Early flight scenario of the Luna-Glob missionBy 1998, NPO Lavochkin evaluated two possible variations of the Luna-Glob spacecraft, which could be launched by the existing Molniya rocket or by the prospective Soyuz-Fregat system. The ambitious project included a cruise module, a cassette with pencil-shape penetrator probes and a 250-kilogram polar lander.
Initial design of Luna-Glob
According to the original design of the Luna-Glob spacecraft, a ring-shaped cassette would hold penetrators attached to its perimeter. The cassette would also feature a programming timer, power battery and solid-propellant motors. At one point, ten "small" and two "large" penetrators were planned. They would be equipped with seismometers and other instruments. In addition to seismic research, large penetrators were expected to be used in the search for traces of water on the Moon. (397)
The original mission scenario
After entering an initial Earth orbit, the upper stage would send the probe on a four-and-half day journey toward the Moon. During the approach to the Moon, the cassette would separate from the mother spacecraft and symmetrically placed solid motors send the module into a spin of three rotations per second. As the spacecraft reached a distance of 700 kilometers from the surface of the Moon, the spin rate would increase to 20 rotations per second, after which, five out of 10 small penetrators would be released. As a result of the centrifugal force, the penetrators would fly away from their carrier with the speed of 20 meters per second, while simultaneously descending toward the lunar surface with a speed of 2.6 kilometers per second.
Key elements of the Luna-Glob payloads circa 2004. On the left is a soil-penetrating vehicle surrounded by a cluster of braking solid-propellant motors which would fire against the direction of descent to soften the impact. A similar method would be used to drop a small research station on the surface of the Moon (center). In addition, a high-speed penetrator (right) would impact the Moon to reach deep into the soil.
At the moment of reaching the lunar surface some 250 seconds after release, the probes would fly in formation shaped as a circle with a diameter of 10 kilometers. The penetrators would strike the ancient lunar soil with a speed of between 60 and 120 meters per second, ensuring their burial into the surface.
In the meantime, the five remaining penetrators would separate at an altitude of 350 kilometers and their impact points would form a circle with a diameter of five kilometers. The two circles of penetrators would thus create a virtual seismic antenna on the surface of the Moon, which would help scientists study the internal composition of the Earth's natural satellite and possibly receive crucial information on the history of the Earth-Moon system.
In the initial stage of the Luna-Glob project, the exact force needed for the penetrator to survive impact with the Moon was still unclear. Future ground tests promised to show whether some additional braking maneuver of the penetrator carrier would be necessary to slow down the approach.
Upon the release of all penetrators, the main spacecraft would fire its engine to enter a lunar orbit with its perigee (lower point) located over the South Pole of the Moon. A small soft-landing vehicle would be released from the altitude of around 500 kilometers and use its own braking engine to reduce its orbital speed of around two kilometers per second. After the separation of the breaking engine, the lander was expected to land on the surface with a speed of around 80 meters per second.
The primary role of the remaining lunar orbiter would be relaying signals from the polar station to Earth. However, with its polar orbit, it could also be used for global cartography of the Moon, if mass and funding allowed. This flight scenario could not be implemented due to lack of funds.
The payload section of the original Luna-Glob mission reconfigured for launch on the Soyuz-Fregat launcher. Credit: NPO Lavochkin
Early designs of the Luna-Glob spacecraft.
A possible configuration of the Luna-Glob orbiter proposed at the Babakin center.