Northrop Grumman Guidance System Keeps MESSENGER On Course to Mercury

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Northrop Grumman Guidance System Keeps MESSENGER On Course to Mercury
Northrop Grumman News Release
November 10, 2004

WOODLAND HILLS, Calif. -- Northrop Grumman Corporation's
(NYSE:NOC) newest space navigation system is providing vital guidance
and control information to NASA's MESSENGER spacecraft during its
eight-year mission to Mercury, which began August 3 when it was launched
from Cape Canaveral Air Force Station in Florida.

This is the first deployment into space for Northrop Grumman's scalable
space inertial reference unit (scalable SIRU). The scalable SIRU is the
next generation of Northrop Grumman's space inertial reference unit
(SIRU (tm). It will continuously provide inertial attitude, velocity and
acceleration data to MESSENGER's attitude control system throughout the
5.8-billion mile space journey.

The new scalable SIRU, designed and produced by Northrop Grumman's
Navigation and Space Sensors Division, uses the company's exclusive
hemispherical resonator gyros (HRG). The inherent high-reliability,
high-performance, radiation tolerant features of the HRG and the dual
redundant features of the scalable SIRU make this the ideal inertial
reference unit for long-term (up to 15 years) space mission applications
such as MESSENGER.

"Our scalable SIRU offers inherent precision performance and high
reliability, which is central to this type of space-based mission," said
Alexis Livanos, vice president and general manager of the Navigation and
Space Sensors Division.

Northrop Grumman was awarded the contract for the MESSENGER mission by
the Applied Physics Lab (APL) in Laurel, Md., part of Johns Hopkins
University. APL manages the mission for NASA's Science Mission
Directorate, built the spacecraft and operates MESSENGER during flight.

The science instruments on MESSENGER will give it the ability to provide
far more data when it finally settles into orbit around Mercury.
MESSENGER's mission is to determine Mercury's composition; gather color
images of its entire surface; map its magnetic field and measure the
properties of its core; determine whether ice or other materials lie in
its permanently shadowed regions; and study Mercury's atmosphere and
magnetosphere.

MESSENGER is the seventh mission in NASA's Discovery Program of lower
cost, scientifically focused exploration projects. It will be the first
spacecraft to orbit Mercury and only the second spacecraft that has been
sent to Mercury. The first spacecraft, Mariner 10, flew past Mercury
three times in 1974-1975 and gathered detailed information on less than
half of the planet.

The HRG uses a thin-walled quartz shell that is energized by an
electrical field to produce an imperceptible vibration pattern within
itself. This pattern is electrically sensed and used to determine the
gyro's output parameters. The vibration is so minute that it creates
virtually no internal stress and fatigue effects, leading to its
unmatched reliability. Northrop Grumman is the exclusive producer of
HRGs, which to date have accumulated more than 4,500,000 hours of
operation in over 50 systems in space without a mission failure.

Northrop Grumman's SIRU was on the first Discovery mission, the Near
Earth Asteroid Rendezvous (NEAR)-Shoemaker spacecraft that reached Eros
in February 2000 and became the first spacecraft to land on an asteroid
in 2001. It will also be on the Deep Impact Discovery mission scheduled
to be launched in December 2004.

Northrop Grumman's Navigation and Space Sensors Division, part of the
company's Baltimore-based Electronic Systems sector, supplies
situational-awareness products for international and domestic defense
and commercial markets and offers integrated avionics, navigation and
positioning systems and sensors for space and high-value platform
products, navigation-grade and tactical-grade inertial systems,
fiber-optic gyro systems designed to customer unique requirements,
underwater fiber-optic sensors, identification friend-or-foe
transponders and interrogators, cockpit displays and computers, and
logistic support products and services.

CONTACT: Don Barteld
Northrop Grumman Electronic Systems
(818) 712-6179