New Radar Plane Rushed Into Duty : Military: Field tests for the JSTARS aircraft are cut short. It will help plot movement of Iraqi ground forces.

The Pentagon has interrupted lengthy field tests of a new, high-technology radar plane and dispatched it to the Persian Gulf, where it could play a key role in plotting the movement of Iraqi ground forces before and during a Mideast war, U.S. officials said Monday.

The JSTARS planes--short for Joint Surveillance and Targeting Acquisition Radar System--were designed for use in monitoring troops and tanks in Europe as they moved to engage NATO forces. But six years before they were to formally enter the U.S. arsenal, two of the modified Boeing 707s--bristling with electronic surveillance equipment--have arrived in Saudi Arabia for potential war duty.

The unusual move is a measure of the extent to which the United States would rely on high-technology weapons, most of them unproven in combat and some not fully tested, to defeat numerically superior Iraqi troops in Kuwait. It may also provide an example of how the services are using Operation Desert Shield to expose new systems to Third World warfare and to help salvage fading support for equipment originally designed for war in Europe.

The JSTARS radar planes, projected to cost at least $370 million by the time all are built, could play another critical role at the outset of a Persian Gulf war: to help detect and target an estimated 70 Iraqi mobile missile launchers that could be used to hurl Scud missiles, possibly tipped with warheads containing chemical or biological agents, at Israel and Saudi Arabia. Officials acknowledged that the U.S. forces’ difficulty in pinpointing the missile launchers, as well as the necessity of destroying them early in a war, may account for the Pentagon’s haste in dispatching the JSTARS aircraft to the gulf theater of operations.

Still formally considered to be in development, the JSTARS planes are designed to scan an enemy’s territory from distances of up to 130 miles and spot vehicles moving along the ground. For ground commanders, the planes would provide the same kind of detailed targeting information that the AWACS airborne command centers provide for commanders of the air war.

If the JSTARS performs to its specifications, the range of its sight would permit ground commanders to peer to the northern edges of Kuwait, near the Iraqi city of Basra, and to look shallowly into Iraq.

In part, the limits of the JSTARS’ sight are imposed by the planes’ vulnerability to a range of threats. To capture the movement of vehicles on the ground, the JSTARS plane pumps out a range of different electronic and radar signals. By picking up those signals, Iraqi air defense radars on the ground can easily find and home in on the signals emitted by the lumbering jets, which carry no defenses of their own.

“It is a very big, juicy target, reasonably easy to detect because of its radiating radar,” said Benoit Morel, a professor of engineering and public policy at Carnegie-Mellon University.

Either the JSTARS must fly well behind the border and out of range of ground threats, in which case its ability to look into Iraq and northernmost Kuwait would be compromised, or it would be vulnerable to air defenses, Morel said.

According to Ted Postal of the Massachusetts Institute of Technology, dust and sand will attenuate the signal the JSTARS uses to detect and track movements on the ground. As a result, its effectiveness could be degraded by the shamal, the sudden storms in the gulf region that bring winds of 30 to 50 m.p.h. and gusts to 80 m.p.h. and can produce walls of sand up to 10,000 feet high.

Still, analysts said that if JSTARS is to work anywhere, it should function at full potential in the Persian Gulf, where Iraq’s electronic jamming is expected to be crude, air defense capabilities minimal and the clutter of competing ground traffic light.

“If it doesn’t work in Iraq, I really don’t think it would work anywhere,” said Morel.