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Over the past 40 years, at a cost of more than $150 billion, the United
States Department of Defense has assembled the world’s most extensive and
powerful military space armada. Besides the military communications satellites,
the armada includes spacecraft, the ELINTS and SIGINTS, that eavesdrop on
voice and data channels or detect and identify radar systems; early-warning
satellites equipped with infrared sensors that detect missile launchers;
meteorological satellites (metsats) that monitor the weather; navigation
satellites; and optical and radar satellites that record images of industrial
and military targets ranging in size from shipbuilding yards to individual
anti-aircraft missiles.

The primary mission of this armada was to monitor the Cold War and,
if cold turned to hot, to fight a nuclear world war with the Soviet Union.
Though some of the spacecraft had been used before, for instance to plan
the abortive Iran hostage rescue mission in 1980 and to attack Tripoli in
1986, it was only when Saddam Hussein invaded Kuwait in the early hours
of 2 August last year that the US space armada was, for the first time,
directed to fight a major war. According to Merrill A. McPeak, US Air Force
Chief of Staff, the Gulf War ‘was the first war of the space age’.

Several of the 16 military communications satellites, which carry three-quarters
of the US armed forces’ overseas communications traffic, linked centres
in the US and overseas with tactical headquarters in the field. For example,
one of the three Defense Satellite Communications System (DSCS) spacecraft
used during Desert Storm, which could handle either 1300 simultaneous voice
conversations or 12.5 megabytes of data a second, moved from its usual geostationary
orbit over the Pacific to a new position above Saudi Arabia so that the
White House could communicate with 128 mobile ground terminals in the Gulf.

Another US strategic space asset adapted to fight Desert Storm was the
Global Positioning System, a constellation of navigation satellites that
allows US forces to determine their location to within 15 metres. Already
installed in US military ships, planes, helicopters and missiles, several
thousand portable GPS receivers were hastily shipped out to ground forces
in the Gulf where they enabled fast-moving armoured units to navigate across
the featureless desert terrain.

Because GPS is a ‘passive’ system, emitting regular signals for navigators
to pick up rather than waiting to be triggered into action, an aircraft
or ship does not reveal its position when it uses the system. On 16 January,
during the first night of Desert Storm, GPS guided low-flying Apache helicopters
into Iraq undetected to destroy radars, opening a breach in the country’s
air defence system through which waves of bombers attacked Baghdad.

The most important components of America’s space armada, however, were
its fleets of weather, early-warning and reconnaissance satellites. Meteorological
satellites in geostationary orbit 36 000 kilometres above the equator provided
the ‘big picture’ of weather fronts approaching the Middle East. From lower
orbits, a network of three satellites over Saudi Arabia, which is part of
the Defense Meteorological Satellite Program, recorded images of regional
weather patterns, including sand and rain storms as they built up over the
Arabian peninsula.

Although these satellites helped allied commanders to plan Desert Storm,
the resolution – about 5 kilometres for metsats in geostationary orbit and
500 metres for the lower-flying DMSPs – was insufficient to locate and identify
Iraqi military targets. For more precise information, the allied commanders
relied on the US’s most powerful, and most expensive, military reconnaissance
satellites. Several strategic satellites, known as KH-11s or Keyholes, were
diverted into orbits that would allow them to focus on Iraq. Keyholes follow
highly elliptical orbits. At the lowest point, or perigee, they come within
250 kilometres of the surface. From here, under ideal weather conditions,
their optical sensors, which are almost as powerful as those designed for
the Hubble Space Telescope, can pick out objects between 15 and 20 centimetres
across. This is enough to identify, for example, the location and size of
a ventilation shaft on the roof of a Baghdad command centre.

Even the Keyholes have their limitations, however. They cannot work
at night nor when the sky is cloudy or filled with plumes from burning oil
installations. In these circumstances, the US armed forces turned to Lacrosse,
a radar satellite that records images of the Earth 24 hours a day, in all
weathers. Though Lacrosse’s resolution is coarser, between 1 and 3 metres,
this is sufficient for it to act as a giant metal detector in the sky. Originally
designed to monitor the military hardware of the Warsaw Pact countries,
Lacrosse helped to locate Scud mobile missile launchers in Iraq.

