Press Release

Boeing MDR Payload Adds New Capabilities to U.S. Air Force Milstar II Satellite

By SpaceRef Editor
February 19, 2001
Filed under ,

A U.S. Air Force
Milstar II satellite equipped with a powerful medium-data-rate (MDR)
communications payload supplied by Boeing Satellite Systems Inc.
(BSS), will launch on Feb. 24 from Cape Canaveral Air Station, Fla.
The four-hour launch window opens at 11:09 a.m. PST (2:09 p.m. EST
and 7:09 p.m. GMT).

The MDR payload provides secure, jam-resistant communications to
U.S. forces through unique onboard signal- and data-processing
capabilities. The satellite’s crosslink payload is also supplied by
BSS, a unit of The Boeing Company located in El Segundo,

“BSS is proud to have been part of the Milstar satellite team
since 1982,” stated Tig H. Krekel, president of Boeing Satellite
Systems. “After a successful launch, this satellite will be the first
with the new MDR communications hardware. This technology will meet
the needs of multiple users by supporting the connectivity of tactical
and conventional forces.”

Designated as F-4, the satellite being orbited in February is the
fourth in a series of six Milstar II spacecraft to be built by a team
headed by prime contractor Lockheed Martin Space Systems of Sunnyvale,
Calif. BSS delivered the MDR and crosslink payload hardware to
Lockheed Martin Space Systems in June 1998. The first BSS-supplied MDR
payload was aboard the F-3 spacecraft, which was left in a useless
orbit after a launch vehicle failure.

The MDR payload dynamically sorts incoming data and routes them to
the proper downlinks to establish networks and provide bandwidth on
demand. Using a 32-channel extremely high-frequency (44 GHz) uplink
and a super-high-frequency (20 GHz) downlink, it sends real-time
voice, video and data to military personnel in the field at rates that
range from 4.8 Kbps to 1.5 Mbps. That is up to 50 times faster than a
common PC modem.

The crosslinks provide communications capability at 60 GHz between
Milstar satellites for both the MDR payload and the 2.4 Kbps low data
rate (LDR) communications payload on the satellites.

As the supplier of the MDR payload, BSS integrates antennas and
electronic units onto the MDR structure, called the -X (minus X) wing,
provided by Lockheed Martin. Together the MDR payload weighs about
1,100 pounds and uses 860 watts of power.

The MDR antenna coverage subsystem consists of eight narrow spot
beam antennas provided by TRW: two narrow spot beams with nulling
capabilities (nuller antennas) and six distributed user coverage
antennas (DUCAs), each supporting two-way communications.

In contrast to commercial communications satellites, whose beams
can cover entire continents, Milstar’s beams are very narrow,
providing less opportunity for enemy detection and penetration. The
nuller antennas resist jamming from within their respective coverage
areas by changing their gain patterns when a jamming signal is
detected. The DUCAs provide high gain/low sidelobes for distributed

Beyond Milstar, Boeing Satellite Systems joined with Lockheed
Martin and TRW in May 2000 to form the Advanced Extremely High
Frequency (Advanced EHF) National Team to build the follow-on to the
DoD’s Milstar highly secure communication satellite program. Formation
of the new team will accelerate the deployment of the new system to
help bridge the gap in military communications capabilities caused by
the loss of the third Milstar satellite.

Under the National Team arrangement, Boeing will lead the payload
effort and will be responsible for payload integration, as well as
production of radio frequency electronics and phased array antennas
for the five satellite Advanced EHF systems.

Boeing Satellite Systems is the world’s leading manufacturer
of commercial communications satellites, and is also a major provider
of space systems, satellites and payloads for national defense,
science and environmental applications.

The Boeing Company, with headquarters in Seattle, is the largest
aerospace company in the world and the United States’ leading
exporter. It is the world’s largest manufacturer of commercial
jetliners and military aircraft, and the largest NASA contractor.

The company’s capabilities in aerospace also include rotorcraft,
electronic and defense systems, missiles, rocket engines, launch
vehicles, and advanced information and communication systems. The
company has an extensive global reach with customers in 145 countries
and manufacturing operations throughout the United States, Canada and

Note to editors: For more information about the Milstar launch, go
to the Milstar Flight 4 launch team Web site at

SpaceRef staff editor.