IEEE Geoscience and Remote Sensing Magazine - September 2023 - 15

authorities, although with a delay, as usual for the USSR media.
When Kalmykov learned about it, he tried to approach
the ad hoc committee put in charge of the rescue mission to
propose his aid. This happened to be nearly impossible. A
legend tells that Kalmykov wrestled his way to the committee
meeting room, showing the satellite imagery printouts
to the KGB guards; however, more probably, he had found
someone who played the role of mediator. Still, this was
not the end. Unexpectedly, the top administration of the
USSR Chief Directorate of the Northern Maritime Route,
the dominant service in the rescue committee, displayed a
huge distrust of the satellite data, which suggested a nontrivial
escape route-to the north of the disaster site. At the
crucial moment, Kalmykov had to voice a threat to file a
complaint to the superpowerful authority: the CC CPSU.
This worked out, and a nuclear-powered icebreaker was
ordered to move north.
OTHER CONTEMPORARY ORBITAL RADAR SYSTEMS:
A MONSTER IN THE SHADOW
The first space-based microwave Earth imaging experiment
using the L-band SAR of the U.S. Seasat-A satellite was conducted
in 1978. That radar worked for three months at the
wavelength of 23 cm with a swath of 100 km and provided
a spatial resolution of 25 m [25], [26]. The results of this
experiment exceeded all expectations and showed the high
capabilities of orbital systems. However, the radar images
were synthesized not onboard but on the ground, with
great delay, which prevented their use in time-sensitive applications.
Essentially the same test SARs operated onboard
the Space Shuttle Columbia in 1981 (five days) and 1984 (seven
days) [25], [26], [27].
It should be noted that, in parallel to Kalmykov's SLR,
the USSR SAR systems were also developed: in Moscow.
Test SAR " Travers " was installed onboard the spacecraft
Resurs-O-1 launched as Cosmos-1689 in 1985 [2], [3]
and, later, on the Priroda module of the orbital station
(OS) Mir. The other SAR required full OS power; it was
launched in 1987 onboard Cosmos-1870 and in 1991 on
OS Almaz-1 [6], [24].
Despite an order of magnitude lower resolution than
SAR, SLR was attractive due to higher radiometric accuracy
and an order wider swath. It could use an available
simple magnetron source, which had less stable characteristics
than needed for SAR; additionally, onboard image
processing, lower cost, and much quicker delivery were
also very important. The orbital system of Cosmos-1500
had no contemporary analogs in the day-to-day practical
monitoring of the ocean and ice. It was true that the Seasat
and shuttle SAR experiments (and later ERS-1, RADARSAT,
and other SAR systems) were primarily designed to
serve oceanography and generally met and even exceeded
expectations. However, they turned out to be even more
useful for land applications, where a several-day delay in
signal processing was not as critical as in maritime navigation.
As a result, the practical components of their space
SEPTEMBER 2023 IEEE GEOSCIENCE AND REMOTE SENSING MAGAZINE
radar programs were focused mainly on monitoring land
parameters [25], [26], [27].
Still, in deep secrecy, there existed another USSR orbital
RA-SLR system for oceanic observations, perhaps
a hundred times more expensive than Cosmos-1500 and
all its derivatives. It was initiated as early as 1960, first
placed into low-Earth orbit in 1975, and finally, closed
in 1988 after at least 39 launches. This radar was called
Chaika, and it and the spacecraft equipped with it were
part of the top-secret naval reconnaissance and targeting
system " Legenda " [24]. In the West, they were known
as Radar Ocean Reconnaissance Satellites (RORSATs) [28],
[29], [30]. Each RORSAT had two magnetrons (principal
and backup); one, or after 1985, two RA-SLRs working
at the frequency of 8.2 GHz; and one or two 10-m-long
slotted-waveguide antennas to provide left-side and rightside
swaths, each 450 km wide (Figure 7). These satellites
were designed to find and track U.S. Navy air carriers,
first of all, in the North Atlantic and North Pacific, and
release the targeting data to the USSR assault triad: Navy
bombers of the Tu-22M3 type, superheavy cruise missile
submarines of the Oskar-I and Oskar-II (Kursk) types,
and heavy guided missile cruisers of the Pyotr Velikiy and
Moskva types.
Each component of the triad had to launch many dozens
of cruise missiles with conventional and nuclear warheads.
For instance, according to a comprehensive description of a
retired USSR Navy officer [31], to attack one U.S. air carrier
from the air, as many as three full regiments of Tu-22M3
medium-range strategic bombers (i.e., 100 aircraft) were assigned.
Some of the bombers and all dedicated submarines
and cruisers were equipped with receivers of the " Legenda "
system (Figure 8). Through the network of communication
satellites known as Parus, RORSAT data information was
passed on to these assets and a dedicated USSR Navy control
center in Noginsk near Moscow [24]. The task of the
system was not just to locate and identify naval ships but to
provide the targeting data that could, allegedly, be fed directly
into antiship missiles, such as the 6-ton X-22 liquidpropellant
ones carried by the Tu-22M3.
The reason for such a tremendous concern was that in
the 1970s and early 1980s, the USSR submarine-launched
ballistic missiles (SLBMs) had limited range and accuracy, so
to fire them, the submarines had to come nearer to the U.S.
East and West Coasts. Therefore, the U.S. Navy air carriers
were viewed as an extremely dangerous force, able to block
or destroy the USSR submarine fleet in their home bases
at the Cola and Kamchatka Peninsulas. Still, traditionally,
according to the USSR and Russian military doctrine and
ethos, all bombers, submarines, and cruisers taking part in
a raid on a U.S. air carrier were viewed as expendables. As for
the bombers, probable losses were estimated at 50%; " Legenda "
was not trusted by the pilots and the air staff, and a
suicide raid of two dedicated Tu-16 reconnaissance aircraft
was always envisaged to make visual contact with air carriers
[31]. Similarly, the Navy staff always sent a destroyer
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IEEE Geoscience and Remote Sensing Magazine - September 2023

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