Also engaged in the hunt for Scud launchers were the early warning satellites
of the US Defense Support Program. These satellites are equipped with infrared
sensors capable of detecting the heat plumes as the missiles were launched.
This enabled allied commanders to determine the trajectories of the Scuds
and give Patriot antimissile batteries up to 2 minutes’ warning of where
they would land.

Before the air war began, the reconnaissance satellites recorded Iraq’s
military infrastructure, from chemical weapons factories and airfields to
command posts, radar sites and missile batteries. This provided precise
targeting information for Cruise missiles and allied aircraft. After each
air attack, the satellites assessed bomb damage and located new targets
for the next wave of bombers.

Unlike the allied forces, Iraq had no access to space reconnaissance,
although it had used space imagery in the past. Both Iran and Iraq used
scenes from Landsat and SPOT, the American and French civil remote-sensing
satellites, during their war of the 1980s. Saddam Hussein may have used
similar images to plan the invasion of Kuwait. SPOT Image, the company that
operates the satellite, confirms it sold images to Iraq shortly before the
invasion, but it will not say whether the images included scenes of Kuwait.

Neither Landsat nor SPOT, with maximum resolutions respectively of 30
metres and 10 metres, can compare with the powerful US reconnaissance satellites.
They can, however, be used to make maps, locate fortifications and monitor
large movements of troops and shipping. According to independent analysts
familiar with scrutinising remote sensing images, SPOT can detect roads
and bridges, count military aircraft parked on runways, and identify surface-to-air
missile batteries, all of which would have been targets for Iraqi forces
during the Kuwait invasion.

The allies recognised the value of civil satellite intelligence in planning
Desert Storm. The American defence department, already the largest single
user of Landsat data, bought thousands of scenes of Kuwait and Iraq from
SPOT Image and from EOSAT, which administers Landsat, to complement the
data from its own satellites.

Even the KH-11s have their limitations. Like a telephoto camera lens,
the optical sensor of a Keyhole provides detail at the expense of field-of-view.
At maximum resolution, one KH-11 image covers an area of about 4 square
kilometres while a SPOT image covers 3600 square kilometres and a Landsat
image around 35 000 square kilometres. This enables SPOT images, for example,
to be used to draw up maps to a scale of 1:50 000 or better.

The civil satellites also provide better multispectral coverage than
their military cousins. Landsat’s primary sensor, the Thematic Mapper, covers
bands in the visible and near to mid-infrared ranges of the radiation spectrum.
Features on the ground reflect visible and infrared light according to their
composition and the heat they radiate. Landsat detects these ‘spectral signatures’,
which, for example, can be used to produce maps that distinguish different
rock types for guiding heavy military vehicles, such as tanks, across hard
ground and away from regions where they could become bogged down.

One problem for military strategists was to coordinate satellite ‘passes’
of the Earth so that important targets could be visited as often as possible.
For while geostationary satellites give a continuous view of the area they
are covering, they provide little detailed information from 36 000 kilometres
up. The civil satellites, SPOT and Landsat, are not much help alone. Landsat
‘revisits’ the same area once every eight days and SPOT every three days.
Military reconnaissance satellites, flying in even lower orbits to make
the most of their high-resolution sensors, make much more frequent passes
although still not as often as the strategists would like. A Keyhole, for
example, examines each target once every 12 hours. However, by arranging
for the passes by civil and military satellites to complement one another,
the spacecraft were able to photograph any one target as often as four times
a day.

Another problem concerned the sheer deluge of information relayed from
space; a single geostationary metsat image, for instance, fills a standard
40-megabyte hard disc. This wealth of digital information kept communication
links running at peak capacity and saturated specialists, who were sifting
and analysing it in both the US and Saudi Arabia. Their interpretations,
crucial to fighting the extended, fast-moving battles of the ground war,
were fed directly to allied columns via mobile satellite terminals. The
aim was to give the allied field commanders not only timely navigation,
terrain and weather information, but also the exact location, strength and
condition of the forces opposing them.

