U.S. IMEWS Space System and Creation of an Advanced Ballistic Missile Launch Detection System
by Lieutenant Colonel A. Andronov and
Captain S.
Garbuk, candidate of technical sciences
ZARUBEZHNOYE VOYENNOYE OBOZRENIYE
No 12, 1994 (signed to press 8 Dec 94) pp 34-40
The IMEWS [Integrated Missile Early
Warning Satellite] space system was deployed in the early 1970's
for giving the U.S. supreme military-political leadership early
warning of a nuclear missile strike against U.S. territory. Its
other name is DSP [Defense Support Program]. Compared with
ground radar equipment, the system permitted detecting the
launches of Soviet and Chinese ICBM's at an earlier
stage.1
But in connection with changes in the military-political
situation and the development of missile technology, a need
arose for upgrading electronic equipment, making requirements
tougher and broadening the range of missions assigned to the
system. The principle of evolutionary modernization of onboard
and ground gear with a gradual increase in the number of
operational satellites and optimization of their orbital
deployment (Fig. 1) was made the basis for this.
Three IMEWS satellites were deployed in geostationary orbit
and two fixed receiving complexes were deployed during
1970-1974: in the United States at Buckley Air Force Base
(Colorado) and in Australia (Woomera). The satellite deployed in
the Indian Ocean zone (Indian) was intended for detecting Soviet
and Chinese ICBM launches, and the two satellites (Atlantic and
Pacific) situated over U.S. coastal waters were to keep an eye
on launches of intermediate-range ballistic missiles from Soviet
submarines (SLBM's) on alert duty off the U.S. coast.
In the latter half of the 1970's the main concern of the
U.S.
military leadership was caused by Soviet increased range SLBM's,
which could reach U.S. territory from remote waters of the
Pacific, Atlantic and Arctic oceans. The Pacific satellite was
displaced almost 30° to the west of the American continent
(in the vicinity of 132-136° West Longitude) to detect
missile launches from these waters. But similar attempts to
shift the Atlantic satellite closer to Europe in 1977 and 1980
proved unsuccessful inasmuch as the ground complex station at
Buckley could not carry on dependable data reception from the
satellite in the remote area of the Atlantic (36° West
Longitude) due to the low elevation at which the satellite was
visible, and the transportable SPS station (a total of two
complexes were made) which was undergoing tests in that period
required substantial modification.
Improved IMEWS satellites launched from 1976 on had an
increased period of design functioning (it increased from 1.5 to
3 years, but in reality they operated for 5-7 years), which
permitted creating an orbital reserve of satellites which had
served their time but had serviceable onboard gear. One reserve
satellite each was deployed in the Indian Ocean zone and over
U.S. territory, which increased the reliability of the system as
a whole (see table).
Characteristics of IMEWS Satellite Models
Characteristics
IMEWS System Satellite Models |
Experimental (Phase 1) | Improved (Phase 2) | MOS/PIM | SED |
DSP-I
|
Years launched | 1970-1973 | 1975-1977 | 1979-1984 | 1984-1987 |
Since 1989
|
Number of satellites launched (serial numbers) | 4 (1st through
4th) | 3 (5th through 7th) | 4 (8th through 11th) | 2 (12th and 13th) |
3 (14th through 16th)
|
Design (actual) operating life, yrs | 1.5 (3) | 3 (5) | 3 (5) |
5 (7) | 5-7 (7-9)
|
Satellite weight, t | 0.9 | 1.04 | 1.2 | 1.68 | 2.38 |
Power supply system output, watts | 400 | 480 | 500 | 705 | 1275 |
Number of telescope IR receiver detectors | 2000 | 2000 | 2000 | 6000 | 6000 |
IR telescope operating wavelength, microns | 2.7 | 2.7 | 2.7 |
2.7 and 4.3 | 2.7 and 4.3
|
Main system development stages determined by improvement
of satellites | Deployment of ICBM and SLBM detection system
| Expansion of zone for monitoring
increased-range ICBM and SLBM launches
| Global monitoring of
launches of ICBM's, SLBM's,
operational-tactical missiles, tactical missiles and missiles of
other classes
|
Special attention was given to Soviet SLBM basing areas in
Arctic waters not viewed from a geostationary orbit. Four
satellites of a new modification designated MOS/PIM (Multi Orbit
Satellite/Payload Improvements) were developed in the mid-1970's
and inserted into geostationary orbit during 1979-1984. In case
of the appearance of crisis situations, the launch of new
satellites to a highly elliptical Molniya type of orbit is
possible for monitoring polar areas of the Arctic Ocean (in
reality IMEWS satellites were not inserted into such orbits).
