The Kontakt rendezvous and docking system
The two manned craft intended
to land Soviet cosmonauts on the Moon, the LOK lunar orbiter and the LK
lander used a rendezvous and docking system called Kontakt. This was developed
in some competition to the system IGLA (described elsewhere at this Web
site) used on Soyuz/Progress/Salyut. Very little is known about Kontakt,
especially its radio system for homing and guidance during rendezvous and
docking. This article is an attempt to locate antennas for the system on
images of LK and LOK and to try to draw conclusions from these antennas.
LOK shown at Kaluga
museum. Credit: © Mark Wade
Antennas on LOK possibly related
The "tower-like" contraption
near the front of LOK seen in the picture above looks very much like the
IGLA antenna tower on Soyuz. However, there is no dish antenna but an "X"
that could be an array antenna - or interferometer antenna
There are three four-turn
helices with a diameter of 10-12 cm (indicating a frequency of 800-960
MHz). Two are facing forwards and one backwards. A
detailed image of the antenna at the front of the spacecraft shows
that the helix is fed at the circumference and not at the center. The antenna
gain of a four-tun helix operating in the axial mode is 11.7 dBi and it
has a beamwidth that is 52 degrees wide.
Antennas and other devices
on LK possibly related to Kontakt
In the figure we can identify
four antennas and two other devices that could possibly have something
to do with the Kontakt system
gain canted turnstiles over a ground plane (A) can be seen at six places.
Four pointing radially outwards from the docking unit at the top. One pointing
forwards from the docking unit and one pointing backwards from block E.
This type of antenna can be seen on many vehicles including around the waist
of LOK. It can be a used for the 922/768 MHz system for command and telemetry
used on many other Soviet/Russian spacecraft such as Soyuz and Progress.
The six antennas provide a compete omnidirectional coverage - something
that is absolutely essential for the command link.
The conical helices were intended
to probably deploy upon landing and are most probably also for the 922/768
The type C antennas that are
called "Homing system antennas" probably belong to Kontakt and most probably
transmit beacon signals that the direction-finding array antenna on LOK
can receive. It is interesting that both the elements of direction-finding
"X-shaped" antenna on LOK and this homing antenna on LK are very small
compared to e.g. the type A and D antennas, indicating a much higher frequency
than those operate on.
helix "D" that can be found also on LOK is probably for receiving range
and range rate signals from LOK that are retransmitted over the "C" antennas
once the direction-finding antenna on LOK has located the LK.
The alignment sensor/fine adjustment
sensors seem to have something to do with final pitch, roll, and yaw alignment
just prior to contact. Whether they are optical devices or not cannot be
judged at this time.
Antennas used during homing
and proximity operations
The figures below are intended
to illustrate these situations.