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The Luna programme
The Luna programme ("Luna" meaning "Moon"),
occasionally called Lunik or Lunnik, was a series of robotic
spacecraft missions sent to the Moon by the Soviet Union between
1959 and 1976. Fifteen were successful, each designed as either an
orbiter or lander, and accomplished many firsts in space
exploration. They also performed many experiments, studying the
Moon's chemical composition, gravity, temperature, and radiation.
Twenty-four spacecraft were formally given the Luna designation,
although more were launched. Those that failed to reach orbit were
not publicly acknowledged at the time, and not assigned a Luna
number. Those that failed in low Earth orbit were usually given
Cosmos designations. The estimated cost of Luna Program was about
$4.5 billion.
Luna 1 missed its intended impact with the Moon
and became the first spacecraft to fall into orbit around the
Sun.
In 1959, the Luna 2 mission successfully
impacted upon the lunar surface, becoming the first man-made object
to reach the Moon.
Luna 3 rounded the Moon later that year, and
returned the first photographs of its far side, which can never be
seen from Earth.
Luna 9 became the first probe to achieve a soft
landing on another planetary body (February 1966). It returned five
black and white stereoscopic circular panoramas, which were the
first close-up shots of the Lunar surface.
Later that year Luna 10 became the first
artificial satellite of the Moon.
Luna 17 and Luna 21 carried vehicles that roamed
around on the Moon's terrain (see Lunokhod programme).
Another major achievement of the Luna programme,
with the Luna 16, Luna 20 and Luna 24 spacecraft, was the ability
to collect samples of lunar soil and return them to Earth, by 1970.
The program returned 0.326 kg of lunar samples. The Luna missions
were the first space-exploration sample return missions to rely
solely on advanced robotics.
Luna 3
The Soviet space probe Luna 3 of 1959 (of the
E-3 series) was the third space probe to be sent to the
neighborhood of the Moon, and this mission was an early feat in the
spaceborne exploration of outer space. Though it returned rather
poor pictures by later standards, the historic, never-before-seen
views of the far side of the Moon caused excitement and interest
when they were published around the world, and a tentative Atlas of
the Far Side of the Moon was created after image processing
improved the pictures. This space probe has been commonly called
"Lunik 3", predominantly in the Western world.
These views showed mountainous terrain, very
different from the near side, and only two dark, low-lying regions
which were named Mare Moscovrae (Sea of Moscow) and Mare Desiderii
(Sea of Desire). Mare Luna Desiderii was later found to be composed
of a smaller mare, Mare Ingenii (Sea of Ingenuity), and several
other dark craters.Contents
The space probe was a cylindric canister with
hemispheric ends and a wide flange near the top. The probe was 130
cm long and 120 cm at its maximum diameter at the flange. Most of
the cylindric section was roughly 95 cm in diameter. The canister
was hermetically-sealed and pressurized to about 0.22 atmosphere
(23 kilopascals). Several solar cells were mounted on the outside
of the cylinder, and these provided electric power to the storage
batteries inside the space probe.
Shutters for thermal control were positioned
along the cylinder and opened to expose a radiating surface when
the internal temperature exceeded 25 celsius. The upper hemisphere
of the probe held the covered opening for the cameras. Four
antennas protruded from the top of the probe and two from its
bottom. Other scientific equipment was mounted on the outside,
including micrometeoroid and cosmic ray detectors, and the
Yenisey-2 imaging system. The gas jets for its attitude control
system were mounted on the lower end of the spacecraft. Several
photoelectric cells helped maintain orientation with respect to the
Sun and the Moon.
Its interior held the cameras and the
photographic film processing system, radio transmitter, storage
batteries, gyroscopic units, and circulating fans for temperature
control. It was spin-stabilized for most of its flight, but its
three-axis attitude control system was activated while taking
photos. Luna 3 was radio-controlled from ground stations in the
Soviet Union.