MOS/PIM satellites now provided surveillance of the entire
Earth's surface visible from orbit without dead spaces and were
equipped with more powerful transmitters, which permitted
receiving satellite data using small antennas of the SPS
transportable stations. The diameter of SPS station antennas was
11 m and that of LPS fixed stations was 18 m.
In the early 1980's greatest concern for American experts
was
caused by new Soviet SS-20 intermediate-range missiles intended
for employment in European TVD's [theaters of military
operations]. One SPS station was deployed in Germany (Kapaun) in
1982 for operational notification of the U.S. European Command,
and in 1984 the operations area of the Atlantic satellite was
shifted 25° closer to Europe. Thus, Soviet ballistic missile
basing areas in the European USSR were under dual monitoring of
the Atlantic and Indian satellites.
The main problem in detecting operational-tactical missile
launches is connected with the low intensity of engine exhaust
flare glow and the short duration of engine operation. IMEWS
satellites of a new generation designated DSP-I (DSP-Improved)
were developed in the 1980's. Their onboard telescopes operated
in two regions of the IR spectrum (mean wavelength values 2.7
and 4.3 microns instead of only 2.7 microns for the old
satellites) and had 6,000 detectors (previously there were
2,000). The new band permitted detecting missiles with low
exhaust flare glow intensity. The second problem, short duration
of operation of operational-tactical missile engines, was
remedied by increasing the number of operational satellites
simultaneously monitoring areas with a missile danger.
To ensure phased development of the new gear and
modernization of the ground complex, two SED (Sensor
Evaluationary Development) transition model satellites (IMEWS-12
and -13), which used the old design base but were equipped with
new telescopes, were launched in 1984 and 1987.
Technical capabilities of the SED and DSP-I model satellites
permitted detecting ballistic missile launches from any area of
Earth. To realize the concept of global monitoring of ballistic
missile launches, the system's orbital grouping had been
reorganized by 1985 in such a way that three operational
satellites were spaced 110-130° in longitude apart
approximately evenly along the Equator.
The onboard gear of the new satellite models (three models
were launched from 1989 through 1993--IMEWS-14, -15 and -16)
permitted detecting ICBM's and operational-tactical missiles as
well as tactical, surface-to-air, antiship and other missiles
and even jet aircraft in an afterburning mode. In this
connection the United States began accelerated development of
gear for prompt communication of warning signals over satellite
communication channels to the U.S. Armed Forces tactical echelon
(for example, to command posts [CP's] of Air Force wings about
mass takeoffs of aircraft, to naval ships about antiship missile
launches, to CP's of Army units and formations about
operational-tactical and tactical missile launches). On
receiving such signals the theater [TVD] commanders can take
retaliatory measures promptly in a combat situation.
From the late 1980's to the early 1990's the IMEWS space
system acquired the importance of a means for global tracking of
launches of different classes of missiles, for conducting
theater [TVD] area reconnaissance in the IR band, and for prompt
warning of users at various Armed Forces command and control
echelons from strategic to operational-tactical.
The expansion in range of missions performed by the system
in
support of command elements of U.S. theater [TVD] forces
required changes in the organizational structure (the system is
subordinate to the U.S. Armed Forces unified Space Command) and
an increase in the number of operational satellites in orbit. A
fourth operational satellite (European) began operation in 1988
in the vicinity of 8-10° East Longitude; it monitored
ballistic missile launches on the European continent and
transmitted data to a receiving station in Germany. A fifth
operational satellite (Far Eastern) was placed in operation in
the eastern Indian Ocean in 1991.
Thus, the system's present-day orbital grouping made up of
five operational satellites provides threefold to fourfold
monitoring of the main areas with missile danger (from the
standpoint of the U.S. leadership) in Europe and Asia, including
in the Near and Far East.
The first combat use of the IMEWS system for warning U.S.