Iraq was denied images from Landsat and SPOT soon after the invasion
of Kuwait. SPOT Image and EOSAT immediately observed a trade embargo imposed
by the UN and closed the skies to Iraq. Denied access to space reconnaissance,
and with his air force destroyed or dispersed, Saddam was effectively blinded
when the land war began. He could not see the allied forces ranged against
him nor where they would strike.

This proved crucial to the swift success of the ground war. On 15 November,
Norman Schwarzkopf, the allied commander, set the stage for the great deception
of the Gulf War. Thousands of US Marines stormed Saudi beaches in what seemed
a grand dress-rehearsal for an amphibious assault on Kuwait. Cable News
Network filmed the operation, known as Imminent Thunder, and Iraqis saw
the report via CNN’s satellite TV network, which was Iraq’s only visual
access to the outside world.

Fooled into thinking that the allied land assault would come from northeast
Saudi Arabia and be supported by US Marines storming Kuwaiti beaches, the
Iraqis were unprepared for the real land offensive: an attack by more than
100 000 US troops, 160 kilometres to the west, moving deep into southern
Iraq and sealing off the Kuwait occupation forces. Civil remote sensing
satellites would easily have detected the deception but no organsation or
country seems to have flouted the UN embargo. ‘When we knew (Iraq) couldn’t
see us any more, we (moved) troops . . . to the extreme west,’ recalled
Schwarzkopf.

Iraq, however, was not the only user of satellite images to be deprived
by the UN sanctions. Apart from the allied forces, SPOT Image applied the
embargo to all its customers, including the growing number of independent
analysts who use civil remote-sensing satellites to monitor environmental
and politico-military issues. The company says it was determined to prevent
Iraq from obtaining intelligence information damaging to the allies, either
directly or via third parties.

To the independent analysts, the decision raises the issue of information
management and censorship. They say that public access to SPOT images during
the initial days of the Iraqi occupation of Kuwait would have enabled them
to assess the strength and intentions of the Iraqis independently of the
information provided by the Pentagon. According to Peter Zimmerman, visiting
professor of engineering and applied science at George Washington University,
Washington DC, ‘cameras in orbit permit the public to ascertain for itself
the validity of government claims in the intelligence field’.

Zimmerman, however, obtained images of the Kuwait area during the occupation
taken by a KFA-1000 camera aboard a Soviet Resurs spacecraft. He judged
the resolution of them to be about 3 metres – better than SPOT and equivalent
to Lacrosse. The Resurs pass occurred on 13 September, the date on which
the Pentagon estimated that there were more than 250 000 Iraqi troops inside
Kuwait, together with 2000 tanks and thousands of support vehicles. This
was cited as evidence that Saddam’s ambitions went further than Kuwait and
of the need to send a large contingent of US forces into neighbouring Saudi
Arabia.

But Zimmerman’s Resurs images seemed to show no evidence of Iraqi fortifications
or facilities in Kuwait. Roads and airfields were deserted. Although the
Soviet images did not cover the whole of Kuwait, what Zimmerman saw appeared
to be a country at peace. ‘The images didn’t tell me there weren’t any Iraqi
troops there. It did tell me there probably weren’t a quarter of a million
on that day.’

According to other independent analysts, the KFA-1000 images imply that
the Iraqi posture was defensive rather than offensive, and that Saddam had
no intention of attacking Saudi Arabia, contrary to what the Pentagon was
claiming at the time. ‘These were the crucial events of the war where the
US government had a monopoly on information,’ says Vipin Gupta of the Verification
Technology Information Centre (VERTIC), an independent organisation based
in London. The Pentagon ‘could determine public attitudes. Remote sensing
using commercial satellites is a way of evaluating the accuracy of this
kind of information. In this case, it seems that it wasn’t. The US was exaggerating.’

Independent remote-sensing analysts rely on unrestricted access to satellite
imagery, a notion they term ‘open skies’. This allows data from the civil
satellites, even that covering militarily sensitive areas such as nuclear
test sites, to be acquired by anyone who can afford to pay the commerical
rate of more than £1000 per image. But the Gulf War closed the skies
to all but the allied forces. EOSAT, unlike SPOT Image, says it sold images
of the Gulf to non-Iraqi clients during the conflict. But the company ensured
that processing delays of up to six weeks rendered the images useless for
evaluating military claims.

