiveness not at all proved, and said it was too soon to predict when the system could enter service.
The report also said testing of the system so far has been simplified, and controlled, in that the system was provided advanced information about the target that would be unavailable during a real attack. The report was recently released by a congressional committee despite Pentagon efforts to keep it confidential.
This is the first major ballistic missile defense test since President Bush took office. Two previous attempts to achieve an intercept failed — and there is tremendous pressure this time to have a successful test.
Defense Secretary Donald Rumsfeld is attempting to dampen expectations of both critics and supporters ahead of Saturday's test.
"My guess is that the outcome will be, unfortunately, simplified when it's over as either succeeding or not succeeding," said Rumsfeld. "But of course in any advanced technology activity, it is seldom that simple. It is often — and most often — a situation where a variety of things work properly and a variety of things may not."
Skepticism in Congress
The test will be watched very closely on Capitol Hill where there are growing signs that the Democratic controlled Senate is not willing to fully fund the spending increases on missile defense sought by the administration.
Senate Armed Services Committee Chairman Sen. Carl Levin, D-Mich., is particularly concerned that spending on missile defense in the 2002 budget is coming at the expense of other national security requirements.
"This budget request would decrease funding for procurement and for science and technology programs below the current year's level while increasing funding for missile defense programs by $3 billion or 57 percent," Levin said in a recent hearing.
He asked all of the heads of the military services to submit a list of their "unfunded" requirements, or programs they deemed necessary but which did not receive budget funding.
Expansive Program Pursued
This latest missile test also represents a fundamental shift under the approach to missile defense. The Clinton administration developed a political marriage with conservative Capitol Hill Republicans to fund development of 100 ground-based interceptors, or defensive missiles, in Alaska for a cost estimated between $30 billion and $60 billion.
Now the Bush administration has rejected that sole focus in favor of a broader $8 billion-a-year initiative to fund research and development of ground, air and sea-based defenses that could attack enemy missiles.
Proposed missile defense programs under this initiative would be tested, and either move forward or be terminated based on their success rates in field testing.
New Plan to Field System
There could be a controversial wrinkle looming in this effort. The Bush administration is proposing to build a new missile defense test site in Alaska with radar, command networks and missile storage and silos for as many as 10 interceptor missiles.
The Pentagon says it wants to build the site so it can do more realistic testing by having the interceptor fly outbound from the United States as it might in a real world scenario. The Pentagon also acknowledges it would reserve the right to actually use the missiles in a crisis.
Critics suggest this plan is a sub-rosa means of fielding a national missile defense without unduly provoking the Russians by keeping the system small.
Pentagon spokesman Rear Admr. Craig Quigley insisted that the Defense Department was not trying to "be sneaky or less than forthcoming." — ABCNEWS.com's David Ruppe contributed to this report.