The N-I or N-1 was a derivative of the American Thor-Delta rocket produced under license in Japan. The "N" stood for "Nippon" (Japan). The vehicle used a Long Tank Thor first stage derived from the PGM-17 Thor intermediate-range ballistic missile, a Mitsubishi Heavy Industries-designed LE-3 engine on the second stage, and three Castor 2 solid rocket motors. An optional third stage, the Star-37N solid motor, was used on three of the seven launches.
Seven N-I rockets were launched between 1975 and 1982, after which the vehicle was replaced by the N-II. Six launches were successful. The fifth flight failed after the payload and third stage collided shortly after separation.
On 29 February 1976, the second N-I launch conducted the only orbital launch on a leap day, as of February 2024.
Launch history
Flight Date (UTC) Launch site Payload Payload mass Orbit Outcome F1 9 September 197505:30 Tanegashima, Osaki ETS-I LEO ETS-I (Engineering Test Satellite I, nicknamed Kiku-1) was the first satellite launched by the NASDA. It had the objective of acquiring information on N-series launch vehicles, orbit injection, and tracking and control. It ceased operations on 28 April 1982. F2 29 February 197603:30 Tanegashima, Osaki ISS LEO ISS (Ionosphere Sounding Satellite, nicknamed UME) was used to monitor radio waves in the ionosphere and forecast conditions for shortwave communications. A power supply issue caused Ume to stop functioning one month after launch. F3 23 February 197708:50 Tanegashima, Osaki ETS-II GTO 3rd stage used. ETS-II (Engineering Test Satellite II, nicknamed Kiku-2) was NASDA's first satellite launched to GEO. It was intended to gather data on geostationary satellite launch, tracking, control, orbit maintenance, and attitude control as well as carrying out experiments on communications equipment. Kiku-2 ceased operations on 10 December 1990, leaving GEO. F4 16 February 197804:00 Tanegashima, Osaki ISS-b LEO ISS-b (Ionosphere Sounding Satellite b, nicknamed UME-2) had similar goals to the original UME satellite, but was much more successful in carrying them out. While it was originally intended to gather data for only a year and a half, UME-2 ceased operations on 23 February 1983. F5 6 February 197908:46 Tanegashima, Osaki ECS GTO 3rd stage used. ECS (Experimental Communications Satellite, nicknamed Ayame). Satellite and third stage collided shortly after separation. The satellite had the intention of conducting millimeter wave experiments. F6 22 February 198008:35 Tanegashima, Osaki ECS-b GTO 3rd stage used. ECS-b (Experimental Communications Satellite b, nicknamed Ayame-2). Repeat of the ECS mission. Satellite stopped transmitting shortly after separation. F9 3 September 198205:00 Tanegashima, Osaki ETS-III LEO ETS-III (Engineering Test Satellite III, nicknamed Kiku-4) was developed to acquire data on designing earth observation satellites with high power requirements. ETS-III completed testing of three-axis attitude control, deployable solar panels, movable heat control, and ion engine operation. On 8 April 1985, the satellite ran out of fuel and ceased operation.
See also Comparison of orbital launchers families Delta rocket H-I H-II H-IIA N-II (rocket) PGM-17 Thor
References