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Radar love: t he tort ured history ofAmerican space radar programs
by Dwayne A. DayMonday, January 22, 2007
On January 11 Reuters published an article indicating
that an experimental National Reconnaissance Office
satellite had suffered a catastrophic failure and was
essentially unusable. Communications with the satellitewere lost, and ground controllers were struggling to
regain them, but the problems with the satellite were
apparently substantial. The most likely candidate is a
satellite launched in December from Vandenberg Air
Force Base that amateur satellite observers suspect is a
radar satellite.
High resolut ion airborne synthet ic apert ure radar image of the Pentagon.
(credit : Sandia National Laboratory)
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For over four decades the United States has undertaken
numerous efforts to develop satellite radar to serve a
variety of purposes, from ocean surveillance to aircraft
detection and tracking to mapping and intelligence
collection. Despite starting almost a dozen separate
programs over this period, the actual number of radarsatellites flown by the United States is relatively lowless
than a dozen. Radar advocates have long made claims
about satellite radar capabilities that were not born out
by experience. What follows is a brief history of that
effort.
From Quil l t o Clipper Bow
Satellite radar imaging is among the most classified
activities conducted by the US intelligence community.The NRO will not even acknowledge the fact of the
existence of such a capability. However, it is no secret
that space radar is possible. Canada, Russia, ESA, and
recently Germany have all launched radar satellites. The
United States flew several civilian Space Shuttle missions
equipped with a radar imager and some of this
equipment currently hangs in the Smithsonian. The
mission these various spacecraft have performed is
producing imagery of the ground using a technique
known as synthetic aperture radar, or SAR, wherebymultiple images of the ground are taken as the satellite
moves overhead and are then stitched together by
computer, producing a high-fidelity three-dimensional
image. But while the space radar efforts of other
countries are relatively well known, in the United States
information on the operational systems is shrouded in
secrecy, and most of what we know concerns canceled
programs.
One of the hazards of writing about intelligence space
programs is the uncertainties inherent to the subject. It is
vital to remember that probabilities dont always add,
increasing certainty, but instead sometimes multiply,
decreasing it. So two conclusions with a fifty percent
confidence level may not produce truth, but a conclusion
that is far less accurate. Nevertheless, there is data to
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support the information in this article.
The possibility of using radar
from space was first discussed in
the US Air Force during the
Eisenhower administration.
However, President Eisenhower
placed very strict controls on
satellite intelligence collection
and at first insisted on personally
approving every photographic
satellite intelligence mission that
the United States conducted. In
this environment, the Air Force space leadership
determined that radar transmissions from a satellite
might be too provocative for a president alreadyconcerned about passively taking pictures and collecting
electronic transmissions, and so they did not start the
program at that time.
Although details remain sketchy, it appears as if an
experimental radar satellite program was started during
the Kennedy administration. This program, known as
Quill, produced three satellites: two flight models and a
test model. One satellite was launched in 1964. It used a
radar that was probably built by Raytheon to take imagesof the ground which were stored on magnetic tape. Quill
used the same recovery system as the Corona
reconnaissance satellite, returning the magnetic tape to
Earth in a recoverable capsule that was caught in mid-air
by an aircraft.
According to someone who talked to Quills program
manager, as well as another researcher who talked to a
former senior intelligence official, the flight and the
mission were successful, but the program was not
continued. It is easy to speculate why. The satellites
relatively low power and early technology undoubtedly
limited its capabilities, particularly the size of objects it
could spot. Quill could probably not spot anything
smaller than a naval vessel. In addition, the data retrieval
technique meant that information was not processed
Satel li te radarimaging is amongthe most classif iedactivitiesconducted by the
US intelligencecommunity. TheNRO will not evenacknowledge the fact of theexistence of such acapability.However, it is nosecret that spaceradar is possible.
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until long after it had been collected. The intelligence
value was therefore probably too limited to justify further
efforts.
By the early 1970s, the US Navy was considering a
program known as Clipper Bow (i.e. the bow of a clipper
ship). Clipper Bow was intended to detect ships at sea so
the information could be transmitted to naval vessels, a
technique employed by the Soviet Union with their Radar
Ocean Reconnaissance Satellite (RORSAT). But Clipper
Bow was soon canceled, apparently for cost and utility
reasons.