Armed Forces about launches of Iraqi operational-tactical
missiles in 1991 was assessed in the U.S. press as very
successful (98 percent of all launches were detected). It was
asserted that the system was not intended for performing such
missions, but modification of gear for detecting
operational-tactical missiles already had been under way since
the mid-1980's. For example, it was reported in the military
press that work was carried out in Europe in 1990 for prompt
communication of warning signals to Patriot SAM system command
posts about Soviet operational-tactical missile launches.
Contemporary articles contain more critical assessments of the
system's functioning.
During the conflict Iraqi missile launches were detected by
the Indian and European IMEWS-16 and -15 satellites (70° and
10° East Longitude respectively), and by the new IMEWS-12
launched in November 1990 and undergoing accelerated testing in
the Far Eastern zone. In addition, the IMEWS-13 Atlantic
satellite (39° West Longitude) could be used; by early 1991
it had limited capabilities due to nine long years of operation.
Essentially all the system's ground equipment processed data
from the satellites: the complex in Woomera (from the Indian and
Far Eastern), the station in Kapaun (from the European) and the
Buckley complex (from the Atlantic). Depending on the volume of
data received, either a full launch report containing data on
time, launch coordinates, type of ballistic missile and
estimated impact area would be transmitted to consumers after
processing (the accuracy of determining the launch point was 3-5
km and warning time was 1-5 minutes), or only a warning signal
about a ballistic missile launch would be transmitted.
The alarm signal came in place of a full report, for
example,
with the launch of the missile which hit the U.S. barracks in
the city of Dhahran, which led to the greatest loss of Americans
in the entire war with Iraq (28 personnel died). A full report
just was not transmitted to the troops despite the fact that the
missile launch was detected by three satellites (IMEWS-12, -13
and -15 made 2-3 fixes each).
The mission of issuing preliminary target designations on
operational-tactical missiles to Patriot system radars also did
not manage to be accomplished in the course of the war. The
IMEWS space system essentially was the first echelon of the ABM
defense system deployed by the multinational forces command in
the Near Eastern Theater [TVD], and also included air, ground
and space imaging and electronic reconnaissance assets, a U.S.
ground radar in Turkey, communications equipment, and the
Patriot systems. Intercepting Iraqi ballistic missiles over
populated areas led to victims and to destruction even if the
interceptor missiles hit the target. Thus, according to data of
Israeli military specialists, the first missile attacks against
Israeli cities not protected by these systems led to fewer
victims and destruction than approximately the very same number
of attacks after deployment of Patriot batteries.
Consequences of missile strikes would have been less serious
if, based on rough target designations back before the moment
approaching Iraqi ballistic missiles were detected by Patriot
system radars, preliminary interceptor missile launches were
made to intercept these ballistic missiles at a maximum distance
from the defended installation.
Despite use of data from four satellites, U.S. specialists
did not succeed in calculating the azimuth of the plane of
departure and coordinates of warhead impact areas with an
accuracy and promptness sufficient for making preliminary
launches. Moreover, because of organizational and technical
disorders, data on the azimuth of ballistic missile launches
were not transmitted to combat complexes of interceptor
missiles, and some army brigades operating outside the zone of
responsibility of corps air defense weapons did not even receive
warning signals of missile strikes.
The problem of vectoring airstrike elements to Iraqi mobile
ballistic missile launchers based on satellite data also was not
solved. Warning signals would arrive at air wing CP's 5-7
minutes after launch and airstrike elements appeared in the
presumed ballistic missile launch areas 15-30 minutes later,
when the launchers already had managed to abandon them.
The problem of detecting mobile launchers even under
moderate
desert terrain conditions proved enormously more difficult than
previously assumed, and although large aerial and space
reconnaissance forces in addition to the IMEWS system were
involved in solving it, Iraq continued to deliver missile
attacks until the end of the war.
In the opinion of the most critical U.S. experts, combat
employment of the IMEWS system might have proven fully
ineffective "had there not been elements of luck and Iraqi
military mistakes." An analysis of its results in the course of
the Persian Gulf conflict lent new impetus to upgrading the
space warning system.