After launching on an 8K72 (number I1-8) rocket
over the North Pole, the Blok-E escape stage was shut down by radio
control to put Luna 3 on its course to the Moon. Initial radio
contact showed that the signal from the space probe was only about
one-half as strong as expected, and the internal temperature was
rising. The spacecraft spin axis was reoriented and some equipment
was shut down, resulting in a temperature drop from 40 celsius to
about 30 celsius. At a distance of 60,000 to 70,000 km from the
moon, the orientation system was turned on and the spacecraft
rotation was stopped. The lower end of the craft was pointed at the
sun, which was shining on the far side of the moon.
The space probe passed within 6,200 km of the
moon near its south pole at the closest lunar approach at 14:16 UT
on 6 October 1959, and continued on over the far side. On 7
October, the photocell on the upper end of the space probe detected
the sunlit far side of the moon, and the photography sequence was
started. The first picture was taken at 03:30 UT at a distance of
63,500 km from the moon, and the last picture was taken 40 minutes
later from a distance of 66,700 km.
A total of 29 pictures were taken, covering 70%
of the far side. After the photography was complete the spacecraft
resumed spinning, passed over the north pole of the moon and
returned towards the Earth. Attempts to transmit the pictures to
the Soviet Union began on October 8th but the early attempts were
unsuccessful due to the low signal strength. As Luna 3 drew closer
to the Earth, a total of about 17 viewable but poor quality
photographs were transmitted by 18 October. All contact with the
probe was lost on 22 October 1959. The space probe was believed to
have burned up in the Earth's atmosphere in March or April 1960.
Another possibility was that it might have survived in orbit until
1962 or later.
The purpose of this experiment was to obtain
photographs of the lunar surface as the spacecraft flew by the
moon. The imaging system was designated Yenisey-2 and consisted of
a dual-lens camera AFA-E1, an automatic film processing unit, and a
scanner. The lenses on the camera were a 200 mm focal length, f/5.6
aperture objective and a 500 mm, f/9.5 objective. The camera
carried 40 frames of temperature- and radiation-resistant 35 mm
isochrome film. The 200 mm objective could image the full disk of
the moon and the 500 mm could take an image of a region on the
surface. The camera was fixed in the spacecraft and pointing was
achieved by rotating the craft itself.
Luna-3 was the first successful three-axis
stabilized spacecraft. During most of the mission, the spacecraft
was spin stabilized, but for photography of the moon, the
spacecraft oriented one axis toward the Sun and then a photocell
was used to detect the moon and orient the cameras towards it.
Detection of the moon signalled the camera cover to open and the
photography sequence to start automatically. The images alternated
between both cameras during the sequence. After photography was
complete, the film was moved to an on-board processor where it was
developed, fixed, and dried. Commands from the Earth were then
given to move the film into a scanner where a spot produced by a
cathode ray tube was projected through the film onto a
photoelectric multiplier. The spot was scanned across the film and
the photomultiplier converted the intensity of the light passing
through the film into an electric signal which was transmitted to
the Earth (via frequency-modulated analog video, similar to a
facsimile). A frame could be scanned with a resolution of 1000
(horizontal) lines and the transmission could be done at a
slow-scan television rate at large distances from the Earth and a
faster rate at closer ranges.
The camera took 29 pictures over 40 minutes on 7
October 1959, from 03:30 UT to 04:10 UT at distances ranging from
63,500 km to 66,700 km above the surface, covering 70% of the lunar
far side. Seventeen (some say twelve) of these frames were
successfully transmitted back to the Earth, and six were published
(frames numbered 26, 28, 29, 31, 32, and 35). They were mankind's
first views of the far hemisphere of the moon.
The imaging system was developed by P.F.
Bratslavets and I.A. Rosselevich at the Leningrad Scientific
Research Institute for Television and the returned images were
processed and analyzed by Iu.N. Lipskii and his team at the
Sternberg Astronomical Institute. The camera AFA-E1 was developed
and manufactured by the KMZ factory (Krasnogorskiy Mekhanicheskiy
Zavod).
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