From sea to ground to air
By the mid-1970s a new proposal emerged for a radar
imaging satellite. Although details are scarce, this was
apparently a controversial battle within the intelligence
community. At the time, CIA officials wanted to add a
radar capability to their new KH-11 real-time
reconnaissance satellite. Department of Defense officials,
though, wanted a dedicated radar satellite. Eventually the
Air Force component of the NRO obtained approval to
start a new program to develop a radar imaging satellite
called Indigo. The name of this program was later
changed to Lacrosse (apparently spelled Lacros inofficial documents) and then to Onyx.
In 1988 the Space Shuttle launched the first Onyx radar
satellite (although a press leak referred to the satellite by
its earlier name, Lacrosse and the program might still
have had this name at the time.) More satellites were
launched in 1991, 1997, 2000, and 2005. In 1998 the
NRO even released images of one of these satellites
under construction. The satellite is a large rectangular
frame to which are attached numerous electronics boxes
covered in gold-colored kapton insulating foil. According
to amateur astronomers who have observed the actual
spacecraft in orbit, the satellite has a large dish and two
large solar panels sticking off the main body.
The satellites average radar resolution was reported to
be about one meter, probably in the standard
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pushbroom mode where the radar essentially looks
straight down and takes a continuous image, like a push
broom being pushed across a floor. However, synthetic
aperture radars have a mode called spotlighting
whereby they spend several seconds taking repeated
images of the same small area to improve resolution. Bytaking images for up to 17 seconds, Onyx reportedly
could obtain a resolution of about 0.3 meters for a small
area. Onyx remains the only operational American radar
satellite system.
Articles by independent analysts contained some
inaccurate speculation about radar satellites during this
period. In 1977, NASA launched a radar satellite known
as Seasat and used to observe the oceans. Seasat failed
early in its mission, and there has long been speculationthat the satellite had successfully detected American
submarines at sea and this was so alarming that it
prompted the Navy and/or the intelligence community to
demand that the satellite be shut off. However, this story
seems highly unlikely. If the satellite had been so
successful, it seems more likely that the military and
intelligence communities would have wanted it to
continue in order to gather more data. At the very least,
they would have wanted to try and track Soviet
submarines. They could have easily classified the data
while keeping the satellite in operation. There has been
enough information released on Seasats failure to make
it clear that a simple malfunction, and not a government
conspiracy, was the real problem.
Another claim, originally made by
the late British writer Anthony
Kenden, was that in January 1982
the US tested an experimentalradar satellite named Indigo.
However, it is now clear that this
launch was actually a modified
photoreconnaissance satellite,
part of a program called Higher
Boy, and not a radar satellite. Indigo was in fact the name
for the initial program to develop a radar satellite, but no
By t aking imagesfor up to 17seconds, Onyxreportedly couldobtain a resolut ionof about 0.3 metersfor a small area. Itremains the onlyoperationalAmerican radarsatellite system.
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actual spacecraft flew under the Indigo name. However,
it seems unlikely that the NRO would have committed to
a major new program without at least conducting some
experimental tests first. Whether these were space-based,
airborne, or simply conducted in a laboratory is
unknown.
By the early 1980s, the Air Force was interested in a new
project then designated Space Based Radar, or SBR. This
was a project championed by Air Force Space Command,
not the Air Force office that was part of the NRO. The
purpose of Space Based Radar was to detect aircraft in
flight. The justification was that such a satellite could act
as a kind of space-based airborne warning and control, or
AWACS, system, detecting Soviet bombers and tactical
aircraft in flight long before they could be spotted byground-based radars in Europe and elsewhere.
Throughout the 1980s, various Air Force generals
declared that Space Based Radar was their highest
priority new program. Despite this constant
endorsement, the proposal was never adopted by the Air
Force leadership or the Secretary of Defense for actual
development. When the Cold War ended, the
fundamental justification for the program evaporated
and Space Based Radar was dead.
Discoverer II, Space Based Radar (again), and FIA
By 1998 a new satellite radar project emerged. The
Defense Advanced Research Projects Agency (DARPA)
proposed a project known as Starlite. This proposal
actually broke a gentlemens agreement that DARPA
would not intrude on the National Reconnaissance
Offices satellite intelligence turf by building
experimental intelligence collection spacecraft.
