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L1S in Shop
L1S in Shop - Soyuz 7K-L1S systems test spacecraft in shop at Baikonur, in preparation for installation on N1 launch vehicle.

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Other Designations: Soyuz 7K-L1S. Article Number: 11F92. Manufacturer's Designation: 7K-L1S, 7K-L1T. Class: Manned. Type: Lunar orbiter. Nation: USSR. Manufacturer: OKB-1.

Hybrid spacecraft used in N1 launch tests. The L1A consisted of a modified Soyuz L1 service module attached to an LOK-sized flange, with a circumlunar Soyuz descent module, topped by an odd hybird propulsion module derived from that to be used on the LOK and LK lunar lander. Probably each L1A differed somewhat from the other, using available surplus components or systems ready for test in space.


Total Mass: 6,900 kg.

Soyuz 7K-L1A Chronology

21 February 1969 N-1 3L Program: Lunar L3. Launch Site: Baikonur . Launch Vehicle: N1. FAILURE: First stage failure.

N-1 serial number 3L was the first N-1 launched. The payload was the 7K-L1A adaptation of the 7K-L1 spacecraft. This had a modified engine block and a total mass of 6900 kg. The planned mission was a lunar orbital flight. The L3 assembly would have been placed into a 204 x 287 km orbit of the earth at 597 seconds after lift-off. Total mass in earth orbit would have been 70.56 tonnes (the Block G, Block D, and 7K-L1A). The launch window for the lunar launch was open from 18 to 21 February; the launch was made on the last possible day. The N1 had a total mass of 2762 tonnes at ignition and 2756 tonnes at lift-off. Lift-off thrust was measured at 4,590 tonnes. The propellants had been densified before loading by chilling the Lox to -191 deg C and the fuel to -15 deg C. The mission plan called for the Block G to put the Block D and 7K-L1A on a translunar trajectory. After a 3.5 coast to the moon, the Block D would fire and place the assembly into lunar orbit. After two days of photography of the lunar surface, the Block D would fire again and place the 7K-L1A on a trans-earth trajectory. The Block D would separate and the 7K-L1A would use its own engines for mid-course corrections on the return leg. After re-entry in the atmosphere, the 7K-L1A would be recovered on Soviet territory.

The vehicle ran into trouble immediately at lift-off. As a result of a rising high frequency oscillation in the gas generator of engine number two, some engine components tore off their mounts, resulting in a forced leak of propellants, setting in motion a fire in the tail compartment. The BKS engine monitoring system detected the fire, but then gave an incorrect signal, shutting down all engines at 68.7 seconds into the flight. The vehicle was destroyed by range safety 70 seconds into the flight. The escape tower did not work as designed. British intelligence detected the launch attempt, but the CIA's technical means for some reason missed it and they denied for years that it had ever occurred. In retrospect the launch team at Baikonur pointed to a grave mistake - at the christening of the first N1, the champagne bottle broke against the crawler-transporter rather than the hull of the rocket.

LOK reaction controlLOK reaction control - The upper half of this item is the ODOP (Orientation and docking engine section) of the LOK, mounted at the top of the orbital module. The cone at top was had grapples for snagging the hexagonal grid of the large disk on top of the LK. Propellants for the orientation and maneuvering engines were in the tanks in this section. The bottom half of this item is similar to a test installation used on the Soyuz 7K-L1S destroyed in the several N1 launches.

Credit: © Mark Wade. 47,373 bytes. 368 x 520 pixels.

03 July 1969 N-1 5L Program: Lunar L3. Launch Site: Baikonur . Launch Vehicle: N1. FAILURE: First stage failure.

N-1 serial number 5L began to fail at 0.25 second after liftoff when the oxidizer pump of engine number 8 ingested a slag fragment and exploded. A fire ensued as the vehicle climbed past the top of the tower. Engines were shutdown until the acceleration dropped below 1 G; then the vehicle began to fall back to the pad at a 45 degree angle. The escape tower fired at the top of the brief trajectory, taking the L1S dummy descent module away from the pad. Upon impact of the base of the N1 with the pad, the vehicle exploded, destroying launch pad 110 east, which would take over 18 months to repair.


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Last update 12 March 2001.
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© Mark Wade, 2001 .