The principal shortcomings of the existing system are
considered to be the following: low periodicity of scanning the
Earth's surface (one scan in 10 seconds), which is connected
with low photodetector sensitivity; presence of centralized data
processing, which diminishes promptness in communicating data to
theater [TVD] consumers; and the existence of periods when
onboard satellite gear is "blinded" by reflected solar radiation.
The U.S. command anticipates purchasing another seven DSP-I
model satellites (from IMEWS-17 to IMEWS-23) and, from satellite
No 19 on, to considerably modernize their onboard gear for
processing and transmitting data to Earth, including to a
theater [TVD] on operational-tactical missile launches, inasmuch
as increasing the promptness of these processes continues to be
a key issue. Those satellites will support system functioning
after 2000.
The MGT mobile systems developed in the mid-1980's for
receiving and processing satellite data and intended above all
for increasing the survivability of the system's ground element
were connected directly with the NORAD CP and were not adapted
for prompt notification of theater [TVD] consumers. New
receiving stations being developed jointly by the U.S. Army and
Navy under the TSD (Tactical Surveillance Demonstration), TAGS
(Tactical Ground Station) and Radiant Ivory programs will be
stationed in a theater [TVD] and will transmit processed data
directly to consumers at the operational-tactical echelon. It is
expected that around $48.4 million will be spent on these
programs up to 1995. During 1993-1994 tests of the first two
prototypes of receiving stations were conducted in the United
States and FRG. The Navy command plans to procure two sets of
stations and the Army five on condition that a sufficient amount
of funds is allocated.
The concept of the new receiving station's operation in
detecting low-signature targets is based on several innovations:
a lowering of thresholds for activating satellite telescope IR
detectors, which increases the likelihood of detection and the
duration of tracking of targets with a low-intensity engine
exhaust flare glow; simultaneous processing of target fixes made
by several satellites from different points of a geostationary
orbit (stereo images), which increases fix accuracy; and
processing of received data using ballistic missile ballistic
models for a more precise forecast of the parameters of
operational-tactical missile trajectories.
A concept on which Air Force specialists are working within
the scope of the Talon Shield program provides for an
alternative centralized scheme of processing data from IMEWS
satellites at the NORAD CP with subsequent transmission of
warning signals to theater [TVD] installations.
In 1992 the Air Force command let a $24.5 million contract
with Aerojet to develop the CTPE (Central Tactical Processing
Element) system for processing data from IMEWS satellites and
other assets (including theater [TVD] radars) on low-signature
targets such as aircraft and missiles with low-intensity engine
exhaust flare emission and with prompt issuance of data to
theater [TVD] consumers. The system is based on a 12-processor
computer system with parallel architecture developed by Silicon
Graphics and installed at the NORAD CP. System speed is 60
million operations per second, clock frequency is 100 MHz, and
subsequently it is planned to increase it to 150 MHz.
In late 1993 it was planned to conduct the first actual
tests
of the CTPE system with "stereo processing" of measurement data
from several IMEWS satellites and with output of warning signals
in near-real time. Work under the Talon Shield program is
planned to be completed by 1997.
The United States connects a further quality leap, which
will
permit expanding the class of targets detected and tracked and
increasing sensitivity and reliability of the space warning
system, with development of new-generation satellites, which
will replace existing satellites after 2005.
Work to create a new ballistic missile launch warning system
has been under way since 1979 in parallel with modernization of
the IMEWS system. U.S. specialists believe that possibilities
for further improving onboard gear of existing satellites have
been exhausted to a considerable extent. The potential
sensitivity of sensors and accuracy of a fix on missiles being
launched are limited by the design scheme adopted in the late
1960's in developing satellites (scanning by rotating the
telescope) and by the low rate of scan of the Earth's surface.
Advanced satellites were being created in various years
under
the AWS (Advanced Warning System), BSTS (Boost Surveillance and
Tracking System) and FEWS (Follow-On Early Warning System)
programs, but these projects did not get to the stage of
full-scale development due to the high cost and risk connected
with the introduction of new technologies for creating
multiple-element, matrix photodetectors which perform a
continuous scan or high-speed scan of the entire Earth's surface
and with the introduction of light, large optics and data
processing systems aboard satellites.