Eventually both the National Reconnaissance Office and
the Air Force were included in what became a joint
program soon designated as Space Based Radar.
Although the program shared the same name as the late
1980s radar program, it had a different focus. Instead of
detecting aircraft, the target of this new satellite system
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was ground vehicles. During the Persian Gulf War in 1991
the Air Force had pressed into service a prototype aircraft
system known as the Joint Surveillance Target Attack
Radar System, or JSTARS. JSTARS was a large synthetic
aperture radar mounted on a modified C-135 aircraft.
JSTARS was a refined version of traditional syntheticaperture radar. JSTARS looked for the strong radar
returns from metallic objects on the battlefield, which
were most likely vehicles. JSTARS also had a capability
known as moving target indicator, which tracked moving
vehicles. But because it was a large aircraft, JSTARS was
limited in where it could go. Even if the United States
controlled the airspace, Air Force commanders were
reluctant to take JSTARS too far behind enemy lines
because of its vulnerability to missiles and aircraft. In
addition, JSTARS was limited by the curvature of theEarth and any terrain such as mountains that could block
its signal from reaching farther distances.
The new Space Based Radar would take JSTARS into
orbit. The initial joint plan was for two experimental
satellites as part of a program known as Discoverer II.
But the Discoverer II program languished for years for
reasons that are complex and also somewhat murky. At
least part of the problem was high cost and poor
management. But the NRO had also never been fond of
the project and there have been rumors that the
intelligence organizations leadership fought Discoverer
II at every opportunity. By early this decade the NRO
withdrew from Discoverer II and the joint project was
canceled.
Around the same time that Starlite had started, the NRO
had also signed a contract with Boeing to develop the
Future Imagery Architecture, or FIA. FIA was to involvea constellation of both photographic imaging and radar
satellites. These would replace both the current fleet of
photographic satellites and Onyx. When FIA was first
unveiledalbeit with little detail due to classification
concernsoutside observers questioned whether FIA
rendered the Discoverer II program moot. After all, if the
NRO was already starting to build a new class of radar
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imaging satellites, did it really need to support
Discoverer II? The FIA radar satellites and Discoverer II
were intended to perform similar but distinct missions.
Independent observers, as well as members of Congress
and some military officials, questioned if these two
missions could be merged. There was no inherenttechnical reason that they could not be merged, although
the requirements for the two systems are different.
Although Discoverer II was dead,
the Air Force continued its
advocacy of Space Based Radar.
For the next several years, the
United States appeared to have
had two separate radar satellite
programs: the radar componentof FIA and Space Based Radar.
Congress officially ordered the NRO and the Air Force to
merge their efforts into a single platform, and in January
2005 the NRO and the Air Force signed an agreement to
make Space Based Radar the radar component of FIA.
However, with SBR not scheduled to become operational
until 2015, one unanswered question was how the NRO
would meet its radar intelligence needs during the next
decade without building new satellites.
Another question was just how much the NRO was
actually cooperating. One possibility is that the NRO
converted its existing FIA radar program into a
demonstration project with the intention of developing
a satellite that could later be declared operational once
the Air Forces Space Based Radar program failedas
many people both within and outside of NRO expected
that it surely would.
As if this story was not convoluted enough, by 2005 the
photographic part of FIA was in major trouble. Ever since
the late 1950s Lockheed had built Americas
photographic reconnaissance satellites. The Onyx was
built by Martin Marietta. When the two companies
merged, the expertise for building both of these kinds of
satellites resided within a single company, and Lockheed
The Discoverer IIprogram languishedfor years forreasons that arecomplex and alsosomewhat murky.At least part of theproblem was highcost and poormanagement.
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Martin lost the FIA contract in a stunning upset. Boeing
later lost the photographic imagery portion of the FIA
contract, but reportedly maintained the radar imaging
portion.
Space Radar redux
By 2006 the Air Force had renamed its program as
simply Space Radar with an estimated operational date
of 2015. Space Radar would consist of a constellation of
satellites, but just how many and how powerful has not
been determined. The goal is to obtain near-continuous
coverage of important areas of the Earth without gaps in
coverage that could allow important events to go
unobserved. The more satellites, the fewer gaps in
coverage and the quicker the response time. However,both the intelligence community and the military may
have different requirements for how much coverage is
necessary.