The independent analysts say it is important for the public to have
access to civilian space pictures on the same basis as governments. ‘Remote
sensing offers a check,’ says Gupta. ‘It keeps government officials on their
³Ù´Ç±ð²õ.’

Gupta’s own experience with satellite images from the Gulf was limited
to information from Europe’s geostationary weather satellite, Meteosat.
Although the resolution was just 8 kilometres, Gupta found that Meteosat
could provide insights into the progress of the war by monitoring the huge
smoke plumes released by oil fires. The satellite provided images every
30 minutes from which Gupta could assess the extent of the fires and how
the plumes spread. The images also enabled Gupta to follow the allied bombing
campaign. He monitored the destruction of Iraq’s oil production facilities
– a strategic objective, he says, that was far beyond the tactical destruction
of oil supplies available to Iraqi forces in and around Kuwait – and he
was able to deduce that US military hardware was not as ‘high-tech’ as claimed.
For instance, when clouds covered Iraq, the ‘all-weather’ F-16 fighter-bomber
was grounded. Conversely, the Iraqis were taking advantage of cloud cover
to launch Scuds, hoping their mobile batteries would be hidden from reconnaissance
satellites and aircraft.

The wartime restrictions imposed on information from space have prompted
calls for an independent remote-sensing system. In May, Pierre Joxe, the
French defence minister, noted that the allied victory had been heavily
dependent on the American reconnaissance satellites and criticised the US
for allowing the French only limited access to this information. In addition
to the 1-metre resolution satellite, known as Helios, that France already
plans to build, Joxe called for a European network of high-resolution satellites
to patrol arms-limitation agreements and monitor global trouble spots independently
of the US and the Soviet Union. The independent analysts, who would have
an important part to play if such a system were built, are still angry that
the Gulf skies were closed. ‘If open skies is to mean anything,’ says Peter
Zimmerman, ‘it has to be invoked even when it’s uncomfortable.’

The 1990s will see a proliferation of remote-sensing satellites. The
European Space Agency’s ERS-1, due to be launched this month, carries a
radar with a resolution of 25 metres. Some ESA scientists believe that,
in addition to its environmental monitoring role, ERS-1 could prove adequate
for arms verification (‘Europe’s orbiting ocean plotter’, New ÐÓ°ÉÔ­´´,
27 April). Japan and Canada aim to launch radar satellites with 18-metre
resolution, while the Soviet Union is already selling high-resolution images
from its remote-sensing satellites.

Other countries, such as India, Israel and China, also possess the technology
to build satellites with the resolution of SPOT or better. And NASA’s Earth
Observation System (EOS), a series of remote-sensing platforms carrying
state-of-the-art instruments, will be working by the end of the century.
‘It’s going to become very difficult, if not impossible, for people to undertake
clandestine activity, whether it’s a secret nuclear test, covert border
incursion, or construction of a new nuclear production facility,’ says Gupta.
And with more satellites flown by more countries, suspending the notion
of open skies, which effectively extends censorship and news-management,
will become more difficult.

But there is also a negative aspect. Many states will have learned from
the Gulf War that they need access to orbital reconnaissance to fight a
modern war. According to the USAF, at least 20 countries will have Scud-type
missiles by early in the next century. By equipping the weapons with GPS
receivers, Scuds would become accurate enough to hit tactical targets such
as airfields, control centres and ammunition dumps. The US is trying to
forestall this by reducing the accuracy of GPS receivers for civilians to
70 metres.

By using SPOT-type satellites to locate and identify targets and assess
battle damage, any one of those 20 countries could possess a missile system
of great accuracy and power. In 10 years time, it may not be possible to
fight a war like Desert Storm, which relied on Iraq’s blindness, without
attacking an adversary’s reconnaissance satellites. Countries other than
the US and the Soviet Union may now decide to build antisatellite systems.
The Gulf War may have been the first war of the space age but it won’t be
the last.

Jon Trux is features editor of the Science Photo Library.