Research under the AWS program was conducted on order of the
U.S. Air Force during 1979-1984. The possibility was studied for
the first time of tracking the operation of several ballistic
missile stages with the help of matrix photodetectors with
tunable optical filters simultaneously in several frequency
bands of the optical spectrum. Data were to be transmitted
directly to theater [TVD] consumers after onboard processing. As
an additional task, it was planned to accomplish the detection
and tracking of airborne targets in the medium-wave region of
the IR spectrum.
After work began under the SDI (Strategic Defense
Initiative)
Program, the AWS was reoriented in 1984 for creating the BSTS
system, which was viewed as the first element of a multi-echelon
ABM defense system. It was proposed that the new system would
support the detection of a mass ICBM launch under conditions of
wide use of countermeasures, including nuclear countermeasures,
and would output preliminary target designation data to the ABM
defense battle management and communications system with an
accuracy of around 1 km. Onboard processing gear would have a
high degree of radiation protection and would reduce the data
flow rate from several hundred megabits per second to tens of
kilobits per second.
Two groups of firms headed by Lockheed and Grumman
respectively were conducting competitive development of new
satellites, on which around one billion dollars were spent. The
first project envisaged use of a less expensive scanning
telescope. Grumman rejected the scanning principle and developed
a focal matrix of 2,000 modules, each of which contains around a
million sensing elements. Both firms used mercury and cadmium
tellurides in fabricating the matrix, and ceramics, beryllium,
and silicon carbide for the telescope mirror, which was around 1
m in diameter. It was planned to make wide use of ultraspeed
radiation-resistant microcircuits as onboard processors.
An external view of the satellite developed by Grumman under
the BSTS program is shown in Fig. 2. A characteristic feature of
the satellite, which weighs 5.4 t, is use of a triple-axis
stabilization system, an optical system with three-mirror
telescope, and a unified module combining photodetectors,
processor and thermal regulation system radiator. The program
was shut down in the early 1990's due to duplication of main
functions by the BSTS and Brilliant Eyes systems and due to its
high cost, which was unacceptable after the cold war ended. But
the main engineering solutions obtained in the course of the
work have been preserved in subsequent projects.
Competitive design of the new FEWS system began in July 1992
by order of the U.S. Air Force; it was carried on by two groups
of firms headed by Thomson-Ramo-Wooldridge and Lockheed (the
contracts are worth $240 million each).
Requirements for the new system now were formulated with
consideration of the experience of the war against Iraq and the
wide proliferation of intermediate-range missile weapons
expected in the world by the end of the 1990's. It was presumed
that the advanced system, whose deployment was supposed to begin
in the 2000's, would support detection of ICBM and
operational-tactical missile launches on a global scale and full
onboard data processing and prompt data transmission to the
theater [TVD]. Specialists believe that because of the
application of the stereo processing principle, the area where
the system calculates a mobile operational-tactical missile
launcher is located will be the size of a "stadium, and not a
city," as is the case for the present-day IMEWS. The onboard
processors also are intended for eliminating background
emissions and false returns, and the use of intersatellite
communications gear will permit rejecting the use of ground
systems outside of U.S. territory.
The FEWS advanced satellite system project developed by
Thomson-Ramo-Wooldridge and by Grumman (Fig. 3) weighs 3.1 t
and, like the BSTS program satellite, has a triple-axis
stabilization system and multiple-element photodetector matrix
installed in the focal plane of a telescope with a three-mirror
optical system. Competitive design of the FEWS system was
stopped in November 1993 at the request of the U.S. Defense
Department because of high cost (around $11.7 billion for the
period 1995-2019), lack of conformity to specifications and
performance characteristics placed on it, and the changed
military-strategic situation in the world.
In 1995 the U.S. Defense Department proposes to begin
development of the new ALARM (Alert, Locate and Report Missiles)
space system for detecting ballistic missile launches, intended
for detecting the launches not only of ICBM's and SLBM's, but
also tactical, operational-tactical and cruise missiles as well
as flights of high-altitude aircraft. U.S. experts believe that
in the next few years this will become one of the main tasks for
the advanced space system for missile launch detection, which is
to provide prompt communication of data to consumers in support
of the theater [TVD] ABM defense organization.
According to the concept being advanced by the Pentagon, the
advanced ALARM system is to hold an intermediate position in
characteristics between the existing IMEWS and rejected FEWS
systems, with the possibility of phased improvement of its gear
as new technological solutions are worked out and
characteristics of the FEWS system are brought up to design
characteristics.
