N1 rocket

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Image:GPN-2002-000188.jpg N1 or N-1 was the Soviet rocket intended to send Soviet cosmonauts to the Moon, preferably ahead of the Americans. Development of the N-1 began in 1956 with the intent of providing a heavy booster for Military Space Stations and a manned Mars flyby using a nuclear engine upper stage. When the US announced the goal of landing a man on the moon in 1961 the N1 was diverted to matching this objective. The Russian Moon rocket program was first led by Sergei Korolev until his death in 1966 and later by his deputy Vasily Mishin when Mishin became the head of Korolev's OKB-1 Design Bureau. However, the project seemed to be insufficiently funded, and was not a success.

The overall rocket system actually bore the designation N1-L3: N1 was the boost rocket, while the L3 was mounted on top for the trip to lunar orbit and, it was hoped, lunar landing.

There is a great deal of confusion among Russian online sources as to whether it is N1-L3 (Russian: Н1-Л3) or N1-LZ (Russian: Н1-ЛЗ) because of the similarity of the Cyrillic letter Ze for "Z" and the number "3". Sometimes both forms will be used within the same Russian website (or even the same article [1] [2]). However, English sources refer only to N1-L3, and it seems clear it is a number because there were lunar projects with code names from L1 to L5. [3]

The N1 was a massive rocket comparable to the American Saturn V. It was designed to send 95 tons of payload into Low Earth orbit, and stood over 100 meters tall — easily the tallest Soviet launch vehicle ever produced. Unfortunately, it was also very complex in engine arrangement and propellant plumbing. In the rush to production, and to save money, its 30 [4] NK-33 (modified from the NK-15 design) rocket motors were never ground tested in combination, only as individual units. There was also the factor that the N1's Baikonur launch complex could not be reached by heavy barge so for transport by rail all the stages had to be broken and re-assembled. Because of this, the complex and destructive vibrational modes (which ripped apart propellant lines and turbines) as well as exhaust plume fluid dynamic problems (causing vehicle roll, vacuum cavitation, and other problems) were not discovered and worked out before flight. It is worth noting that the successful American Saturn V rocket had only five large (F-1) engines in its first stage, rather than the 30 smaller engines of the Russian design, although it is not definitively known whether this design was superior - NASA expended a colossal effort developing the larger engines, and it would have been interesting to see whether a greater or lesser effort would have been necessary to make the N1 design reliable.

As a result of its technical difficulties, in turn due to lack of funding for full-up testing, the N1 never successfully completed a test flight. All four unmanned launches out of 12 planned test launches ended in failure, even before first-stage separation. The longest flight lasted 107 seconds, just before 1st stage separation. Two test launches occurred in 1969, one in 1971 and the final one in 1972. Mishin continued with the project after the cancellation of plans for a manned moon landing in the hope that the booster would be used to launch a large space station comparable to the US Skylab. The program was terminated in 1974 before a final test launch which the engineers believed would have been a success.

The program was followed by the "Vulkan" concept for a huge Proton-like hypergolic fuelled vehicle, and then in 1976 by the commencement of the Energia/Buran program.

Two flight-ready N1s were scrapped and their remains could be still be found around Baikonur years later used as shelters and storage sheds. The program left behind a large stockpile of advanced liquid oxygen/kerosene engines (the NK-33 and NK-43) which are rugged and reliable as a standalone unit whose design was largely perfected before the cancellation. About 50 engines survived a cover-up which was supposed to include complete hardware destruction. In the mid-1990s, Russia sold 36 engines to the major U.S. rocket engine manufacturer Aerojet for $1.1 million USD each. This company also acquired a license for the production of new engines. Supplied through Aerojet, three of the engines were incorporated into Japanese rockets J-1 and J-2. The U.S. company Kistler Aerospace Corporation continues to work on incorporating these engines into a new rocket design, with which Kistler seeks to eventually offer commercial launch services. In Russia, N1 engines were not used again until 2004, when the remaining 20 or so engines were incorporated into a new rocket design. As of 2005, the project has been frozen due to the lack of funding.

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Launch history

February 21 1969: Explosion at 12,200 meters altitude, 69 seconds after liftoff
July 3 1969: At liftoff, a loose bolt sucked into a fuel pump caused Stage 1 explosion, destroying rocket and launch tower in the biggest explosion in the history of rocketry
June 24 1971: Uncontrolled roll immediately after liftoff; vehicle destroyed 51 seconds after liftoff
November 22 1972: Pogo oscillation at stage 1 initial cutoff; vehicle destroyed 107 seconds after liftoff

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