Software upgrade key to NMD future

The Pentagon plans to upgrade software and make other repairs in a key flight

control system that officials believe was responsible for the failure of

a test of the proposed national missile defense system.

Although a detailed review of the July 7 test has not been completed,

the critical error occurred "somewhere in the data bus [or a] circuit board,"

Pentagon spokesman Ken Bacon said at a press briefing Thursday.

Officials have focused on an avionics signal processor that was supposed

to tell the rocket motor when to separate from the part of the rocket that

carries the warhead, or "kill" vehicle. During the test, that signal never

reached its destination, and the rocket spun out of control.

The modified Minuteman II rocket will use the same avionics processor

during the next two planned tests of NMD, but the Pentagon is considering

changes and upgrades.

"We're looking at a way to avoid what I call the single source of failure,"

Bacon said at a briefing on Tuesday. The solution "could be as simple as

a software change," he said.

The upper stages of the test rocket house all the systems electronics

and navigation equipment. However, the rocket that will be used for the

final, fielded version of the NMD system will use a new booster and new

avionics and electronics, Bacon said. "We want to make fixes in the old

one and design the new one in a way that doesn't have a single source of

failure for the separation mechanism or data transfer that this one had."

At a July 25 hearing on NMD before the Senate Armed Services Committee,

Defense Secretary William Cohen said that the July 7 test "while not successful,

was not without benefit and does not show, as some have claimed, that the

system is not technologically feasible."

"It demonstrated that the sensors and battle management systems could

and did work together as an integrated system. Satellite sensors and upgraded

early warning radars worked as specified, the X-band radar prototype worked

better than anticipated, and the command and control system performed well,"

Cohen said.

Cohen has since emphasized that he has not made a final decision as

to whether he will recommend to President Clinton to go forward with the

NMD system deployment. The overall maturity of the technology will be a

key element in his decision.

John Pike, a defense expert with the Federation of American Scientists,

said election-year politics likely will play more of a role in Cohen's decision

than anything else. "Al Gore thinks he needs an affirmative deployment decision

to get elected, and Cohen will oblige," Pike said.