It is presumed that ALARM satellites will have less cost and
capabilities compared with FEWS, but better characteristics than
present-day IMEWS satellites for detecting operational-tactical
and tactical missiles. The following are the principal
directions for lowering its cost:
- combining ALARM and IMEWS ground systems, as a result of
which the need for creating costly ground stations disappears;
supporting detection of tactical and operational-tactical
missile launches only in two regions of the Earth instead of
global coverage as for the FEWS system;
- rejecting the
installation of instruments aboard the advanced satellites for
detecting nuclear explosions (accommodated on NAVSTAR
satellites) and gear for onboard data processing and
intersatellite communications (which satellites of the first
models have);
- using medium class booster rockets instead of
costly Titan IV heavy rockets (around $300 million).
As a result of the proposed measures, the cost of developing
the ALARM system can be around one billion dollars during
1995-1999 instead of the five billion planned to be allocated
for creating the FEWS system in this same period.
In case of U.S. Congressional approval of the ALARM project,
it is planned to carry out competitive preliminary design work
during 1995-1997 and to begin full-scale development in October
1997, as a result of which the first satellite may be inserted
into geosynchronous orbit in 2004.
The ALARM project already now is coming under harsh
criticism. According to U.S. Congressional Budget Office
estimates, the cumulative cost of the life cycle of the ALARM
and FEWS systems during 1995-2019 is approximately $11.3 and
11.7 billion respectively, and the former's capabilities are
substantially lower. U.S. Defense Department specialists assert
that the main saving (compared with FEWS) will be achieved in
the next decade beginning with the fourth model (after 2007) as
a result of the technology of manufacturing onboard gear having
been upgraded. The U.S. Congress will make the final decision on
work under the ALARM program at the end of the current year.
Questions of operation and upgrading of the space missile
launch detection system presently are acquiring political
coloration. In view of the fact that such costly systems,
created only in the United States and Russia, are losing
importance as the first echelon of a strategic warning system
with the end of the cold war, the American side is examining
questions of presenting satellite data to other countries for
detecting operational-tactical missile launches during local
conflicts.
IMEWS system data already have been transmitted to Israel in
1993, for example, during the delivery of strikes by U.S. cruise
missiles against Iraqi targets (for timely detection of possible
retaliatory launches of operational-tactical missiles by Iraq
against Israel). Options are being considered for presenting
warning data to South Korea, Japan and European countries in
case a threat of delivery of missile strikes appears on the part
of North Korea, China or the Arab states. Such data will be
provided along with deliveries to these countries of very costly
components of theater [TVD] ABM defense systems (Patriot systems
or their more advanced versions). As the missile launch
detection system is developed further, its ground receiving
complexes will become an important part of advanced theater
[TVD] ABM defense systems.
Footnotes
1. For more detail on the IMEWS system see ZARUBEZHNOYE
VOYENNOYE OBOZRENIYE, No 6, 1992, pp 51-57--Ed.
Fig. 1. Diagram of IMEWS
satellite deployment:
Key:
1. IMEWS-14 (Pacific)
2. IMEWS-13 (Atlantic)
3. IMEWS-15 (European)
4. IMEWS-16 (Indian)
5. IMEWS-12 (Far Eastern)
A vertical line denotes deployment areas of operational
satellites, a broken vertical line denotes deployment areas of
reserve satellites, and a broken horizontal line denotes a
transfer to other orbits
Fig. 2. External view of BSTS
satellite:
Key:
1. Module with photodetector matrix
and subsystems for thermal regulation and data processing and
transmission
2. Payload module with optical telescope
3. Service subsystems model
4. Motor compartment
Fig. 3. Advanced FEWS program
satellite:
Key:
1. Focal plane with photodetector
matrix
2. Telescope hood
3. Secondary telescope
mirror
4. Primary telescope mirror
5. Tertiary
telescope mirror
6. Intersatellite communications radio
link antenna
7. Service subsystems compartment
8.
Radio link antenna for data transmission to Earth
9. Solar
battery panels
NEWSLETTER
|
Join the GlobalSecurity.org mailing list
|
|