Chem-bio sensors for strykers not yet perfected.

The Army may scale back plans to equip its new Stryker combat vehicles with advanced sensors that detect chemical agents while the vehicle is moving at high speeds.

Even though Stryker production is proceeding as scheduled, the chemical sensors have failed critical tests and may get scrapped from the program.

The Stryker is a 19-ton armored troop carrier that comes in I0 different models. One of the variants, called the NBC RV, is a reconnaissance vehicle equipped with nuclear, biological and chemical sensors. Each Stryker brigade--with nearly 300 combat vehicles, 12 cannons, and hundreds of trucks--is intended to deploy with three NBC RVs.

Although the infantry-carrier version of the Stryker already is in full-rare production, the NBC RV remains in development and is expected to be operational by 2006. The first Stryker brigade already has seen combat in Iraq, and a second already is training for a future deployment.

Serving as an interim replacement for the NBC RV is the Fox tracked armored vehicle, which can sense chemical agents, but has no biological detector. The Fox is out of production, but the Army has about 100 in the inventory, 60 of which have been upgraded with new sensors.

Until the NBC RV sensor problems are resolved, the Stryker brigades will employ the Fox vehicle. The Army expects to field six brigades during the next decade. The entire $4 billion program includes 2,100 vehicles.

The NBC RV originally was to be equipped with a new joint service lightweight standoff chemical agent detector, or JSLSCAD. The sensor scans on the move, providing 360-degree coverage at distances up to 5 kilometers. It is a more sophisticated version of the currently fielded M21 chemical detector, a standoff sensor that has a shorter range and only works in a stationary position. It can detect nerve, blister, and blood-agent vapor clouds.

The Fox vehicles that will deploy with the Stryker brigades are equipped with the M21 detector. If the JSLSCAD gets delayed or cancelled, the new NBC RVs also will be outfitted with the M21 detector.

JSLSCAD is unlikely to be deployed aboard Stryker vehicles in the foreseeable future. The program is having "serious problems," according to a senior official on the Army staff.

Military and industry sources confirmed that both the JSLSCAD and the joint chemical agent detector (JCAD) programs are under scrutiny by the office of the assistant secretary of the Army for acquisition, Claude Bolton. "Both programs are being reviewed closely" and possibly could be canceled if the technical glitches aren't fixed, the Army official said.

JCAD is a handheld detector for use throughout the Defense Department and the services. Like JSLSCAD, it failed to detect simulated agents in recent tests.

The joint program office for chemical and biological defense, which manages the development and testing of both systems, did not respond to several requests for information on the status of JSLSCAD and JCAD.

Although the JSLSCAD was not the system specified originally for the Stryker NBC RV, it was the "system the Army wanted, because it provides standoff range on the move," said a Stryker program official.

Wendy A. Staiger, program manager at General Dynamics Land Systems, said the Stryker NBC RV is scheduled to begin low rate production in September 2004, pending an Army review. "But that won't happen unless the sensor problems are resolved," she told National Defense.

Industry sources said the Army held "emergency meetings" during the month of April to address the sensor problems and to outline a plan to conduct new tests this summer at Dugway Proving Ground, Utah.

The Stryker NBC RV will have a four-soldier crew: two in the back, a commander and a driver.

The sensor package preferred by the Army is the JSLSCAD, the JBPDS (joint biological point detection system), and a chemical-biological mass spectrometer. A division of General Dynamics, called GD Advanced Technical Products, is the contractor for both the JSLSCAD and the JBPDS. Hamilton Sunstrand supplies the mass spectrometer.

Col. Nickolas G. Justice, acting assistant deputy for acquisition and systems management, told reporters that the Stryker brigade would not suffer if the NBC RV vehicle is delayed, because the Fox system can do the job, for the most part. "We are not looking to rush that [NBC RV] vehicle to production," Justice said. "We have the Fox. I don't want to field something that is no greater capability than what I've already got."

Experts said it is not surprising to see standoff chemical detectors encounter difficulties, even though the Defense Department has been working on these technologies since the 1960s.

Unlike "point" detectors, which scan a specific area until a suspicious agent is found, the standoff detectors are expected to find agents at long distances, often having difficulties distinguishing chemical warfare agents from regular industrial fumes, for example.

"There are fundamental physics issues" that make it difficult for the Army to develop standoff detectors that work, said Stephen E. Kelly, senior vice president at Battelle, a research and development company.

The same could be said about biological detectors. "Bio detection is even a harder problem," he said. "There are tens of hundreds of particles in the air."

The on-the-move detection the Army wants for the Stryker brigade is complicated. Retired Marine Corps Lt. Col. Tom Manley, a former chemical-warfare officer, said that engine exhaust and rapid airflow that brings dust and moisture can impede accurate detection. "Taking samples at high speeds can foul up the system," he said. It often happens that detectors "work in the lab, but have trouble in real-world environments."