Intelligence community requirements and military
requirements apparently primarily diverge over the issue
of moving target indicator capability, and it is this issue
that also has a major impact on the size and cost of the
satellites. A synthetic aperture radar capability for the
intelligence mission can utilize a relatively small antennaof approximately 40 square meters. However, such an
antenna would be hard pressed to detect relatively slow
moving targets on the ground. According to a recent
estimate, successfully detecting ground vehicles traveling
under about 30 kilometers per hour might require an
antenna as big as 100 square meters, thus driving up cost
and size, for a mission that the intelligence community
does not need.
The Space Radar program has been in funding limbo for
yearsfor fiscal 2006 the administration requested $228
million for Space Radar. Congress only gave the Air Force
$103 million. In 2007 the Air Forces request was
similarly chopped back.
There are several reasons for this.
One is the lack of a clearTo call Space Radarexpensive i s li ke
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justification. The Air Force has
not been able to make the case
that Space Radar is necessary for
its most important missions. Its
utility in the war on terror is
highly questionable. Osama bin Laden isnt made ofmetal and therefore wont show up on radar, even if he
does travel faster than 30 kilometers per hour. Closely
related to this is the Air Forces inability to demonstrate
how such a system would be used and whether it would
be better than a mixed fleet of radars mounted on various
aircraft, including large platforms like JSTARS and small
drones.
However, above all, is the overriding issue of cost.
To call Space Radar expensive is like calling the Pacific
Ocean a body of waterit doesnt exactly convey the
enormity of the issue. The Air Force repeatedly refused to
put a cost estimate on the program, saying that it would
be premature. However, the Air Force did want Congress
to commit to building it. One early estimate for Space
Radar put the cost at $34 billion for a nine-satellite
constellation. But the Air Force disavowed this estimate
at the same time it refused to provide another one. The
cost is driven by several factors, not only the number ofsatellites required for the constellation, but also the
amount of processing power required for the satellites
and their ground stations, and of course the size of the
radar antenna. Space Radar would also dwarf current
transmission bandwidth and signal processing
requirements for the military.
Considering the fact that the Air Force had long refused
to provide a clear cost estimate of the program, it was
inevitable that Congress would seek an independent
estimate. In early January the Congressional Budget
Office released a report on alternatives for space radar,
and the information it contained was rather startling. For
a 20-year lifetime, the CBO determined that such a
system could cost between $25 and $90 billion
depending upon the size of the system. CBO determined
calling the PacificOcean a body ofwaterit doesn texactly convey theenormit y of t heissue.
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that for its reference architecture of nine satellites with
40-square meter radar arraysessentially the system
that the Air Force has advocatedtotal costs would range
from $3550 billion.
To put this in context, consider that the largest current
space program that the Air Force has underway has a
cost estimate of around $12 billion. Other large projects
have cost estimates of around $10 billion. Simply put,
even the simplest version of Space Radar would cost
twice as much as any other military space program on the
drawing board, and the baseline version the Air Force is
seeking will cost three to four times as much as the most
expensive current space project.
However, what makes the situation more severe is thefact that many of the most expensive military space
programs now in development were originally estimated
to cost far less than their current estimates. The NPOESS
weather satellite, for instance, was supposed to cost $6
billion and will now cost $12 billionwith a significant
reduction in its capabilities. The SBIRS missile warning
satellite was supposed to cost $4 billion and will now cost
over $11 billion. Even though the Space Radar cost
estimates were done by the CBO, Congress has little
reason to believe that costs will not spiral out of control.Does Congress really want to fund a program that would
start costing three times as much as the most expensive
current space program, and could end up costing many
times greater?
Beams in the sky
Whether or not the December launch from Vandenberg
was an experimental radar satellite (and there are still
substantial questions about that), its failure can only
exacerbate the overall recent woes of military space
programs, contributing to the bad reputation that the
military space program has acquired. That is
unfortunate, because the American military space
program is vital to American defense, and its recent
troubles have been extremely disconcerting.
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Dw ayne A. Day frequently w rites on the history of
civilian and m ilitary space program s. His article on
NASAs future planning for hum an spaceflight appears
in the February issue ofSpaceflight m agazine. He can be
reached atzircon [email protected].
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