N series (rocket)
The N-series is a Japanese launch vehicle series from the 1970s. It was developed by the Japanese space agency NASDA . The Kappa ( K-series ) and Lambda (L-series) rockets offered no prospect of entering commercial space travel due to their low payload capacities, so the tried and tested program of the guided economy - initially a replica of existing technology and then in-house development - elected. It was accepted that no (international) commercial use was possible at the time US technology was used.
construction
The missile was developed largely on the basis of American technologies . The agreement on this was made in October 1970. The Delta-M from McDonnell-Douglas served as a template . The N launch vehicle had three stages : the first and second stage had a liquid rocket engine , the third stage was equipped with a solid propulsion unit.
First rocket stage
The first stage of the rocket is identical to the first stage of the Thor launcher. In 1972 was Mitsubishi Heavy Industries (MHI), the license for reproduction of the Long Tank Thor. Ishikawajima-Harima Heavy Industries (IHI) was to replicate the Thor liquid engine MB-3 III . The first engines for five N rockets were supplied from the USA as a template for the adoption of the technology . The US version of the engine delivers a thrust of 765 kN with a burning time of 218 seconds (specific impulse 2460 Ns / kg). Liquid oxygen and kerosene , which were pumped into the combustion chamber , served as fuel . The first stage was additionally coated solid three boosters of the type Castor-II fitted, whereby the total thrust to 1450 kN increased (licensee Nissan).
Second stage rocket
The second rocket stage of the N series is a Japanese in-house development with the storable nitrogen tetroxide and Aerozin 50 as fuel. However, the pressurized gas-powered liquid engine with the type designation LE-3 was built with the support of US companies. The Vernier control nozzles in particular were manufactured under licenses from TRW. In terms of size, design and fuel, it was roughly equivalent to its counterpart Aerojet AJ10-118F in the Delta, but it was not quite as effective. It developed a thrust of 53 kN. The burning time was 246 seconds, the specific pulse was 285 seconds. This means that the performance data was considerably lower than that of the Delta. On the second stage, the flight control, a combination of radio and inertial control analogous to the BTL-600 supplied by Bell Labs for the Delta, was installed. Production should be Nippon Electric Co. Ltd. take over.
Third rocket stage
An American solid propulsion engine of the type Thiokol TE-364-4 with a thrust of about 39 kN (burning time 40 seconds) was used as the drive for the third stage. Nissan was to take over production.
Payload fairing
The payload fairing was completely imported from the USA.
commitment
The first six N launchers started with flight control systems from the USA, as there were initially difficulties in Japan with the newly developed on-board electronics . The first flight took place on September 9, 1975 from the Tanegashima Space Center . The Japanese test satellite Kiku , which weighed 82.5 kg, was shot into orbit between 1105 and 977 km. At the third launch on February 23, 1977 , the first geostationary satellite in Japan was launched with Kiku-2 (ETS-2). This made Japan the third country to master this technology. The NI ended after seven starts. The apogee level failed on two starts.
N-II
To increase the payload of the rocket, the fuel tank of the first stage was extended and this was provided with nine solid fuel boosters (NKai-I launcher). An image of the Delta 1904 was created , which, however, never flew in this form in the USA. The improvement of the second rocket stage and the associated increase in payload to 500 kg led to the type N-II (NKai-II). Licenses had to be used even more. The N-II was used successfully eight times.
